HEREDITARY METABOLIC DISEASES
Most of the foods and drinks people ingest are complex materials that the body must break down into simpler substances. This process may involve several steps. The simpler substances are then used as building blocks, which are assembled into the materials the body needs to sustain life. The process of creating these materials may also require several steps. The major building blocks are carbohydrates, amino acids, and fats (lipids). This complicated process of breaking down and converting the substances ingested is called metabolism.
Metabolism is carried out by chemical substances called enzymes, which are made by the body. If a genetic abnormality affects the function of an enzyme or causes it to bedeficient or missing altogether, various disorders can occur. The disorders usually result from an inability to break down some substance that should be broken down—so that some intermediate substance that is toxic builds up—or from an inability to produce some essential substance. Metabolic disorders are classified by the particular building block that is affected
Some hereditary disorders of metabolism (such as phenylketonuria and the lipidoses) can be diagnosed in the fetus using amniocentesis or chorionic villus sampling. Usually, the diagnosis of a hereditary disorder of metabolism is made using a blood test or an examination of a tissue sample to determine whether a specific enzyme is deficient or missing.
Amino acids are the building blocks of proteins and have many functions in the body. Hereditary disorders of amino acid processing can be the result of defects either in the breakdown of amino acids or in the body’s ability to get the amino acids into cells. Because these disorders produce symptoms early in life, newborns are routinely screened for several common ones. In the
Amino acid metabolism
Phenylketonuria
Phenylketonuria (PKU) is a disorder that causes a buildup of the amino acid phenylalanine, which is an essential amino acid that cannot be synthesized in the body but is present in food. Excess phenylalanine is normally converted to tyrosine, another amino acid, and eliminated from the body. Without the enzyme that converts it to tyrosine, phenylalanine builds up in the blood and is toxic to the brain, causing mental retardation.
PKU occurs in most ethnic groups. If PKU runs in the family and DNA is available from an affected family member, amniocentesis or chorionic villus sampling with DNA analysis can be performed to determine whether a fetus has the disorder.
Most affected newborns are detected during routine screening tests. Newborns with PKU rarely have symptoms right away, although sometimes an infant is sleepy or
eats poorly. If not treated, affected infants progressively develop mental retardation over the first few years of life, which eventually becomes severe. Other symptoms include seizures, nausea and vomiting, an eczema-like rash, lighter skin and hair than their family members, aggressive or self-injurious behavior, hyperactivity, and sometimes psychiatric symptoms. Untreated children often give off a “mousy” body and urine odor as a result of a by-product of phenylalanine (phenylacetic acid) in their urine and sweat.
To prevent mental retardation, phenylalanine intake must be restricted (but not eliminated altogether as people need some phenylalanine to live) beginning in the first few weeks of life. Because all natural sources of protein contain too much phenylalanine for children with PKU, affected children cannot have meat, milk, or other common foods that contain protein. Instead, they must eat a variety of phenylalanine-free processed foods, which are specially manufactured. Low-proteiatural foods, such as fruits, vegetables, and restricted amounts of certain grain cereals, can be eaten.
A restricted diet, if started early and maintained well, allows for normal development. However, if very strict control of the diet is not maintained, affected children may begin to have difficulties in school. Dietary restrictions started after 2 to 3 years of age may control extreme hyperactivity and seizures and raise the child’s eventual IQ but do not reverse mental retardation. Recent evidence suggests that functioning of some mentally retarded adults with PKU (born before newborn screening tests were available) may improve when they follow the PKU diet.
A phenylalanine-restricted diet should continue for life or intelligence may decrease and neurologic and psychiatric problems may ensue.
Maple Syrup Urine Disease
Children with maple syrup urine disease are unable to metabolize certain amino acids (leucine, isoleusine, valine). By-products of these amino acids build up, causing neurologicchanges, including seizures and mental retardation. These by-products also cause body fluids, such as urine and sweat, to smell like maple syrup. This disease is most common among Mennonite families.
the most severe form, infants develop neurologic abnormalities, including seizures and coma, during the first week of life and can die within days to weeks. In the milder forms, children initially appear normal but develop vomiting, staggering, confusion, coma, and the odor of maple syrup particularly during physical stress, such as infection or surgery.
In some states, newborns are routinely screened for this disease with a blood test.
Infants with severe disease are treated with dialysis. Some children with mild disease benefit from injections of the vitamin B1 (thiamin). After the disease has been brought under control, children must always consume a special artificial diet that is low in the particular amino acids that are affected by the missing enzyme.
Homocystinuria
Children with homocystinuria are unable to metabolize the amino acid homocysteine, which, along with certain toxic by-products, builds up to cause a variety of symptoms. Symptoms may be mild or severe, depending on the particular enzyme defect.
Infants with this disorder are normal at birth. The first symptoms, including dislocation of the lens of the eye, causing severely decreased vision, usually begin after 3 years of age. Most children have skeletal abnormalities, including osteoporosis; the child is usually tall and thin with a curved spine, elongated limbs, and long, spiderlike fingers. Psychiatric and behavioral disorders and mental retardation are common. Homocystinuria makes the blood more likely to spontaneously clot, resulting in strokes, high blood pressure, and many other serious problems.
In a few states, children are screened for homocystinuria at birth with a blood test. The diagnosis is confirmed by a test measuring enzyme function in liver or skin cells.
Some children with homocystinuria improve when given vitamin B6 (pyridoxine) or vitamin B12 (cobalamin).
Tyrosinemia
Children with tyrosinemia are unable to completely metabolize the amino acid tyrosine. By-products of this amino acid build up, causing a variety of symptoms. In some states, the disorder is detected on the newborn screening tests.
There are two main types of tyrosinemia: I and II. Type I tyrosinemia is most common in children of French-Canadian or Scandinavian descent. Children with this disorder typically become ill sometime within the first year of life with dysfunction of the liver, kidneys, and nerves, resulting in irritability, rickets, or even liver failure and death. Restriction of tyrosine in the diet is of little help. An experimental drug, which blocks production of toxic metabolites, may help children with type I tyrosinemia. Often, children with type Ityrosinemia require a liver transplant.
Type II tyrosinemia is less common. Affected children sometimes have mental retardation and frequently develop sores on the skin and eyes. Unlike type I tyrosinemia, restriction of tyrosine in the diet can prevent problems from developing.
Carbohydrates metabolism
Carbohydrates are sugars. Some sugars are simple, and others are more complex. Sucrose (table sugar) is made of two simpler sugars called glucose and fructose. Lactose (milk sugar) is made of glucose and galactose. Both sucrose and lactose must be broken down into their component sugars by enzymes before the body can absorb and make use of them. The carbohydrates in bread, pasta, rice, and other carbohydrate-containing foods are long chains of simple sugar molecules. These longer molecules must also be broken down by the body. If an enzyme needed to process a certain sugar is missing, the sugar can accumulate in the body, causing problems.
Glycogen is made of many glucose molecules linked together. The sugar glucose is the body’s main source of energy for the muscles (including the heart) and brain. Any glucose that is not immediately used for energy is held in reserve in the liver, muscles, and kidneys in the form of glycogen and released wheeeded by the body.
There are many different glycogen storage diseases (also called glycogenoses), each identified by a romaumeral. These diseases are caused by a hereditary lack of one of the enzymes that is essential to the process of forming glucose into glycogen and breaking down glycogen into glucose. About 1 in 20,000 infants has some form of glycogen storage disease.
Some of these diseases cause few symptoms; others are fatal. The specific symptoms, age at which symptoms start, and their severity vary considerably among these diseases. For types II, V, and VII, the main symptom is usually weakness. For types I, III, and VI, symptoms are low levels of sugar in the blood and protrusion of the abdomen (because excess or abnormal glycogen may enlarge the liver). Low levels of sugar in the blood cause weakness, sweating, confusion, and sometimes seizures and coma. Other consequences for children may include stunted growth, frequent infections, or sores in the mouth and intestines. Glycogen storage diseases tend to cause uric acid, a waste product, to accumulate in the joints (which can cause gout) and in the kidneys (which can cause kidney stones). In type I glycogen storage disease, kidney failure is common in the second decade of life or later.
The specific diagnosis is made when a chemical examination of a sample of tissue, usually muscle or liver, determines that a specific enzyme is missing.
Treatment depends on the type of glycogen storage disease. For many people, eating many small carbohydrate-rich meals every day helps prevent blood sugar levels from dropping. For people who have glycogen storage diseases that produce low blood sugar, glucose levels are maintained by giving uncooked cornstarch every 4 to 6 hours around the clock. Sometimes carbohydrate solutions are given through a stomach tube all night to prevent low blood sugar levels from occurring at night.
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Galactosemia (a high blood level of galactose) is caused by lack of one of the enzymes necessary for metabolizing galactose, a sugar present in lactose (milk sugar). A metabolite builds up that is toxic to the liver and kidneys and also damages the lens of the eye, causing cataracts.
A newborn with galactosemia seems normal at first but within a few days or weeks loses his appetite, vomits, becomes jaundiced, has diarrhea, and stops growing normally. White blood cell function is affected, and serious infections can develop. If treatment is delayed, affected children remain short and become mentally retarded or may die.
Galactosemia is detectable with a blood test. This test is performed as a routine screening test oewborns iearly all states in the
Galactosemia is treated by completely eliminating milk and milk products—the source of galactose—from an affected child’s diet. Galactose is also present in some fruits, vegetables, and sea products, such as seaweed. Doctors are not sure whether the small amounts in these foods cause problems in the long term. People who have the disorder must restrict galactose intake throughout life.
If galactosemia is recognized at birth and adequately treated, the liver and kidney problems do not develop, and initial mental development is normal. However, even with proper treatment, children with galactosemia often have a lower intelligence quotient (IQ) than their siblings, and they often have speech problems. Girls often have ovaries that do not function, and only a few are able to conceive naturally. Boys, however, have normal testicular function.
Hereditary Fructose Intolerance
In this disorder, the body is missing an enzyme that allows it to use fructose, a sugar present in table sugar (sucrose) and many fruits. As a result, a by-product of fructose accumulates in the body, blocking the formation of glycogen and its conversion to glucose for use as energy. Ingesting more than tiny amounts of fructose or sucrose causes low blood sugar levels (hypoglycemia), with sweating, confusion, and sometimes seizures and coma. Children who continue to eat foods containing fructose develop kidney and liver damage, resulting in jaundice, vomiting, mental deterioration, seizures, and death. Chronic symptoms include poor eating, failure to thrive, digestive symptoms, liver failure, and kidney damage.
The diagnosis is made when a chemical examination of a sample of liver tissue determines that the enzyme is missing. Treatment involves excluding fructose (generally found in sweet fruits), sucrose, and sorbitol (a sugar substitute) from the diet. Acute attacks respond to glucose given intravenously; milder attacks of hypoglycemia are treated with glucose tablets, which should be carried by anyone who has hereditary fructose intolerance.
Lipids metabolism
Fats (lipids) are an important source of energy for the body. The body’s store of fat is constantly broken down and reassembled to balance the body’s energy needs with the food available. Groups of specific enzymes help the body break down and process fats. Certain abnormalities in these enzymes can lead to the buildup of specific fatty substances that normally would have been broken down by the enzymes. Over time, accumulations of these substances can be harmful to many organs of the body. Disorders caused by the accumulation of lipids are called lipidoses. Other enzyme abnormalities result in the body being unable to properly convert fats into energy. These abnormalities are called fatty acid oxidation disorders.
In Gaucher’s disease, glucocerebrosides, which are a product of fat metabolism, accumulate in tissues. Gaucher’s disease is the most common lipidosis. The disease is most common in Ashkenazi (Eastern European) Jews. Gaucher’s disease leads to an enlarged liver and spleen and a brownish pigmentation of the skin. Accumulations ofglucocerebrosides in the eyes cause yellow spots called pingueculae to appear. Accumulations in the bone marrow can cause pain and destroy bone.
Most people who have Gaucher’s disease develop type 1, the chronic form, which results in an enlarged liver and spleen and bone abnormalities. Most are adults, but children also may have type 1. Type 2, the infantile form, develops in infancy; infants with the disease have an enlarged spleen and severe nervous system abnormalities and usually die within a year. Type 3, the juvenile form, can begin at any time during childhood. Children with the disease have an enlarged liver and spleen, bone abnormalities, and slowly progressive nervous system abnormalities. Children who survive to adolescence may live for many years.
Many people with Gaucher’s disease can be treated with enzyme replacement therapy, in which enzymes are given intravenously, usually every 2 weeks. Enzyme replacement therapy is most effective for people who do not have nervous system complications.
In Tay-Sachs disease, gangliosides, which are products of fat metabolism, accumulate in tissues. The disease is most common in families of Eastern European Jewish origin. At a very early age, children with this disease become progressively retarded and appear to have floppy muscle tone. Spasticity develops and is followed by paralysis, dementia, and blindness. These children usually die by age 3 or 4. Tay-Sachs disease can be identified in the fetus by chorionic villus sampling or amniocentesis. The disease cannot be treated or cured.
Niemann-Pick Disease
In Niemann-Pick disease, the deficiency of a specific enzyme results in the accumulation of sphingomyelin (a product of fat metabolism) or cholesterol. Niemann-Pick disease has several forms, depending on the severity of the enzyme deficiency and thus accumulation of sphingomyelin or cholesterol. The most severe forms tend to occur in Jewish people. The milder forms occur in all ethnic groups.
In the most severe form (type A), children fail to grow properly and have multiple neurologic problems. These children usually die by age 3. Children with type B disease develop fatty growths in the skin, areas of dark pigmentation, and an enlarged liver, spleen, and lymph nodes; they may be mentally retarded. Children with type C disease develop symptoms in childhood, with seizures and neurologic deterioration.
Some forms of Niemann-Pick disease can be diagnosed in the fetus by chorionic villus sampling or amniocentesis. After birth, the diagnosis can be made by a liver biopsy (removal of a tissue specimen for examination under a microscope). None of the types of Niemann-Pick disease can be cured, and children tend to die of infection or progressive dysfunction of the central nervous system.
In Fabry’s disease, glycolipid, which is a product of fat metabolism, accumulates in tissues. Because the defective gene for this rare disorder is carried on the X chromosome, the full-blown disease occurs only in males. The accumulation of glycolipid causes noncancerous skin growths (angiokeratomas) to form over the lower part of the trunk. The corneas become cloudy, resulting in poor vision. A burning pain may develop in the arms and legs, and the person may have episodes of fever. People with Fabry’s disease eventually develop kidney failure and heart disease, although most often they live into adulthood. Kidney failure may lead to high blood pressure, which may result in stroke.
Fabry’s disease can be diagnosed in the fetus by chorionic villus sampling or amniocentesis. The disease cannot be cured or even treated directly, but researchers are investigating a treatment in which the deficient enzyme is replaced by transfusion. Treatment consists of taking analgesics to help relieve pain and fever. People with kidney failure may need a kidney transplant.
Fatty Acid Oxidation Disorders
Several enzymes help break fats down so that they may be turned into energy. An inherited defect or deficiency of one of these enzymes leaves the body short of energy and allows breakdown products, such as acyl-CoA, to accumulate. The enzyme most commonly deficient is medium chain acyl-CoA dehydrogenase (MCAD). MCAD deficiency is one of the most common inherited disorders of metabolism, particularly in people of Northern European descent.
Symptoms usually develop between birth and age 3. Children are most likely to develop symptoms if they go without food for a period of time (which depletes other sources of energy) or have an increased need for calories because of exercise or illness. The level of sugar in the blood drops significantly, causing confusion or coma. The child becomes weak and may have vomiting or seizures. Over the long term, children have delayed mental and physical development, an enlarged liver, heart muscle weakness, and an irregular heartbeat. Sudden death may occur.
Some states screeewborns for MCAD deficiency with a blood test. Immediate treatment is with intravenous glucose. For long-term treatment, the child must eat often, never skipping meals, and consume a diet high in carbohydrates and low in fats. Supplements of the amino acid carnitine may be helpful. The long-term outcome is generally good.
Caring for Families, Developmental Theories
From conception to death, individuals are constantly changing. Physical growth, psychological development, emotional maturation, cognitive development, moral development, and spiritual growth occur throughout life. Progression through each developmental stage influences health status. A thorough understanding of developmental concepts is essential for professional quality nursing practice. This chapter discusses the changes occurring in each stage of the life cycle.
Fundamental Concepts of Growth And Development
Development occurs continuously through the life span. Adults continue to have transition periods during which growth and development occur.
Growth is the quantitative (measurable) changes in physical size of the body and its parts, such as increases in cells, tissues, structures, and systems. Examples of growth are physical changes in height, weight, bone density, and dental structure. Even though growth is not a steady process through the life cycle, growth patterns can be predicted. Variations in growth, such as rapid increases contrasted with slower rates of physical change, occur with each individual. Rapid growth is most common in the prenatal, infant, and adolescent stages.
Development refers to behavioral changes in functional abilities and skills. Thus, developmental changes are qualitative, that is, not easily measured.
Maturation is the process of becoming fully grown and developed and involves physiological and behavioral aspects of an individual. Maturation depends on biological growth, functional changes, and learning (assimilation of information with a resultant change in behavior). During each developmental stage of the life cycle, certain goals (developmental tasks) must be achieved. These developmental tasks set the stage for future learning and adaption.
The critical period is the time of the most rapid growth or development in a particular stage of the life cycle. During these critical periods, an individual is most vulnerable to stressors of any type. Growth, development, maturation, and learning are interdependent processes. For learning to occur, the individual must be mature enough to grasp the concepts and make required behavioral changes. Cognitive maturation precedes learning. Physical growth is also a prerequisite for many types of learning; for example, a child must have the physical ability to control the anal sphincter before toilet training skills are learned.
Principles of Growth and Development
All persons have individual talents and abilities that contribute to their development as unique entities. There are no absolute rules in predicting the exact rate of development for an individual. However, some general principles relate to the growth and development of all humans.
The sequence of development is predictable even though the emergence of specific skills varies with each person. For example, not all infants roll over at the same age, but most roll over before they crawl.
Factors Influencing Growth and Development
Multiple factors such as heredity, life experiences, health status, and cultural expectations influence a person’s growth and development. The interaction of these factors greatly influences how an individual responds to everyday situations; the choices a person makes regarding health behaviors are also greatly determined by these factors.
Heredity A complex series of processes transmits genetic information from parents to children. The genetic composition of an individual determines physical characteristics such as skin color, hair texture, facial features, body structure, as well as a predisposition to certain diseases (i.e., Tay-Sachs, sickle cell anemia). Heredity is a genetic blueprint from which an individual grows and develops; it determines to a great extent the rate of physical and mental development.
Life Experiences A person’s experiences can also influence the rate of growth and development. For example, contrast the differences in physical growth rates between a child whose family can afford food, shelter, and health care and a child whose family has little, if any, resources. The child who is poor has a higher risk of experiencing physical and mental lags in growth and development. Another example of the influence of life experiences, is an elderly person who is enjoying retirement, has an adequate income, and an active support system. If this individual had an impairment in any of these variables, psychological development would likely be affected in a negative way.
Health Status Individuals experiencing wellness are progressing normally along the life cycle. However, illness or disability can interfere with the achievement of developmental milestones. Individuals with chronic conditions will often meet developmental milestones but with a time delay.
Cultural Expectations Society expects people to master certain skills in each developmental period. The age at which an individual masters a particular task is determined in part by culture. For example, the time for mastery of toilet training is greatly influenced by cultural norms. The following are examples of how societal expectations can either promote or hinder one’s growth and development:
• A child who grows up in an economically deprived home may receive inadequate food, shelter, emotional nurturing, or intellectual stimulation with resultant impairments in physical, psychosocial, and cognitive development.
• A woman may not be expected to fully use her intellectual abilities, thus she has altered cognitive development.
• A man may be discouraged from showing tenderness and nurturing behaviors; such discouragement results in dysfunctional psychosocial development.
Theoretical Perspectives of Human Development
Nurses must have a thorough understanding of human growth and development in order to provide individualized care. Remember that chronological age and developmental age are not synonymous. An overview of the major developmental theories is presented below. These theories are discussed more fully in the specific sections about each developmental period.
Physiological Dimension Physiological growth (physical size and functioning) of an individual is influenced primarily by interaction of genetic predisposition, the central nervous system (CNS), the endocrine system, and maturation. The role of heredity in human development is complex and not yet fully understood. Genetics is the foundation for achievement of specific tasks. Factors such as the psychosocial environment and health status help individuals live up to their genetic potential.
Psychosocial Dimension The psychosocial dimension of growth and development consists of subjective feelings and interpersonal relationships. A favorable self-concept(view of one’s self, including body image, self-esteem, and ideal self) is likely the most important key to a person’s success and happiness. Following are characteristics of an individual with a positive self-concept:
• Self-confidence
• Willingness to take risks
• Ability to receive criticism without defensiveness
• Ability to adapt effectively to stressors
• Innovative problem-solving skills
People with a healthy self-concept believe in themselves; as a result, they set goals that can be achieved. The goal achievement reinforces the positive belief about one’s self.
A person with a positive self-concept is likely to engage in health-promoting activities. For example, a person who values self is more likely to change unhealthy habits (such as smoking and sedentary lifestyle) to promote health. There are many different psychosocial theories that explain the development of self-concept. This chapter presents the intrapsychic and interpersonal models of personality development.
Intrapsychic Theory
Intrapsychic theory (also called psychodynamic) focuses on an individual’s unconscious processes. Feelings, needs, conflicts, and drives are considered to be motivators of behavior, learning, and development. Sigmund Freud and Erik Erikson are two major intrapsychic theorists. Freud’s theories, developed in the early 1930s, continue to influence current concepts related to human development. A basic belief of the Freudian model is that all behavior has some meaning. According to Freud (1961), to mature, a person must successfully travel through five stages of development.
In each stage, there is a task to be mastered; if the task is not achieved, the individual is halted (develops a fixation) at this stage. A fixation is characterized as either inadequate mastery or failure to achieve a developmental task. A fixation in earlier stages inhibits healthy progression through subsequent stages. Erikson (1968) expanded Freud’s concept of developmental stages by theorizing that psychosocial development is a lifelong process that does not end with the cessation of adolescence. Just as physical growth patterns can be predicted, certain psychosocial tasks must be mastered in each developmental stage. Erikson’s model proposes that psychosocial development is a series of conflicts that can have favorable or unfavorable outcomes.
Havighurst (1972) theorized that there are six developmental stages of life, each with essential tasks to be achieved. Mastery of a task in one developmental stage is essential for mastery of tasks in subsequent stages. When a task in one stage is mastered, it is learned for life, independent of subsequent neurological change (which may occur with disease or injury). Table 17-4 presents Havighurst’s developmental stages with the associated tasks.
Levinson (1978) studied men to determine developmental phases of young and middle adulthood.
As a result of Levinson’s research, five “seasons” or “eras” (phases) were identified (see the accompanying display). The midlife transition, which begins at approximately age 40, includes examining and structuring one’s life to one’s own satisfaction (Edelman & Mandle, 1997).
Interpersonal Theory Harry Stack Sullivan theorized that relationships with others influence how one’s personality develops. Approval and disapproval from significant others shape the formation of one’s personality. To form satisfying relationships with others, an individual must complete six stages of development.
Cognitive Dimension The cognitive dimension is characterized by the intellectual process of knowing, which includes perception, memory, and judgment, and develops as an individual progresses through the life span. Intelligence is an adaptive process. Individuals use intelligence to adapt by changing the environment to meet their needs and by altering their responses to environmental stressors. The ability to change behavior in response to the demands of an ever-changing environment is characteristic of intelligent beings. Jean Piaget (1963) studied the differences between children’s thinking patterns at different ages and how intelligence is used to solve problems and answer questions. He theorized that children learn to think by playing. Four factors are catalysts to intellectual development:
1. Maturation of the endocrine and nervous systems
2. Action-centered experience that leads to discovery (“learning by doing”)
3. Social interaction with opportunities for receiving feedback
4. A self-regulating mechanism that responds to environmental stimuli categorized intellectual development into four phases: sensorimotor, preoperational, concrete operations, and formal operations.
Each phase is characterized by the ways in which the child interprets and uses the environment. Approximate ages are indicated for each phase, but there is great variation among individuals. The individual learns by interacting with the environment through three processes: assimilation, accommodation, and adaptation.
Assimilation is the process of taking iew experiences or information.
Accommodation allows for readjustment of the cognitive structure (mindset) to take in the new information; thus, understanding is increased.
Adaptation refers to the changes that occur as a result of assimilation and accommodation .
Moral Dimension The moral dimension consists of a person’s value system that helps in differentiating right and wrong.
Moral maturity (the ability to independently decide for oneself what is “right”) is closely related to emotional and cognitive development. Lawrence Kohlberg (1977) established a framework for understanding how individuals determine a moral code to guide their behavior. Kohlberg’s model states that a person’s ability to make moral judgments and behave in a morally correct manner develops over a period of time. There are six stages of moral development. Each stage is built on the previous stage and becomes the foundation for successive stages. Moral development progresses in relationship to cognitive development. Individuals who are able to think at higher levels have the necessary reasoning skills on which to base moral decisions.
Kohlberg stated that individuals move through the six stages in a sequential fashion; however, not everyone reaches stages 5 and 6 in their development of personal morality . Gilligan’s theory of moral development is based on research that studied women. Women tend to describe moral issues in the context of human relationships and seek to avoid hurting others. Women’s moral judgment revolves around three basic issues: a concern with survival, a focus on goodness, and an understanding of others’ need for care.
Spiritual Dimension The spiritual dimension is characterized by a sense of personal meaning.
Spirituality refers to relationships with one’s self, with others, and with a higher power or divine source. Spirituality does not refer to a specific religious affiliation; rather, it can be defined as the core of a person. Development of spirituality is an ongoing, lifelong process. Fowler’s theory of spiritual development was influenced by the works of Erikson, Piaget, and Kohlberg. Fowler’s theory is composed of a pre-stage and six distinct stages of faith development (Fowler, 1981). Even though individuals will vary in the age at which they experience each stage, the sequence of stages remains the same. Table 17-9 describes Fowler’s theory.
Holistic Framework for Nursing
Providing care to the whole person is a basic concept of professional nurses. Knowledge of growth and development concepts are essential for nurses because nursing interventions must be appropriate to each client’s developmental stage. Nursing’s holistic perspective recognizes the progression of individual development across the life span. Developmental progress, or lack of progress, in one aspect affects all other dimensions of life. Figure 17-2 shows the holistic nature of individuals.
Growth and development theories are useful to nurses as assessment parameters. Alterations in expected patterns are indicators for early intervention. Listed below are situations in which knowledge of developmental milestones is essential for prompt identification of problems and comprehensive intervention:
• The infant who does not sit, crawl, or walk at expected times
• The adolescent girl who has not experienced menarche at the expected time
• The adult who has failed to develop adequate problem- solving skills
Stages of The Life Cycle
For purposes of this discussion, eleven developmental stages are presented: prenatal period, neonate, infant, toddler, preschooler, school-age child, preadolescent, adolescent, young adult, middle adult, and older adult. For each stage, the manifestations of growth and development in the physiological, psychosocial, cognitive, moral, and spiritual dimensions are discussed with the relevant nursing implications.
Prenatal Period
The prenatal period (the developmental stage beginning with conception and ending with birth) is a critical time in a human being’s development and consists of three developmental phases: the germinal, embryonic, and fetal stages.
The germinal stage begins with conception and lasts approximately 10 to 14 days. This stage is characterized by rapid cell division and implantation of the fertilized egg in the uterine wall. In this very early stage, the CNS is already beginning to form.
The embryonic stage (the first 2 to 8 weeks after fertilization of an egg by a sperm) is characterized by rapid cellular differentiation, growth, and development of the body systems. This critical period is when the embryo is most vulnerable to noxious stimuli, which may lead to a spontaneous abortion (miscarriage).
The fetal stage (the intrauterine developmental period from 8 weeks to birth) is characterized by rapid growth and differentiation of body systems and parts.
Nursing Implications The pregnant womaeeds to have physical examinations and screenings during the entire pregnancy. Early prenatal care is essential for a positive pregnancy outcome. Learning that one is pregnant is accompanied by several emotions: happiness, fear, sadness, excitement, and anxiety. Emotions lead to alterations in biochemicals; therefore, the mother’s emotional state can bring about biochemical changes in the fetus. By teaching pregnant women how to relax, the nurse can promote a supportive environment for the developing embryo and fetus.
Wellness Promotion The uterus is the primary environment affecting prenatal growth and development. Ideally, this environment nurtures positive growth of the embryo and fetus. An ample supply of nutrients must be provided by the gestating woman. Women who consume insufficient amounts of protein during pregnancy have a high rate of giving birth to premature and low birth weight infants. Such infants are at risk for developmental alterations. When teaching the pregnant woman about nutrition, the nurse must emphasize that vitamin supplements are not to be substituted for adequate intake of food. Other nursing interventions that promote prenatal health include:
• Screening (blood pressure measurement, urine sugar analysis)
• Teaching (nutritional guidelines)
• Counseling (e.g., guidance about bonding with the child and incorporating a child into a family unit)
• Promoting the use of complementary/alternative modalities to reduce stress
• Working with economically disadvantaged clients to obtain prenatal care
Safety Considerations The fetus is especially vulnerable to substances consumed by the mother. In addition to providing the fetus with wholesome nutrients, maternal blood can also transport toxins. Cigarettes contain several toxic substances, such as nicotine, that cross the placental barrier and interfere with the transport of oxygen to the fetus. Such toxins often result in increased risk of premature birth, retarded growth, learning difficulties, and fetal death. Use of alcohol during pregnancy can result in fetal alcohol syndrome (FAS), a condition in which fetal development is impaired and is manifested in the infant by characteristic physical attributes and intellectual problems. Typically, FAS infants are small, have facial abnormalities (such as thin upper lips and short, upturned noses), and may have some degree of brain damage. Alcohol consumption is most dangerous during the first 3 months of pregnancy when the embryo’s brain and other vital organs are developing. The effects of alcohol on the fetus are permanent. FAS is considered to be the leading cause of mental retardation among infants, and the incidence continues to increase (Wong, 1998). In addition to nicotine and alcohol, there are many other teratogenic substances.
A teratogenic substance is any substance that can cross the placental barrier and impair normal growth and development. Client education consists of teaching pregnant women to check labels of all medicines for information about potential effects on the fetus. The Food and Drug Administration requires that all manufactured drugs list their potential for causing birth defects. The use of illegal drugs by pregnant women presents a very serious threat to the unborn. Substance abuse prevention programs can be effective in preventing or reducing this risk.
Neonate The neonatal period (the first 28 days of life following birth) is a time of major adjustment to extrauterine life. The energies of the neonate (newborn) are focused on achieving equilibrium through stabilization of major body systems.
The neonate’s activities, which are reflexive iature, consist primarily of sucking, crying, eliminating, and sleeping.
The neonate blinks in response to bright lights and demonstrates the startle reflex in response to loud noises. Neonatal reflexes play a major role in the ability to survive.
During the first month of life, the neonate progresses developmentally from a mass of reflexes to behavior that is more goal directed (purposeful). In addition to the major physiological adjustments necessitated by extrauterine life, the neonate also undergoes psychological adaptation. The major psychological task of neonates is to adjust to the parental figures. Bonding, the formation of attachment between parent and child, begins at birth when the neonate and parent make initial eye contact. The quality of parent-neonate bonding lays the foundation for trust that is necessary for the development of future interpersonal relationships.
Nursing Implications A complete and thorough assessment of the neonate, which is performed immediately after delivery, includes evaluation of the neonate’s reflexes. In addition to focusing on the reflexes, the assessment also evaluates respiratory and cardiac functioning.
Diaper rash is a common skin problem for newborns and infants because of the ammonia from urine in wet diapers. The ammonia burns and irritates the skin, resulting in localized irritation, blisters, or fissures. In addition to prompt changing of wet diapers, bathing and use of protective creams are useful in preventing skin breakdown.
Infant Infancy (the developmental stage from the first month to the first year of life) is a time of continued adaptation. During this stage, the infant experiences rapid physiologic growth and psychosocial development.
Nursing Implications The nurse caring for an infant must focus on safety, prevention of infection, and teaching parents about incorporating the child into the family. Teaching parents and other caregivers about developmental milestones is essential. Nursing care involves the provision of support, reassurance, and information to the parents.
Wellness Promotion
Nurses promote infant wellness by teaching growth and development concepts to parents and other caregivers. Knowledge of the type of behavior to expect at certain times during infancy serves as both guidance and reassurance for parents. Three specific areas in which parents need guidance from the nurse in caring for their infants are nutrition, protection from infection, and promotion of sleep. A major factor influencing health maintenance of the infant is the provision of adequate nutrients delivered in a loving, consistent manner. Caregivers should be taught that the nutrients must be germ free and provide the recommended amounts of carbohydrates, protein, calcium, iron, and vitamins. It is recommended that infants be breastfed for the first 6 to 12 months (Murray & Zentner, 1997).
Breastmilk has several benefits over commercially prepared formulas, including:
• Offers immunologic benefits (e.g., contains immunoglobulins, lymphocytes, and other bacteria growth retardants)
• Is more easily digested because of smaller curds than those in cow’s milk and formula
• Enhances absorption of fat and calcium
• Is readily available and economical.
The act of breastfeeding promotes maternal-infant bonding. There are some cultural sanctions against breastfeeding and some cultures view bottle-feeding as a status symbol. Normal growth and development can occur without breastfeeding. Special formulas are available for infants who are hypersensitive to protein, who have PKU, and who experience fat malabsorption. Soy-based formulas have been developed for the infant with lactose deficiency or who is allergic to regular formula. Infants who are formula fed generally have greater deposits of subcutaneous fat. The Nursing Checklist provides teaching strategies for parents of bottle-fed infants. It is important that the nurse provide accurate information about the types of feeding available and support the parents’ decision about the method chosen. Solid foods are usually introduced at 3 to 4 months of age. Rice cereal is the first solid food of choice because it has the fewest allergic responses. Infants are especially vulnerable to developing infections. Because the immune system is not fully matured, infections pose a great threat. Immunizations are of utmost importance in preventing infections. Nurses should confirm that infants receive all necessary immunizations.
In the first few hours after birth, encourage the parents to cuddle the newborn. Explain the neonate’s interactive abilities. Encourage mutual eye contact betweeeonate and parents by showing parents how to hold the child facing them.
Wellness Promotion
Teaching is one of the most important nursing activities that promote neonatal wellness. First-time parents need information about basic newboreeds (to be held, rocked, and talked to), nutrition, infection control (especially handwashing and hygienic diaper changing practices), care of the umbilicus, and incorporating the newborn into the family unit. Knowledge of growth and development milestones is necessary for parents to provide appropriate neonatal stimulation and have realistic expectations. Other nursing interventions that promote neonatal wellness are listed below:
• Continually assessing the neonate’s physiological status
• Providing a warm environment (neonates breathe more easily when they are warm)
• Monitoring nutritional status. It is normal for neonates to lose weight (up to 10% of birth weight) during the first week of life.
• Providing a clean environment to protect neonates from infection and teaching parents that neonates need a clean environment, not a sterile one
• Conducting screening tests; for example, the blood test for phenylketonuria (PKU), a genetic disorder that, if untreated, can lead to impaired intellectual functioning
• Promoting early parent-neonate interaction
Selection of a feeding method for the neonate is a major decision for parents. Breastfeeding is the most natural option. However, commercially prepared formula is sometimes used due to the neonate’s special needs or parental choice. For a comparison of feeding methods, see the discussion about nutrition for the infant. Safety Considerations
Safety is of primary concern when caring for neonates because neonates are totally dependent on others to meet their needs. Accidents are the primary cause of neonatal mortality. One of the most important neonatal accident prevention methods is to teach parents about the use of infant car seats. Under current federal law, neonates and infants must be secured in an approved infant car seat every time the child travels in a car. In addition to accidents, infections pose a serious health risk to the neonate. Newborns should not be in contact with anyone experiencing an infectious disease. The skin is the body’s major defense against invasion by disease-producing microorganisms; therefore, it is essential that the neonate’s
Parents ofteeed information about normal sleep patterns of infants and how the patterns change with maturation. Activities that promote sleep include:
• Providing a quiet room for the infant
• Scheduling feedings and other care activities during periods of wakefulness instead of drowsy times
• Developing sensitivity to the unique sleep and rest periods established by the infant
• Providing comfort and security measures (e.g., rocking, singing)
• Establishing routine times for sleep
Safety Considerations
The majority of infant injuries and deaths are related to motor vehicle accidents. Therefore, the consistent and proper use of infant car seats is one of the most effective measures parents can take to ensure their infant’s safety. See the Nursing Checklist for guidelines that the nurse can share with parents to prevent infant accidents.
Toddler
The toddler period begins at 12 to 18 months of age, when a child begins to walk alone, and ends at approximately age 3. The family is very important to the toddler in that the family promotes language development and teaches toileting skills. During this stage, the child becomes more independent. Frequently, when attempts to demonstrate autonomy are prevented, the child will have a temper tantrum; thus, this stage is often referred to as “the terrible twos.” Parents must understand that the toddler’s frequent use of the word “no” is an expression of developing autonomy. Nurses can greatly influence the quality of parentchild interaction by teaching parents about developmental concepts. This information helps parents form realistic expectations of the toddler’s behavior. The use of firm limits set in a consistent manner helps the toddler learn while providing parameters for safe and socially acceptable behavior.
Nursing Implications Nurses who work with toddlers must be sensitive to the fact that children of this age are likely to be anxious and fearful in the presence of strangers. The establishment of rapport with the child will help alleviate this stranger anxiety. Play is an effective tool for building rapport with toddlers. When toddlers are hospitalized (for an extended time or only a day), fear and anxiety can make the experience a negative one. The major stressor resulting from hospitalization is the toddler’s separation from parents. An unfamiliar environment also results in stress for the toddler. Nurses can help reduce stress in the hospitalized toddler by teaching both the child and parents about procedures. Toddlers need to have regular health examinations, and immunizations remain an essential part of health care. Encourage parents to be involved during the examination and immunizations. Parents can alleviate the toddler’s stress by holding the child and talking in a calm manner when in the presence of the health care provider.
Some specific nursing approaches to use with toddlers are listed below:
• Explain what is being done in a calm tone of voice.
• Use play to alleviate anxiety (e.g., have the child examine a teddy bear or doll).
• Give short, simple directions.
• After a painful procedure, comfort the child (cuddling, rocking).
• Encourage parents’ active participation in the care.
Phenylketonuria (PKU) is a disorder that causes a buildup of the amino acid phenylalanine, which is an essential amino acid that cannot be synthesized in the body but is present in food. Excess phenylalanine is normally converted to tyrosine, another amino acid, and eliminated from the body. Without the enzyme that converts it to tyrosine, phenylalanine builds up in the blood and is toxic to the brain, causing mental retardation.
PKU occurs in most ethnic groups. If PKU runs in the family and DNA is available from an affected family member, amniocentesis or chorionic villus sampling with DNA analysis can be performed to determine whether a fetus has the disorder.
Most affected newborns are detected during routine screening tests. Newborns with PKU rarely have symptoms right away, although sometimes an infant is sleepy or eats poorly. If not treated, affected infants progressively develop mental retardation over the first few years of life, which eventually becomes severe. Other symptoms include seizures, nausea and vomiting, an eczema-like rash, lighter skin and hair than their family members, aggressive or self-injurious behavior, hyperactivity, and sometimes psychiatric symptoms. Untreated children often give off a “mousy” body and urine odor as a result of a by-product of phenylalanine (phenylacetic acid) in their urine and sweat.
To prevent mental retardation, phenylalanine intake must be restricted (but not eliminated altogether as people need some phenylalanine to live) beginning in the first few weeks of life. Because all natural sources of protein contain too much phenylalanine for children with PKU, affected children cannot have meat, milk, or other common foods that contain protein. Instead, they must eat a variety of phenylalanine-free processed foods, which are specially manufactured. Low-proteiatural foods, such as fruits, vegetables, and restricted amounts of certain grain cereals, can be eaten.
A restricted diet, if started early and maintained well, allows for normal development. However, if very strict control of the diet is not maintained, affected children may begin to have difficulties in school. Dietary restrictions started after 2 to 3 years of age may control extreme hyperactivity and seizures and raise the child’s eventual IQ but do not reverse mental retardation. Recent evidence suggests that functioning of some mentally retarded adults with PKU (born before newborn screening tests were available) may improve when they follow the PKU diet.
A phenylalanine-restricted diet should continue for life or intelligence may decrease and neurologic and psychiatric problems may ensue.
Maple Syrup Urine Disease
Children with maple syrup urine disease are unable to metabolize certain amino acids (leucine, isoleusine, valine). By-products of these amino acids build up, causing neurologicchanges, including seizures and mental retardation. These by-products also cause body fluids, such as urine and sweat, to smell like maple syrup. This disease is most common among Mennonite families.
There are many forms of maple syrup urine disease; symptoms vary in severity. In the most severe form, infants develop neurologic abnormalities, including seizures and coma, during the first week of life and can die within days to weeks. In the milder forms, children initially appear normal but develop vomiting, staggering, confusion, coma, and the odor of maple syrup particularly during physical stress, such as infection or surgery.
In some states, newborns are routinely screened for this disease with a blood test.
Infants with severe disease are treated with dialysis. Some children with mild disease benefit from injections of the vitamin B1 (thiamin). After the disease has been brought under control, children must always consume a special artificial diet that is low in the particular amino acids that are affected by the missing enzyme.
Homocystinuria
Children with homocystinuria are unable to metabolize the amino acid homocysteine, which, along with certain toxic by-products, builds up to cause a variety of symptoms. Symptoms may be mild or severe, depending on the particular enzyme defect.
Infants with this disorder are normal at birth. The first symptoms, including dislocation of the lens of the eye, causing severely decreased vision, usually begin after 3 years of age. Most children have skeletal abnormalities, including osteoporosis; the child is usually tall and thin with a curved spine, elongated limbs, and long, spiderlike fingers. Psychiatric and behavioral disorders and mental retardation are common. Homocystinuria makes the blood more likely to spontaneously clot, resulting in strokes, high blood pressure, and many other serious problems.
In a few states, children are screened for homocystinuria at birth with a blood test. The diagnosis is confirmed by a test measuring enzyme function in liver or skin cells.
Some children with homocystinuria improve when given vitamin B6 (pyridoxine) or vitamin B12 (cobalamin).
Tyrosinemia
Children with tyrosinemia are unable to completely metabolize the amino acid tyrosine. By-products of this amino acid build up, causing a variety of symptoms. In some states, the disorder is detected on the newborn screening tests.
There are two main types of tyrosinemia: I and II. Type I tyrosinemia is most common in children of French-Canadian or Scandinavian descent. Children with this disorder typically become ill sometime within the first year of life with dysfunction of the liver, kidneys, and nerves, resulting in irritability, rickets, or even liver failure and death. Restriction of tyrosine in the diet is of little help. An experimental drug, which blocks production of toxic metabolites, may help children with type I tyrosinemia. Often, children with type Ityrosinemia require a liver transplant.
Type II tyrosinemia is less common. Affected children sometimes have mental retardation and frequently develop sores on the skin and eyes. Unlike type I tyrosinemia, restriction of tyrosine in the diet can prevent problems from developing.
Carbohydrates metabolism
Carbohydrates are sugars. Some sugars are simple, and others are more complex. Sucrose (table sugar) is made of two simpler sugars called glucose and fructose. Lactose (milk sugar) is made of glucose and galactose. Both sucrose and lactose must be broken down into their component sugars by enzymes before the body can absorb and make use of them. The carbohydrates in bread, pasta, rice, and other carbohydrate-containing foods are long chains of simple sugar molecules. These longer molecules must also be broken down by the body. If an enzyme needed to process a certain sugar is missing, the sugar can accumulate in the body, causing problems.
Glycogen Storage Diseases
Glycogen is made of many glucose molecules linked together. The sugar glucose is the body’s main source of energy for the muscles (including the heart) and brain. Any glucose that is not immediately used for energy is held in reserve in the liver, muscles, and kidneys in the form of glycogen and released wheeeded by the body.
There are many different glycogen storage diseases (also called glycogenoses), each identified by a romaumeral. These diseases are caused by a hereditary lack of one of the enzymes that is essential to the process of forming glucose into glycogen and breaking down glycogen into glucose. About 1 in 20,000 infants has some form of glycogen storage disease.
Some of these diseases cause few symptoms; others are fatal. The specific symptoms, age at which symptoms start, and their severity vary considerably among these diseases. For types II, V, and VII, the main symptom is usually weakness. For types I, III, and VI, symptoms are low levels of sugar in the blood and protrusion of the abdomen (because excess or abnormal glycogen may enlarge the liver). Low levels of sugar in the blood cause weakness, sweating, confusion, and sometimes seizures and coma. Other consequences for children may include stunted growth, frequent infections, or sores in the mouth and intestines. Glycogen storage diseases tend to cause uric acid, a waste product, to accumulate in the joints (which can cause gout) and in the kidneys (which can cause kidney stones). In type I glycogen storage disease, kidney failure is common in the second decade of life or later.
The specific diagnosis is made when a chemical examination of a sample of tissue, usually muscle or liver, determines that a specific enzyme is missing.
Treatment depends on the type of glycogen storage disease. For many people, eating many small carbohydrate-rich meals every day helps prevent blood sugar levels from dropping. For people who have glycogen storage diseases that produce low blood sugar, glucose levels are maintained by giving uncooked cornstarch every 4 to 6 hours around the clock. Sometimes carbohydrate solutions are given through a stomach tube all night to prevent low blood sugar levels from occurring at night.
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Galactosemia
Galactosemia (a high blood level of galactose) is caused by lack of one of the enzymes necessary for metabolizing galactose, a sugar present in lactose (milk sugar). A metabolite builds up that is toxic to the liver and kidneys and also damages the lens of the eye, causing cataracts.
A newborn with galactosemia seems normal at first but within a few days or weeks loses his appetite, vomits, becomes jaundiced, has diarrhea, and stops growing normally. White blood cell function is affected, and serious infections can develop. If treatment is delayed, affected children remain short and become mentally retarded or may die.
Galactosemia is detectable with a blood test. This test is performed as a routine screening test oewborns iearly all states in the
Galactosemia is treated by completely eliminating milk and milk products—the source of galactose—from an affected child’s diet. Galactose is also present in some fruits, vegetables, and sea products, such as seaweed. Doctors are not sure whether the small amounts in these foods cause problems in the long term. People who have the disorder must restrict galactose intake throughout life.
If galactosemia is recognized at birth and adequately treated, the liver and kidney problems do not develop, and initial mental development is normal. However, even with proper treatment, children with galactosemia often have a lower intelligence quotient (IQ) than their siblings, and they often have speech problems. Girls often have ovaries that do not function, and only a few are able to conceive naturally. Boys, however, have normal testicular function.
Hereditary Fructose Intolerance
In this disorder, the body is missing an enzyme that allows it to use fructose, a sugar present in table sugar (sucrose) and many fruits. As a result, a by-product of fructose accumulates in the body, blocking the formation of glycogen and its conversion to glucose for use as energy. Ingesting more than tiny amounts of fructose or sucrose causes low blood sugar levels (hypoglycemia), with sweating, confusion, and sometimes seizures and coma. Children who continue to eat foods containing fructose develop kidney and liver damage, resulting in jaundice, vomiting, mental deterioration, seizures, and death. Chronic symptoms include poor eating, failure to thrive, digestive symptoms, liver failure, and kidney damage.
The diagnosis is made when a chemical examination of a sample of liver tissue determines that the enzyme is missing. Treatment involves excluding fructose (generally found in sweet fruits), sucrose, and sorbitol (a sugar substitute) from the diet. Acute attacks respond to glucose given intravenously; milder attacks of hypoglycemia are treated with glucose tablets, which should be carried by anyone who has hereditary fructose intolerance.
Lipids metabolism
Fats (lipids) are an important source of energy for the body. The body’s store of fat is constantly broken down and reassembled to balance the body’s energy needs with the food available. Groups of specific enzymes help the body break down and process fats. Certain abnormalities in these enzymes can lead to the buildup of specific fatty substances that normally would have been broken down by the enzymes. Over time, accumulations of these substances can be harmful to many organs of the body. Disorders caused by the accumulation of lipids are called lipidoses. Other enzyme abnormalities result in the body being unable to properly convert fats into energy. These abnormalities are called fatty acid oxidation disorders.
Gaucher’s Disease
In Gaucher’s disease, glucocerebrosides, which are a product of fat metabolism, accumulate in tissues. Gaucher’s disease is the most common lipidosis. The disease is most common in Ashkenazi (Eastern European) Jews. Gaucher’s disease leads to an enlarged liver and spleen and a brownish pigmentation of the skin. Accumulations ofglucocerebrosides in the eyes cause yellow spots called pingueculae to appear. Accumulations in the bone marrow can cause pain and destroy bone.
Most people who have Gaucher’s disease develop type 1, the chronic form, which results in an enlarged liver and spleen and bone abnormalities. Most are adults, but children also may have type 1. Type 2, the infantile form, develops in infancy; infants with the disease have an enlarged spleen and severe nervous system abnormalities and usually die within a year. Type 3, the juvenile form, can begin at any time during childhood. Children with the disease have an enlarged liver and spleen, bone abnormalities, and slowly progressive nervous system abnormalities. Children who survive to adolescence may live for many years.
Many people with Gaucher’s disease can be treated with enzyme replacement therapy, in which enzymes are given intravenously, usually every 2 weeks. Enzyme replacement therapy is most effective for people who do not have nervous system complications.
Tay-Sachs Disease
In Tay-Sachs disease, gangliosides, which are products of fat metabolism, accumulate in tissues. The disease is most common in families of Eastern European Jewish origin. At a very early age, children with this disease become progressively retarded and appear to have floppy muscle tone. Spasticity develops and is followed by paralysis, dementia, and blindness. These children usually die by age 3 or 4. Tay-Sachs disease can be identified in the fetus by chorionic villus sampling or amniocentesis. The disease cannot be treated or cured.
Niemann-Pick Disease
In Niemann-Pick disease, the deficiency of a specific enzyme results in the accumulation of sphingomyelin (a product of fat metabolism) or cholesterol. Niemann-Pick disease has several forms, depending on the severity of the enzyme deficiency and thus accumulation of sphingomyelin or cholesterol. The most severe forms tend to occur in Jewish people. The milder forms occur in all ethnic groups.
In the most severe form (type A), children fail to grow properly and have multiple neurologic problems. These children usually die by age 3. Children with type B disease develop fatty growths in the skin, areas of dark pigmentation, and an enlarged liver, spleen, and lymph nodes; they may be mentally retarded. Children with type C disease develop symptoms in childhood, with seizures and neurologic deterioration.
Some forms of Niemann-Pick disease can be diagnosed in the fetus by chorionic villus sampling or amniocentesis. After birth, the diagnosis can be made by a liver biopsy (removal of a tissue specimen for examination under a microscope). None of the types of Niemann-Pick disease can be cured, and children tend to die of infection or progressive dysfunction of the central nervous system.
Fabry’s Disease
In Fabry’s disease, glycolipid, which is a product of fat metabolism, accumulates in tissues. Because the defective gene for this rare disorder is carried on the X chromosome, the full-blown disease occurs only in males. The accumulation of glycolipid causes noncancerous skin growths (angiokeratomas) to form over the lower part of the trunk. The corneas become cloudy, resulting in poor vision. A burning pain may develop in the arms and legs, and the person may have episodes of fever. People with Fabry’s disease eventually develop kidney failure and heart disease, although most often they live into adulthood. Kidney failure may lead to high blood pressure, which may result in stroke.
Fabry’s disease can be diagnosed in the fetus by chorionic villus sampling or amniocentesis. The disease cannot be cured or even treated directly, but researchers are investigating a treatment in which the deficient enzyme is replaced by transfusion. Treatment consists of taking analgesics to help relieve pain and fever. People with kidney failure may need a kidney transplant.
Fatty Acid Oxidation Disorders
Several enzymes help break fats down so that they may be turned into energy. An inherited defect or deficiency of one of these enzymes leaves the body short of energy and allows breakdown products, such as acyl-CoA, to accumulate. The enzyme most commonly deficient is medium chain acyl-CoA dehydrogenase (MCAD). MCAD deficiency is one of the most common inherited disorders of metabolism, particularly in people of Northern European descent.
Symptoms usually develop between birth and age 3. Children are most likely to develop symptoms if they go without food for a period of time (which depletes other sources of energy) or have an increased need for calories because of exercise or illness. The level of sugar in the blood drops significantly, causing confusion or coma. The child becomes weak and may have vomiting or seizures. Over the long term, children have delayed mental and physical development, an enlarged liver, heart muscle weakness, and an irregular heartbeat. Sudden death may occur.
Some states screeewborns for MCAD deficiency with a blood test. Immediate treatment is with intravenous glucose. For long-term treatment, the child must eat often, never skipping meals, and consume a diet high in carbohydrates and low in fats. Supplements of the amino acid carnitine may be helpful. The long-term outcome is generally good.
Caring for Families, Developmental Theories
From conception to death, individuals are constantly changing. Physical growth, psychological development, emotional maturation, cognitive development, moral development, and spiritual growth occur throughout life. Progression through each developmental stage influences health status. A thorough understanding of developmental concepts is essential for professional quality nursing practice. This chapter discusses the changes occurring in each stage of the life cycle.
Fundamental Concepts of Growth And Development
Development occurs continuously through the life span. Adults continue to have transition periods during which growth and development occur.
Growth is the quantitative (measurable) changes in physical size of the body and its parts, such as increases in cells, tissues, structures, and systems. Examples of growth are physical changes in height, weight, bone density, and dental structure. Even though growth is not a steady process through the life cycle, growth patterns can be predicted. Variations in growth, such as rapid increases contrasted with slower rates of physical change, occur with each individual. Rapid growth is most common in the prenatal, infant, and adolescent stages.
Development refers to behavioral changes in functional abilities and skills. Thus, developmental changes are qualitative, that is, not easily measured.
Maturation is the process of becoming fully grown and developed and involves physiological and behavioral aspects of an individual. Maturation depends on biological growth, functional changes, and learning (assimilation of information with a resultant change in behavior). During each developmental stage of the life cycle, certain goals (developmental tasks) must be achieved. These developmental tasks set the stage for future learning and adaption.
The critical period is the time of the most rapid growth or development in a particular stage of the life cycle. During these critical periods, an individual is most vulnerable to stressors of any type. Growth, development, maturation, and learning are interdependent processes. For learning to occur, the individual must be mature enough to grasp the concepts and make required behavioral changes. Cognitive maturation precedes learning. Physical growth is also a prerequisite for many types of learning; for example, a child must have the physical ability to control the anal sphincter before toilet training skills are learned.
Principles of Growth and Development
All persons have individual talents and abilities that contribute to their development as unique entities. There are no absolute rules in predicting the exact rate of development for an individual. However, some general principles relate to the growth and development of all humans.
The sequence of development is predictable even though the emergence of specific skills varies with each person. For example, not all infants roll over at the same age, but most roll over before they crawl.
Factors Influencing Growth and Development
Multiple factors such as heredity, life experiences, health status, and cultural expectations influence a person’s growth and development. The interaction of these factors greatly influences how an individual responds to everyday situations; the choices a person makes regarding health behaviors are also greatly determined by these factors.
Heredity A complex series of processes transmits genetic information from parents to children. The genetic composition of an individual determines physical characteristics such as skin color, hair texture, facial features, body structure, as well as a predisposition to certain diseases (i.e., Tay-Sachs, sickle cell anemia). Heredity is a genetic blueprint from which an individual grows and develops; it determines to a great extent the rate of physical and mental development.
Life Experiences A person’s experiences can also influence the rate of growth and development. For example, contrast the differences in physical growth rates between a child whose family can afford food, shelter, and health care and a child whose family has little, if any, resources. The child who is poor has a higher risk of experiencing physical and mental lags in growth and development. Another example of the influence of life experiences, is an elderly person who is enjoying retirement, has an adequate income, and an active support system. If this individual had an impairment in any of these variables, psychological development would likely be affected in a negative way.
Health Status Individuals experiencing wellness are progressing normally along the life cycle. However, illness or disability can interfere with the achievement of developmental milestones. Individuals with chronic conditions will often meet developmental milestones but with a time delay.
Cultural Expectations Society expects people to master certain skills in each developmental period. The age at which an individual masters a particular task is determined in part by culture. For example, the time for mastery of toilet training is greatly influenced by cultural norms. The following are examples of how societal expectations can either promote or hinder one’s growth and development:
• A child who grows up in an economically deprived home may receive inadequate food, shelter, emotional nurturing, or intellectual stimulation with resultant impairments in physical, psychosocial, and cognitive development.
• A woman may not be expected to fully use her intellectual abilities, thus she has altered cognitive development.
• A man may be discouraged from showing tenderness and nurturing behaviors; such discouragement results in dysfunctional psychosocial development.
Theoretical Perspectives of Human Development
Nurses must have a thorough understanding of human growth and development in order to provide individualized care. Remember that chronological age and developmental age are not synonymous. An overview of the major developmental theories is presented below. These theories are discussed more fully in the specific sections about each developmental period.
Physiological Dimension Physiological growth (physical size and functioning) of an individual is influenced primarily by interaction of genetic predisposition, the central nervous system (CNS), the endocrine system, and maturation. The role of heredity in human development is complex and not yet fully understood. Genetics is the foundation for achievement of specific tasks. Factors such as the psychosocial environment and health status help individuals live up to their genetic potential.
Psychosocial Dimension The psychosocial dimension of growth and development consists of subjective feelings and interpersonal relationships. A favorable self-concept(view of one’s self, including body image, self-esteem, and ideal self) is likely the most important key to a person’s success and happiness. Following are characteristics of an individual with a positive self-concept:
• Self-confidence
• Willingness to take risks
• Ability to receive criticism without defensiveness
• Ability to adapt effectively to stressors
• Innovative problem-solving skills
People with a healthy self-concept believe in themselves; as a result, they set goals that can be achieved. The goal achievement reinforces the positive belief about one’s self.
A person with a positive self-concept is likely to engage in health-promoting activities. For example, a person who values self is more likely to change unhealthy habits (such as smoking and sedentary lifestyle) to promote health. There are many different psychosocial theories that explain the development of self-concept. This chapter presents the intrapsychic and interpersonal models of personality development.
Intrapsychic Theory
Intrapsychic theory (also called psychodynamic) focuses on an individual’s unconscious processes. Feelings, needs, conflicts, and drives are considered to be motivators of behavior, learning, and development. Sigmund Freud and Erik Erikson are two major intrapsychic theorists. Freud’s theories, developed in the early 1930s, continue to influence current concepts related to human development. A basic belief of the Freudian model is that all behavior has some meaning. According to Freud to mature, a person must successfully travel through five stages of development.
In each stage, there is a task to be mastered; if the task is not achieved, the individual is halted (develops a fixation) at this stage. A fixation is characterized as either inadequate mastery or failure to achieve a developmental task. A fixation in earlier stages inhibits healthy progression through subsequent stages. Erikson (1968) expanded Freud’s concept of developmental stages by theorizing that psychosocial development is a lifelong process that does not end with the cessation of adolescence. Just as physical growth patterns can be predicted, certain psychosocial tasks must be mastered in each developmental stage. Erikson’s model proposes that psychosocial development is a series of conflicts that can have favorable or unfavorable outcomes.
Havighurst theorized that there are six developmental stages of life, each with essential tasks to be achieved. Mastery of a task in one developmental stage is essential for mastery of tasks in subsequent stages. When a task in one stage is mastered, it is learned for life, independent of subsequent neurological change (which may occur with disease or injury). Table 17-4 presents Havighurst’s developmental stages with the associated tasks.
Levinson studied men to determine developmental phases of young and middle adulthood.
As a result of Levinson’s research, five “seasons” or “eras” (phases) were identified (see the accompanying display). The midlife transition, which begins at approximately age 40, includes examining and structuring one’s life to one’s own satisfaction.
Interpersonal Theory Harry Stack Sullivan theorized that relationships with others influence how one’s personality develops. Approval and disapproval from significant others shape the formation of one’s personality. To form satisfying relationships with others, an individual must complete six stages of development.
Cognitive Dimension The cognitive dimension is characterized by the intellectual process of knowing, which includes perception, memory, and judgment, and develops as an individual progresses through the life span. Intelligence is an adaptive process. Individuals use intelligence to adapt by changing the environment to meet their needs and by altering their responses to environmental stressors. The ability to change behavior in response to the demands of an ever-changing environment is characteristic of intelligent beings. Jean Piaget (1963) studied the differences between children’s thinking patterns at different ages and how intelligence is used to solve problems and answer questions. He theorized that children learn to think by playing. Four factors are catalysts to intellectual development:
1. Maturation of the endocrine and nervous systems
2. Action-centered experience that leads to discovery (“learning by doing”)
3. Social interaction with opportunities for receiving feedback
4. A self-regulating mechanism that responds to environmental stimuli (Murray & Zentner, 1997) Piaget and Inhelder (1969) categorized intellectual development into four phases: sensorimotor, preoperational, concrete operations, and formal operations.
Each phase is characterized by the ways in which the child interprets and uses the environment. Approximate ages are indicated for each phase, but there is great variation among individuals. The individual learns by interacting with the environment through three processes: assimilation, accommodation, and adaptation.
Assimilation is the process of taking iew experiences or information.
Accommodation allows for readjustment of the cognitive structure (mindset) to take in the new information; thus, understanding is increased.
Adaptation refers to the changes that occur as a result of assimilation and accommodation (Murray & Zentner, 1997).
Moral Dimension The moral dimension consists of a person’s value system that helps in differentiating right and wrong.
Moral maturity (the ability to independently decide for oneself what is “right”) is closely related to emotional and cognitive development. Lawrence Kohlberg (1977) established a framework for understanding how individuals determine a moral code to guide their behavior. Kohlberg’s model states that a person’s ability to make moral judgments and behave in a morally correct manner develops over a period of time. There are six stages of moral development. Each stage is built on the previous stage and becomes the foundation for successive stages. Moral development progresses in relationship to cognitive development. Individuals who are able to think at higher levels have the necessary reasoning skills on which to base moral decisions.
Kohlberg stated that individuals move through the six stages in a sequential fashion; however, not everyone reaches stages 5 and 6 in their development of personal morality (Kohlberg, 1977). Gilligan’s theory of moral development is based on research that studied women. Women tend to describe moral issues in the context of human relationships and seek to avoid hurting others (Gilligan, 1982). Women’s moral judgment revolves around three basic issues: a concern with survival, a focus on goodness, and an understanding of others’ need for care (Gilligan & Attanucci, 1988).
Spiritual Dimension The spiritual dimension is characterized by a sense of personal meaning.
Spirituality refers to relationships with one’s self, with others, and with a higher power or divine source. Spirituality does not refer to a specific religious affiliation; rather, it can be defined as the core of a person. Development of spirituality is an ongoing, lifelong process. Fowler’s theory of spiritual development was influenced by the works of Erikson, Piaget, and Kohlberg. Fowler’s theory is composed of a pre-stage and six distinct stages of faith development (Fowler, 1981). Even though individuals will vary in the age at which they experience each stage, the sequence of stages remains the same. Table 17-9 describes Fowler’s theory.
Holistic Framework for Nursing
Providing care to the whole person is a basic concept of professional nurses. Knowledge of growth and development concepts are essential for nurses because nursing interventions must be appropriate to each client’s developmental stage. Nursing’s holistic perspective recognizes the progression of individual development across the life span. Developmental progress, or lack of progress, in one aspect affects all other dimensions of life. Figure 17-2 shows the holistic nature of individuals.
Growth and development theories are useful to nurses as assessment parameters. Alterations in expected patterns are indicators for early intervention. Listed below are situations in which knowledge of developmental milestones is essential for prompt identification of problems and comprehensive intervention:
• The infant who does not sit, crawl, or walk at expected times
• The adolescent girl who has not experienced menarche at the expected time
• The adult who has failed to develop adequate problem- solving skills
Stages of The Life Cycle
For purposes of this discussion, eleven developmental stages are presented: prenatal period, neonate, infant, toddler, preschooler, school-age child, preadolescent, adolescent, young adult, middle adult, and older adult. For each stage, the manifestations of growth and development in the physiological, psychosocial, cognitive, moral, and spiritual dimensions are discussed with the relevant nursing implications.
Prenatal Period
The prenatal period (the developmental stage beginning with conception and ending with birth) is a critical time in a human being’s development and consists of three developmental phases: the germinal, embryonic, and fetal stages.
The germinal stage begins with conception and lasts approximately 10 to 14 days. This stage is characterized by rapid cell division and implantation of the fertilized egg in the uterine wall. In this very early stage, the CNS is already beginning to form.
The embryonic stage (the first 2 to 8 weeks after fertilization of an egg by a sperm) is characterized by rapid cellular differentiation, growth, and development of the body systems. This critical period is when the embryo is most vulnerable to noxious stimuli, which may lead to a spontaneous abortion (miscarriage) (Murray & Zentner, 1997).
The fetal stage (the intrauterine developmental period from 8 weeks to birth) is characterized by rapid growth and differentiation of body systems and parts.
Nursing Implications The pregnant womaeeds to have physical examinations and screenings during the entire pregnancy. Early prenatal care is essential for a positive pregnancy outcome. Learning that one is pregnant is accompanied by several emotions: happiness, fear, sadness, excitement, and anxiety. Emotions lead to alterations in biochemicals; therefore, the mother’s emotional state can bring about biochemical changes in the fetus. By teaching pregnant women how to relax, the nurse can promote a supportive environment for the developing embryo and fetus.
Wellness Promotion The uterus is the primary environment affecting prenatal growth and development. Ideally, this environment nurtures positive growth of the embryo and fetus. An ample supply of nutrients must be provided by the gestating woman. Women who consume insufficient amounts of protein during pregnancy have a high rate of giving birth to premature and low birth weight infants. Such infants are at risk for developmental alterations. When teaching the pregnant woman about nutrition, the nurse must emphasize that vitamin supplements are not to be substituted for adequate intake of food. Other nursing interventions that promote prenatal health include:
• Screening (blood pressure measurement, urine sugar analysis)
• Teaching (nutritional guidelines)
• Counseling (e.g., guidance about bonding with the child and incorporating a child into a family unit)
• Promoting the use of complementary/alternative modalities to reduce stress
• Working with economically disadvantaged clients to obtain prenatal care
Safety Considerations The fetus is especially vulnerable to substances consumed by the mother. In addition to providing the fetus with wholesome nutrients, maternal blood can also transport toxins. Cigarettes contain several toxic substances, such as nicotine, that cross the placental barrier and interfere with the transport of oxygen to the fetus. Such toxins often result in increased risk of premature birth, retarded growth, learning difficulties, and fetal death. Use of alcohol during pregnancy can result in fetal alcohol syndrome (FAS), a condition in which fetal development is impaired and is manifested in the infant by characteristic physical attributes and intellectual problems. Typically, FAS infants are small, have facial abnormalities (such as thin upper lips and short, upturned noses), and may have some degree of brain damage. Alcohol consumption is most dangerous during the first 3 months of pregnancy when the embryo’s brain and other vital organs are developing. The effects of alcohol on the fetus are permanent. FAS is considered to be the leading cause of mental retardation among infants, and the incidence continues to increase (Wong, 1998). In addition to nicotine and alcohol, there are many other teratogenic substances.
A teratogenic substance is any substance that can cross the placental barrier and impair normal growth and development. Client education consists of teaching pregnant women to check labels of all medicines for information about potential effects on the fetus. The Food and Drug Administration requires that all manufactured drugs list their potential for causing birth defects. The use of illegal drugs by pregnant women presents a very serious threat to the unborn. Substance abuse prevention programs can be effective in preventing or reducing this risk.
Neonate The neonatal period (the first 28 days of life following birth) is a time of major adjustment to extrauterine life. The energies of the neonate (newborn) are focused on achieving equilibrium through stabilization of major body systems.
The neonate’s activities, which are reflexive iature, consist primarily of sucking, crying, eliminating, and sleeping.
The neonate blinks in response to bright lights and demonstrates the startle reflex in response to loud noises. Neonatal reflexes play a major role in the ability to survive.
During the first month of life, the neonate progresses developmentally from a mass of reflexes to behavior that is more goal directed (purposeful). In addition to the major physiological adjustments necessitated by extrauterine life, the neonate also undergoes psychological adaptation. The major psychological task of neonates is to adjust to the parental figures. Bonding, the formation of attachment between parent and child, begins at birth when the neonate and parent make initial eye contact. The quality of parent-neonate bonding lays the foundation for trust that is necessary for the development of future interpersonal relationships.
Nursing Implications A complete and thorough assessment of the neonate, which is performed immediately after delivery, includes evaluation of the neonate’s reflexes. In addition to focusing on the reflexes, the assessment also evaluates respiratory and cardiac functioning.
Diaper rash is a common skin problem for newborns and infants because of the ammonia from urine in wet diapers. The ammonia burns and irritates the skin, resulting in localized irritation, blisters, or fissures. In addition to prompt changing of wet diapers, bathing and use of protective creams are useful in preventing skin breakdown.
Infant Infancy (the developmental stage from the first month to the first year of life) is a time of continued adaptation. During this stage, the infant experiences rapid physiologic growth and psychosocial development.
Nursing Implications The nurse caring for an infant must focus on safety, prevention of infection, and teaching parents about incorporating the child into the family. Teaching parents and other caregivers about developmental milestones is essential. Nursing care involves the provision of support, reassurance, and information to the parents.
Wellness Promotion
Nurses promote infant wellness by teaching growth and development concepts to parents and other caregivers. Knowledge of the type of behavior to expect at certain times during infancy serves as both guidance and reassurance for parents. Three specific areas in which parents need guidance from the nurse in caring for their infants are nutrition, protection from infection, and promotion of sleep. A major factor influencing health maintenance of the infant is the provision of adequate nutrients delivered in a loving, consistent manner. Caregivers should be taught that the nutrients must be germ free and provide the recommended amounts of carbohydrates, protein, calcium, iron, and vitamins. It is recommended that infants be breastfed for the first 6 to 12 months.
Breastmilk has several benefits over commercially prepared formulas, including:
• Offers immunologic benefits (e.g., contains immunoglobulins, lymphocytes, and other bacteria growth retardants)
• Is more easily digested because of smaller curds than those in cow’s milk and formula
• Enhances absorption of fat and calcium
• Is readily available and economical.
The act of breastfeeding promotes maternal-infant bonding). There are some cultural sanctions against breastfeeding and some cultures view bottle-feeding as a status symbol. Normal growth and development can occur without breastfeeding. Special formulas are available for infants who are hypersensitive to protein, who have PKU, and who experience fat malabsorption. Soy-based formulas have been developed for the infant with lactose deficiency or who is allergic to regular formula. Infants who are formula fed generally have greater deposits of subcutaneous fat. The Nursing Checklist provides teaching strategies for parents of bottle-fed infants. It is important that the nurse provide accurate information about the types of feeding available and support the parents’ decision about the method chosen. Solid foods are usually introduced at 3 to 4 months of age. Rice cereal is the first solid food of choice because it has the fewest allergic responses. Infants are especially vulnerable to developing infections. Because the immune system is not fully matured, infections pose a great threat. Immunizations are of utmost importance in preventing infections. Nurses should confirm that infants receive all necessary immunizations.
In the first few hours after birth, encourage the parents to cuddle the newborn. Explain the neonate’s interactive abilities. Encourage mutual eye contact betweeeonate and parents by showing parents how to hold the child facing them.
Carbohydrates metabolism
Carbohydrates are sugars. Some sugars are simple, and others are more complex. Sucrose (table sugar) is made of two simpler sugars called glucose and fructose. Lactose (milk sugar) is made of glucose and galactose. Both sucrose and lactose must be broken down into their component sugars by enzymes before the body can absorb and make use of them. The carbohydrates in bread, pasta, rice, and other carbohydrate-containing foods are long chains of simple sugar molecules. These longer molecules must also be broken down by the body. If an enzyme needed to process a certain sugar is missing, the sugar can accumulate in the body, causing problems.
Glycogen Storage Diseases
Glycogen is made of many glucose molecules linked together. The sugar glucose is the body’s main source of energy for the muscles (including the heart) and brain. Any glucose that is not immediately used for energy is held in reserve in the liver, muscles, and kidneys in the form of glycogen and released wheeeded by the body.
There are many different glycogen storage diseases (also called glycogenoses), each identified by a romaumeral. These diseases are caused by a hereditary lack of one of the enzymes that is essential to the process of forming glucose into glycogen and breaking down glycogen into glucose. About 1 in 20,000 infants has some form of glycogen storage disease.
Some of these diseases cause few symptoms; others are fatal. The specific symptoms, age at which symptoms start, and their severity vary considerably among these diseases. For types II, V, and VII, the main symptom is usually weakness. For types I, III, and VI, symptoms are low levels of sugar in the blood and protrusion of the abdomen (because excess or abnormal glycogen may enlarge the liver). Low levels of sugar in the blood cause weakness, sweating, confusion, and sometimes seizures and coma. Other consequences for children may include stunted growth, frequent infections, or sores in the mouth and intestines. Glycogen storage diseases tend to cause uric acid, a waste product, to accumulate in the joints (which can cause gout) and in the kidneys (which can cause kidney stones). In type I glycogen storage disease, kidney failure is common in the second decade of life or later.
The specific diagnosis is made when a chemical examination of a sample of tissue, usually muscle or liver, determines that a specific enzyme is missing.
Treatment depends on the type of glycogen storage disease. For many people, eating many small carbohydrate-rich meals every day helps prevent blood sugar levels from dropping. For people who have glycogen storage diseases that produce low blood sugar, glucose levels are maintained by giving uncooked cornstarch every 4 to 6 hours around the clock. Sometimes carbohydrate solutions are given through a stomach tube all night to prevent low blood sugar levels from occurring at night.
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Galactosemia
Galactosemia (a high blood level of galactose) is caused by lack of one of the enzymes necessary for metabolizing galactose, a sugar present in lactose (milk sugar). A metabolite builds up that is toxic to the liver and kidneys and also damages the lens of the eye, causing cataracts.
A newborn with galactosemia seems normal at first but within a few days or weeks loses his appetite, vomits, becomes jaundiced, has diarrhea, and stops growing normally. White blood cell function is affected, and serious infections can develop. If treatment is delayed, affected children remain short and become mentally retarded or may die.
Galactosemia is detectable with a blood test. This test is performed as a routine screening test oewborns iearly all states in the
Galactosemia is treated by completely eliminating milk and milk products—the source of galactose—from an affected child’s diet. Galactose is also present in some fruits, vegetables, and sea products, such as seaweed. Doctors are not sure whether the small amounts in these foods cause problems in the long term. People who have the disorder must restrict galactose intake throughout life.
If galactosemia is recognized at birth and adequately treated, the liver and kidney problems do not develop, and initial mental development is normal. However, even with proper treatment, children with galactosemia often have a lower intelligence quotient (IQ) than their siblings, and they often have speech problems. Girls often have ovaries that do not function, and only a few are able to conceive naturally. Boys, however, have normal testicular function.
Hereditary Fructose Intolerance
In this disorder, the body is missing an enzyme that allows it to use fructose, a sugar present in table sugar (sucrose) and many fruits. As a result, a by-product of fructose accumulates in the body, blocking the formation of glycogen and its conversion to glucose for use as energy. Ingesting more than tiny amounts of fructose or sucrose causes low blood sugar levels (hypoglycemia), with sweating, confusion, and sometimes seizures and coma. Children who continue to eat foods containing fructose develop kidney and liver damage, resulting in jaundice, vomiting, mental deterioration, seizures, and death. Chronic symptoms include poor eating, failure to thrive, digestive symptoms, liver failure, and kidney damage.
The diagnosis is made when a chemical examination of a sample of liver tissue determines that the enzyme is missing. Treatment involves excluding fructose (generally found in sweet fruits), sucrose, and sorbitol (a sugar substitute) from the diet. Acute attacks respond to glucose given intravenously; milder attacks of hypoglycemia are treated with glucose tablets, which should be carried by anyone who has hereditary fructose intolerance.
Lipids metabolism
Fats (lipids) are an important source of energy for the body. The body’s store of fat is constantly broken down and reassembled to balance the body’s energy needs with the food available. Groups of specific enzymes help the body break down and process fats. Certain abnormalities in these enzymes can lead to the buildup of specific fatty substances that normally would have been broken down by the enzymes. Over time, accumulations of these substances can be harmful to many organs of the body. Disorders caused by the accumulation of lipids are called lipidoses. Other enzyme abnormalities result in the body being unable to properly convert fats into energy. These abnormalities are called fatty acid oxidation disorders.
Gaucher’s Disease
In Gaucher’s disease, glucocerebrosides, which are a product of fat metabolism, accumulate in tissues. Gaucher’s disease is the most common lipidosis. The disease is most common in Ashkenazi (Eastern European) Jews. Gaucher’s disease leads to an enlarged liver and spleen and a brownish pigmentation of the skin. Accumulations ofglucocerebrosides in the eyes cause yellow spots called pingueculae to appear. Accumulations in the bone marrow can cause pain and destroy bone.
Most people who have Gaucher’s disease develop type 1, the chronic form, which results in an enlarged liver and spleen and bone abnormalities. Most are adults, but children also may have type 1. Type 2, the infantile form, develops in infancy; infants with the disease have an enlarged spleen and severe nervous system abnormalities and usually die within a year. Type 3, the juvenile form, can begin at any time during childhood. Children with the disease have an enlarged liver and spleen, bone abnormalities, and slowly progressive nervous system abnormalities. Children who survive to adolescence may live for many years.
Many people with Gaucher’s disease can be treated with enzyme replacement therapy, in which enzymes are given intravenously, usually every 2 weeks. Enzyme replacement therapy is most effective for people who do not have nervous system complications.
Tay-Sachs Disease
In Tay-Sachs disease, gangliosides, which are products of fat metabolism, accumulate in tissues. The disease is most common in families of Eastern European Jewish origin. At a very early age, children with this disease become progressively retarded and appear to have floppy muscle tone. Spasticity develops and is followed by paralysis, dementia, and blindness. These children usually die by age 3 or 4. Tay-Sachs disease can be identified in the fetus by chorionic villus sampling or amniocentesis. The disease cannot be treated or cured.
Niemann-Pick Disease
In Niemann-Pick disease, the deficiency of a specific enzyme results in the accumulation of sphingomyelin (a product of fat metabolism) or cholesterol. Niemann-Pick disease has several forms, depending on the severity of the enzyme deficiency and thus accumulation of sphingomyelin or cholesterol. The most severe forms tend to occur in Jewish people. The milder forms occur in all ethnic groups.
In the most severe form (type A), children fail to grow properly and have multiple neurologic problems. These children usually die by age 3. Children with type B disease develop fatty growths in the skin, areas of dark pigmentation, and an enlarged liver, spleen, and lymph nodes; they may be mentally retarded. Children with type C disease develop symptoms in childhood, with seizures and neurologic deterioration.
Some forms of Niemann-Pick disease can be diagnosed in the fetus by chorionic villus sampling or amniocentesis. After birth, the diagnosis can be made by a liver biopsy (removal of a tissue specimen for examination under a microscope). None of the types of Niemann-Pick disease can be cured, and children tend to die of infection or progressive dysfunction of the central nervous system.
Fabry’s Disease
In Fabry’s disease, glycolipid, which is a product of fat metabolism, accumulates in tissues. Because the defective gene for this rare disorder is carried on the X chromosome, the full-blown disease occurs only in males. The accumulation of glycolipid causes noncancerous skin growths (angiokeratomas) to form over the lower part of the trunk. The corneas become cloudy, resulting in poor vision. A burning pain may develop in the arms and legs, and the person may have episodes of fever. People with Fabry’s disease eventually develop kidney failure and heart disease, although most often they live into adulthood. Kidney failure may lead to high blood pressure, which may result in stroke.
Fabry’s disease can be diagnosed in the fetus by chorionic villus sampling or amniocentesis. The disease cannot be cured or even treated directly, but researchers are investigating a treatment in which the deficient enzyme is replaced by transfusion. Treatment consists of taking analgesics to help relieve pain and fever. People with kidney failure may need a kidney transplant.
Fatty Acid Oxidation Disorders
Several enzymes help break fats down so that they may be turned into energy. An inherited defect or deficiency of one of these enzymes leaves the body short of energy and allows breakdown products, such as acyl-CoA, to accumulate. The enzyme most commonly deficient is medium chain acyl-CoA dehydrogenase (MCAD). MCAD deficiency is one of the most common inherited disorders of metabolism, particularly in people of Northern European descent.
Symptoms usually develop between birth and age 3. Children are most likely to develop symptoms if they go without food for a period of time (which depletes other sources of energy) or have an increased need for calories because of exercise or illness. The level of sugar in the blood drops significantly, causing confusion or coma. The child becomes weak and may have vomiting or seizures. Over the long term, children have delayed mental and physical development, an enlarged liver, heart muscle weakness, and an irregular heartbeat. Sudden death may occur.
Some states screeewborns for MCAD deficiency with a blood test. Immediate treatment is with intravenous glucose. For long-term treatment, the child must eat often, never skipping meals, and consume a diet high in carbohydrates and low in fats. Supplements of the amino acid carnitine may be helpful. The long-term outcome is generally good.
Caring for Families, Developmental Theories
From conception to death, individuals are constantly changing. Physical growth, psychological development, emotional maturation, cognitive development, moral development, and spiritual growth occur throughout life. Progression through each developmental stage influences health status. A thorough understanding of developmental concepts is essential for professional quality nursing practice. This chapter discusses the changes occurring in each stage of the life cycle.
Fundamental Concepts of Growth And Development
Development occurs continuously through the life span. Adults continue to have transition periods during which growth and development occur.
Growth is the quantitative (measurable) changes in physical size of the body and its parts, such as increases in cells, tissues, structures, and systems. Examples of growth are physical changes in height, weight, bone density, and dental structure. Even though growth is not a steady process through the life cycle, growth patterns can be predicted. Variations in growth, such as rapid increases contrasted with slower rates of physical change, occur with each individual. Rapid growth is most common in the prenatal, infant, and adolescent stages.
Development refers to behavioral changes in functional abilities and skills. Thus, developmental changes are qualitative, that is, not easily measured.
Maturation is the process of becoming fully grown and developed and involves physiological and behavioral aspects of an individual. Maturation depends on biological growth, functional changes, and learning (assimilation of information with a resultant change in behavior). During each developmental stage of the life cycle, certain goals (developmental tasks) must be achieved. These developmental tasks set the stage for future learning and adaption.
The critical period is the time of the most rapid growth or development in a particular stage of the life cycle. During these critical periods, an individual is most vulnerable to stressors of any type. Growth, development, maturation, and learning are interdependent processes. For learning to occur, the individual must be mature enough to grasp the concepts and make required behavioral changes. Cognitive maturation precedes learning. Physical growth is also a prerequisite for many types of learning; for example, a child must have the physical ability to control the anal sphincter before toilet training skills are learned.
Principles of Growth and Development
All persons have individual talents and abilities that contribute to their development as unique entities. There are no absolute rules in predicting the exact rate of development for an individual. However, some general principles relate to the growth and development of all humans.
The sequence of development is predictable even though the emergence of specific skills varies with each person. For example, not all infants roll over at the same age, but most roll over before they crawl.
Factors Influencing Growth and Development
Multiple factors such as heredity, life experiences, health status, and cultural expectations influence a person’s growth and development. The interaction of these factors greatly influences how an individual responds to everyday situations; the choices a person makes regarding health behaviors are also greatly determined by these factors.
Heredity A complex series of processes transmits genetic information from parents to children. The genetic composition of an individual determines physical characteristics such as skin color, hair texture, facial features, body structure, as well as a predisposition to certain diseases (i.e., Tay-Sachs, sickle cell anemia). Heredity is a genetic blueprint from which an individual grows and develops; it determines to a great extent the rate of physical and mental development.
Life Experiences A person’s experiences can also influence the rate of growth and development. For example, contrast the differences in physical growth rates between a child whose family can afford food, shelter, and health care and a child whose family has little, if any, resources. The child who is poor has a higher risk of experiencing physical and mental lags in growth and development. Another example of the influence of life experiences, is an elderly person who is enjoying retirement, has an adequate income, and an active support system. If this individual had an impairment in any of these variables, psychological development would likely be affected in a negative way.
Health Status Individuals experiencing wellness are progressing normally along the life cycle. However, illness or disability can interfere with the achievement of developmental milestones. Individuals with chronic conditions will often meet developmental milestones but with a time delay.
Cultural Expectations Society expects people to master certain skills in each developmental period. The age at which an individual masters a particular task is determined in part by culture. For example, the time for mastery of toilet training is greatly influenced by cultural norms. The following are examples of how societal expectations can either promote or hinder one’s growth and development:
• A child who grows up in an economically deprived home may receive inadequate food, shelter, emotional nurturing, or intellectual stimulation with resultant impairments in physical, psychosocial, and cognitive development.
• A woman may not be expected to fully use her intellectual abilities, thus she has altered cognitive development.
• A man may be discouraged from showing tenderness and nurturing behaviors; such discouragement results in dysfunctional psychosocial development.
Metabolism is carried out by chemical substances called enzymes, which are made by the body. If a genetic abnormality affects the function of an enzyme or causes it to bedeficient or missing altogether, various disorders can occur. The disorders usually result from an inability to break down some substance that should be broken down—so that some intermediate substance that is toxic builds up—or from an inability to produce some essential substance. Metabolic disorders are classified by the particular building block that is affected.
Some hereditary disorders of metabolism (such as phenylketonuria and the lipidoses) can be diagnosed in the fetus using amniocentesis or chorionic villus sampling. Usually, the diagnosis of a hereditary disorder of metabolism is made using a blood test or an examination of a tissue sample to determine whether a specific enzyme is deficient or missing.
Amino acids are the building blocks of proteins and have many functions in the body. Hereditary disorders of amino acid processing can be the result of defects either in the breakdown of amino acids or in the body’s ability to get the amino acids into cells. Because these disorders produce symptoms early in life, newborns are routinely screened for several common ones. In the
Amino acid metabolism
Phenylketonuria
Phenylketonuria (PKU) is a disorder that causes a buildup of the amino acid phenylalanine, which is an essential amino acid that cannot be synthesized in the body but is present in food. Excess phenylalanine is normally converted to tyrosine, another amino acid, and eliminated from the body. Without the enzyme that converts it to tyrosine, phenylalanine builds up in the blood and is toxic to the brain, causing mental retardation.
PKU occurs in most ethnic groups. If PKU runs in the family and DNA is available from an affected family member, amniocentesis or chorionic villus sampling with DNA analysis can be performed to determine whether a fetus has the disorder.
Most affected newborns are detected during routine screening tests. Newborns with PKU rarely have symptoms right away, although sometimes an infant is sleepy or eats poorly. If not treated, affected infants progressively develop mental retardation over the first few years of life, which eventually becomes severe. Other symptoms include seizures, nausea and vomiting, an eczema-like rash, lighter skin and hair than their family members, aggressive or self-injurious behavior, hyperactivity, and sometimes psychiatric symptoms. Untreated children often give off a “mousy” body and urine odor as a result of a by-product of phenylalanine (phenylacetic acid) in their urine and sweat.
To prevent mental retardation, phenylalanine intake must be restricted (but not eliminated altogether as people need some phenylalanine to live) beginning in the first few weeks of life. Because all natural sources of protein contain too much phenylalanine for children with PKU, affected children cannot have meat, milk, or other common foods that contain protein. Instead, they must eat a variety of phenylalanine-free processed foods, which are specially manufactured. Low-proteiatural foods, such as fruits, vegetables, and restricted amounts of certain grain cereals, can be eaten.
