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Mental function.

June 19, 2024

Mental function. Localization of Function centers in brain cortex. Syndromes of lesion.

Membranes of the Brain and Spinal Cord. Cerebrospinal Fluid. Physiology of the Cerebrospinal Fluid. Technics of Lumbar Puncture. Pathology of the Cerebrospinal Fluid. Meningeal and Cerebrospinal Fluid’s Hypertension Syndromes

Scientists consider that our brain is the most complicated mechanism which has ever been constructed. The weight of the human brain is from one to two kg. It has a volume of about 3.21 litres and consists of about 12 billion cells. Each cell is connected to the other directly or indirectly by nerve fibers. The brain is the centre of a wide system of communication. The nervous cells of the cortex are the most delicate and younger of all the cells of the human body. To estimate the function of different areas of the brain many experiments have been carried out by the investigators.

Anatomically cortex is a plate of grey substance that covers external surface of hemispheres. There are external surface, internal one and base of hemispheres. There is sulcus cerebri centralis on the external surface that separates Frontal and Parietal lobes. There is also sulcus cerebri lateralis that separates Temporal lobe from Parietal and Frontal one. Occipital lobe is separated from Parietal and Temporal one by means of sulcus that continues sulcus parietooccipitalis. Thus there are four lobes on the external surface of brain. They are Frontal, Parietal, Temporal and Occipital one.

External surface

There are three gyri on the external surface of the Frontal lobe. They are upper, middle and lower one. And they are separated by sulcus frontalis superior et inferior.

Parietal lobe is divided by sulcus interparietalis into upper and lower parietal lobes. The lower one contains gyrus supramarginalis and gyrus angularis.

Temporal lobe is divided by sulcus temporalis into upper, middle and lower temporal gyri.

Internal surface

On the internal surface Occipital lobe is separated from the Temporal one by means of sulcus parietooccipitalis. There is Cuneus which is located a little bit upper then fissura calcarina and gyrus Lingualis which is located a little bit lower then fissura calcarina. There is also gyrus Hyppocampi in the anterior part of the temporal lobe.

The basis of hemispheres

There are frontal lobes, occipital and temporal one, bulbus and tractus olfactorii, hiasma opticum, peduncles, pons, oblongate brain and cerebellum.

The microscopic structure of cortex includes six layers. They are:

1. molecular level under the meninges which has a little cortical cells

2. external level which has a lot of small cells

3. the level of small and middle pyramidal cells

4. internal level

5. ganglion level consists of big pyramidal cortical cells

6. polymorphic cells level near the white matter

In cortex of the brain there are 10 or 13 billions of nervous cells. Among them the 8 bill cells have big and middle size (3-5-6 levels) and near the 5 bill have small size (from different levels). Beside the cortex cells, there are many other cells of glia (microgliocytes, oligodendrocytes, astrocytes).

There are three types of cortex fibers:

1. conductive (for example, Pyramidal tract) – to connect cortex of the brain with other underlying structures of nervous system

2. associative (for example, fibrea arcuatae, fasciculus uncinatus) – to connect different part of the brain cortex together.

3. commissural (for example, corpus callosum, commissural anterior) – to connect right and left hemispheres of the brain together.

The main functions of brain cortex:

1. It is the top level of CNS

2. It provides active movements. It is the source of motor way.

3. Cortex is the structure of conscious reception of sensory stimuli.

4. It is anatomical basis for conditioned reflexes.

5. It is the structure of analysis and synthesis of all stimuli from internal organs and environment.

6. It provides our individual experience.

7. It is the main structure responsible for mental activity and language.

8. It regulates and controls the other structures of nervous system.

Frontal lobe Localization of functions

Frontal lobe provides motor activity, motor mechanisms of speech, behaviour, mental activity and memory of human being.

1. Precentral gyrus provides motor activity of the opposite side of the body.

The projection of certain muscle groups is represented vice verse to its location on the body:

· The upper part of precentral gyrus – is responsible for the lower extremity;

· The middle part of precentral gyrus – is responsible for the upper extremity;

· The lower part of precentral gyrus – is responsible for the muscles of face, tongue, pharynx, and larynx.

2. Posterior part of upper frontal gyrus is the center of straight walking and straight standing. It provides movements of the body and is connected with opposite hemisphere of cerebellum.

3. Posterior part of middle frontal gyrus is the center of eyes movements in the opposite direction. It is connected with the fasciculus longitudinalis posterior in the brain stem.

4. The center of writing is located not far from the center of head and eyes movements in the opposite direction.

5. The center of Broca or the center of motor expressive speech is situated in the posterior part of left lower frontal gyrus.

The main symptoms of lesion and irritation

1. The lesion of precentral gyrus causes central paralysis and paresis. Usually it manifests as monoparesis or monoplegia on the opposite side.

2. The irritation of precentral gyrus causes Jackson’s epilepsy in the certain muscular groups (according to the involved part of the brain cortex). It occurs on the opposite side and isn’t associated with the loss of consciousness.

3. The irritation of posterior part of upper lobe gyrus causes sudden seizures of the opposite muscles with the loss of consciousness.

4. The irritation of posterior parts of middle frontal gyrus causes movements of head and eyes in the opposite direction.

5. The irritation of opercular part of lower frontal gyrus causes rhythmical chewing, licking and smacking of one’s lips.

6. The lesion of anterior parts of upper and middle frontal gyri causes frontal ataxia. The last one manifests as astasia (inability to standing) and abasia (inability to walking without paresis). There is fox-like gait.

7. The lesion of posterior parts of middle frontal gyrus causes gaze into the side of lesion. It is called cortical gaze paralysis.

8. The lesion of posterior part of lower frontal lobe (the center of Broca) causes Broca’s aphasia.

Broca’s aphasia occurs in case of motor encoding area involved and means the impairment of spontaneous speech, repetition, reading aloud, naming (but recognizes object) and writing, retained the comprehension of both spoken and written language function. Testing:

1. Speech is slow, nonfluent, produced with great effort, and poorly articulated. There is marked reduction of total speech, which may be “telegraphic” with the omission of small words or endings.

2. Comprehension of written and verbal speech is good.

3. Repetition of single words may be good, though it is done with great effort; phrase repetition is poor, especially phrases containing small function word (eg, “no if’s, and’s, or but’s”).

4. The patient always writes aphasically.

5. Object naming is usually poor although it may be better than spontaneous speech.

6. Hemiparesis (usually greater in the arm than in the leg) is present, as the motor cortex is close to Broca’s area.

7. The patient is aware of his deficit; he is frustrated and frequently depressed.

8. Interestingly, the patient may be able to hum a melody normally. Curses or other ejaculatory speech may be well articulated.

According to Lurie there are three types of motor aphasia. They are:

1. afferent

2. efferent

3. dynamic

1. Afferent motor aphasia is associated with the lesion of lower parts of postcentral gyrus which provide innervation of oral muscles. In this case articulation of sounds suffers. That means the loss of automatically speech, repetition, naming. This kind of aphasia is connected with oral apraxia.

2. Efferent motor aphasia is Broca’s aphasia. It means it occurs at lesion of the center of Broca. In this case articulation is preserved. But the patient cannot spell some sounds, words and phrases. At completely aphasia the patient doesn’t speak at all. At partial aphasia he uses only nouns.

3. Dynamic motor aphasia is usually caused by lesion of cortical zone in front of Broca’s center. For this type of aphasia aspontanic speech is typical. The patient refuses to speech in active manner. But he is able to repeat certain sentences, words, answer the questions.

9. Agraphia – the loss of ability to write. The patient with agraphia will be unable to take dictation, to copy letters he sees, or to imitate letters or words that are written for him. Milder degrees of agraphia will show up as poorly formed letters, reversals of letters, and substitutions.

10. Subcortical reflexes can be observed at frontal lobe lesion.

11. Grasp phenomena. The patient grasps everything that touches his palm.

12. Counteraction phenomena. The patient counteracts the doctor in his attemp to change the patient’s extremities position.

13. Mental disorders are developed at diffuse lesion of frontal lobe or the lesion of polus of frontal lobe. It is known as frontal mental disorders.

It manifests as

· apathy

· torpid mental reactions

· slackening of memory and attention

· the absence of criticism

· inadequate appreciation of disease severity

· euphoria

· gross humor

· the patients are childish

· untidiness

14. Sometimes general hypokinesia can be observed, because of extrapyramidal system lesion.

15. Frontal apraxia. It is a disturbance of purposeful movement.

Parietal lobe

The main function of Parietal lobe is associated with space, time orientation and analysis of information from sensory stimuli.

Localization of functions

1. There is nucleus of general sensitivity analyser in the postcentral gyrus. Sensitivity from lower extremities is represented in upper parts of postcentral gyrus, sensitivity from upper extremities is represented in middle parts of postcentral gyrus, and sensitivity from face is represented in lower parts of postcentral gyrus.

2. Complicated kinds of sensitivity are located in upper parietal lobe. They are stereognosis, sense of localization, discrimination, sense of weight, pressure, position of different parts of the body in space.

3. The center of praxis is situated in gyrus supramarginalis. The center of reading and calculation are located in the gyrus angularis.

The main symptoms of parietal lobe lesion

1. The lesion of postcentral gyrus causes conductive sensory disorders on the opposite side of the body. They are called monoanesthesia.

2. The irritation of postcentral gyrus causes the attacks of sensory Jackson’s epilepsy. That means parasthesia in certain extremities of the opposite side.

3. The lesion of upper parietal lobe causes bathyanesthesia, the loss of light touch sense, the sense of localization and discrimination, asthereognosis.

4. The lesion of upper parietal lobe can cause

· Autotopagnosia (somatotopagnosia) includes disturbances in recognition of the patient’s own body or body parts.

· Pseudomelia – the patient has a sensation of presence (pseudopolymelia) or the absence (pseudoamelia) of additional extremities.

· Anosognosia is lack of awareness or denial of the existence of disease. An obvious example is a denial by the hemiplegic patient that he is paralyzed.

These symptoms can be observed at right parietal lobe lesion.

5. Apraxia occurs at lesion of gyrus supramarginalis lesion of the dominant hemisphere.

Apraxia – is a disturbance of purposeful movements which is not due to elementary motor or sensory impairments. Apraxia is divided on:

1. motor or kinetic

2. ideational

3. constructional and dressing

Kinetic Apraxia The patient has lost the ability to make fine skilled movements such as finger wiggling, opposition, writing, or piano playing.

Ideational Apraxia In ideational apraxia there is inability or failure to comprehend, develop, or retain the concept of what is desired (step 1). Such a patient will have difficulty in understanding what is desired and will fail to complete the desired act. This becomes apparent when he is asked to carry out a series of simple acts such as “Put the pencil in the cup and hand me the matches.” After requiring that the request should be repeated, he may pick up the pencil and fail to do anything more. The patient with ideational apraxia has lost the idea.

Ideokinetic Apraxia. Another common form of apraxia is known as “ideokinetic” or “ideomotor” apraxia. This occurs when there is a break in transmitting or converting the idea into the appropriate motor act (as in step 2). Despite knowing what is desired, the patient is unable to carry out a desired complex performance. He may, for example, hesitantly touch his forehead when asked to touch his nose. He may recognize a comb but be unable to use one to comb his hair when asked. Then, surprisingly, he may carry out the same acts automatically that he is unable to perform volitionally on request. Perseveration of a previous motor act is common in such patients. Ideokinetic apraxia generally subsides spontaneously with the passage of time.

Constructional and Dressing Apraxia Constructional apraxia may be demonstrated by having the patient try to copy geometric forms or draw the face of a clock. Further testing includes having the patient try to arrange sticks in a specific pattern or to arrange Kohs blocks in a desired design. Dressing apraxia is tested simply by asking the patient to put on a shirt or bathrobe. To increase the difficulty of the test, one arm of the garment can be turned inside out prior to the test.

6. Alexia and acalculia occurs at lesion of gyrus angularis of the dominant hemisphere.

That means the patient is not able to read, write (optical agraphy). Acalculia means one is not able to count.

Temporal lobe Localization of functions

This lobe receives information from auditory, smell, taste stimuli and speech sounds.

1. Auditory zone is located in upper temporal gyrus.

2. Smell zone is located in gyrus parahippocampalis.

3. Taste zone is located not far from the smell one.

These zones of each hemisphere have connections with both – right and left receptors.

4. Wernicke center (the center of sensory speech) is located in the left upper temporal lobe.

5. The center of mnestic speech (the center of naming) is situated in posterior parts of temporal and lower parts of parietal lobes.

The main symptoms of lesion

1. Wernicke’s aphasia occurs in case of auditory association area involved and means the impairment of comprehension of spoken language, repetition of spoken language, naming comprehension of written language, spontaneous speech, the spoken language is fluent but impaired (jargon). Testing:

1. Speech is fluent with normal rhythm and articulation, but it conveys information poorly because of circumlocutions, use of empty words and incorrect words (paraphasic errors).

2. The patient uses wrong words and sounds –ie, makes paraphasic errors (“treen” for train; “here is my clover” for here is my hand).

3. The patient is unable to comprehend written or verbal speech.

4. The content of writing is abnormal, as is speech, though the penmanship may be good.

5. Repetition is poor.

6. Object naming is poor.

7. Hemiparesis is mild or absent, since the lesion is far from the motor cortex. A hemianopsia or quadrantopsia may be present.

8. Patients may not realize the nature of their deficit and often are not depressed in the acute stage.

2. Anomic (nominal) aphasia is impairment of naming objects and spontaneous speech. Spoken language fluent but rambling and vague. Retained the repetition, comprehension of both spoken and written language.

1. This type of aphasia may be seen at small lesions in the angular gyrus, toxic or metabolic encephalopathy, or with focal space-occupying lesions far from the speech area, but which exert pressure effects.

2. Speech is fluent but conveys information poorly because of paraphasic errors and circumlocutions (written language is impaired in the same way). Even though this aphasia is termed anomic aphasia (difficulty iaming objects), anomia is not unique to this type of aphasia.

3. The patient can understand both written and spoken speech.

4. There is no hemiplegia.

5. Comprehension and repetition are normal.

3. Semantic aphasia occurs at lesion of temporal-parietal-occipital border of left hemisphere. The patients cannot realize the difference between “The brother of the father“and “the father of the brother “.

4. Lesion of the temporal lobe tends to produce quadrantic defects which extend to the point of fixation without macular sparing. Lesion of the temporal lobe around the inferior horn of the lateral ventricle give rise to defects in upper quadrants of the homonymous half-fields on the side opposite the lesion.

5. Lesion of the temporal lobe may produce temporal ataxia.

6. The attacks of vestibular-cortical dizziness, associated with auditory hallucinations.

7. Auditory verbal agnosia. Such patients can read, speak, and write appropriately but are unable to understand or respond to what is said to them.

8. Smell and taste agnosia.

9. Irritative lesions of the temporal lobes produce the auditory, smell, and taste hallucinations. Usually it is the first symptom of epileptic attack.

10. Petit mal is a typical symptom of temporal lobe lesion. Usually it manifests as short lasting loss of consciousness.

11. Development of sleep like state is very typical for temporal lobe lesion. In this case it seems to the patient that everything around him is unreal, unnatural, but at the same time it seems to him that he has seen it before.

Occipital lobe Localization of functions

Visual zone is located in the internal surface of occipital lobes in the depth of fissura calcarine. The region above the sulcus calcarinus is called cuneus and it represents the lower quadrants of visual fields. The region below the sulcus calcarinus is called gyrus lingualis and it represents upper quadrants of visual fields.

The symptoms of lesion

1. Quadrant hemianopsia. At cuneus lesion the lower quadrant visual fields are lost. At gyrus lingualis lesion the upper visual fields are lost.

2. Homonymous hemianopsia of opposite visual fields occurs at lesion in fissura calcarina on the internal surface of occipital lobe.

3. Scotoma is a defect within the visual fields.

4. Hemiambliopia – decreased vision.

5. An early symptom of visual analyzer lesion is the loss of color sense in the opposite visual fields.

6. At lesion of sulcus calcarinus seldom cause total blindness. Usually central or macular vision of both eyes is preserved.

The lesion of convex surface of occipital lobe causes next symptoms:

7. Visual agnosia: Visual object recognition is simply the ability to recognize objects that are seen. Formal testing may not be necessary if it is apparent that the patient caame and use various objects. If there is any doubt, his ability can be tested by presenting him with one object and having him pick out the matching object from a group; or, for convenience, pictures may be used instead of objects.

8. Metamorphopsia means disability to recognize objects’ contours. It seems to the patient that they are destroyed, damaged.

9. Irritation of the occipital lobe can cause visual hallucinations. Thus simple hallucination (fotoma) occurs at irritation of sulci calcarini. They manifest as light or coloured phenomena, for example flash, fire, shadow.

10. Complex hallucinations occur at external surface of occipital lobe irritation. They manifest as figures, moving subjects. As a rule they are aura of epileptic attack.

Thus for the right hemisphere lesion three groups of symptoms are typical:

· body scheme agnosia (autotopagnosia, anosognosia, psudomelia)

· mental disorders (euphoria, memory impairment, confabulations)

· parakynesis (involuntary movements of healthy extremitie – automatic gesticulation).

For the left hemisphere lesion the next symptoms are typical:

· aphasia

· agraphia

· alexia

· acalculia

· apraxia (kinetic, ideational, constructional).

Mental Status Examination

Speech

Since most of the mental status examination requires verbal communication, the first task in assessing mental status should be an assessment of language functioning. We wish chiefly to consider language, which may be defined as the understanding and production of individual words and groupings of words for the communication of ideas and feelings. The exchange of information between the patient and the examiner has already given the examiner an opportunity to make an assessment of the patient’s ability to communicate and to express ideas.

Broca’s aphasia occurs in case of motor encoding area involved and means the impairment of spontaneous speech, repetition, reading, aloud, naming (but recognizes object) and writing, retained the comprehension of both spoken and written language function. Testing:

2. Comprehension of written and verbal speech is good.

4. The patient always writes aphasically.

5. Object naming is usually poor although it may be better than spontaneous speech.

6. Hemiparesis (usually greater in the arm than in the leg) is present, as the motor cortex is close to Broca’s area.

7. The patient is aware of his deficit; he is frustrated and frequently depressed.

8. Interestingly, the patient may be able to hum a melody normally. Curses or other ejaculatory speech may be well articulated.

Wernicke’s aphasia occurs in case of auditory association area involved and means the impairment of comprehension of spoken language, repetition of spoken language, naming comprehension of written language, spontaneous speech, the spoken language is fluent but impaired (jargon). Testing:

1. Speech is fluent with normal rhythm and articulation, but it conveys information poorly because of circumlocutions, use of empty words and incorrect words (paraphasic errors).

2. The patient uses wrong words and sounds –ie, makes paraphasic errors (“treen” for train; “here is my clover” for here is my hand).

3. The patient is unable to comprehend written or verbal speech.

4. The content of writing is abnormal, as is speech, though the penmanship may be good.

5. Repetition is poor.

6. Object naming is poor.

7. Hemiparesis is mild or absent, since the lesion is far from the motor cortex. A hemianopsia or quadrantopsia may be present.

8. Patients may not realize the nature of their deficit and often are not depressed in the acute stage.

Anomic (nominal) aphasia is impairment of naming objects and spontaneous speech. Spoken language fluent but rambling and vague. Retained the repetition, comprehension of both spoken and written language.

3. The patient can understand both written and spoken speech.

4. There is no hemiplegia.

5. Comprehension and repetition are normal.

Defects of reading follow a pattern generally similar to that discussed under defects of listening. Before testing for such defects, however, it is necessary to take into consideration the patient’s visual acuity. In addition, it is important to check for a visual field defect that may interfere with reading, especially if the defect is thought to be of recent origin. More subtle changes, such as indifference to a homonymous field or spatial disorientation, also may need to be investigated. Such deficits may cause the patient to lose his place while reading. Severe defects of reading with inability to recognize letters or words have been known as visual verbal agnosia, alexia, or word blindness. Testing for these disorders may be done by placing a card containing large printed letters in front of the patient and asking him to point to various letters, one at a time. If the patient passes this test he may be presented with a list of single words; the examiner may name certain words at random and ask the patient to point to the words one at a time. Patients with mild defects demonstrate difficulties only with sentences or paragraphs. Sentences requiring that the patient point to various objects in the room are presented on cards and the patient is asked to read each one silently and to carry out the instruction. Finally, the patient may be given a printed paragraph which he is asked to read silently and to remember as much as possible. He is then requested to tell the story he has just read.

Apraxia of the motor act of writing also may occur. It is comparable to apraxia of speech and is one form of agraphia. It is, of course, unlikely that a patient will be in a situation where he will write automatically in the way the oral verbal apractic patient will speak automatically. The patient with agraphia will be unable to take dictation, to copy letters he sees, or to imitate letters or words that are written for him. Milder degrees of agraphia will show up as poorly formed letters, reversals of letters, and substitutions.

Calculation It is a matter of dispute whether arithmetic calculation dysfunction is an aphasic or a higher integrative disorder. Regardless of where it falls in terms of its classification, aphasic patients as well as those with intellectual deficit from diffuse brain damage frequently have difficulty with arithmetic. The ability to calculate may be tested:

Numerical relationships 2+7= 18+27= 12×12= 9 – 4 = 29 – 14 = 12 X 13 =

Astereognosia – the patient is unable to identify object by touch. Stereognosis is the ability to identify an object by handling it.

Visual Object Agnosia Visual object recognition is simply the ability to recognize objects that are seen. Formal testing may not be necessary if it is apparent that the patient caame and use various objects. If there is any doubt, his ability can be tested by presenting him with one object and having him pick out the matching object from a group; or, for convenience, pictures may be used instead of objects.

Auditory Verbal Agnosia Rare cases have been reported of patients who have an intact central language process but an isolated loss of word recognition, or so-called auditory verbal agnosia. Such patients can read, speak, and write appropriately but are unable to understand or respond to what is said to them.

Smell and taste agnosia. The patient is asked to recognize well-known substances by smelling and tasting them. He is not able to do it in case of smell and taste agnosia.

Autotopagnosia (somatotopagnosia) includes disturbances in recognition of the patient’s own body or body parts. It is due to lesions of the posterior-inferior parietal lobe in the region of the interparietal sulcus of the dominant hemisphere or to a subcortical lesion isolating this area from the thalamus. It is often associated with acalculia, visual verbal agnosia, or anosognosia. Autotopagnosia may be limited to one part of the body or may be more general, involving relationships of the body as a whole. The limited form includes lack of recognition of one half of the body or one extremity and inability to recognize and name individual fingers (finger agnosia) or other body parts. In mild forms the patient may have a sense of distortion of the involved parts of the body and disturbances of laterality. This may be tested by asking the patient to name various parts of his own body and to identify right and left. It is often manifested by inattention to or lack of use of the part.

Apraxia – is a disturbance of purposeful movement which is not due to elementary motor or sensory impairments. It occurs at lesions of the posterior parietal region of the dominant hemisphere usually in association with aphasic syndromes.

Apraxia is divided on:

1. motor or kinetic

2. ideational

3. constructional and dressing

Ideational Apraxia In ideational apraxia there is inability or failure to comprehend, develop, or retain the concept of what is desired (step 1). It is usually due to general suppression or loss of cerebral function and resembles extreme absent-mindedness. Such a patient will have difficulty in understanding what is desired and will fail to complete the desired act. This becomes apparent when he is asked to carry out a series of simple acts such as “Put the pencil in the cup and hand me the matches.” After requiring that the request should be repeated, he may pick up the pencil and fail to do anything more. The patient with ideational apraxia has lost the idea.

Ideokinetic Apraxia. Another common form of apraxia is known as “ideokinetic” or “ideomotor” apraxia. This occurs when there is a break in transmitting or converting the idea into the appropriate motor act (as in step 2). This form of apraxia occurs most commonly at lesions of the major hemisphere at the junction of the temporal, parietal, and occipital lobes or its connections with the frontal lobes. The phenomenon is usually associated with a hemiplegia opposite the lesion, and the apractic disability affects the “good” extremities. Despite knowing what is desired, the patient is unable to carry out a desired complex performance. He may, for example, hesitantly touch his forehead when asked to touch his nose. He may recognize a comb but be unable to use one to comb his hair when asked. Then, surprisingly, he may carry out the same acts automatically that he is unable to perform volitionally on request. Perseveration of a previous motor act is common in such patients. Ideokinetic apraxia generally subsides spontaneously with the passage of time.

Kinetic Apraxia Failure of the third step produces kinetic apraxia. This phenomenon is considered to be due to a lesion of the premotor frontal cortex, and the disability is limited to one extremity or a part of it. There is no actual weakness, and the patient is able to use the extremity for gross movements and automatically. He has lost the ability to make fine skilled movements such as finger wiggling, opposition, writing, or piano playing.

During the history taking and the carrying out of the neurologic examination one should note the general mobility of the patient and whether he is hyperkinetic or relatively immobile. Observations for awkwardness while carrying out relatively complicated acts such as dressing and undressing should be made. It should be noted whether the patient has difficulty in conceiving how to hop, how to touch his nose, and how to wiggle his fingers or tap his toes.

Specific Testing Observations on the motor-pattern performance of a patient are made during the various parts of the neurologic examination when the patient is asked to show his teeth, stick out his tongue, wiggle his fingers, tap his toes, hop, walk tandem, touch his nose, and so forth. All these tests are performed in conjunction with the testing of motor power and coordination. Further study of motor patterns may require utilization of the following tests. These suggested tests may be modified or amplified according to the requirements of the patient.

Instruct the patient by word or gesture to:

1. Touch his nose.

2. Drink from a glass or paper cup.

3. Use a folder of matches.

Get the patient to follow simple spoken directions. Say to the patient:

1. Close your eyes.

2. Point to your nose and your chin.

3. Put the pencil in the glass (or paper cup) and hand me the matches.

4. Repeat after me, “I bought a new hat, a pair of shoes, and a white shirt.”

Constructional and Dressing Apraxia Lesions of the posterior parietal region of the nondominant hemisphere may impair performances related to spatial concepts. Such lesions produce special forms of apraxia. Constructional apraxia may be demonstrated by having the patient try to copy geometric forms or draw the face of a clock. Further testing includes having the patient try to arrange sticks in a specific pattern or to arrange Kohs blocks in a desired design. Dressing apraxia is tested simply by asking the patient to put on a shirt or bathrobe. To increase the difficulty of the test, one arm of the garment can be turned inside out prior to the test.

Level of consciousness

1. Amnesia is memory impairment. It manifest as disability to preserve and restore previous knowledge.

2. Anterograde amnesia is a kind of memory impairment that concerns those events which happened just after consciousness disorder or psychic disorders.

3. Retrograde amnesia is a kind of memory impairment that concerns those events which have happened before consciousness disorder or psychic disorders.

4. Somnolence (Grade 1) The somnolent patient may be roused by various stimuli and will then make appropriate motor and verbal responses. When aroused, such a patient may be clear mentally but often is somewhat confused. Illusions, delusions, hallucinations, or delirium is common in such patients. In somnolence the patient generally drifts back to sleep when the stimulus ceases. Spontaneous movements and spontaneous speech or muttering are usual. The patient may be restless or may show paucity of movement.

5. Stupor (Grade 2) In stupor the patient will often have considerable spontaneous movement. He will respond to pain, tactile stimuli, loud auditory stimuli, or bright lights. The usual response is one of withdrawal, but occasionally a combative response may be elicited. Repeated and persistent stimuli will often rouse the patient to the point where he will respond briefly to questions or follow very simple commands. Spontaneous movements are common, and there may be twitching or picking motions. Control of bowel and bladder is variable.

6. Semicoma (Grade 3) At this level organized withdrawal or other. Simple adaptive movements occur in response to painful stimuli. Persistent tactile stimulation or shaking may produce a similar response. Verbal responses are limited to groaning or muttering. As soon as the stimulus ceases, the patient resumes his previous status. Reflex responses are present, but the patient is usually incontinent. Spontaneous movements are uncommon unless the patient is roused.

7. Deep Coma (Grade 4) In deep coma the patient makes no response to any stimulus or at most will move slightly to a very painful stimulus. Effective stimuli which may produce a response are limited generally to deep pain. This may be elicited by pressure over the styloid process in the neck, the supra-orbital nerve, the root of the fingernails, or periosteal surfaces of bone. Squeezing muscle bellies or tendons have a similar effect. Care must be observed not to harm the patient while producing the painful stimulus and, if relatives are present, it is wise to explain the need for the procedure. The pectoralis muscle may be squeezed unobtrusively without giving the appearance of harming the patient. The muscle-stretch reflexes, Babinski signs, corneal reflex, and even pupillary responses tend to disappear. There are no spontaneous movements, and the musculature is flaccid. The patient is incontinent of urine and feces. The pulse is usually rapid, the respirations are periodic, and the blood pressure may tend toward shock levels.

8. When confusion becomes combined with illusions, hallucinations, and severe anxiety or panic, the result is delirium.

9. Dementia is severe psychic processes impairment without involving cheerfulness.

10. Pseudowakeful States. Of particular interest clinically are the pseudowakeful states. When this condition is fully developed, the patient lies or sits with eyes open but fails to follow objects or lights. Similarly he fails to turn his eyes toward a noise. He remains mute. In less marked instances, the patient may follow objects or people slowly with his eyes; he may turn slowly toward a sound and look as if he were about to speak but does not. This appearance has been described as a “reptilian stare.” The patient responds to external stimuli in a manner similar to that of the patient in stupor or semicoma. Some patients in a pseudowakeful state are restless and hyperkinetic, and pluck at the bedclothes.

11. Some patients in a pseudowakeful state lack spontaneous movements and speech (akinetic mutism). The pseudowakeful states may be seen in coma of “toxic” origin or in focal lesions implicating the diencephalon, either primarily or secondarily by pressure.

EXAMINATION OF THE ACUTELY COMATOSE PATIENT

The evaluation of the acutely comatose patient is a common situation encountered in the emergency room. The examination should begin by attempting to obtain information from those who are familiar with or who have had some contact with the patient, including relatives, police, and the emergency services team. A history of hypertension, diabetes, drug abuse, epilepsy, or recent head trauma is invaluable.

Immediate Action

Although the patient may have already been seen by others in the emergency department, the examiner should check to see whether immediate action is necessary. The patient’s airway should be clear, and there should be no signs of respiratory obstruction. If there is evidence of respiratory failure, the patient should be intubated and placed on a mechanical ventilator. The comatose patient may be hypotensive or become hypotensive at any time. This complication should be immediately treated with fluid challenge, transfusions, or, if necessary, dopamine infusion. Hypotension is rarely caused by intracranial lesions. If the patient is in cardiac arrest or showing severe cardiac arrhythmias, the cardiopulmonary resuscitation team should be called immediately.

Stabilization

The neurological evaluation begins by ensuring that the patient’s condition is stable. Two peripheral intravenous lines, one measuring central venous pressure (CVP) and the other for the administration of intravenous fluids, should be inserted. A Foley catheter is passed into the bladder, and a nasogastric tube passed into the stomach. A cervical collar is applied until a cervical fracture can be ruled out by radiography. A blood sample is obtained and sent for electrolytes, glucose, blood urea nitrogen, serum creatinine, complete blood count, a drug screen, liver function tests, and a blood alcohol level in cases of suspected alcohol intoxication. Arterial blood gases are ordered if hypoxia is suspected. The patient is attached to a cardiac monitor and an electrocardiogram is obtained to rule out a recent myocardial infarct, detect arrhythmias, or discover evidence of electrolyte imbalance. A urine specimen taken from the Foley catheter is tested for the presence of glucose and blood and sent for urinalysis culture and bacterial sensitivity. The nasogastric tube aspirate is sent for analysis if poisoning or intoxication is suspected.

Table 2-1.

Causes of coma

1. Intracranial

a. Traumatic: penetrating injuries of the brain—closed head injury, concussion, contusion, shearing, epidural hemorrhage, subdural hematoma, intracranial hemorrhage.

b. Infection: subdural empyema, bacterial or fungal meningitis, chronic meningitis from any cause, brain abscess, viral encephalitis, Reye’s syndrome.

c. Neoplastic: brain tumor, primary or metastatic, meningeal carcinomatosis.

d. Vascular: infarction, intracerebral hemorrhage, venous-sinus thrombosis, sickle cell disease, isolated angiitis, polyarteritis nodosa.

2. Metabolic

a. Electrolyte and acid-base disorders: hyper- or hyponatremia, hyper- or hypokalemia, hypercalcemia, hypophosphatemia, hypermagnesemia, hyperammonemia, central pontine myelinosis.

b. Endocrine disorders: diabetes, nonketotic hyperosmolar coma, hypoglycemia, Cushing’s disease, thyrotoxicosis, myxedema, hyper- and hypoparathyroidism, adrenal insufficiency, pituitary apoplexy.

c. Hepatic coma.

d. Uremic coma.

e. Anoxic encephalopathy: airway obstruction, pulmonary dysfunction, cardiac arrest, carbon monoxide, cyanide.

f. Vitamin deficiencies: thiamine (Wernicke’s encephalopathy), niacin, vitamin B₁₂.

g. Poisons and intoxicants: alcohol, heroin, barbiturates, benzodiazepines, organic solvents, pentachlorophenol.

Once the patient is stabilized, a bedside glucose determination using a reagent strip test should be performed.¹ An intravenous injection of 50 niL of 50% dextrose is given to all patients with a glucose level of less than 80 mg/dL. Dextrose therapy is no longer recommended for all cases of coma because glucose can be detrimental to ischemic brain tissue in patients with elevated blood glucose levels presumably owing to conversion of glucose to lactate in the presence of incomplete ischemia.

However, when an intravenous administration of dextrose is indicated, it should be accompanied by

thiamine 100 mg intravenously. This is particularly important to malnourished or alcohol abusing patients, or in those suffering from Wernicke’s encephalopathy (ophthalmoplegia, nystagmus, vomiting, ataxia, and mental deterioration). Likewise, patients with hemodialysis, peritoneal dialysis, cancer, postgastric surgery, acquired immunodeficiency syndrome, intractable vomiting, bulemia, hypereme-sis gravidarum, eating disorders, fadist diets, and those receiving hyperalimentation are candidates for immediate thiamine therapy.

Patients with suspected opiate overdose (respirations 12 per minute or less, pinpoint pupils, and evidence of opioid abuse such as drug paraphernalia, needle tracks, or bystander corroboration) require intravenous nalaxone 0.1 to 2.0 mg depending on the level of respiratory depression. When intubation is required, a repeated dose of nalaxone 2 mg intravenously every 2 min to a maximum of 10 mg may be required.

Flumazenil 0.2 mg intravenously every 30 seconds up to a maximum of 5 mg is indicated in patients with altered mental status caused by benzodiazepine intoxication. Flumazenil should not be used when benzodiazepines have been used or may be re-quired for seizure control. In addition, flumazenil is not recommended in patients who have taken tricyclic antidepressants where toxicity produces hypertonia, clonus, hyperreflexia, myoclonus, and a tachycardia or multiple premature ventricular contractions. The use of flumazenil in such cases carries an increased risk of inducing seizures.

General Physical Examination

A systematic examination of the patient should I be performed. The patient should first be observed. I The dress; age; stigmata of chronic illness, such as I gingival hypertrophy in the epileptic patient on I phenytoin therapy; pattern of respiration; and position! of the body and limbs should be noted. The col matosed patient with an acute hemiplegia lies with! the affected lower limb externally rotated. The exam-J iner notes the presence of spontaneous movements! such as myoclonic jerks or spontaneous decerebral tion. A general physical examination should be done to identify evidence of organ failure or trauma.

The odor of the breath should be noted. The examiner may detect the odor of alcohol, the smell of ketones in diabetic coma, of urine in uremia, and fetor hepaticus in liver failure. The scalp should be palpated by running the fingers of both hands through the hair from the frontal area to the occiput in an effort to detect any depressed fractures or lacerations. The external auditory meatus should be examined for the presence of cerebrospinal fluid (CSF) or hemorrhage indicating fracture of the petrous temporal bone. The mastoid area should be examined for the presence of bruising (Battle’s sign), indicating a fracture of the middle cranial fossa. The zygomatic arches should be palpated and the sclera of the eyes examined for hemorrhages. A hemorrhage of the lateral aspect of the eye that is not bordered posteriorly by normal sclera is indicative of a fracture of the anterior cranial fossa. The nose should be examined for fractures of the nasal bones and epistaxis. Persistent drainage of a clear, watery fluid suggests the possibility of a fracture of the cribriform plate with drainage of CSF. The mouth should be examined and any broken or loose teeth removed to prevent aspiration. Lacerations of the tongue are almost always caused by a recent generalized seizure and most commonly occur on the lateral borders of the tongue. The neck should be palpated for the presence of hematomas and abnormalities of the vertebral bodies. The examination continues with palpation of the clavicles and auscultation and observations of the chest to detect absence of breath sounds and paradoxical respirations. The chest should be palpated for rib fractures. The trachea should be in the midline, and the examiner should palpate the left side of the chest for the apex beat and note its position. Auscultation of the heart is carried out and the presence of arrhythmia or murmurs noted. The abdomen is palpated for the presence of muscle rigidity, indicating possible abdominal hemorrhage or infection. The limbs are then examined for the presence of fractures.

Neurological Examination

Given that the comatosed patient is unable to respond, the neurological examination must be modified to obtain responses that are largely reflex and vegetative iature.

Appreciation of the respiratory pattern and rhythm is important when examining a semicomatose or comatose patient (Table 2-2). Posthyper-ventilation apnea is present when 3 min of hyperventilation is followed by a period of apnea of more than 30 s. This respiratory response is associated with diffuse metabolic or structural forebrain damage. Cheyne-Stokes respiration is characterized by rhythmic waxing and waning of respiration separated by periods of apnea. This type of respiration is frequently associated with early brainstem compression or bilateral deep cerebral hemisphere damage. Central neurogenic hyperventilation is characterized by regular, rapid, deep, machinery-like breathing and is associated with lesions of the midbrain or pons (or both). Apneustic breathing is characterized by a pause at the completion of inspiration and is associated with pontine lesions. Ataxic breathing is characterized by an irregular rhythm and depth of respiration and is associated with dysfunction of the medullary respiratory centers.

The pupils should be equal in size and briskly reactive to light. Constricted pupils occur when there is paralysis of sympathetic function or stimulation of parasympathetic connections. This occurs in severe bilateral hemorrhage or after ingestion of narcotics. Dilated pupils indicate paralysis of parasympathetic function or stimulation of sympathetic connections, which occurs after overdosage with hallucinogens, central nervous system (CNS) stimulants, or anticholinergic drugs. A unilateral fixed and dilated pupil is indicative of a third nerve paralysis in a comatose patient, providing a mydriatic agent was not applied in an effort to obtain a better view of the fundus, a procedure that should never be performed in an emergency room. Pressure on the third nerve results in pupillary dilatation, which precedes paralysis of extraocular muscles because the fibers subserving the light reflex surround an inner core of fibers that innervate the extraocular muscles. Dilatation of the pupil may indicate herniation of the medial aspect of the temporal lobe over the free edge of the tentorium cerebelli (uncal herniation). This ominous sign indicates the need for immediate treatment of increased ICP. A metabolic abnormality should be suspected when the patient is nonresponsive with absent corneal reflexes and absent extraocular movement, yet the pupils are reactive.

Table 2-2.

Signs of rostral-caudal deterioration and level of dysfunction”

Oculocephalic

Pupil size and

reflexes (“doll’s-

Response to

Level of

pupillary light

eye movements”)

painful

dysfunction

reflex

caloric testing

Respiratory pattern

stimuli

Normal

Calorics; normal

Normal

Appropriate

Briskly reactive

nystagmus present

Hemispheres

Small

Doll’s eyes present

Cheyne-Stokes or

Decorticate posturing

Reactive

Calorics; eyes may be

posthyperventilation

tonically deviated

apnea

Diencephalic

Small 1-3 cm

Doll’s eyes present

Normal

Decorticate posturing

Reacting

Calorics; brisk may be

tonic deviation

Midbrain

Midposition

Doll’s eyes present

Central neurogenic

Decerebrate posturing

3-5 cm fixed

Calorics; poor response,

hyperventilation

may be internuclear

ophthalmoplegia

Pons

Midposition

± present

Central neurogenic

Decerebrate posturing

hyperventilation or

or flaccid

Apneustic

Medulla

Midposition and fixed

Absent

Ataxic or absent

Flaccid

Terminally dilated

and fixed

“Plum F, Posner JB: The Diagnosis of Stupor and Coma. 3rd ed. Philadelphia, FA Davis, 1980.

The eyes should be examined while at rest. The examiner should note the position of the eyelids and whether they are completely closed. The lids may be gently raised and allowed to close; slow and incomplete closure is associated with deep coma. The corneal reflexes should be tested. There should be a brisk direct and consensual response. If the patient’s eyes are open it is possible to evaluate the visual fields by making a threatening gesture with the hands on one side and repeating the procedure on the other side, noting if the patient shows reflex blinking. The position of the eyes at rest should be noted. Complete paralysis of the third nerve produces abduction of the affected eye. Bilateral sixth nerve palsies may occur with increased ICP, and this sign is of no localizing value as an isolated phenomenon and does not necessarily indicate brain stem damage. Fixed conjugate deviation of the eyes indicates an ipsilateral destruc–

tive lesion, a contralateral irritative lesion of the frontal lobe, or a destructive lesion of the contralateral brainstem. Ocular bobbing is associated with an upper brainstem lesion, while skew deviation of the j eyes indicates a severe pontine lesion.

The fundus should be examined in all comatose I patients. The retina and optic nerves should be carefully evaluated for the presence of papilledema, hem-1 orrhages, hypertensive or diabetic change, or spasm I of the retinal arteries. Subarachnoid hemorrhage isj often accompanied by a subhyaloid hemorrhage,! which appears as a blotlike hemorrhage on the sur-j face of the retina (Fig. 2-1).

Reflex eye movements should be tested in i comatose patients provided there is no evidence of 1 fracture of the cervical spine. Reflex eye movement! are elicited by briskly turning the head to the rigii followed by turning it to the left and flexing and extending the head. If the patient’s brainstem reflexes are intact, the eyes move in conjugate fashion in the opposite direction to the head movement and the “doll’s-eye” movements are said to be present. It is usually not possible to elicit this reflex in the conscious, alert patient because visual fixation overrides the reflex response. Reflex eye movements become increasingly difficult to elicit with progressive brainstem dysfunction. Paralysis of reflex eye movements will be total when the connections between the vestibular nuclei and the sixth nerve are disrupted at the level of the pontomedullary junction. With damage to the paramedian pontine reticular formation, the eyes move in conjugate fashion but fail to cross the midline when the examiner moves the head. With lesions of the medial longitudinal fasciculus there is abduction of one eye but failure of adduction of the other eye on the side of the medial longitudinal fasciculus lesion.

Caloric testing is used to augment the information obtained when testing reflex eye movements or when the possibility of a cervical spine fracture prohibits movement of the neck. The supine patient should be positioned with the head flexed forward 30°, which places the horizontal semicircular canals in a horizontal position. The external canal should be free of cerumen, and the tympanic membrane should be intact. A slow injection of 50 mL of iced water should be made into the external canal. In the normal situation the eyes will slowly deviate to the ipsilateral side with a quick corrective return to the midline. Under these conditions, nystagmus is named by the fast component: injection of the left ear with iced water produces a right nystagmus. If warm water is injected, the slow phase will be toward the opposite side: warm water injection into the left ear produces a left nystagmus. In patients with dysfunction of the cerebral hemispheres there is an ipsilateral tonic deviation of the eyes following injection of iced water, whereas injection of warm water produces a contralateral tonic deviation. Absence of response to caloric stimulation indicates total disruption of the connections between the vestibular nuclei and sixth nerve nucleus.

Absence of reflex eye movements with preservation of caloric responses indicates the potential for a good outcome in the comatose patient. Absence of both reflex eye movements and caloric responses, however, indicates a poor prognosis. Absence of caloric responses and lack of pupillary light reflexes indicates a fatal outcome in all cases of coma.

In the absence of cervical fracture the head should be flexed forward onto the chest to detect the presence of nuchal rigidity. Tests for the presence of Kernig’s and Brudzinski’s signs should be performed. Nuchal rigidity suggests the possibility of encephalitis, meningitis, or subarachnoid hemorrhage. A lum–

bar puncture is indicated in patients who have nuchal rigidity. A magnetic resonance or computed tomography scan should be obtained before a lumbar puncture is performed if equipment is available to rule out the presence of a rapidly expanding supratentorial lesion.

The position of the limbs should be noted and the tone of each compared. In acute hemiplegia the upper limb is flaccid and the lower limb is flaccid and externally rotated. The tendon reflexes should be evaluated for the presence of any asymmetry. It is not unusual to find a bilateral extensor plantar response in a deeply comatose patient. A unilateral response suggests the presence of a contralateral, supratentorial mass lesion. The response of the patient to painful stimuli should be noted. The examiner may press on the supraorbital notch, squeeze the trapezius or any muscle mass, or prick the skin. The patient may either wince in pain and attempt to withdraw from the stimulus, assume a decorticate or decerebrate posture (Fig. 2-2), or remain unresponsive, indicating deep coma.

The neurological status of the patient should be repeatedly evaluated and the responses systematically recorded for later comparison.

“Plum F, Posner JB: The Diagnosis of Stupor and Coma. 3rd ed. Philadelphia, FA Davis, 1980.

COMPLICATIONS

Deterioration of the neurological status may indicate incipient or ongoing herniation. Five types of herniation are of clinical importance.

1. Rostral-caudal deterioration when there is pressure on the brainstem from above by an expanding mass with progressive loss of brainstem function in a caudal direction (see Table 2-2).

2. (A) Uncal herniation with pressure on the brainstem caused by a herniation of the medial aspect of the temporal lobe over the free edge of the tentorium cerebelli.

Uncal herniation differs from rostral-caudal deterioration in that there is no diencephalic stage in uncal herniation. Coma develops rapidly and is preceded by unilateral dilatation of the pupil on the side of the uncal herniation. This pupil initially shows a poor, then an eventual absence of response to light due to pressure on the third nerve by the herniating mass. This is followed by lateral deviation of the eyes leading to external ophthalmoplegia on the affected side as the oculomotor fibers are paralyzed, then coma, bilateral decerebrate rigidity (see Fig. 2-2), and eventual total flaccidity. Hemiplegia associated with a fixed and dilated pupil is usually contralateral because uncal herniation usually occurs on the same side as an acute supratentorial mass lesion. However, if the mass shifts the brainstem so that the contralateral cerebral peduncle is compressed against the tentorium (Kernohan-Woltman’s notch), the hemiplegia will be ipsilateral to the mass lesion. However, this is an unusual situation and the hemiplegia is almost invariably contralateral to the mass lesion in an acute situation. In the more common central diencephalic syndrome of rostral caudal deterioration with central pressure from above on the brainstem, there are no localizing pupillary signs.

Further deterioration in brainstem function is similar to the pontine and medullary stages in Table 2-2 except that the dilated fixed pupil remains larger on the side of the uncal herniation.

3. (B) Cingulate herniation. In cingulate herniation the cingulate gyrus may herniate underneath the falx. This may be associated with compression of the anterior cerebral arteries followed by ischemia and infarction in the region of the paracentral lobules.

4. (C) Upward cerebellar herniation. In posterior fossa lesions cerebellar hemorrhage or infarction may produce coma due to direct pressure on the brainstem or by upward herniation. There may be premonitory headache, vertigo, nausea, and vomiting followed by unreactive or poorly reactive pinpoint pupils, paralysis of upward or conjugate lateral gaze, and bilateral decerebrate rigidity followed by flaccid quadriplegia.

5. (D) Cerebellar tonsillar herniation. Posterior fossa lesions may also produce herniation of the cerebellar tonsils through the foramen magnum. This situation is associated with increasing occipital headache, nuchal rigidity, flexion of the head toward the side of the cerebellar tonsillar herniation, and cardiac and respiratory arrest due to pressure on the medulla (Fig. 2-3).

PROGNOSIS

The outcome in coma is not unpredictable, and a number of general statements can be made. Except for drug overdose, the presence of coma generally predicts a poor outcome.² When a patient in coma is admitted to an intensive care unit (ICU) and coma persists for more than 48 h, the mortality rate is 77 percent. Any patient in shock admitted to an ICU carries a 55 percent mortality rate at 36 h. However, if shock and coma are combined, a 95 percent mortality rate exists at 36 h. In subarachnoid hemorrhage, only 5 percent of patients recover from coma. Coma and hypoxic encephalopathy carry a 10 percent recovery, coma and hepatic encephalopathy a 27 percent recovery rate.

Any type of coma superimposed with stroke, including intracerebral hemorrhage, cerebral infarction, both ischemic and hemorrhagic type, carries a fatality rate of 65 percent. However, coma with intracerebral hemorrhage carries an 84 percent mortality rate and coma with infarction due to thromboembolism a 60 percent mortality. In contrast, drug overdose carries a mortality rate of 1 percent, even when the patient has been in coma, provided immediate and proper therapy is instituted.

In patients who have received cardiopulmonary resuscitation and are comatose at 72 h, the overwhelming chances are that the patient will recover to a vegetative state and die within 1 year. For those with cardiopulmonary resuscitation, some 13 percent will regain consciousness, and 10 percent will achieve independent functioning. When resuscitation exceeds 30 min, however, there is no survival.

Patients in coma 72 h with a Glasgow Coma Scale score of less than 5 are all dead or in a vegetative state at 1 year. Those who lack signs of brainstem activity (brainstem dead patients) die from cardiac asystole within 3 days in 81 percent and within 7 days in 97 percent of cases.³

Trauma (see Chap. 18) carries a considerable mortality if associated with coma. An acute subdural hematoma has a 50 percent mortality rate even if the hemorrhage is drained by craniotomy, traumatic intracerebral hemorrhage a 26 percent mortality whether the hemorrhage is drained or not, an epidural hemorrhage 18 percent mortality after craniotomy. An acute subdural hematoma with a Glasgow Coma Scale score between 3 and 5 carries a 74 percent mortality rate.⁵

Early predictions of poor outcome in coma states can be determined at the time of initial examination in some cases. For instance, if there is absence

of pupillary light reflexes at the time of initial exami nation, less than 20 percent of the patients will regai independent functioning.⁴ If pupillary light reflexe are present with conjugate roving eye movements, 4 percent of the patients will make a complete recover In trauma cases at 24 h, if the patient is openin the eyes and responding to pain, there is a 63 percei chance of complete recovery.

Students’ practical Study Program.

Step I. Aim: To study investigation tests of mental function. For this purpose it is necessary:

1. To gather an anamnesis and to examine patients status

1. In course of analysis of the complaints of the patient to find out presence of lesions of brain cortex (defect of speech, praxis, calculation, gnosis, intellectual functions, memory, ability to write and to read).

2. To carry out tests on speech, writing, reading, calculation, praxis, gnosis. To pay attention on motor and sense cortex disturbances.

3. To formulate a conclusion about presence or absence of lesion signs of brain cortex.

Step II. Aim: To determine the character of brain cortex lesion. For this purpose it is necessary:

Analyse the patient’s neurological status using the following criteria:

Aphasia – is a disorder of language, the aphasic patient uses language incorrectly or comprehends it imperfectly. Aphasia must be recognized clinically because it localizes the lesion in the cortex (or immediately under the cortex) and the left hemisphere. There are two exceptions: some (less than 50 %) left-handed people use the right hemisphere for speech; anomic aphasias may result from metabolic disorders or space-occupying lesions with pressure effects. Since different types of aphasia may imply different etiologies, the clinician must first be able to recognize that aphasia exists and then to characterize it.

Anatomy of aphasia. Language “ability” is a function of the left hemisphere for almost all right-handed and for most left-handed individuals. The anatomic components of the language are located primarily in the region of the middle cerebral artery surrounding the Sylvian and Rolandic fissures. Speech production involves four regions in this area, moving from posterior to anterior. Thus, speech connections exist between Wernicke’s area (W) on the posterior part of the first temporal gyrus; the angular gyrus (AG); the arcuate fascicules (AF); and Broca’s (B) on the posterior third frontal gyrus.

Types of aphasia.

The lesion of posterior part of lower frontal lobe ( the center of Broca ) causes Broca’s aphasia.

9. Speech is slow, nonfluent, produced with great effort, and poorly articulated. There is marked reduction of total speech, which may be “telegraphic” with the omission of small words or endings.

10. Comprehension of written and verbal speech is good.

11. Repetition of single words may be good, though it is done with great effort; phrase repetition is poor, especially phrases containing small function word (eg, “no if’s, and’s, or but’s”).

12. The patient always writes aphasically.

13. Object naming is usually poor although it may be better than spontaneous speech.

14. Hemiparesis (usually greater in the arm than in the leg) is present, as the motor cortex is close to Broca’s area.

15. The patient is aware of his deficit; he is frustrated and frequently depressed.

16. Interestingly, the patient may be able to hum a melody normally. Curses or other ejaculatory speech may be well articulated.

According to Lurie there are three types of motor aphasia. They are:

1. afferent; 2. efferent; 3. dynamic.

1. Afferent motor aphasia is associated with the lesion of lower parts of gyrus postcentralis which provide innervation of oral muscles. In this case articulation of sounds suffers. That means the loss of automatical speech, repetition, naming. This kind of aphasia is connected with oral apraxia.

2. Efferent motor aphasia is Broca’s aphasia . It means it occurs at lesion of the center of Broca. In this case articulation is preserved. But the patient cannot spell some sounds, words and phrases. At completely aphasia the patient doesn’t speak at all. At partial aphasia he uses only nouns.

3. Dynamic motor aphasia is usually caused by lesion of cortical zone in front of Broca’s center. For this type of aphasia aspontanic speech is typical. The patient refuses to speek in active manner. But he is able to repeat certain sentences, words, answer the questions.

9. Speech is fluent with normal rhythm and articulation, but it conveys information poorly because of circumlocutions, use of empty words and incorrect words (paraphasic errors).

10. The patient uses wrong words and sounds –ie, makes paraphasic errors (“treen” for train; “here is my clover” for here is my hand).

11. The patient is unable to comprehend written or verbal speech.

12. The content of writing is abnormal, as is speech, though the penmanship may be good.

13. Repetition is poor.

14. Object naming is poor.

15. Hemiparesis is mild or absent, since the lesion is far from the motor cortex. A hemianopsia or quadrantopsia may be present.

16. Patients may not realize the nature of their deficit and often are not depressed in the acute stage.

6. This type of aphasia may be seen at small lesions in the angular gyrus, toxic or metabolic encephalopathy, or with focal space-occupying lesions far from the speech area, but which exert pressure effects.

7. Speech is fluent but conveys information poorly because of paraphasic errors and circumlocutions (written language is impaired in the same way). Even though this aphasia is termed anomic aphasia (difficulty iaming objects), anomia is not unique to this type of aphasia.

8. The patient can understand both written and spoken speech.

9. There is no hemiplegia.

10. Comprehension and repetition are normal.

3. Semantic aphasia occurs at lesion of temporal-parieto-occipital border of left hemisphere. The patients cannot realize the difference between “ The brother of the father “ and “ the father of the brother “.

Examination of the aphasic patient.

It must first be established whether the patient is in fact aphasic; then determine the nature of the aphasia.

1. Listen to speech output. Is it fluent or nonfluent? If fluent the lesion is posterior; if nonfluent it usually is anterior.

2. Can the patient read and write with no errors? If so, he is not aphasic.

3. Is there hemiparesis? If so, the lesion must be anterior, involving the motor area.

4. To delineate the various types of fluent aphasias, check to see if the patient can repeat, comprehend, and name:

– Wernicke’s: cannot repeat or comprehend; names poorly;

– Conduction: cannot repeat but can comprehend; names poorly;

– Anomic: can both repeat and comprehend but has trouble with naming.

The importance of defining the aphasia.

The definition of aphasia localizes the level of the nervous system lesion. If aphasia is present, the lesion is usually in the left cerebral cortex. Someone with difficulty using his right hand and a mild aphasia has hemisphere disease, not a brachial plexus lesion.

Aphasia implies dysfunction of middle cerebral artery territory and is often caused by disease of the internal carotid in the neck. Marked stenosis of the internal carotid may be surgically correctable, and if recognized and treated in time a mild or transient aphasia may be prevented from becoming global.

The sudden onset of fluent aphasia without hemiparesis often means an embolus to the posterior branch of the middle cerebral artery. Look for an embolic focus in the heart or in the carotid artery. If the heart is the source, anticoagulation should be considered; if the carotid is the suspected source, angiography is usually performed in search of a surgically remediable lesion. Remember the clinical rule: the sudden onset of aphasia without hemiparesis suggests embolus.

Apraxia is a disturbance of purposeful movement which is not accounted for by elementary motor or sensory impairments. It occurs commonly in association with aphasic syndromes. Apraxia is deviated in:

1. motor or kinetic

2. ideational

3. constructional and dressing

Ideational Apraxia. In ideational apraxia there is inability or failure to comprehend, develop, or retain the concept of what is desired. It is usually due to general suppression or loss of cerebral function and resembles extreme absent-mindedness. Such a patient will have difficulty in understanding what is desired and will fail to complete the desired act. This becomes apparent when he is asked to carry out a series of simple acts such as “Put the pencil in the cup and hand me the matches.” After requiring that the request be repeated, he may then pick up the pencil and fail to do anything more. The patient with ideational apraxia has lost the idea.

Ideokinetic Apraxia. Another common form of apraxia is known as “ideokinetic” or “ideomotor” apraxia. This occurs when there is a break in transmitting or converting the idea into the appropriate motor act. This form of apraxia occurs most commonly with lesions of the major hemisphere at the junction of the temporal, parietal, and occipital lobes or its connections with the frontal lobes. The phenomenon is usually associated with a hemiplegia opposite the lesion, and the apractic disability affects the “good” extremities. Despite knowing what is desired, the patient is unable to carry out a desired complex performance. He may, for example, hesitantly touch his forehead when asked to touch his nose. He may recognize a comb but be unable to use one to comb his hair when asked. Then, surprisingly, he may carry out the same acts automatically that he is unable to perform volitionally on request. Perseveration of a previous motor act is common in such patients. Ideokinetic apraxia generally subsides spontaneously with the passage of time.

Kinetic Apraxia. Failure of the third step produces kinetic apraxia. This phenomenon is considered to be due to a lesion of the premotor frontal cortex, and the disability is limited to one extremity or a part of it. There is no actual weakness, and the patient is able to use the extremity for gross movements and automatically. He has lost the ability to make fine skilled movements such as finger wiggling, opposition, writing, or piano playing.

During the taking of the history and the carrying out of the neurological examination one should note the general mobility of the patient and whether he is hyperkinetic or relatively immobile. Observations for awkwardness while carrying out relatively complicated acts such as dressing and undressing should be made. It should be noted whether the patient has difficulty in conceiving how to hop, how to touch his nose, and how to wiggle his fingers or tap his toes.

Specific Test. Observations on the motor-pattern performance of patient are made during the various parts of the neurological examination when the patient is asked to show his teeth, stick out his tongue, wiggle his fingers, tap his toes, hop, walk tandem, touch his nose, and so forth. All these tests are performed in conjunction with the testing of motor power and coordination. Further study of motor patterns may require utilization of the following tests. These suggested tests may be modified or amplified according to the requirements of the patient.

Instruct the patient by word or gesture to:

1. Touch his nose.

2. Drink from a glass or paper cup.

3. Use a folder of matches.

Get the patient to follow simple spoken directions. Say to the patient:

1. Close your eyes.

2. Point to your nose and your chin.

3. Put the pencil in the glass (or paper cup) and hand me the matches.

4. Repeat after me, “I bought a new hat, a pair of shoes, and a white shirt.”

Constructional and Dressing Apraxia. Lesion of the posterior parietal region of the nondominant hemisphere may impair performances related to spatial concepts. Such lesion produce special forms of apraxia. Constructional apraxia may be demonstrated by having the patient try to copy geometric forms or draw the face of a clock. Further testing includes having the patient try to arrange sticks in a specific pattern or to arrange Koch blocks in a desired design. Dressing apraxia is tested simply by asking the patient to put on a shirt or bathrobe. To increase the difficulty of the test, one arm of the garment can be turned inside out prior to the test.

Agnosias are disorders of recognition which are not accounted for by elementary motor or perceptual disturbances.

Testing for tactile recognition (stereognosis) is considered as a part of the general sensory examination, while the tests for recognition of various forms of auditory and visual recognition are considered in the chapter on language and motor speech. Defects of recognition on a somewhat different integrated level are considered here.

Autotopagnosia – agnosia for body parts there may be lack of recognition of hands, eyes, feet, and so forth, of the patient, of the examiner, and even in pictures. With agnosia for parts of a whole the patient is able to recognize a bicycle but is unable to recognize and name the wheels, handlebars, seat, and other parts.

Bodyscheme agnosia includes various disturbances of the patient’s concepts of his own body.

Autotopagnosia (somatotopagnosia) includes disturbances in recognition of the patient’s own body or body parts. It is due to lesions of the poster-inferior parietal lobe in the region of the interparietal sulcus of the dominant hemisphere or to a subcortical lesion isolating this area from the thalamus. It is often associated with acalculia, visual verbal agnosia, or anosognosia. Autotopagnosia may be limited to one part of the body or may be more general, involving relationships of the body as a whole. The limited form includes lack of recognition of one half of the body or one extremity and inability to recognize and name individual fingers (finger agnosia) or other body parts. In mild forms the patient may have a sense of distortion of the involved parts of the body and disturbances of laterality. This may be tested by asking the patient to name various parts of his own body and to identify right and left. It is often manifested by inattention to or lack of use of the part.

Anosognosia is lack of awareness or denial of the existence of disease. An obvious example is a denial by the hemiplegic patient that he is paralyzed. This usually is associated with severe disturbance of sensation but is not due to the sensory loss; for instance, knowledge of the paraplegic patient that the paralyzed and anesthetic limbs belong to him. Hysterical conversion reactions may give a superficially similar appearance of denial of disease. True anosognosia occurs with lesions of the inferior parietal lobe in the region of the supramarginal gyrus. Inquiring of the patient concerning his disability will generally be sufficient to demonstrate anosognosia.

The generalized form includes loss of identification of self as a person, loss of orientation of self in space, loss of sense of motion, and disturbances of sense of time. Such disturbances are more subtle and may be masked by complaints of “things seeming different” or of “eyes blurring.” Inquiries into these phenomena may be made by having the patient close his eyes and describe how he pictures himself. He may be asked to imagine himself walking, standing, and sitting.

1. Make a conclusion about presence of pathology of brain cortex function.

Step III. Aim: To study syndromes of brain cortex lesions.

Step IV. Aim: To make differential diagnosis of a pathological process level localization by means of “Algorithm of differential diagnosis of brain cortex lesions” or using “The Methodical indicatings on a theme: “A brain cortex. The anatomic-physiological data”.

Step V. Aim: 1. To read the tasks of real-life situations.

2. To lead diagnosis.

CSF

Meningeal and Cerebrospinal Fluid’s Hypertension Syndromes.

Characteristics of Normal Cerebrospinal Fluid

Appearance

clear and colorless

Pressure

Less than 180 mm of CSF.

Cells

0 to 5, usually lymphocytes (more than 8 cells is abnormal)

Total protein

0,15 to 0,33 mmol/ liter

Glucose

2,2 to 3,3 mmol/ liter

Chlorides

120-130 mEq. Per liter

Cerebrospinal fluid’s hypertension syndrome:

1. Diffuse headache (in the morning);

2. Dizziness;

3. Nausea, vomiting;

4. Convulsive seizures;

5. Lesion of cranial nerves;

6. Prostration;

7. Protein- cell dissociation;

8. Papilledema;

9. Increased pressure of the cerebrospinal fluid.

Meningeal syndrome

Meningeal syndrome manifests as neck stiffness, Kernig sign, Brudzinski signs (upper, middle and lower ones), Lessage symptom (in children), Bechterev’s cheek bone phenomena. Increased intracranial pressure causes bulging of an unclosed anterior fontanelle in children.

The nuchal rigidity – the patient can’t to flex the head and place the chin on the chest.

The Kernig’s sign supplies the same information as the straight leg raising test is one of the classic sign ieurology for aid in diagnosis of meningitis. With the patient in the supine position the examiner flexes the hip and then extends the knee as far as possible without producing significant pain. Normally the knee can be extended so that the angle between the posterior surface of the thigh and leg is approximately 135 degrees. Results of the test are considered positive if extension of the knee is limited decidedly by involuntary spasm of the hamstring muscles and, as a rule, if pain evoked.

Brudzinski’s signs: 1) when the head is flexed on the chest – the knees are flexion too; 2) when the examiner to do the Kernig’s test – the contralateral leg is flex.

Pain phenomena: pain points of Trigeminal nerve, occipital points, pain in eyeballs.

Upon meningeal symptoms general cerebral signs are developed. They are:

– headache (as a result of increased intracranial pressure),

– vomiting, nausea,

– general hyperesthesia,

– hallucination, prostration,

– photophobia,

– phonophobia,

– Changes of consciousness,

– psychomotor agitation,

– seizures.

LUMBAR PUNCTURE—INDICATIONS, CONTRAINDICATIONS, TECHNIQUE, AND COMPLICATIONS

Indications

Lumbar puncture is indicated to:

1. Confirm a diagnosis. This is particularly important when the computed tomography (CT) scan is negative for subarachnoid hemorrhage (SAH) but clinical signs are indicative of meningeal irritation. The accuracy of CT in documenting SAH diminishes after 24 h and diagnosis is often dependent on lumbar puncture.

2. Identify an organism

3. Test for antibiotic sensitivity

4. Establish the need for treatment of children who are contacts in the case of meningococcal or haemophilus meningitis

Contraindications

Lumbar puncture is contraindicated when there is suspicion of increased intracranial pressure (ICP) caused by an intracranial mass lesion. Papilledema should be excluded. Other contraindications include serious cardiorespiratory disease or when the area through which the spinal needle must pass is infected. If available, a CT scan or magnetic resonance imaging (MRI) scan should be obtained before lumbar puncture. Contraindications to lumbar puncture, because of increased risk of herniation, include lateral shift of the midline structures, loss of suprachiasmatic and basilar cisterns, obliteration of the fourth ventricle, or obliteration of the superior cerebellar and quadrigem-inal cisterns with sparing of the ambiens cisterns.

There is no evidence to recommend CT scan of the brain before lumbar puncture for suspected acute meningitis, unless any of the following features are present: unconsciousness, focal findings, papilledema, other atypical features (e.g., immune compromise, sinusitis, otitis media).

The risk of complications associated with a lumbar puncture, even in patients with papilledema, is 10 to 20 times lower than the risks associated with acute bacterial meningitis alone.

Treatment without lumbar puncture can be considered in cases where there is unequivocal diagnosis of meningitis in a seriously ill individual with a positive blood culture, who has impaired consciousness, raised ICP, and signs of brainstem involvement by uncal herniation or central pressure.echnics of lumbar puncture.

1) Lumbar puncture should be carried out in an operating room equipped for the purpose and with nursing personnel experienced in the procedure when possible.

2) The patient is placed on his side on a firm but padded table of adequate size and given a small pillow on which to rest his head. The patient is disrobed sufficiently to expose a generous portion of his back from about the midgluteal to the midthoracic region. The area thus exposed is cleansed thoroughly with surgical soap and swabbed in turn with alcohol, ether, and an appropriate antiseptic solution.

3) The widest suitable interspace for puncture is selected by observation and palpation. Usually the fifth lumbar interspace between the sacrum and the fifth lumbar vertebra can be identified. When the doctor injected a local anesthetic agents (may be 1 per sent Lidocaine solution).

4) The lumbar puncture needle should not be inserted sooner than 1 minute after injection of the local anesthetic. During this interval the physician can discuss the procedure with the patient.

5) For obtaining pressures we use an open-end glass manometer of 1 mm. The adapter with manometer attached is connected to the spinal puncture needle, allowing as little cerebrospinal fluid to escape as possible during the procedure. The initial pressure is obtained. If the initial pressure is high (more than 180 mm of cerebrospinal fluid), every effort must be made to be certain that the elevated pressure is not due to extraneous factors. In same cases we must carefully executed Queckenstedt test (The patient is encouraged to remain relaxed and to continue breathing at the normal rate while an assistant compresses both jugular veins firmly with the palmer surfaces of the extended fingers. This is more easily accomplished while the assistant is standing behind the patient. Compression is maintained by the assistant for 10 seconds and suddenly released, after which 10-second intervals are called out to the examiner and the pressure readings made by the latter at 10-second intervals are recorded. An average normal result might be recorded as «11-30-11», indicating that the initial pressure was110 mm. of cerebrospinal fluid, that it rose to 300 mm within 10 second after compression of the jugular veins, and that it returned to the initial level of 110 mm within 10 seconds after release of compression. A partial dynamic block might be recorded as «11-20-16-14-11’, while complete block would be represented by readings of «10-10-10».

6) We take 7 to 10 ml of cerebrospinal fluid for the laboratory tests.

7) After that, the needle is simply withdrawn and a sterile dressing is applied to cover the punctured wound.

Table 16-1

Normal CSF indices

Appearance: clear, colorless, does not clot in tube Opening pressure: 70-200 mmH₂0 Cells: O-5/mm³ (mononuclear)

Na⁺: 142-150 mEq/L; K⁺: 2.2-3.3 mEq/L; CI: 120-130 mEq/L

CO₂: 25 mEq/L; pH: 7.35-7.40 Glucose:45-80mg/100dL ‘

Protein: 5-15 mg/dL (ventricular), 10-25 mg/dL (cisternal), 15-45 mg/dL (lumbar)

Gamma globulin: 5-12% of total protein

Transaminase (GOT): 7-49 U; LDH: 15-71 U; CPK: 0-3 IU

BUN: 5-25 mg/dL; bilirubin: 0 Amino acids: 30% of blood level Lactic acid 0.8-2.8 mmol/L

BUN, blood urea nitrogen; CPK, creatine phosphokinase; GOT, glutamic oxaloacetic transaminase; LDH, lactate dehydrogenase

1- normal, 2. subarachnoid haemorrhage, 3. intracerebral haematoma, 4. serous meningitis

Complications

1. Postlumbar puncture headache is probably caused by continued leakage of CSF through the puncture hole in the dura created by the needle. This causes a reduction in ICP and traction on the intracerebral dura. Other causes include decreased production of CSF and reduced CSF pressure. Headache can be avoided by the use of a 20-gauge Sprotte atraumatic needle, removing the smallest volume of CSF necessary for chemical and bacteriological studies, and by replacing the stylet and rotating the needle 90° before withdrawing the needle.

2. Labyrinthine disturbances. Complaints of vertigo associated with a change in posture often accompany headache and should be treated with rest, sedation, and adequate fluid intake.

3. Ocular motor disturbances producing diplopia are the result of downward movement of the brainstem following removal of CSF and traction on the third or sixth nerves, usually the latter.

4. Postlumbar puncture backache is usually the result of multiple unsuccessful attempts to place the needle in the subarachnoid space. The resultant muscle spasm produces pain. This may be avoided by allowing no more than two attempts to enter the subarachnoid space. The patient should be referred for needle insertion under fluoroscopy after a second attempt has failed. Intravenous and oral caffeine are often effective in the treatment of post-lumbar puncture headache. An epidural blood patch is indicated when noninvasive treatment is unsuccessful and is often effective in relieving symptoms.

5. Intracranial subdural hematoma can occur in patients with brain atrophy who have tension on the perforating veins crossing the subdural space. A sudden decrease in pressure produces further traction and rupture of these veins. This complication should always be considered in elderly patients who have become less responsive or develop hemiplegia following lumbar puncture.

6. Infection, including meningitis or subdural empyema, may result from a break in sterile technique during lumbar puncture. The alpha-hemolytic streptococcus is a major pathogen of iatrogenic meningitis following lumbar puncture indicating the need to wear a face mask when performing this procedure.

7. Uncal herniation is the most devastating complication of lumbar puncture and is due to sudden change in ICP. Lumbar puncture should not be performed if there is any suspicion of an intracranial mass lesion.

8. A traumatic tap results from the laceration of vessels in the venous plexus of the spinal canal. Bleeding can be avoided by keeping the needle in the midline and not penetrating to the anterior wall of the spinal canal.

CSF changes manifest as:

1. cellular – protein dissociation,

2. protein – cellular dissociation,

3. colour changes,

4. cerebrospinal fluid is cloudy (purulent),

5. the sugar content is decreased;

6. clot formation on standing is observed at tuberculous meningitis.

Table 16-2

Cerebrospinal fluid findings in various central nervous system disorders

Pressure

Appearance

Glucose

Protein

Cells

Viral

Normal or

Clear, colorless

Normal

Normal or slightly

Increased

encephalitis

mildly

increased

lymphocytes

increased

Aseptic

Normal

Usually clear,

Normal

Normal or slightly

Lymphocytes

meningitis

colorless

increased

occasionally

normal early or

increased to

>500 cells/mm

Acute pyogenic

Increased

Cloudy

Decreased

Increased

Polymorpho-

meningitis

nuclears, usually

>500 cells/mm

Tuberculous

Increased

Usually clear,

Decreased

Increased

meningitis.

may be cloudy

lymphocytes

syphilis

Fungal

Increased

Varies with

Increased

infections

organism

lymphocytes

Abscess

Increased

Clear, colorless

Normal

Increased

Increased poly-

morphonuclears

Cerebral

Normal or

Clear, colorless

Normal

Normal or

Normal or very mild

infarction

mildly

increase in poly-

increased

morphonuclear

cells <50/mm

Subarachnoid

Increased

Bloody, does

Normal

Increased

Red cells maximal at

hemorrhage

not clot,

onset decreasing

supernatant—

and disappearing

xanthochromic

in about 5 days;

mild to moderate

polymorphonu-

clear and later

lymphocytic

pleocytosis occur

as fluid clears

Traumatic

Normal

Bloody, clots

Normal

4 mg/dL

Same as peripheral

lumbar

spontaneously,

increase per

blood; fewer red

puncture

supernatant—

5000 red

cells last speci–

not

blood cells

men than first

xanthochromic

specimen

Spinal cord

Decreased

Cloudy, may be

Normal

Increased,

May be mildly

tumor

xanthochromic

may clot spon–

increased

taneously (Froin

lymphocytes

syndrome)

Frequent

Normal

Clear, colorless

Normal

<80/mm³ mostly

seizures

polymorphonu-

-_.—————-—

clear

Students’ Practical Study Program

Step I. Aim: Find out the symptoms of meningeal and cerebrospinal fluid’s hypertension

syndromes. For this purpose it’s necessary to examine the patient, paying attention on such symptoms: headache, nausea, vomiting, dizziness, prostration, common hyperesthesia, convulsive seizure, and lesion of cranial nerves, special signs (nuchal rigidity, Kernig’s and Brudzinski’s signs, and Bechterev’s symptom).

Make the conclusion about the presence or the absent of the meningeal and cerebrospinal fluid’s hypertension syndromes.

Step II. Aim: To do differential diagnosis meningeal and cerebrospinal fluid’s hypertension syndromes.

Meningeal syndrome

Cerebrospinal fluid’s hypertension syndrome

Headache

Headache (in the morning)

vomiting

common hyperesthesia

dizziness

Nuchal rigidity, Kernig’s sign, Brudzinski’s signs, Bechterev’s symptom

convulsive seizure

hallucination

lesion of cranial nerves

the pulse is rapid

prostration

cell-protein dissociation

protein- cell dissociation

the patient is irritable

Optic fundus edema

hemorrhages in the cerebrospinal fluid

increased pressure of the cerebrospinal fluid

meningeal posture

To analyze the special methods results (ophthalmoscopy, cerebrospinal fluid; the roentgenograms of the scull). To use algorithm of differential diagnosis from methodological indication for students.

Step III. Aim: Make the conclusion about the presence or the absence of the meningeal and cerebrospinal fluid’s hypertension syndromes.

DISORDERS OF CEREBROSPINAL FLUID AND CIRCULATION

Hydrocephalus

Definition Hydrocephalus is an excessive accumulation of CSF within the cranial cavity.

Etiology and Pathology The classical concept of CSF circulation is based on the belief that CSF is secreted by the cells of the choroid plexus of the lateral, third and fourth ventricles and flows through the ventricular system and the foramina Luschka and Magendie into the subarachnoid space. The fluid then flows up and over the cerebral convexities and is absorbed, principally through the arachnoid granulations along the superior sagittal sinus. Part of the fluid passes into the central canal of the spinal cord and is absorbed into the general circulation. In addition, the CSF must also communicate with the interstitial fluid in the brain, across the ependymal layer and pial surface of the brain.¹⁹⁰ Thus, water and small molecules may be exchanged in a bidirectional fashion through the intracellular spaces in the CNS and this communication may play an important role in brain volume control. However, because the brain does not have a lymphatic system, the passage of interstitial fluid from the CNS will depend on absorption at the capillary level and drainage through the venous system. Consequently, volume control is a complex matter involving not only the classical concept of CSF production by the choroid plexus and absorption through the arachnoid villi, but also bidirectional flow through the intracellular spaces and absorption into the venous system. The several channels of cerebrospinal flow are usually in a state of dynamic equilibrium, which can be disturbed by a variety of factors leading to hydrocephalus, which should be regarded as a multifactorial disease with diverse pathogenesis.¹⁹¹

Hydrocephalus may occur under the following conditions:

1. Cerebral malformation. A failure or arrest in development of a part of the brain is associated with accumulation of CSF in the area of the abnormality. These defects vary from failure of development of the cerebral hemispheres (anencephaly) to minor developmental abnormalities.

2. Increased production of CSF. This rare condition occurs with papilloma of the choroid plexus and resolves following excision of the tumor.

3. Obstruction of CSF circulation

a. Tumors of the lateral ventricles

b. Obstruction of the third ventricle by tumors, colloid cysts, or parasitic cysts

c. Pressure on the third ventricle by pineal tumors posteriorly or pituitary tumors, cranial pharyn-giomas, hypothalamic tumors, optic nerve gliomas or metastatic tumors from below

d. Aqueductal narrowing by congenital stenosis, forking or septum formation, or by pressure from a pontine glioma

e. Obstruction in the fourth ventricle by tumors or parasitic cysts

f. Occlusion of the foramina of Luschka and Magendie by cerebellopontine angle tumors or by fibrosis following meningitis or subarachnoid hemorrhage

g. Impaired circulation of CSF in the subarachnoid space at the base of the brain or over the convexities, following subarachnoid hemorrhage with fibrosis, chronic meningitis, other granulomatous diseases, following trauma with brain injury, or by the presence of fibrinogen in the CSF and its transformation into fibrin, and the presence of intramedullary spinal cord tumors.

4. Reduced absorption of CSF. The absorptive capacity of the arachnoid granulations may be damaged following meningitis or subarachnoid hemorrhage. A thrombosis of the major venous sinuses may also decrease CSF absorption.

5. Compensation for cerebral atrophy. Loss of brain substance leads to accumulation of increased amounts of CSF in the ventricular system and over the surface of the brain. This is termed hydrocephalus ex vacuo.

Clinical Features Hydrocephalus is a frequent accompaniment of meningitis, encephalitis, or subarachnoid hemorrhage when the signs of increased intracranial pressure (ICP) are masked by the acute disease progress. In some cases, however, symptoms of hydrocephalus are delayed for weeks or months after the acute event and present as classical features of increasing ICP. Similarly, hydrocephalus may be the sole manifestation of a brain tumor or parasitic cyst. More chronic presentation of hydrocephalus consists of headache, nausea, vomiting, visual impairment, and ataxia. Headache is intermittent at first, often awakening the patient in the early hours of the morning and persisting in the morning, and then gradually resolving. This may be the result of higher P_c0 during sleep, which increases cerebral blood volume and ICP. Eventually the headache becomes constant. Vomiting is usually a later feature of hydrocephalus when headache is severe. Seizures may occur at any time. Progressive ataxia involving trunk and limbs produces a broad-based gait. Visual disturbances consist of intermittent blurring of vision progressing to visual failure as hydrocephalus and ICP increase. There is usually papilledema bilaterally at this stage and diplopia due to stretching of the sixth nerve, owing to downward pressure on the brainstem.

Diagnostic Procedures

1. The MRI and CT scans will demonstrate hydrocephalus and frequently identify the cause.

2. Lumbar puncture should be delayed or avoided, if possible, in the presence of hydrocephalus and symptoms of increased TCP because of the risk of cerebellar tonsillar herniation or increased downward pressure on the brainstem.

Treatment

1. Tumors or cysts causing hydrocephalus should be removed surgically if possible.

2. Ventriculostomy and ventricular drainage may be required in emergency situations.

3. In less emergent situations, a ventricular peritoneal shunt can be used initially to reduce increased ICP before attempting more definitive procedures to remove a tumor or cyst.

Infantile Hydrocephalus

Definition Infantile hydrocephalus is a progressive hydrocephalus that develops in infants and children.

Etiology and Pathology One of the more common causes of infantile hydrocephalus is obstruction of the sylvian aqueduct at the level of the midbrain. The aqueduct may show the presence of stenosis with or without gliosis; “forking” in which the aqueduct is replaced by a number of small, inefficient

channels; or septum formation. Certain inherited or dysgraphic malformations are associated with hydrocephalus, including Arnold-Chiari malformation, the Dandy-Walker syndrome in which atresia of the foramen of Magendie is associated with failure of development of the vermis of the cerebellum, and the presence of a cranial or spinal encephalocele. Other conditions producing infantile hydrocephalus include prenatal intraventricular hemorrhage, prenatal viral infections, and possible exposure to toxins or drugs during pregnancy.¹⁹³ Meningitis with an inflammatory exudate and subsequent fibrosis can block the sylvian aqueduct, the foramina of Luschka and Magendie, or the subarachnoid space at the base of the brain. Subarachnoid hemorrhage, which usually results from trauma in children, produces the same effect. Posterior fossa tumors are a rare but potent cause of hydrocephalus in children.

Infantile hydrocephalus is characterized by dilatation of the ventricular system and compression of the brain. The width of tissue between the dilated ventricles and the surface of the brain may be less than 2 cm in some cases. Increased ICP results in enlargement of the skull and separation of the cranial sutures.

Clinical Features Hydrocephalus is unusual at birth but can cause difficult labor, which may require cesarean section. The great majority of hydrocephalic children appear normal at birth and signs and symptoms do not appear until later in infancy or early childhood. The head gradually enlarges and the normal proportions of the cranial cavity are distorted. The face has an abnormal appearance, but there may be some degree of exophthalmus and prominence of the sclerae, due to anterior displacement of orbital contents. The children are often surprisingly alert but eventually fall behind in developmental milestones. Examination reveals an enlarged head, prominent scalp veins, and enlarged fontanelles. There may be progressive visual loss and optic atrophy, with a poor pupillary reaction to light, failure of upward gaze, impairment of lateral gaze, strabismus, nystagmus, paralysis or spasm of convergence and absence of visual fixation. Percussion of the skull produces a typical “cracked pot” sound. In advanced cases, the head may be so enlarged that the child is unable to lift the head from the pillow. Increased intraventricular pressure results in damage to the corticospinal tracts, with increased tendon reflexes and a bilateral extensor plantar response.

Untreated children eventually develop necrosis of the scalp with leakage of CSF, followed by infection, and death. A minority of patients used to survive before shunting procedures were available, and the child with arrested hydrocephalus would show enlargement of the head, some degree of mental retardation, spasticity of the limbs, and impairment of bladder function.

Diagnostic Procedures

1. The MRI or CT scan will clearly define the extent of the hydrocephalus and the presence or absence of any cerebral malformations.

2. Transcranial Doppler ultrasound will demonstrate hemodynamic changes in infants with progressive hydrocephalus. The value of this technique has been questioned¹⁹⁴ but endorsed by others.

3. The skull should be measured at each visit to record the progression of the hydrocephalus.

4. The fundi should be examined for the development of optic atrophy. The presence of papilledema is unusual. All infants should receive transillumination to exclude hydroencephaly and subdural hygroma.

Treatment All cases of infantile hydrocephalus should have a ventriculoperitoneal or lum-boperitoneal shunting procedure. The procedure is not without complications, which include shunt occlusion, infection of the shunt or valves, subdural hematoma, low pressure headaches, and thromboembolism.

Prognosis More than 80 percent of children with infantile hydrocephalus will benefit from a shunting procedure. Irreversible damage from previous meningitis, subarachnoid hemorrhage, or cerebral trauma may produce permanent neurological deficits. Shunting should be performed as soon as possible to avoid the development of permanent neu–

rological deficits, such as visual impairment and mental retardation.

Normal Pressure Hydrocephalus

Definition Normal pressure hydrocephalus is a chronic hydrocephalus that occurs in children and adults and is associated with a delay in circulation or absorption of CSF and progressive neurological deficits.

Etiology and Pathology In the majority of cases, the etiology cannot be determined, but when cause can be established, it is apparent that normal pressure hydrocephalus is a syndrome. Obstruction of the subarachnoid space may occur months or years after subarachnoid hemorrhage, chronic meningoencephalitis, or trauma. It is possible that some cases are due to aqueductal stenosis, which slowly decompensates as the patient ages. Other causes include obstruction of the third ventricle by slowly growing tumors or cysts, or by enlargement of the basilar artery. Dural sinus thrombosis is another factor in this syndrome. It has been postulated that the condition is the result of altered CSF dynamics in the subcortical and periventricular white matter, possibly the result of subcortical arteriosclerotic encephalopathy, because there is a significant association with hypertension, diabetes mellitus, and normal pressure hydrocephalus. Other white matter diseases, such as Lyme disease, might produce the same effect.

Pathological changes consist of dilatation of all of the ventricles, without cortical atrophy.

Clinical Features This syndrome presents with increasing clumsiness of gait. The gait disturbance is followed by urgency of micturition and eventually by incontinence. After a period of several months or a year or two, definite evidence of dementia appears. The patient shows progressive unsteadiness and frequent falls due to a mixture of ataxia, spasticity, and dyspraxia of gait. There is a general slowing of function, with complaints of weakness and fatigue. The patient may develop dysesthesias of the feet and lower legs. There may be psychotic-like symptoms or obsessive-compulsive disorder in a minority of cases.

Diagnostic Procedures

1. The MRI or CT scan shows the presence of ventricular dilatation, with enlargement of the third, fourth, and lateral ventricles. Cortical atrophy is often absent, but the presence of cortical atrophy does not rule out the diagnosis of normal pressure hydrocephalus.

2. The CSF is under normal pressure. The appearance, cell count, and chemical composition are normal. Improvement in gait after removal of 50 mL CSF correlates with a good outcome following a shunting procedure.

3. Radioactive cisternography, which is performed by injecting a radiopharmaceutical into the lumbar subarachnoid space, shows prolonged retention of the radioactive material within the ventricular system and impaired diffusion of radioactive material over the cerebral convexities.

4. A demonstrable increase in regional cerebral blood flow, following the administration of glycerol, predicts a successful response to a shunting procedure.²⁰³

Differential Diagnosis The main problem in an elderly patient is the separation of Alzheimer disease from normal pressure hydrocephalus. Patients with Alzheimer disease present with progressive cognitive decline, with a characteristic pattern of cerebral atrophy by MRI, and a distinctive pattern on the SPECT scan. This contrasts with normal pressure hydrocephalus, where there is progressive impairment of gait associated with ataxia and incontinence, with initial mild cognitive impairment.

Treatment

1. There may be transient improvement in the early stages of normal pressure hydrocephalus by repeated lumbar puncture, with removal of 15 to 20 mLCSF.

2. A ventriculoperitoneal shunt procedure can produce dramatic improvement in some cases. Improvement in postoperative cognitive function is more likely if there is a known cause for the condition. However, most patients with normal pressure hydrocephalus of unknown etiology, who present primarily with gait disorder, experience significant improvement in gait.Complications of the shunting procedure consist of infection of the catheter or valve and an occasional occurrence of subdural hematomas. These complications have decreased over the years as technique has improved.

3. A lumboperitoneal shunt is an alternative method of treatment with similar results and complications.