Theme: Autonomic nervous system (peripheral and segment parts, Hypothalamus, Limbic-Reticular system).
Special Clinical Examinations of Diseases of Nervous System
The Autonomic nervous system. Anatomy. Functions.
The symptoms of lesion
The autonomic nervous system is a part of nervous system that regulates the activity of internal organs, glands, blood and lymphatic vessels, smooth and striated muscles and organs of sensation.
The modern physiology defines Autonomic nervous system as a part of nervous system due to which the activity of internal organs and metabolism is regulated.
The autonomic nervous system is a purely efferent system of nerve fibers with ganglia and plexuses outside the central nervous system innervating the blood vessels, heart, viscera, glands, and smooth muscles throughout the body. Although afferent nerve fibers conveying impulses from these structures to the central nervous system are present in autonomic nerves such as the vagus and the splanchnic nerves as well as in peripheral somatic nerves, they are considered separate from the autonomic nervous system. These visceral afferent nerve fibers are thinly myelinated or nonmyelinated and the impulses they carry are related to visceral sensations, such as pain and distention, and to visceral reflexes underlying functions such as respiration, maintenance of blood pressure, and micturition. Their cells of origin are in spinal dorsal root ganglia and in certain cranial nerve ganglia. The visceral afferent fibers terminate in the spinal cord and brain stem oeurons subserving local visceral reflexes and oeurons forming secondary visceral tracts. In the spinal cord these visceral tracts probably exist as multiple chains of neurons, crossed and uncrossed and not well defined into specific tracts, in the lateral columns of white matter near the ventral horns.
There is a close connection and similarity between the autonomic and somatic nervous system.
- The morphological and functional unit of both of them is a neuron
- The main functional unit is a reflex arch.
- The autonomic nervous fibers go within cranial nerves and spinal nerves.
Anatomy
The autonomic nervous system is divided into such parts:
- Central (all the structures that are within the brain and spinal cord)
- Peripheral (all the others structures)
The central autonomic nervous system is divided into:
· above – segmental level (the limbic system, reticular formation, hypothalamus)
· segmental level
The last one according to the structure and functional peculiarities is divided into sympathetic and parasympathetic nervous system.
The peripheral part of autonomic nervous system is presented by:
· The nodus of Ashof – Towar
· The plexus of Meisner and Auerbach
· Sympathetic noduses
· Solar and hypogastrical plexuses
· White and gray fibers
Anatomically, the autonomic nervous system consists of two divisions:
1. cranial-sacral (parasympathetic) outflow
2. thoracic-lumbar (sympathetic) outflow
Arising from nerve cells in the midbrain, medulla oblongata, and the second, third, and fourth segments of the sacral spinal cord, the preganglionic parasympathetic fibers synapse in ganglia which are outside the central nervous system and located close to, or in, the structures they supply. The preganglionic sympathetic fibers arise from nerve cells in the intermediolateral column of gray matter in spinal cord segments Thl through L2, and they synapse in the two paravertebral sympathetic ganglionic chains and in the several prevertebral ganglia (celiac, superior and inferior mesenteric and aortic). Preganglionic nerve fibers are myelinated; postganglionic nerve fibers are not.
The cranial portion of the parasympathetic outflow consists of nerve fibbers carried in the third, seventh, ninth, and tenth cranial nerves.
The sacral portion of the parasympathetic outflow arises from nerve cells located in the intermediolateral zone of gray matter of the second, third, and fourth sacral segments of the spinal cord.
There are two main functions of autonomic nervous system.
· Ergotropic (homeokinesis) – adjustment to the changes of environment and providing the needs of the organism.
· Trophotropic (homeostasis) – it supports the constant internal reactions and provides anabolic processes.
The limbic system was described by French neuro – anatomist Broka in 1878. Mc Lein continued its studying in 1952. It consists of:
· Bulbus olphactorius, tractus olphactorius, trigonum olphactorii, substantia perforata anterior
· Septum pellucidum
· Gyrus cinguli
· Gyrus hypocampalis
· Orbital part of frontal lobe
· Corpus amygdaloideum
· The pole of temporal lobes
Function
1. Emotional reactions
2. The reception of afferent impulses from internal organs
3. It is a memory substratum; it preserves information about previous genetically inherited experience
4. It provides motivation to thirstiness, hunger, sexual desire
5. It regulates the state of sleepiness and liveliness
6. It indirectly regulates the function of internal organs
The symptoms of lesion
1. Emotional disturbances.
2. Anorexia or bulimia.
3. Sleeping disorders.
4. Sexual disturbances.
5. Memory disorders.
The lesion of temporal lobe leads to the changes of eating behaviour. For example mice catch and put into the mouth different objects and even snakes in spite of the fact that normally they are afraid of snakes.
The lesion of corpus amygdaloideum leads to increasing of appetite and obesity (the experiment was held on cats).
Hypersexuality was noticed in experiments in spite of the animals’ family and sex.
The lesion of gyrus cinguli is associated with memory disorders especially on current events. All these events are forgotten in 2 – 3 min. But those events that are associated with emotions, visual, smell, auditory influences are much more stable.
The irritation of some structures leads to aggression.
Reticular formation
It is a tonus motor of the brain, which works constantly in the brain stem. It was described by Deiters, Bechterev, and Ramon & Kachal. It consists of great number of cells, the axons of which are going in different directions and create a reticule.
In spite of the other cells of nervous system the cells of reticular formation accept pain, light, temperature and humoral impulses and send them to the brain cortex.
Thus the main functions of reticular formation are:
· To support the brain cortex tonus, its state of liveliness which is necessary for the normal activity. The reticular formation energizes the brain.
· It supports the certain level of activity of autonomic centers (the activity is very similar to that of sympathetic nervous system. There is also the same mediator – noradrenalinum)
Function
1. The control of sleepiness and liveliness.
2. To accept the information from the environment.
3. To keep in tonus all the forms of behaviour, those have long – lasting character.
The symptoms of lesion
· The low activity of RF – the patient is unconscious.
· Decreased activity of RF – sleepiness.
The lower parts of RF have general and long – lasting influence on consciousness and behavior, the upper ones have short – lasting and specific influence.
Hypothalamus
Hypothalamic region has 32 pairs of nuclei of cranial nerves. They can be divided into three groups.
· Anterior – it is associated with parasympathetic function
· Middle – endocrine – trophic
· Posterior – has mainly sympathetic influence.
The peculiarities of activity:
1. Motor cortex receives 440 capillaries per 1 mm3, visual cortex – 900/mm3, hypothalamic region – from 1650 to 2600/mm3.
2. Almost all the arterial brain systems give their branches to hypothalamic region. That makes impossible disturbances of its activity.
3. There is no space of glia between the vessels and gangliocytes. That provides quick reaction to the changes of internal surroundings.
Hypothalamus is closely connected with cortex, thalamus, extrapyramidal nervous system, nuclei of brain stem and spinal cord, reticular formation and hypophysis.
The function of hypothalamus
1. Regulation of heart – vascular activity
2. Regulation of lipid, water, mineral metabolism
3. Thermoregulation
4. Regulation of vessels’ and tissue membranes penetrance
5. Regulation of endocrine glands’ function
6. Constant internal surroundings support
7. Adaptation
8. Biorhythm
9. Emotional behaviour
Hypothalamus rules the internal world by means of three ways:
· Through the nervous impulses
· Humoral
· Hormonal
The very important role belongs to the releasing factors. In hypophysis there are 7 tropic hormones that activate the production of certain hypophysis hormone:
- Corticoliberinum
- Tirioliberinum
- Luliberinum
- Foliliberinum
- Somatoliberinum
- Prolactoliberinum
- Melanocytoliberinum
There are 3 inhibiting hormones:
- Prolactostatinum
- Melanocytostatinum
- Somatostatinum
Hypothalamic syndromes are those that are associated with the lesion or deficiency of hypothalamus.
1. Autonomic – vascular – visceral – is associated with crisis of paroxysmal character.
· Sympathetic – adrenal
· Vago – insular
· Mixed
2. Neuro – endocrine – metabolic – is associated with increasing or decreasing of hypophysis function (Itsenko – Kushing, acromegaly, early climax, impotence, non sugar diabetes, tyreotoxicosis).
3. Neuro – trophic is associated with trophic disturbances (dryness, neurodermitis, ulcers, bed sores, acute perforates of stomach and esophagus).
4. Neuro – muscular – hypothalamus provides chemical and biochemical activity of extrapyramidal nervous system and cerebellum.
· Myasthenia
· Myotonia
· Paroxysmal myoplegia
5. Thermoregulation disturbances – the temperature is 37,1 – 37,5, there is asymmetry under the arms, in the mouth and in rectum. Sometimes this symptom has paroxysmal character and is associated with trembling.
6. Sleeping disorders
· Insomnia
· Lethargy (a special form – narcolepsy) – sudden attack of sleepiness that can happen in any place and position of the patient. Sometimes they are associated with catalepsy (the loss of muscle tonus)
· Sleeping inversion
Parasympathetic nervous system is presented by:
· Mesencephalic level (nuclei of Perlea and Yakubovich), the fibers are going within the III CN and provide innervating of m. Sphincter pupillae, m. Ciliaris
· Bulbar (n.salivatorius superor et inferior, n. dorsalis nervi Vagi) within VII, IX, X CN’s innervate parotid, sublingual, submandibular glands and internal organs (except the pelvic organs)
· Sacral part – the cells of lateral horn S2 – S4 – innervating of pelvic organs.
There is the arch of pupil reflex on mesencephalic level. The symptoms of lesion are:
· Spasm or paralysis of accommodation
· Mydriasis
· Direct or indirect symptom of Argil – Robertson
The symptoms of lesion of bulbar level:
1. Salivation or kserostomy
2. Tears or kserophthalmy
3. Dyspnoe, Biot, Chein – Stocks types of breathing
4. Tachycardia, arterial hypertension, arythmia, asystoly
Sympathetic nervous system consists of the cells of lateral horn of spinal cord from C8 to L2. The axons within the anterior roots leave the spinal cord. Some of them are finished in sympathetic trunk (it consists of 20 – 23 noduses) – 3 cervical, 10 – 12 thoracic, 3 – 4 lumbar, 4 pelvic. The rest fibers are going to the prevertebral noduses or plexuses.
Common features:
1. There are 2 neurons. The second neuron is located in ganglion
2. Preganglionar fibers are myelin –associated.
3. Postganglionar fibers are without myelin.
Differential features:
1. Mediator
Sympathetic nervous system – adrenalin, noradrenalin
Parasympathetic nervous system – acetylcholine
2. The length of fibers
Sympathetic nervous system – short pre- and long postganglionar fibers
Parasympathetic nervous system – long pre – and short postganglionar fibers
Symptoms of lesion
1. The lesion of lateral horns of spinal cord:
· Autonomic – vascular (pale, cyanosis)
· Trophic (edema, arthropaty)
· Secreting (dryness of the skin, hyperhydrosis)
C8 – Th3 – head and neck
Th4 – Th7 – shoulders and arms
Th8 – Th9 – body
Th10 – L3 – pelvis and legs
2. The lesion of segments of the spinal cord – S3 – S5
· Retention of urine
· Truly urine incontinence
· Ishuria paradoxa
3. The lesion of upper cervical sympathetic nodes:
· Causalgia
· Paresthesia, hypesthesia
· Vasomotor, secreting, trophic disorders in head and neck region
· Horner syndrome
4. The lesion of Nodus stellatum:
· Causalgia
· Paresthesia, hypesthesia
· Vasomotor, secreting, trophic disorders in head and neck region
5. The lesion of upper thoracic noduses:
· Cardialgia
· Tachycardia
· Breathing disorders plus all the above named symptoms.
6. The lesion of Lower thoracic and lumbar noduses:
· Visceral and autonomic disorders of the organs of abdominal cavity.
7. The lesion of Solar plexus:
· Dull pain in the abdomen
· Increased aorta pulsation
· Instable AP
· Instable stool
· Poli – oligouria
· Glucosuria
8. The lesion of Posterior neck sympathetic nodus:
· Neck pain like “casque putting off”
· Photopsia
· Vestibular syndrome
The disturbance of vegetative functions:
1. The paroxysmal signs
Sympathy-adrenal attacks: Vagoinsular attacks:
a) skin is pail a) hyperemia
b) xerostomia b) hyperhidrosis
c) dryness of hair and skin c) oily skin and hair
d) tachycardia d) bradycardia
e) high blood pressure e) low blood pressure
f) midriasis and widing of f) miosis
eye-slit g) angina pectoris
g) exophthalmia h) salivation
h) tremor i) breathlessness
i) gooseflesh j) abdominal spastic pain
k) diarrhea,
l) frequent and abundant urination
2. The lesion signs:
a) periarthritis a) incontinence of urine and feces
b) epicondilitis b) ischuria /retention of urine
c) miositis c) eye accommodation paralysis
d) hyperkeratosis d) midriasis
e) fissures of skin e) breath
f) arthropatias f) dyspnea
g) trophic ulcer g) apnea
h) alopecia h) cardiac arrhythmia
i) hyperpigmentation i) asystolia
j) Horner’s sign j) collapse
(ptosis, miosis, enophthalmia)
Methods of investigation of autonomic nervous system
There are numerous clinical, laboratory and instrumental methods of investigation of ANS. The choice of the method depends on our aim.
First of all we start with investigation of present state of ANS. For this purpose different tables are used.
Normally there is a balance between the sympathetic and parasympathetic nervous system. But it can be changed in different periods of our life.
There are five types of neurologic disorders of urination and urinary bladder control:
- The centrally uninhibited bladder
- The sensory paralytic bladder
- The motor paralytic bladder
- The automatic reflex bladder
- The autonomous bladder
The centrally uninhibited bladder functions well in respect to emptying; but urgency, frequency, and incontinence are common. This type of disorder occurs especially in elderly people and is attributed to diffuse brain disease with resultant inadequate control over the primitive micturition reflex. It is often confused with the symptoms of prostatism.
The sensory paralytic bladder results from peripheral or radicular sensory denervation. The bladder becomes atonic, loses the feeling of distention or the elicitation of reflex emptying, and gradually retains a significant amount of residual urine. This condition occurs in tabes dorsalis, diabetic neuropathy, and the combined-system disease of pernicious anemia.
The motor paralytic bladder is also atonic but is due to neuronal loss in the S2-4 segments or their axons in the parasympathetic outflow. Poliomyelitis and trauma to the conus medullary may produce this syndrome.
The automatic reflex bladder is a consequence of spinal cord disease above the S-2 level (e.g., trauma, compression, multiple sclerosis) in which local reflex arcs are intact. The sensation of fullness is impaired or lost. Frequency, urgency, incontinence, incomplete emptying, and and the inability to void are the usual symptoms. Though micturition may be possible with incomplete cord lesions, urinary tract damage may still result from ureteral reflux or infected residual urine.
The autonomous bladder has no neural connection on either side of the reflex arc and functions imperfectly on a myogenic basis. An atonic bladder with secondary overflow incontinence and impaired drainage of the upper urinary tract is characteristic.
The pupillary reactions. Normally the pupils are round and equal in diameter. Normal pupils are small in sleep and dilate with arousal. Difference in size (anisocoria), if small, may not represent disease and can be evaluated accurately only with reference to other findings, such as ptosis. Pupillary diameter is chiefly dependent on intensity of illumination but is greater in children than in adults and is usually small in the elderly. In ordinary room light the diameter may vary from 2 to
Fibers carrying impulses resulting from light stimulation of the retina (the afferent side of the reflex arch), both crossed and uncrossed, traverse the optic tract and bypass the lateral geniculate body to synapse in the pretectal region of the midbrain. Here another crossing is made they further ensures that stimulation of one eye will cause the contralateral as well as the stimulated pupil to constrict—the consensual reaction. The pupil of a blind eye will not constrict when its retina is exposed to light. But it will do so when the other, normal eye is stimulated.
The efferent limb of the reflex originates in the Edinger-Westphal nucleus, a part of the third-nerve nucleus. The pupillomotor fibers course with other fibers of the third cranial nerve to synapse again in the ciliary-ganglion, from which terminal fibers innervate the iris and ciliary body.
When the pupils are unequal in size (anisocoria), either or both may be abnormal. The larger pupil may react poorly to light as a result of a partial third-nerve paralysis, or the smaller pupil may be part of Horner’s syndrome. When anisocoria is present it is important to examine the pupils in both light and dark. The difference in pupillary size in Horner’s syndrome will increase in dark, whereas that due to partial third-nerve paralysis will increase in light.
Horner’s syndrome, when complete, is characterized by:
1. ptosis of the upper lid,
2. miosis,
3. loss of sweating on the same side of the face.
4. pupillary reaction to light is normal, but the pupil does not dilate to psychosensory stimuli such as a loud noise.
The syndrome may be produced by a central or peripheral lesion and may be partial or complete. The importance of the syndrome derives from the vulnerability of the sympathetic pathways at different points in their long course (see above). Associated signs can help locate the level of a lesion after Horner’s syndrome has betrayed the interruption of pathways.
The Argyll Robertson pupils of tabetic neurosyphilis are small (miotic), irregular, and often unequal in size. They react little or not at all to light but constrict promptly when the eyes converge on a near object. A similar dissociation between the light reaction and the near response may be seen in patients with diabetes, encephalitis, and midbraieoplasm.
There are Trophic disorders:
Students’ practical Study Program.
I step. Aim: To determine presence of signs of vegetative system lesion. For this purpose it is necessary:
The scheme of diagnostic search of vegetative disorders
I. To gather an anamnesis and to examine patient’ status.
II. At the analysis of the complaints of the patient to find out presence of attributes of a lesion of a vegetative system:
a. activity of inner organs (attacks of tachy- and bradycardia, breath, dyspeptic disturbance after meals, abdominal spastic pain, diarrhea, frequent and abundant urination),
b. activity of cardiovascular system (attacks of a skin pallor and hyperemia, high and low of blood pressure),
c. activity of the sweating, sebaceous glands and lacrimal organs (salivation, hyperhidrosis, dry skin, eyewatering, xeroftalmia),
d. activity of pelvic (urogenital) organs (ischuria /retention of urine/, incontinence of urine and feces),
e. trophic disturbance (hyperkeratosis, skin lesion, peeling of the skin, fissures of skin, pustules, skin edema, hyperpigmentation, alopecia, hemiatrophia, osteoarthropathia),
f. disturbance of height and substances exchange (low and high height, increasing of weight, cachexia, acromegalia),
g. disturbance of sleep, thermoregulation, memory, emotions and tendencies.
II step. Aim: To determine part of vegetative nerve system (sympathetic, parasympathetic) lesion. Make a conclusion about presence of pathology of sympathetic or parasympathetic part of vegetative nervous system.
III step. Aim: To find level of lesion vegetative nervous system.
IV step. Aim: To make topical diagnosis of a pathological process level localization in vegetative nervous system. In topical diagnosis it is necessary to point main vegetative signs (syndromes), the character of vegetative pathology.
Special Clinical Examinations of Neurological Patients
(Electromyography, Echo-Electroencephalography, Electroencephalography, CT-scan, Pneumocephalography, Cerebral Angiography, Roentgenography, Reoencephalography, MRI).
Electroencephalography (EEG)
The EEG involves recording of the spontaneous electric activity of the brain from the scalp and activity elicited by activation procedures. The amplitude of EEG activity recorded by the scalp electrodes is generally about 10 to 60 microvolt. Usually, the EEG is sampled simultaneously from 8 to 16 pairs of electrodes in selected combinations (montages). The most characteristic feature of the normal EEG of an adult during relaxed is the alpha rhythm (8 to 12 Hz – rate, 100 mV – amplitude) and the beta rhythm (14 to 40 Hz, 15 mV). The pathological rhythm is the delta (less than 3 Hz) and theta (4 to 5 Hz)
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Electromyography (EMG)
Electromyography, in which the electric activity produced by muscles is studied: This methods help to diagnosis of disease which affect the lower motor neuron, neuromuscular junction, or skeletal muscle fibers. Iormal muscle at rest no electric activity is detected, but during voluntary contraction the action potentials of motor units appear. In the presence of disease of the motor unit, electric activity of various types may appear in the resting muscle and the action potentials of motor units may have abnormal forms and patterns of activity. Types of abnormal muscle fibers response: «positive waves», «myotonic discharge», «bizarre repetitive potential», «fibrillation», «fasciculation», «repetitive discharge», «muscle cramp».
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Ultrasonic doplerography – finds out the absence or presence of stenosis and occlusions of magistral arteries of head and neck.
RADIOLOGICAL EXAMINATION OF THE BRAIN AND SPINAL CORD
Roentgenography of the spinal column (spondilography)
Plain roentgenograms should always be obtained first, for they can provide diagnostic information quickly and economically. Descriptions of some of the spinal disorders that may be identified by means of a plain roentgenogram follow. Diffuse widening of the spinal canal, scoliosis, kyphosis, multiple vertebral anomalies, spondilolysis, spondilolistesis, osteoporosis, ostheochondrosis, and traumatic lesion of the spinal column.
Roentgenography of the scull (RG – cranio graphy)
To find out the signs of the increased intracranial pressure (separation of the cranial sutures in children, the bones of the calvarium may be thinned, demineralization of the posterior clinoid processes and the dorsum of the sella turcica), destruction of the born. Meningiomas often are associated with hyperostosis of bone. Acoustic neuroma often causes erosion of the internal auditory canal. Pituitary tumors produce characteristic enlargement of the sella when they attain sufficient size. Erosion of the clinoid processes and dorsum of the sella may be apparent, and at times the tumor may erode through the floor of the sella into the sphenoid sinus. Occasionally an intracellar aneurysm will produce a similar appearance.
n The usual set of skull films comprises a series made AP, PA (in several degrees of sagittal flexion of the neck), lateral (each side in turn close to the plate), as well as one of the basilar projections in which the ray is directed so that it superimposes the complex basilar structures upon the less complex calvarial cap. The lateral view of the skull shows the two halves of the coronal suture superimposed. The two parts of the lambdoidal suture are seen. Sutures usually remain visible throughout life, distinguishable from fracture lines by their serpiginous character and white margins, while a fracture will be more linear, not at all marginated, and usually more radiolucent. Study the normal skull films on the next slayds.
Normal pituitary fossa:
The white line forming the floor and the dorsum sellae. Pituitary tumour causing enlargement of the pituitary fossa with a
sloping floor. The floor appears as a double line on the lateral view
(arrows).
n Traumatic brain injuries include concussion, contusion, skull fracture, and hemorrhage, which may be epidural, subdural, subarachnoid, or intraparenchymal. Epidural hematoma results from rupture of a meningeal artery and follows a hyperacute course, whereas subdural hematoma results from rupture of bridging veins and follows an acute or a chronic course, depending on the severity of the injury. Trauma of the spinal cord produces a variety of neurologic deficits not only from direct neurologic trauma, but also from direct and delayed damage to the vasculature, with resultant paraplegia or quadriplegia, depending on the level of injury.
PA projection with fractures both linear and depressed. A plate of bone seen in tangent (between the arrows) is slightly depressed. This is not a simple linear fracture but a comminuted one, therefore. Note fillings in the teeth. Identify: odontoid seen through the nose, frontal sinuses, petrous tips with internal auditory canals seen through orbits.
Pneumocephalography
To enable to visualization of the various portion of the ventricular and subarachnoid system. The patient seated straddling the chair, lumbar puncture is performed. Then the doctor brings in 20 – 35 sm3 of air in the subarachnoid system. This method is used for diagnostic tumors and inflammatory diseases.
Cerebral angiography
It is the method of roentgenologic visualization of the vascular system of the brain during the injection of radiopaque material into the arterial blood stream. A complete angiogram includes the arterial, capillary, and venous phases and is obtained by making rapid, successive roentgenography exposure after injection of the contrast medium. The arterial phase outlines the characteristics of the surface of the brain, whereas the venous phase demonstrates the deep cerebral structures. Secular’s aneurysms, arteriovenous malformations, tumors of blood vessels, and occlusive vascular disease lend themselves well to angiographic demonstration.
Computerized transaxial tomography (CT-scan)
It’s a recently developed radiographic method, detects the X-ray density of many cranial and
intracra nial structures and permits their visualization. Its scan the heard in a series of horizontal slices.
n The newer imaging modalities have had a greater impact on the diagnosis of diseases of the skull, spine and central nervous system than on any other body system. Computed tomography (CT) and magnetic resonance imaging (MRI) have become the standard investigations for most disorders of the brain. Plain films are still the initial investigation for disorders of the bones of the skull – particularly fractures, but otherwise have limited uses. Radionuclide imaging has been almost entirely replaced by CT and MRI. Arteriography is now limited to demonstrating arterial stenoses, aneurysms and some arteriovenous malformations.
Large midline tumour meningioma (arrow) beneath the frontal lobes
Glioma, CT scan, post i.v. contrast
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Metastasis
Students’ Practical Study Program
Step II. Aim: To estimate the parameters of the electrophysiological and the roentgenologic methods of examination of neurological patients. Students must know the normal parameters of the electrophysiological and the roentgenologic methods.
Disease |
Signs |
Tumors |
EEG – demonstration a focal abnormality of brain activity ( the delta- and theta- rhythm), asymmetry; CT-scan – areas of decreased density or as areas of mixed increased and decreased density, often surrounded by edema RG – the signs of the increased intracranial pressure (separation of the cranial sutures in children, the bones of the calvarium may be thinned demineralization of the posterior clinoid processes and the dorsum of the sella turcica, erosion of the internal auditory canal). Meningiomas often are associated with hyperostosis of bone. Acoustic neuroma often causes erosion of the internal auditory canal. Pituitary tumors produce characteristic enlargement of the sella when they attain sufficient size. Erosion of the clinoid processes and dorsum of the sella may be apparent, and at times the tumor may erode through the floor of the sella into the sphenoid sinus. Echo -EG – asymmetry (> Cerebral angiography – tumors of blood vessels |
Infarction |
EEG – the delta- rhythm in the areas of infarction CT-scan – ill-defined region of decreased density, many cerebral infarcts have a characteristic triangular shape with the base toward the cortex. |
Hemorrhage |
EEG – the delta- rhythm in the areas of infarction CT-scan – region of increased density Echo -EG – asymmetry (> |
Convulsive seizure |
EEG – patterns include certain types of sporadic spices, sharp waves, spike – and – slow – waves complexes |
Amyotrophic lateral sclerosis |
EMG – fibrillations and reduce numbers of motor unit potential under voluntary control. |
Myasthenia |
EMG – the «jitter» is increased, and when excessively prolonged, an impulse may not appear at all at the expect time; this is called «blocking» and the number of blockings is increased in myasthenic muscle. |
Step III. Aim: To make topical and clinical diagnosis. For this aim it’s necessary to use algorithm of differential diagnosis, which is in methodological indication for students.