NERVOUS SYSTEM

Neurologic evaluation

History

An accurate history obtained from one or more members of the family is often the most vital part of neurological evaluation: A child older than 3-5 years might provide information that not only is valuable but also may be more reliable than that by his parents.

Present history

· The onset, duration, and rate of progression of the illness will sort out most neurologic illness into specific categories; static, progressive, regressive, or intermittent.

- Static abnormalities noted early in life suggest congenital abnormalities, or brain injury during the neonatal period.

- Progressive disorders suggest neoplastic, or degenerative diseases; regressive disorders suggest traumatic, vascular, or inflammatory diseases, whereas intermittent abnormalities indicate paroxysmal disorders as seizures.

·  Specific questions should routinely be asked about; headache, visual disturbances, speech disorders, cranial nerve disorders (e.g. blurring of vision, squint, deafness, vertigo, swallowing difficulties or voice change as nasal tone, nasal regurgitation, and hoarseness of voice), motor disorders (e.g. incoordination, weakness, abnormal gait, involuntary movements), sensory disorders (e.g. pain, numbness, or tingling), sphincteric disorder (e.g. incontinence, retention), and mental disorders (e.g. change of memory, behavior or intelligence).

Past history

Length of pregnancy, problems or medications during pregnancy, Mode of delivery, neonatal complications. As a rule, the youngster who has had an uncomplicated neonatal period and was discharged with the mother will not have sustained perinatal asphyxia even though the infant might have low Apgar scores or meconium staining.

· Information should be obtained for any serious illness or injury requiring hospitalization.

· A review of patient's history, or medical records may disclose systemic illnesses predisposing to neurologic disease (e.g. congenital cyanotic heart disease, renal disease) and neurologic manifestations of systemic disease (e.g. cardiomyopathy, liver cirrhosis).

· Full growth and developmental history of the child should be recorded including physical growth, motor, and mental development.

· The environmental history may disclose chronic exposure to toxins or infections.

· The patient's school performance in both academic and social areas must be recorded and compared to previous years performance.

Feeding history

Many children who later present with delayed development  have had feeding problems, notably regurgitation excessive colic. Failure to thrive frequent formula  changes. Constipation is acommon finding in patients with cerebral palsy and it's etiology is multifactorial  (colonic dysmotility, excessive cow's milk consumption and low fiber diet).

·           Excessive vomiting is very common in neurometabolic drseases partuculasly urea cycle defecty and fatty acid oxidation defects.

·           A history of abnormal sleeping habits and excessive crying is also not unusual in the brain damaged youngester.

Vaccination history:

·           History of polio vaccine is essnatial in acute flaccid paralysis particularly if asymmetric

·           DPT vaccine induce FC in the first 48hs

·           MMR vaccine B Induce FC after 2wks

Diurnal variation and relation to sleep

·           BHS don’t occur during sleep

·           Benign rolandic epilepsy_70% during sleep

·           Night terrors occure during early sleep

·           Myotonia worsen in the morning

·           Myasthenia improve in the morning

·           Juvenile myoclonic epilepsy common occus in the morrning

·           Infantile spasms clusters on arousal from sleep.

History of recurrent injuries suggests hyperactive child, impaired coordination or recurrent loss of consciousness.

Developmental history

    The main objective of assessing a young child's development is the early detection of delayed or abnormal development to:

1.      Help children acheive their maximum potential by early interference with rehabilitation programs

2.      Provide treatment or therapy promptly Particularly important for impairment of hearing and vision.

3.      Acts as entery point for the care and management of the children with special needs:

·           There are four fields of developmental skills to consider when a young child is seen

1-      Gross motor                                2- vision and fine motor

3-              Hearing speech and language

4-      Social, emotional and behavioral

The acquisition of developmental abilities for each skill field fallows a remarkable constant pattern between children , but may vary in rate. Thus the pattern of acquisition of skills

1. Is sequentially constant
2. Varies in between children.

As the child grows, additional skills become important , such as attention and concentration.

   Affection of one skill may have on impact on the other as hearing impairment may affect language, social , communication and behavior.

Median age and limit age

 Median age is the age when half of a standard population of children achieve this level. It serves as a guide to when stages of development are likely to be reached but does not tell us if the child's skill is outside normal range.

Limit age is the age by which the skill must be achieved ,they are usually two standard deviations from the mean, they are more useful as a guide to whether a child's development is normal than the median age. for example walking unsupported median age is 12 months and limit age is 18 months.

 Adjusting for prematurity is justified up to the age of 2ys .

Family history

·           Most neurodegenerative diseases are transmitted as recessive

·           Some epilepsies and migraine are transmitted as dominant traits.

Family history should document any neurologic disease including epilepsy, and heridofamilial disorders.

· It should be determined whether the parents are relatives, because the incidence of metabolic and degenerative disorders affecting CNS is increased significantly in children of consanguineous marriages.

General examination

In the healthy school – aged children, the general physical and neurologic examination can be performed in the same manner as for adults except that their more uncomfortable aspects as fundus, gag and corneal reflexes and sensory testing should be postponed to until to the end.

The younger child, the neurologic examination is a catch- as- catch-can procedure, with a considerable amount of informations revealed by youngester play activities as, persistant hand fisting , thumb adduction, frequent shoulder extension, hand preference , fanning on grasp , winging on running, head tilt, ptosis, toe walker.

The toddler is more difficult to examine. The toddler is best approached by seating the child in the mother's , or father's lap and talking to the child. Because toddlers are fearful of strangers, the physician must first observe the youngster and defer touching him or her until some degree of rapport has been established . offering a small interesting toy may bridge the gap. In any case the physician must be patient and wait for the youngster to make the first approach . once frightened, most toddlers are difficult to reassure and are lost for the remainder of the examination.  

· Observation during interaction with parents while playing, or during the time when little attention is directed to the child can provide useful information (e.g. characteristic facies, unusual posture, abnormal motor function).

· Careful examination of the head is important.

- Abnormalities in the size or shape of the head may suggest an underlying neurologic disease (e.g. microcephaly, hydrocephalus).

- Anterior fontanel should be assessed (e.g. bulging anterior fontanel is a sign in cases of increased intracranial tension, and wide fontanel in cases of hydrocephalus).

- Transillumination is a helpful screen for hydrocephalus.

- Percussion of the head produces a "cracked pot" sound in children with increased intracranial pressure.

· Fundus examination: is important to see if there is papilledema, optic atrophy, pigmentation or cherry red spot.

· Look for abnormal shape or site of ears (e.g. in Down Syndrome), stiff neck (e.g. in meningitis), kyphosis, scoliosis, or midline defects (e.g. spina bifida with myelomeningocele, cutaneous dimples, tufts of hair, or pigmentation).

· Examination of the hands and feet may reveal the presence of abnormal palmer creases, polyda- ctyly or syndactyly.

· Examination of skin may reflect nervous system lesions (e.g. café'- au- lait spots in neurofibro- matosis).

· Careful examination of chest, heart, abdomen and genitalia may detect signs associated with neurologic disease.

* presence of an unusual body odor may offer a clue to metabolic disorder

Neurological examination

Skull examination

1. Head circumference
2. Dilated veins
3. Fontanells normally it is slightly depressed and pulsations are hardly felt
4. Skull shape                               

·        occipital flattening

·        occipital prominence

·        scaphocephally

·        plagiocephally

·        temporal fossa scalloping

5-      transillumination

6-      percussion

7-      auscultation

Cranial nerve evaluation

The evaluation of cranial nerve function depends upon the stage of maturation of the child's brain, and on the ability of the child to cooperate.

Evaluation of cranial nerve I (olfactory): the child's sense of smell is difficult to assess. Beginning at the age of 2-3yrs, aromatic substances such as perfumes and ground coffee should be utilized. Anosmia may be due to meningitis, diseases of the nose, or brain tumors affecting the olfactory bulb , trauma with fracture of cribriform plate 

Evaluation of cranial nerve II (optic):

- In infants, peripheral vision can be obtained by noting the infant's detection of objects brought into the visual field from behind.

- Blink reflex in infants starts at 3 to 4 months, in 50% at 5 months, 100% at 1 year

- Optokinetic nystagmus 

- Visual acuity is detected by the ability of the infant to visually locate and track small objects. In older children, standard visual acuity charts, and confrontational testing of peripheral vision are utilized.

- The pupillary reflex is assessed using a focused bright light. A lesion of the optic nerve in one side will abolish pupillary response to light on the same side as well as in the contralateral eye. When light is shown in the normal eye, it’s pupil and the contralateral pupil will constrict.

- Visual field examination

fundus examination(optic atrophy , papilledema, retinal hge, chorioretinitis , cherry red spots

Evaluation of cranial nerves III, IV,VI; (occulomotor, trochlear, abducent): extraocular movements may be observed as the infant follows objects.

Occulomotor nerve (III): paralysis produces ptosis, dilatation of the pupil, displacement of the eye outwards and downward, impairment of adduction and elevation of the eye.

Clinical syndromes may affect cranial nerve III and produce miosis or mydriasis. Miosis occurs in:

  - Horner syndrome (ptosis, miosis, anhidrosis and enophtalmos).

- Pontine lesions (sympathetic paralysis).

- organophosphorus poisoning

Trochlear nerve (IV): paralysis causes the eye to deviate upwards and outwards often with head tilt.

Abducent nerve (VI): paralysis causes medial deviation of the eye and the inability to abduct beyond the midline. VI nerve palsy also may be a non-specific sign of increased intracranial pressure.

Dollś eye maneuver: this technique is used to examine horizontal and vertical eye movements in the infant, the uncooperative, or the comatosed patient. If the head is suddenly turned to one side the eyes look to the other side in a symmetric fashion. Vertical movements may be assessed in a similar fashion by rapid flexion and extension of the head.

Setting sun sing indicates increased intracranial pressure with impairment of vertical gaz center.

Evaluation of cranial nerve V (trigeminal):

- In infant, the muscles of mastication can be assessed while watching him suck and swallow. Jaw jerk can be done by asking the patient to relax. Place a finger on the chin and tap it with reflex hammer. A movement of the jaw is detected.

When exaggerated suggest UMNL abova the pons

- Deviation of jaw to paralytic side

- Atrophy of temporalis muscal

- Facial sensation of light touch and pain can be obtained with a cotton gauze and pinprick.

- The corneal reflex is done by touching with wisp of wet cotton wool. A blink response should occur (Cranial nerves V and VII ).

Evaluation of cranial nerve VII (facial):

- An isolated weakness of the depressor angularis oris is, common in children

- The assessment of facial symmetry at rest and during sucking activity or crying can be utilized in assessing the small infant. Beyond infancy, the muscles of facial expression are assessed in voluntary basis (e.g. closure of eyes for upper face muscles, or showing teeth for lower face muscles).

- UMNL weakness accentuated by volutional movements but not with crying or laughing . the converse UMNL facial weakness appears on emotions but not voluntarily occurs in thalamic lesions   

- Decreased voluntary movements of the lower face with flattening of the nasolabial angle on the ipsilateral side indicates an upper motor neuron lesion, while affection of upper and lower face indicates lower motor affection. In the cooperative child taste can be tested by using solution of saline or glucose placed on one side of the extended tongue.

Evaluation of cranial nerve VIII (vestibulo-cochlear):

- The auditory nerve is tested in infants by observing the startle reaction to a loud noise.

-  deviate eyes to sounds by 8 wks

- By 3-4 months, the child will turn towards sounds.

- The older child can be tested by rubbing the fingertips near the ear. If hearing loss is suspected, an audiogram should be obtained. Vestibular function may be evaluated by the “caloric test“: cold water introduced to the ear canal normally causes nystagmus with the quick component towards the opposite side. In  infants and newborn by rotation test

Evaluation of cranial nerves IX, X (glossopharyngeal, vagus)

Gag reflex: depress patient’s tongue and touch palate, pharynx or tonsil on one side until the patient “gags.” Compare sensitivity on each side (lX nerve) and observe the symmetry of the palatal contraction (X nerve). Uvula deviation towards the stronger unaffected side suggests unilateral palsy of IX and /or X. Absent gag reflex means either loss of sensation (bilateral IX palsy) and/or loss of motor power (bilateral X palsy).

Evaluation of cranial nerve XI (accessory):

- The functions of the trapezius and sternocleido- mastoid muscles are assessed by observing the infant’s posture and spontaneous activity.

- Head tilt and drooping of the shoulder are suggestive of lesions involving cranial nerve XI. In older children, direct examination of these muscles is possible.

Evaluation of cranial nerve XII (hypoglossal):

- Examination of the tongue for atrophy and fasciculation is done at any age. By 1 year of age, specific tongue movements can be assessed by having the child follow a lollypop with the tongue, and by 3-4 years tongue movement to command is possible.

- The tongue when protruded deviates towards the affected side in unilateral lower motor neuron lesion. If the lesion is bilateral, tongue protrusion is not possible and dysphagia may be present.

Motor examination

Gait: when the infant begins to walk, gait is assessed. In early infancy, the gait is broad based and unsteady. The base narrows with age and the 6 yr child is able to tandem walk.

- Pyramidal tract dysfunction will result in circumduction gait.

- Lower motor neuron lesion results in a wide-based unsteady gait due to weakness.

- Cerebellar dysfunction results in a broad based unsteady gait accompanied by difficulty in executing turns.

- A waddling gait results from weakness of the proximal hip girdle.

Muscle power:

- In the toddler, muscle strength is assessed by observation.

- Arm and shoulder muscle strength is tested by observing the child’s ability to raise the arms above the head, and the resistance the examiner feels when lifting the child by placing his or her hands in the infant’s axillae.

- The ability of the child to stand from the supine posture evaluates strength of the back, hip, and proximal leg muscles.

- The ability of the child to walk on the heels tests the anterior tibial muscles. Muscle weakness of pyramidal origin is associated with spasticity, extrapyramidal weakness is associated with rigidity, and the weakness of lower motor neuron origin is associated with flaccid tone.

- Muscle fasciculations suggest denervation.

Grades of muscle power

     0 = No movement.                                                1 = Movement with gravity eliminated.

     2 = Full range against gravity.                              3 = Movement against slight resistance.

     4 = Movement against moderate resistance.        5 = Normal strength.

Muscle bulk:

- Muscle atrophy is seen in both pyramidal and extrapyramidal lesions, but is most striking in those involving the lower motor neuron.

- Bulk is assessed by observation, palpation and comparison to contralateral extremities. Excessive muscle bulk is seen in pseudo hyper- trophic muscle dystrophy.

Muscle tone: is tested by assessing the degree of resistance when an individual joint is moved passively.

- In pyramidal disease, increased resistance to passive movement that suddenly gives way at a critical point (clasp knife) is noted.

- In extrapyramidal disease, an increase in resistance is present throughout the passive movement of the joint (rigidity).

- In lower motor neuron disease, decreased resistance to passive movement is present.

Deep tendon reflexes

They commonly include biceps, (C₅,C₆) triceps (C_6,C₇) knee (L_2, L_3, L₄) and ankle reflexes (S_1, S₂). They are elicited by sudden tendon stretch and can be obtained at any age.

- They are absent or decreased in primary disorders of the muscle (myopathy), nerve (neuropathy), myoneural junction, and abnormalities of the cerebellum.

- They are increased (exaggerated) in upper motor neuron lesions.

- Asymmetry of deep tendon reflexes suggests a lateralizing lesion. Sustained clonus reflects upper motor neuron lesion.

Superficial reflexes

1- Plantar response (S₁): it is obtained by stimulation of the external portion of the sole of the foot, beginning at the heel and extending to the base of the toes. Firm pressure of the examiner's thumb is a useful method eliciting the response. Flexion should occur in normal persons.

Babinski reflex is characterized by extension of the great toe and by fanning of the remaining toes. If present after 2yrs of age it indicates an upper motor neuron lesion. Asymmetry of the plantar response between extremities is a useful lateralizing sign.

2- Abdominal reflexes (T_6-T₁₂): strike or scratch the skin lightly towards the umbilicus in each quadrant of abdomen in turn. Look for abdominal muscle contraction. If absent or impaired it indicates upper motor neuron lesion, though the sign is less reliable than the plantar response.

3- Cremasteric reflex (L₁): scratch inner thigh. Observe contraction of cremasteric muscle causing testicular elevation in males. Loss of this reflex occurs in corticospinal lesions, but is rarely of importance unless unilateral.

Planter, abdominal, and cremastric reflexes are normal in lower motor neuron lesions unless their neurons are interrupted.

Primitive reflexes: normally they appear and disappear in sequence during specific periods of development (e.g. Moro, grasp, tonic neck, and parachute reflexes). Their absence or persistence beyond a given time frame signifies CNS dysfunction.

Sensory examination

- Evaluation of the sensory system includes an assessment of pain, touch, hot and cold temperature, and joint position sense.

- The sensory examination of the infant is limited to observing the perception of a pin prick by watching for crying, eye closure, facial grimace, or withdrawal of the involved part of the body. In the cooperative child, touch, heat and cold, as well as position sense can be evaluated.

- Cortical sensation (tactile localization, two point discrimination and stereognosis) can be reliably assessed only in older children. Properly demarcating a sensory level can help to localize a lesion.

Involuntary movements

1- Ataxia: it refers to incoordination of movements or disturbance of balance.

Cerebellar lesions cause trunkal ataxia, intention tremors, dysmetria, rebound phenomena, dysdiad- ochokinesia, hypotonia, dysarthria, nystagmus and decreased deep tendon reflexes. 

Ataxia may be demonstrated by finger-to-nose and heel- to- shin tests.

Sensory ataxia is found with diseases of the spinal cord and peripheral nerves.

In these disorders, Romberg sign is positive (patient is unsteady with eyes closed but not open).

2- Chorea: it is characterized by involuntary movements of the major joints, trunk, and the face that are rapid and jerky (see rheumatic chorea).

3- Athetosis: it is a slow twisting movement that is often associated with abnormalities of muscle tone. Chorea and athetosis are the result of basal ganglia lesions.

4- Dystonia: it is an involuntary slow; twisting movement that primarily involves the proximal muscle of extremities, trunk and neck. Perinatal asphyxia and Wilson disease are among the principle causes.

Special diagnostic procedures

1- Lumbar puncture and cerebrospinal fluid (CSF) examination: it is essential in confirming the diagnosis of meningitis, encephalitis, and subarachnoid hemorrhage.

CSF findings in health and disease are shown in table 16-1.

2- Subdural and ventricular taps: subdural tap may be indicated to establish the diagnosis of subdural effusion or hematoma. Ventricular tap is used for the removal of CSF in the management of life-threating increased ICP associated with hydrocephalus, when conservative measures have failed.

3- Neuro-imaging: skull roentgenogram, CT scan, MRI, myelography, cranial ultrasound, and cerebral angiography may be helpful in special situations.

4- Electro-encephalography (EEG): it records electrical activity generated by the cerebral cortex. It is important to confirm the diagnosis of epilepsy and helps in its classification, and in the detection of focal lesions.