cns 1

NEUROLOGY

Assessment
The process and interpretation of the neurologic examination vary with age. The examination of a newborn is unique with transient and primitive reflex patterns. The examination of an adolescent is similar to that of an adult.

NEUROLOGIC EXAMINATION OF A NEONATE The neurologic examination of a neonate is used to assess the function of the basal ganglia, brainstem, and more caudal structures. The results of the examination should be used cautiously in predicting developmental outcome.

Neonatal reflexes

Numerous primitive reflexes, present at birth, assess the functional integrity of the brainstem and basal ganglia . They are symmetric and disappear at 4 to 6 months of age, indicating the normal maturation of descending inhibitory cerebral influences (Moro reflex). The grasp and rooting reflexes are inhibited by maturation of frontal lobe structures and may reappear later in life with frontal lobe lesions. The Landau and parachute reflexes become apparent after the newborn period, indicating proper maturation of appropriate brain structures. Asymmetry or persistence of the primitive reflexes may indicate focal brain or peripheral nerve lesions.

Posture

Posture is the position that an infant naturally assumes when placed supine. An infant at 28 weeks of gestation shows an extended posture. By 32 weeks, there is a slight trend toward increase in tone of the lower extremities with more lower extremity flexion. At 34 weeks, the lower extremities are flexed, and the upper extremities are extended. At term, the infant flexes lower and upper extremities. Recoil is defined as a liveliness with which an arm or leg springs back to its original position after passive stretching and release. Recoil is essentially absent in a small premature infant but is brisk at term.

NEUROLOGIC EXAMINATION OF A CHILD

The purpose of the neurologic examination is to "localize" or identify the region within the neuraxis from which the symptoms are arising. The mental status examination assesses various zones of the cerebral cortex. The cranial nerve examination evaluates the integrity of the brainstem. The motor examination evaluates upper and lower motor neuron function. The sensory examination assesses the peripheral sensory receptors and their central reflections. The deep tendon reflexes assess the upper and lower motor connections. The gait assessment puts the motor system into a dynamic state for better functional assessment.

Mental Status Evaluation

Alertness is assessed in infants by observing spontaneous activities, feeding behavior, and visual ability to fix and follow the movement of objects. Response to tactile, visual, and auditory stimuli is noted. In circumstances of altered consciousness, the response to painful stimuli is noted. Toddlers are expected to play at a level appropriate for their age. Older children can be tested for orientation to time, place, person, and purpose.



The best way to assess intellectual abilities is through language skills. Language function is receptive (understanding speech or gesture) and expressive (speech and the use of gestures). Abnormalities of language resulting from disorders of the cerebral hemispheres are referred to as dysphasia or aphasias. Anterior, expressive, or Broca aphasia is characterized by sparse, nonfluent language. Posterior, receptive, or Wernicke aphasia is characterized by an inability to understand language. Speech is fluent but nonsensical. Global aphasia refers to impaired expressive and receptive language.

CRANIAL NERVE EVALUATION MOTOR EXAMINATION (Power, Tone) Gait: the toddler gait is normally wide-based and unsteady. The base narrows with age. By 6 years old, a child is able to tandem walk and walk high on the toes and heels. Cerebellar dysfunction results in a broad-based, unsteady gait accompanied by difficulty in executing turns. Corticospinal tract dysfunction produces a stiff, scissoring gait and toe walking. Arm swing is decreased, and the arm is flexed across the body. Extrapyramidal dysfunction produces a slow, shuffling gait with dystonic postures. There also may be choreoathetotic movements. Lower motor neuron disease results in either a waddling gait (if the proximal muscles are weak) or a steppage gait (if the distal muscles are weak).

Reflexes

Deep tendon reflexes at the triceps, biceps, brachio-radialis, knee, and ankle are elicited by sudden tendon stretch and can be obtained at any age. These reflexes are decreased in lower motor neuron disease and increased with the development of clonus in chronic upper motor neuron disease. The Babinski response or extensor plantar reflex with an upward movement of the great toe and flaring of the toes on noxious stimulation of the side of the foot is a sign of corticospinal tract dysfunction. This reflex is unreliable in the neonates except when asymmetric because the "normal" response at this age varies. The plantar response is consistently flexor (toes down) after 18 months of age.

Primary symptoms of neurological disease

Visual or hearing loss. Impairment of swallowing or respiration. Weakness. Numbness or parasthesia. Difficulty walking or talking. Incontinence. Deterioration in thinking. Change in personality. Seizures. Headache and dizziness.

Congenital anomalies of the nervous system

Spina bifida: It range in severity from simple defect at L5 or S1 vertebral arch, to major defect that uncovered by skin or bone on baby's back(myelocele).or the defect involve the skull (encephalocele). Symptoms: Total paralysis , loss of sensation in the legs , incontinence of bowel and bladder. Meningocele : The spinal canal and the cystic meninges are exposed but the spinal cord is functionally and anatomically normal. Prevention: folic acid

Macrocephaly and microcephaly

Macrocephaly : (large head ) 1-Macrocrania- 2-Hydrocephalus- 3-Megalencephaly- Microcephaly: (small head) 1-Crainocynostenosis: 2-Small brain:( infection, metabolic, toxic , vascular disorder)



Etiology of microcephaly
1-Chromosomal disorder: Trisomy 13 , trisomy 18 2-Genetic disorder: Microcephaly Vera ,sex linked microcephaly ,microcephaly with other brain malformation. 3-Microcephaly with syndrome: Prader-willi syndrome ,angelman syndrome 4-Infection: TORCHS 5-Toxic: Radiation ,fetal alcohol syndrome,phenylketonuria ,hypoxic-ischemic injury.

CNS reflexes of infancy

Moro :start at birth disappear at 4 months Grasp : Rooting : Placing : Tonic neck: Trunk incurvation: Parachute: start at 6-8 months and never disappear.

Increased intracranial pressure(ICP)

A symptom of serious intracranial pathology and a cause of irreversible neurological injury.The skull is rigid container ,brain accounts for 80-85% of volume,CSF 10-15%,blood 5-10%,Brain herniation:It occur when the brain shift in response to the continuing elevation of ICPEtiology: mass lesion , hydrocephalus , brain swellingSymptoms: headache ,vomiting , lethargy ,irritability ,6th nerve palsy , diplopia , papillodema accept infant?Sign: bulging fontanel , suture diastasis , distended scalp veins , sun set eyes , rapid growth of OFC.Cushing triad :↑ICP ,↓pulse , irregular respiration.

Brain abscess

It causes ↑ICP by:1-large size 2-blockage of CSF 3- blockage of venous outflow4-cerebral edema(vasogenic edema)Etiology: chronic cardiac or pulmonary disease by embolizationSymptoms:-focal neurological sign.-↑ICP-fever , malaise , anorexia , stiff neck.Diagnosis : CT scan , (LP is contraindicated)Treatment : surgery.

Hydrocephalus

Produces slowly evolving syndrome of ↑ICP extending over wks or ms.Pressure is exerted by both enlarging ventricle & interstitial edema.CSF:Ultra filtration of plasma produced by choroids' plexus. Volume 50 ml in neonate ,150 ml in adultFlow from lateral v →3rd V through foramen of Monro then through cerebral aqueduct →4th V then through foramen of Magendie and Luschka to the subarachnoid space.Absorption: by arachnoid villi.

Types of hydrocephalus

hydrocephalus
Obstructive
nonobstructive
Choroid papilloma

Etiology

Obstructive 1-congenital a- Arnold-Chiari malformation is characterized by progressive hydrocephalus with a myelomeningocele. This lesion represents an anomaly of the hindbrain, probably due to a failure of pontine flexure during embryogenesis, and results in elongation of the 4th ventricle and kinking of the brainstem, with displacement of the inferior vermis, pons, and medulla into the cervical canalb b-Dandy-Walker consists of a cystic expansion of the 4th ventricle in the posterior fossa and midline cerebellar hypoplasia, which results from a developmental failure of the roof of the 4th ventricle during embryogenesis c- aqueduct stenosis) results from an abnormally narrow aqueduct of Sylvius that is often associated with branching or forking 2-congenital infection. toxoplasmosis 2-post meningoencephalitis. 4-tumor( I V tumer ). 5-other(neurofibromatosis , AV malformation , achondroplasia ,rickets).

Non obstructive 1- congenital(arachnoid villi). 2-infection. 3-hemorrhage.

Clinical feature
1-symptoms&sign of ↑ICP.2-ataxia&spasticity (lower limb)3-endocrine dysfunction.4-visual dysfunction.5-˝sun set eyes˝.6-dilated scalp veins.7-widly opening fontanel.8-rappid ↑in OFC by serial measures.

Diagnosis

1-clinically 2-imiging study(ultrasound). 3-radiological study(CT scan).

Treatment

Medical : (Meningitis, subarachnoid Hr) acetazolamide
Surgery : -(cyst ,tumer ,AVM) Removal. -shunt placing.

Dandy-walker

Floppy baby



Neonatal immobility: The 1st step in evaluations of an infant who doesn't move spontaneously or in response to stimuli is to determine whether awareness is intact ? The cortical activity is intact if the baby is bright eyed able to follow and try to smile but is unable to move . If the face and eyes are immobile the problem is more difficult . Clinical questions: Does the infant response to :flashlight , bell , nasal cotton stimuli? Does the eyes follow if the lids are lifted? Are reflexes increase? UML


EEG
Sever slowing of EEG +↑reflex Normal or near normalEEG and immobility+↓reflex Cerebral disease
Neuromuscular disease or Spinal cord disorder
If the clinical exam. Doesn't settle the question then EEG will be helpful

Etiology of neonatal immobility

Sever hypoxic ischemic encephalopathy: Flaccidity Areflexia Complete ptosis Ophthalmoplegia Absent corneal&gag reflex Intoxication : Mg sulfate Barbiturate Narcotics Benzodiazepines General anesthesia Metabolic encephalopathy: Hypoglycemia hyperbilirubinemia

Hypotonia without major weakness

acute systemic illness. Mental retardation: Specific syndromes Down syndrome Cerebrohepatorenal syndrome Kinky hair syndrome Prader-willi syndrome Connective tissue disorder: Ehlers-Danlos syndrome Marfan syndrome


Nutritional-metabolic disease: Rickets Renal tubular acidosis Celiac disease Biliary Artesia Congenital heart disease Benign congenital hypotonia: Exhibit the condition at 9-12 months. Delayed motor milestone. Normal social , intelligence , fine motor movement. Head lag , slip-through ventral suspension. Complete lab. Investigation are necessary. Most of children become normal by 3 yrs.