Hydrocephalus
Hydrocephalus
Hydrocephalus
DEFINITION
Hydrocephalus is a condition caused by an imbalance in the production and absorption of CSF in the ventricular system, when production is greater than absorption. CSF accumulates within the ventricular system, under increased pressure, producing passive dilation of the ventricles.
CSF CIRCULATION
ETIOLOGY
CONGENITAL HYDROCEPHALUS Intrauterine infections- mainly Rubella, Toxoplasma, Cytomegalovirus. Congenital malformations like aqueduct stenosis. Amold- chiari malformation ( displacement of the brain stem and cerebellum through formen magneum ) Dandy-walker anomaly ( congenital septum or membrane blocking the out let of 4th ventricle ) Intracranial hemorrhage Congenital brain tumor Malformation of arachnoid ventricle
ETIOLOGY (conti)
ACQURIRED HYDROCEPHALUS Inflammation Meningitis, Encephalitis Trauma- Birth injury, head injury, Intracranial hemorrhage. Neoplasm- tuberculoma, subdural hematoma or abscess gliomas, ependymoma asterocytoma, choroid plexus papiloma, pseudo tumor cerebrai.
ETIOLOGY (conti)
Chemical- Hypervitaminosis A Connective tissue disorder- Hurler syndrome achondroplasia. Degenarative atrophy of brain-Hydrocephalus Ex vaculo Arteriovenous malformation, ruptured aneurysms,cuvernous sinus thrombosis etc.
TYPES OF HYDROCEPHALUS
COMMUNICATING HYDROCEPHALUS
PATHOPHYSIOLOGY
Due to above causes , the ventricular system becomes greatly distended and dilated Increased ICP leads to thinning of cerebral cortex and cranial bones Ependymal lining of ventricles is disrupted resulting in preventricular ooze.
Edema occurs and white matter is compressed, 3rd ventricle compress the optic nerve and dilation of sella turica, atrophy of choriod plexus Enlargement of skull and previously closed sutures lines may become diastatic or open ( especially sagital suture)
CLINICAL MANIFESTATIONS
Depends upon age of child, types and duration of hydrocephalus, closing of anterior fontanel or fusion of cranial sutures. The features may manifest rapidly, slowly, steadly advancing or remittent. INFANCY ( EARLY) Abnormally rapid head growth Bulging fontanels ( anterior) without head enlargement, tense, nonpulsatile. Dilated scalpveins Separated sutures Macewen sign ( cracked pot sound on percussion) Thinning of skull bones.
CHIDHOOD Head ache on awakening, upright posture or emesis Papilledema Strabismus Ataxia Irritability Lethargy Apathy Confusion Incoherence Vomiting Urinary incontinence Usually not accompanied by big head as in infancy
INCIDENCE
Not exactly known Acquired hydrocephalus occurs 1 in every 1000 children Some time found to be associated with meningomyelocele
DIAGNOSTIC EVALUATION
Physical examination and neurological examination Increase in head circumference in first 3 months of life, more than 1cm every 15 days and persistent widening of saquamo-partial sutures should arose the suspicion. Typical cracked pot sound (Makmens sign) of the skull bone Ophthalmoscope are important measures. MRI, CT scan, cranial ultrasonography X ray
MEDICAL MANGEMENT
The goal to establish equilibrium between production and absorption. Use of acetazonamide (Diamox), a drug ( 50mg/kg/day) that reduce the production of CSF occasionally Repeated lumber puncture can be done to maintain the pressure in case of acute hydrocephalus or subarachnoid hemorrhage or bacterial meningitis.
SURGICAL MANGEMENT
The removal of the obstruction- For the flow of CSF, through the surgical removal of the tumor. Reduction in the amount of CSF production Through destruction of the portion of choriod plexus ( choriod plexotomy) or a third or fourth ventriculostomy. Shunting the CSF from the ventricle to another site in the normal circulating pathway -For non communicating type. Shunting from the ventricle to an area outside the CNS -Used most commonly for communicating type and non communicating type in infants.