Hydrocephalus Hydrocephalus Definition A condition affiliated with excessive fluid in the brain. Causes, incidence, and risk factors The fluid in the brain (cerebrospinal fluid or CSF) is formed in the brain. CSF usually circulates through parts of the brain, its covering, and the spinal canal, and is then absorbed into the circulatory system. When the circulation or absorption of this fluid is blocked, or excessive fluid is produced, the volume of fluid in the brain becomes higher than normal. The accumulation of fluid puts pressure on the brain forcing it against the skull and damaging or destroying the tissues. Symptoms vary depending on the cause of the obstruction to CSF circulation, the age at which the problem develops, and the extent of damage to brain tissue caused by the hydrocephalus. In infants, fluid accumulates in the central nervous system, causing the fontanelle (soft spot) to bulge and the head to expand.
The head can enlarge because the bony plates which make up the skull have not yet fused together. However, once the skull bones are completely fused together, at about age 5, the skull will no longer expand. In small children, risks for developing hydrocephalus include congenital defects, tumors of the central nervous system, intrauterine infection, infections in an infant or child that affect the central nervous system (such as meningitis or encephalitis), injury occurring during the birth process, or trauma before or after birth (including subarachnoid hemorrhage). Myelomeningocele, a disorder involving incomplete closure of the spinal column, is strongly associated with hydrocephalus. In older children, risks include history of congenital or developmental defects, space-occupying lesions or tumors of the brain or spinal cord, central nervous system infections, bleeding anywhere in the brain, and trauma.
The incidence is approximately 1 out of 1,000 people. Hydrocephalus most often occurs in children, but may also occur in adults and the elderly. Prevention Protect the head of an infant/child from injury by handling the child carefully. Prompt treatment of infections (such as meningitis) and other disorders associated with hydrocephalus may reduce the risk of developing the disorder. Symptoms EARLY SYMPTOMS, IN INFANTS * enlargement of the head (see increased head circumference) * bulging fontanelles (soft spots of the head) with or without enlargement of the head size * sutures – separated SYMPTOMS OF CONTINUED HYDROCEPHALUS * irritability, poor temper control * muscle spasticity (spasm LATE SYMPTOMS * decreased mental function * delayed development * decreased movement * slow or restricted movement * difficulty feeding * lethargy, excessive sleepiness * urinary incontinence (loss of control over bladder) * brief, shrill, high-pitched cry * slow growth (child 0-5 years) IN OLDER INFANTS AND CHILDREN Symptoms vary depending on the amount of damage caused by pressure in the brain. Symptoms may be similar to symptoms of progression of hydrocephalus in children, or may include the following or other symptoms: * headache * vomiting * vision changes * crossed eyes * uncontrolled eye movements * loss of coordination * poor gait (walking pattern) * mental aberrations (such as confusion or psychosis) Signs and Tests Tapping with the fingertips (percussion) on the skull may show abnormal sounds associated with thinning and separation of skull bones. Scalp veins may appear dilated. The circumference of the head may be large, or there may be enlargement of only part of the head, most commonly the frontal area. Measurements of the circumference of the head, repeated over time, may show progressive enlargement.
The eyes may be depressed, with a setting-sun sign where the sclera (white portion of the eye) is visible above the iris (colored portion of the eyes). A neurologic examination may show focal neurologic deficits (localized loss of function), and reflexes may be abnormal for the age of the child. Tests: * Transillumination of the head (shining a light against the head) may show abnormal fluid accumulation in various areas of the head. * A head CT scan indicates if hydrocephalus is present (best test). * A lumbar puncture (spinal tap) and examination of the CSF may be performed (rarely) * Skull X-rays show thinning and/or separation of skull bones and enlargement of the skull * A brain scan using radioisotopes may show abnormalities of the fluid pathway.
* An arteriography of brain blood vessels may show vascular causes of hydrocephalus. * An echoencephalogram, a form of ultrasound of the brain, may show dilation of the ventricles caused by hydrocephalus or intraventricular bleeding This disease may also alter the results of a RHISA scan. Treatment The goal of treatment is to minimize or prevent brain damage by improving CSF flow. Surgical interventions are the primary treatment of hydrocephalus. This includes direct removal of the obstruction, if possible.
Surgical placement of a shunt within the brain may allow CSF to bypass the obstructed area if the obstruction cannot be removed. Shunting of CSF to an area outside of the brain (such as to the right atrium of the heart or to the abdominal peritoneum) is an alternative to shunting within the brain. Surgical cautery or removal of the parts of the ventricles that produce CSF may (theoretically) reduce CSF production. Antibiotics are used aggressively at any sign of infection. Severe infections may necessitate removal of a shunt. Follow-up examinations should continue throughout the child’s life to evaluate the child’s developmental level and to treat any intellectual, neurologic, or physical impairments. Public health/visiting nurses, social services, support groups, and local agencies provide emotional support and assist with the care of the child with hydrocephalus.
Complications * shunt dysfunction (kinking, obstruction, separation of tubing, or similar problems) * infection * meningitis * encephalitis * infection of the area to which CSF is shunted * intellectual impairment * neurologic damage (decrease in movement, sensation, function) * physical disabilities * complications of surgery Expectations (prognosis) Untreated hydrocephalus has a 50 to 60% death rate, with the survivors having varying degrees of intellectual, physical, and neurologic disabilities. Prognosis for treated hydrocephalus varies depending on the cause. If the child survives for one year, over 80% will have a fairly normal life span. Approximately one-third will have normal intellectual function, but neurologic difficulties may persist. Hydrocephalus that is caused by disorders not associated with infection carries the best prognosis (probable outcome), although hydrocephalus caused by tumors has a very poor prognosis.