Hydrocephalus

(Congenital, Normal pressure, and Obstructive Hydrocephalus)

Hydrocephalus is the buildup of fluid in the spaces, or ventricles, within the brain and skull. Normally, the body produces about a pint of cerebrospinal fluid each day. After circulating through these spaces, the fluid is reabsorbed into the bloodstream and replaced by a fresh supply. Most often, hydrocephalus develops when a ventricle becomes blocked. The blockage may be the result of an overgrowth of tissue, a cerebral hemorrhage, inflammation, or a head injury. In rare cases, hydrocephalus results from an overproduction of cerebrospinal fluid caused by a brain tumor.

Congenital hydrocephalus is quite common in newborn babies, especially premature ones. Worldwide, approximately one infant in a thousand is born with it. Premature babies are particularly vulnerable, because they often develop bleeding into the brain ventricles, resulting in inflammation and scar tissue that blocks the fluid outflow. Other causes include viral infections transmitted by the mother to her fetus during pregnancy, birth defects, or an injury during birth.

A baby who is born with congenital hydrocephalus often has an abnormally large and deformed head. The infant may also cry constantly, vomit frequently, and exhibit spastic movements. If the condition occurs early in fetal development, major brain damage is always a consequence. Hydrocephalus that develops after age five, when the skull bones have knit together and closed permanently, results in increased pressure within the skull on the brain itself. This type of hydrocephalus may be caused by diseases affecting the brain, including meningitis, encephalitis, or a brain abscess or tumor. The symptoms might include a severe headache, mental changes, blurred vision, vomiting, dizziness, and impaired coordination.

A condition known as normal pressure hydrocephalus sometimes occurs in elderly persons. It produces mental changes and a shambling gait that is often mistaken for Alzheimer's disease or other degenerative brain disorders. The cause of the disorder is unknown, although some patients have a history of head injuries or meningitis.

Diagnostic Studies and Procedures

A doctor will suspect congenital hydrocephalus if a baby has been born with an over sized head or is demonstrating some of the other symptoms. Blood tests will be ordered to rule out an infection, and electroencephalography will be done to determine if seizures are due to epilepsy. Other procedures include examination of the head with ultrasound, trans illumination, in which the brain is examined by using a bright light, tapping the head to see if it produces a characteristic 'cracked pot' sound, and listening for abnormal sounds typically produced by deformed blood vessels.

After the age of one, a diagnosis of hydrocephalus can be confirmed by CT brain scans or an MRI. These imaging studies can also detect possible causes, such as a brain cyst, abscess, or tumor. The scans are especially important in elderly patients to rule out Alzheimer's disease and other forms of dementia.

Medical Treatments

Prompt treatment is critical in all types of hydrocephalus to prevent permanent brain damage and even death. Among babies born with the condition, about half die without treatment. Among those who do receive prompt surgery and survive, about 40 percent will have normal intelligence, the remaining 60 percent are likely to suffer from varying degrees of mental or neurological impairment. In some instances, giving a combination of acetazolamide (Diamox) and glycerol will reduce the production of cerebrospinal fluid. The majority of cases, however, are treated surgically.

Treatment may begin with punctures in the lumbar region of the spine to remove some of the fluid. But the standard operation consists of implanting a shunt into the ventricle to reroute the fluid from the head, under the skin, and into the peritoneal cavity of the abdomen, where it is reabsorbed into the bloodstream. The shunt is made of plastic rubber, which does not deteriorate nor interact with body tissues. In a baby, the neurosurgeon will insert extra tubing to accommodate growth. A shunt may malfunction or become blocked and thus require removal or replacement. Otherwise, these devices are usually left in place for years.

Surgical shunting for normal pressure hydrocephalus in the elderly is most successful when it is done within one year of the appearance of symptoms. In such cases, surgery often succeeds in reversing the mental deterioration.

Alternative Therapies

Although alternative therapies cannot be used to treat hydrocephalus itself, some can help patients improve their impaired coordination.

Dance and Music Therapy. When used as a movement therapy, these modalities can improve coordination and gait.

T'ai Chi. The range-of-motion exercises that are incorporated into this movement therapy can help older patients overcome the shuffling gait seen in normal pressure hydrocephalus.

Self-Treatment

Hydrocephalus does not lend itself to self-treatment.

Other Causes of Brain Symptoms

Reye's syndrome, a rare childhood disease that causes brain swelling, can cause symptoms similar to those of hydrocephalus. In older people, Parkinson's disease causes a shuffling gait. In addition to disorders mentioned earlier, chronic alcoholism and severe malnutrition can lead to mental deterioration and gait disturbances.