What is Hydrocephalus?
Hydrocephalus, also known as water on the brain, is a build-up of fluid inside the skull, leading to brain swelling. The disorder is due to a problem with the flow of cerebrospinal fluid (CSF), the liquid that surrounds the brain and spinal cord. CSF moves through pathways of the brain called ventricles, but it also flows around the outside of the brain and through the spinal canal. Higher-than-normal amounts of CSF can occur in the brain if the flow or absorption of CSF is blocked, or if too much CSF is produced. The build up of fluid puts pressure on the brain, pushing the brain up against the skull and damaging or destroying brain tissues.
The symptoms depend on the cause of the blockage, the person's age, and how much brain tissue has been damaged by the swelling. In infants with hydrocephalus, CSF fluid builds up in the central nervous system, causing the fontanelle (soft spot) to bulge and the head to expand. Early symptoms may also include irritability, muscle spasms and vomiting. Symptoms that occur later in the disease may include decreased mental function, difficulty feeding, excessive sleepiness, loss of bladder control, and slow growth.
When a health care provider taps fingertips on the skull, there may be abnormal sounds that indicated thinning and separation of skull bones. Scalp veins may appear stretched or enlarged. Part or the entire head may be larger than normal, especially the front part of the head. The eyes may look “sunken in.” The white part of the eye may appear above the colored part of the eye, given the eyes a “setting-sun” appearance. Reflexes may be abnormal. A head CT scan is one of the best tests for identifying hydrocephalus. Other tests include:
- Brain scan using radioisotopes
- Cranial ultrasound (an ultrasound of the brain)
- Lumbar puncture and examination of the cerebrospinal fluid
- Skull X-rays
- Transillumination of the head (shining a light against the head)
The goal of treatment is to reduce or prevent brain damage by improving the flow of CSF. The blockage may be surgically removed, if possible. If the blockage cannot be removed, a shunt may be placed within the brain to allow CSF to flow around the blocked area.Antibiotics are given if there are signs of infection. Severe infections may require the shunt to be removed. Another option is endoscopic third ventriculostomy (ETV), which relieves pressure without replacing the shunt. Removing or burning away (cauterizing) the parts of the brain that produce CSF may reduce CSF production.
Untreated hydrocephalus has a 50-60 percent death rate, with the survivors having varying degrees of intellectual, physical, and neurological disabilities. The outlook for treated hydrocephalus depends on the cause. Hydrocephalus that is caused by disorders not associated with infection has the best outlook. Persons with hydrocephalus caused by tumors usually do very poorly. Most children with hydrocephalus that survive for 1 year will have a fairly normal life span. Approximately a third will have normal intellectual function, but neurological difficulties may persist.
Protect the head of an infant or child from injury. Prompt treatment of infections and other disorders associated with hydrocephalus may reduce the risk of developing the disorder.
Hydrocephalus treatment at Hopkins Children’s is managed by the Division of Neonatal-Perinatal Medicine.