Hydrocephalus is a buildup of fluid inside the skull, leading to brain swelling. Hydrocephalus means "water on the brain."
Water on the brain
Causes, incidence, and risk factors:
Hydrocephalus is due to a problem with the flow of cerebrospinal fluid (CSF), the liquid that surrounds the brain and spinal cord. The fluid brings nutrients to the brain, takes away waste from the brain, and acts as a cushion.
CSF normally moves through areas of the brain called ventricles, then around the outside of the brain and the spinal cord. It is then reabsorbed into the bloodstream. Buildup of CSF can occur in the brain if its flow or absorption is blocked or if too much CSF is produced.
This buildup of fluid puts pressure on the brain, pushing the brain up against the skull and damaging or destroying brain tissues.
Hydrocephalus may start while the baby is growing in the womb. It is commonly present with myelomeningocele , a birth defect involving incomplete closure of the spinal column. Genetic defects and certain infections that occur during pregnancy may also cause hydrocephalus.
In young children, hydrocephalus may also be associated with the following conditions:
- Infections that affect the central nervous system (such as meningitis or encephalitis), especially in infants
- Bleeding in the brain during or soon after delivery (especially in premature babies)
- Injury before, during, or after childbirth, including subarachnoid hemorrhage
- Tumors of the central nervous system, including the brain or spinal cord
- Injury or trauma
Hydrocephalus most often occurs in children, but may also occur in adults and the elderly. See: Normal pressure hydrocephalus
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 be larger than expected. Early symptoms may also include:
- Eyes that appear to gaze downward
- Separated sutures
Symptoms that may occur in older children can include:
- Brief, shrill, high-pitched cry
- Changes in personality, memory, or the ability to reason or think
- Changes in facial appearance and eye spacing
- Crossed eyes or uncontrolled eye movements
- Difficulty feeding
- Excessive sleepiness
- Irritability, poor temper control
- Loss of bladder control (urinary incontinence)
- Loss of coordination and trouble walking
- Muscle spasticity (spasm)
- Slow growth (child 0 - 5 years)
- Slow or restricted movement
Signs and tests:
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. Enlargement is most commonly seen in the front part of the head. Head circumference measurements, repeated over time, may show that the head is getting bigger.
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 that may be done include:
- Brain scan using radioisotopes
- Cranial ultrasound (an ultrasound of the brain)
- Lumbar puncture and examination of the cerebrospinal fluid (rarely done)
- Skull x-rays
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 (flexible tube) may be placed within the brain to allow CSF to flow around the blocked area. The shunt tubing travels to another part of the body, such as the abdomen, where the extra CSF can be absorbed.
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.
Follow-up examinations generally continue throughout the child's life. These are done to check the child's developmental level and to treat any intellectual, neurological, or physical problems.
Visiting nurses, social services, support groups, and local agencies can provide emotional support and assist with the care of a child with hydrocephalus who has significant brain damage.
Untreated hydrocephalus has a 50 - 60% 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.
Shunt placement may lead to blockage. Symptoms of such a blockage include headache and vomiting. Surgeons may be able to help the shunt open without having to replace it.
There may be other problems with the shunt, such as kinking, tube separation, or infection in the area of the shunt.
Other complications may include:
- Complications of surgery
- Infections such as meningitis or encephalitis
- Intellectual impairment
- Nerve damage (decrease in movement, sensation, function)
- Physical disabilities
Calling your health care provider:
Seek immediate medical care if your child has any symptoms of this disorder. Go to the emergency room or call 911 if emergency symptoms occur, which include:
- Breathing problems
- Extreme drowsiness or sleepiness
- Feeding difficulties
- High-pitched cry
- No pulse (heart beat)
- Severe headache
- Stiff neck
You should also call your health care provider if the child has been diagnosed with hydrocephalus and the condition gets worse and you are unable to care for him or her at home.
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.
Kinsman SL, Johnston MV. Congenital anomalies of the central nervous system. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 592.
Golden JA, Bönnemann CG. Developmental structural disorders. In: Goetz CG, eds. Textbook of Clinical Neurology. 3rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 28.