Hydrocephalus is a buildup of fluid inside the skull that leads 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 the fluid that surrounds the brain. This fluid is called the cerebrospinal fluid, or CSF. It surrounds the brain and spinal cord, and helps cushion the brain.
CSF normally moves through the brain and the spinal cord, and is soaked into the bloodstream. CSF levels in the brain can rise if:
- The flow of CSF is blocked
- It does not get absorbed into the blood properly
- Your brain makes too much of it
Too much CSF puts pressure on the brain. This pushes the brain up against the skull and damage brain tissue.
Hydrocephalus may begin while the baby is growing in the womb. It is common in babies who have a myelomeningocele
, a birth defect in which the spinal column does not close properly.
Hydrocephalus may also be due to:
- Genetic defects
- Certain infections during pregnancy
In young children, hydrocephalus may be due to:
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. Another type, called normal pressure hydrocephalus
, may occur in adults and the elderly.
Symptoms of hydrocephalus depend on:
- Amount of brain damage
- What is causing the buildup of CSF fluid
In infants with hydrocephalus, it causes 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
The doctor or nurse will examine the baby. This may show:
- Stretched or swollen veins on the baby's scalp
- Abnormal sounds when the health care provider taps lightly on the skull, suggesting a problem with the skull bones
- All or part of the head may be larger than normal, usually in the front part
- Eyes that look "sunken in"
- White part of the eye appears over the colored area, making it look like a "setting sun"
- Reflexes may be normal
Head circumference measurements, repeated over time, may show that the head is getting bigger.
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.
Surgery may be done to remove a blockage, if possible.
If not, a flexible tube called a shunt may be placed in the brain to re-route the flow of CSF. The shunt sends CSF to another part of the body, such as the belly area, where it can be absorbed.
Other treatments may include:
- Antibiotics are given if there are signs of infection. Severe infections may require the shunt to be removed.
- A procedure called endoscopic third ventriculostomy (ETV), which relieves pressure without replacing the shunt.
- Removing or burning away (cauterizing) the parts of the brain that produce CSF.
The child will need regular check-ups to make sure there are no further problems. Tests are regularly done to check the child's developmental and for 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.
Without treatment, up to 6 in 10 people with hydrocephalus will die. Those who survive have different amounts of intellectual, physical, and neurological disabilities.
The outlook depends on the cause. Hydrocephalus that is not due to an 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.
The shunt may become blocked. 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:
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. Hydrocephalus. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 585.11.
Rosenberg GA. Brain edema and disorders of cerebrospinal fluid circulation. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann; 2008:chap 63.
Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, David R. Eltz, Stephanie Slon, and Nissi Wang.