Hydrocephalus: A-to-Z Guide from Diagnosis to Treatment to Prevention

The brain and spinal cord are bathed and protected by cerebrospinal fluid (CSF). A baby has less than 2 ounces of spinal fluid; a typical adult has about 5 ounces.

A typical child makes about 2 ounces of new spinal fluid every 3 hours. This spinal fluid flows in and around the brain through waterways and aqueducts before it completes its journey and is reabsorbed.

What is it?

It is the build-up of excessive spinal fluid. This can be caused by a blockade or narrowing along the CSF circulation route (called obstructive or noncommunicating hydrocephalus). It can also be caused by impaired resorption of spinal fluid that has completed its journey (communicating hydrocephalus). Very rarely, it can be caused by over-production of CSF.

Who gets it?

Sometimes abnormally narrow CSF passageways run in families. Sometimes it is the result of other problems, such as neural tube defects (e.g. spina bifida), meningitis, encephalitis, head bleeds, brain tumors, mumps, tuberculosis, or streptococcal infections.

What are the symptoms?

In small children, the main sign of hydrocephalus is a rapidly expanding head. The anterior fontanel is wide open.

In older children, it is not as easy to detect.

Either way, vomiting, decreased appetite, and irritability are common. Between bouts of irritability, kids are often somewhat lethargic.

The eyes may deviate downward (the sunset sign). General muscle tone may be increased, and reflexes may be too brisk.

Older children often describe a headache.

Is it contagious?

No, although some of the underlying causes are contagious.

How long does it last?

Hydrocephalus often continues until it is treated.

How is it diagnosed?

The diagnosis is suspected based on the history and the physical exam. It is confirmed with imaging studies of the head, such as CT, MRI, or ultrasound.

How is it treated?

While medicines are available to temporarily decrease CSF production, the mainstay of treatment is usually to place a shunt to remove the excess CSF.

How can it be prevented?

Often it cannot be prevented. Preventing the underlying conditions that lead to hydrocephalus may be the most effective form of prevention.

Related concepts:

Communicating hydrocephalus, Noncommunicating hydrocephalus, Obstructive hydrocephalus, Water on the brain.