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If your doctor says your child has hydrocephalus, you probably have a lot of questions.

Hydrocephalus is not a single disease, but rather the condition of having too much cerebrospinal fluid (CSF) in the brain. Hydrocephalus is a serious condition but has multiple excellent treatments. The best treatment depends on your child’s underlying diagnosis.

Here’s what you need to know about hydrocephalus.

What Is Hydrocephalus?

Cerebrospinal fluid is an incredibly important substance. While it resembles water, CSF is in fact a special liquid that contains minerals, nutrients, proteins and even cells that are necessary for normal brain function. The brain is constantly producing new CSF, cycling it through a series of special cavities called ventricles, and reabsorbing it.

In hydrocephalus, more CSF builds up in the brain than it is capable of reabsorbing. The literal translation of hydrocephalus (“water in the head”), while not entirely correct in its name, reflects this imbalance of CSF production and reabsorption. Excess CSF puts pressure on the brain, and this pressure can be harmful or even lethal.

Hydrocephalus is relatively common. The National Institute of Neurological Disorders and Stroke estimates it affects 1 to 2 of every 1,000 children born in the United States. It’s the most common reason for a child to have brain surgery.

What Causes Hydrocephalus?

Hydrocephalus can occur at any age but is most commonly diagnosed in childhood. Hydrocephalus may be congenital (present at birth) or acquired. There are two broad forms of hydrocephalus, each of which can result from distinct causes.

Obstructive hydrocephalus

Obstructive hydrocephalus results from a blockade of CSF flow through the ventricles, the normal spaces within the brain where CSF is produced. Obstructive hydrocephalus may be present at birth but is more commonly acquired. The most common causes of obstructive hydrocephalus are:

• Aqueductal stenosis/tectal plate stenosis.
• Aqueductal webs.
• Brain tumors.
• Chiari malformation.
• Tectal plate glioma.

Communicating hydrocephalus

Communicating hydrocephalus occurs when there is an imbalance of CSF production and reabsorption despite the ventricles being open and working properly (“communicating”). The causes of communicating hydrocephalus are much more varied and include:

• Bleeding in or around the brain, especially when due to prematurity.
• Infection in or around the brain.
• Specific types of tumors.
• Spina bifida.
• Trauma.

Hydrocephalus Symptoms

Many symptoms may be associated with hydrocephalus. In newborns, infants and toddlers, symptoms of hydrocephalus include:

• An unusually large head.
• A rapid increase in head size.
• A fontanelle (the soft spot on top of a baby’s head) that bulges outward.
• Fussiness.
• Being unusually tired.
• A poor appetite.
• Vomiting.
• Eyes that look downward all the time (doctors call this “sun setting”).
• Eyes that can’t turn outward.
• Slowed development.
• Seizures.

In older children, symptoms may include:

• Headache.
• Blurred or double vision.
• Slow development.
• Vision problems.
• Nausea and vomiting.
• Balance problems.
• Decline in school performance.
• Loss of bladder control.
• Coordination problems.
• Having a hard time waking up.
• Changes in personality.
• Memory loss.
• Irritability.

The symptoms that may be associated with hydrocephalus can be nonspecific. Because of that, an experienced neurologist or neurosurgeon should evaluate possible cases of hydrocephalus to know when this diagnosis should be seriously considered.

Complications of Hydrocephalus

Children with untreated hydrocephalus may suffer long-term complications if the hydrocephalus is not treated promptly. These complications may include:

• Epilepsy.
• Learning disabilities.
• Memory and organizational problems.
• Problems with physical coordination.
• A short attention span.
• Speech and vision problems.

If your child has complications from hydrocephalus, it’s important to get extra support. Your child may benefit from physical and occupational therapy or an early intervention program.

Diagnosing Hydrocephalus

Doctors diagnose hydrocephalus using a combination of history-taking, physical examination, and brain imaging. Specific aspects of the workup for hydrocephalus include:

• A complete medical history — A detailed history of the child’s pregnancy, childhood development, and current and past medical history will be performed. Some causes of hydrocephalus may run in families, so a detailed family history is also necessary.
• A neurological exam — A detailed neurologic exam is required to test the child’s level of consciousness, reflexes, vision, hearing, balance, and motor function.
• Fundoscopic exam — A fundoscopic exam is a noninvasive test performed by an eye doctor. This exam can detect papilledema, which is swelling of the optic nerves where they insert into the back of the eye. Papilledema during a routine eye exam is sometimes the first sign of hydrocephalus that is detected incidentally.
• Prenatal ultrasound — Sometimes, doctors detect early signs of hydrocephalus before birth using prenatal ultrasound, which may show an enlarged head or enlarged ventricles.
• Head ultrasound — In young children with an open fontanelle (under 1 year old), head ultrasound (HUS) is a noninvasive test that can help identify enlarged ventricles and sometimes identify a cause.
• Magnetic resonance imaging (MRI) — A brain MRI is a test that gives a complete picture of the brain with excellent anatomic detail. A brain MRI may take longer to perform than a child is able to stay still. In this case, they may need temporary sedation, which is safe. No radiation is involved in performing a brain MRI.
• Computed tomography (CT) — A head CT (HCT) scan is a 3D x-ray of the brain. It can show whether the ventricles are enlarged and show more obvious abnormalities within the brain. It involves a small amount of radiation that is safe to administer in children.
• Lumbar puncture (spinal tap) — A lumbar puncture involves inserting a small needle into the CSF space in the lower back to remove a small amount of fluid for tests and measure CSF pressure.
• Intracranial pressure monitoring (ICP) — In cases where the diagnosis of hydrocephalus is unclear, the pressure within the brain must be measured directly using an ICP monitor. This is a procedure performed by a neurosurgeon that requires a child to remain in the hospital while their pressure is monitored. After enough data are collected, the ICP monitor is removed.

Hydrocephalus Treatment

Treatment for hydrocephalus may depend on your child’s age and the cause of the hydrocephalus. Regardless of treatment, hydrocephalus will require long-term follow-up to ensure adequate treatment. Follow-up typically becomes less frequent with age.

Surgical treatment

There are two main surgeries for hydrocephalus:

• Shunt surgery — Doctors place a piece of tubing that connects the ventricles to a cavity in the body capable of reabsorbing the CSF. The most common type of shunt surgery is a ventriculoperitoneal shunt, where CSF is shunted to the peritoneal cavity (where the stomach and bowels are). Other types of shunts include ventriculopleural shunt (where CSF is reabsorbed by the lining of the lungs) and ventriculoatrial shunt (where CSF is placed directly into the bloodstream).
• Endoscopic third ventriculostomy (ETV) — Here, a neurosurgeon makes a tiny hole in the bottom of the third ventricle in order to bypass an obstruction in the ventricles. Sometimes, the choroid plexus, the organ that makes CSF, is ablated in the same procedure to lower CSF production. This is called choroid plexus cauterization (CPC).

While hydrocephalus surgery is usually intended to be definitive, children with hydrocephalus often need more than one surgery for treatment as they grow.

Nonsurgical treatment

After surgery, your child will need follow-up care. Depending on the cause of hydrocephalus, your child might need:

• An early intervention program.
• Occupational therapy.
• Physical therapy.

Editor's Note: This article was originally published on December 14, 2022, and was last reviewed on May 28, 2025.