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What is hydrocephalus?

Hydrocephalus — also called “water on the brain” — is a term used to describe several different problems that cause cerebrospinal fluid (CSF) to build up in or around the brain or to drain improperly. This causes the brain’s ventricles (fluid spaces inside the brain) to enlarge.

This can happen if:

  • a blockage in the brain’s anatomy stops the fluid from flowing as it should
  • a hemorrhage or infection causes scarring within the fluid’s pathways
  • a tumor, cyst, or other mass blocks the normal pathways for fluid

Hydrocephalus progresses over time and causes increasing pressure and stretching of tissue in the brain. If this pressure isn’t relieved, it can interfere with normal brain growth and development and lead to permanent damage in the brain.

Hydrocephalus is often congenital, meaning babies are born with it, but older children can also develop it. In some cases, hydrocephalus can develop as a complication of another condition.

Hydrocephalus | Symptoms & Causes

What are the symptoms of hydrocephalus?

Symptoms of hydrocephalus can vary widely depending on your child’s age and how advanced the condition is when it’s discovered.

Infants with hydrocephalus may have:

  • an unusually large head
  • a rapid increase in head size
  • extreme sleepiness
  • vomiting that is frequent and severe
  • trouble looking up when the head is facing forward
  • seizures that have no known cause

Older children with hydrocephalus may have:

  • severe headaches, often with nausea and vomiting
  • blurred or double vision
  • problems with balance
  • trouble looking up when the head is facing forward
  • problems with coordination
  • trouble standing or walking
  • loss of bladder control
  • extreme tiredness
  • irritability for no apparent reason
  • delays in reaching developmental milestones
  • trouble remembering and focusing
  • sudden changes in personality

See a medical professional right away if your child has any of these symptoms.

What causes hydrocephalus?

There is no one cause for the type of hydrocephalus babies are born with. It may be linked to a genetic defect or a complication of another disorder, such as spina bifida or encephaloceles.

Children may also develop hydrocephalus after birth as a complication of:

Hydrocephalus | Diagnosis & Treatments

How is hydrocephalus diagnosed?

When a baby is born with hydrocephalus, it doesn’t usually develop until the third trimester of the mother’s pregnancy. Fetal ultrasound is used to diagnose hydrocephalus when a baby is still in the womb.

In infants and older children, hydrocephalus is diagnosed with one or more of the following tests:

What are the treatments for hydrocephalus?

Hydrocephalus needs to be treated with surgery. There are three options:

  • Shunt placement: This is the most common treatment for hydrocephalus. During the procedure, a shunt (a thin, flexible tube) is placed in the brain or spinal cord to drain the extra fluid. A one-way valve on the shunt regulates the flow of fluid. Many shunts can also be adjusted externally, using a magnetic device. Shunts need adjustment and replacement over time, and must be checked by a neurosurgeon on an ongoing basis.
  • Endoscopic third ventriculostomy (ETV): This surgery may be an option for older children with hydrocephalus, especially for those who have a blocked connection between the third and fourth ventricles of the brain. This is a minimally invasive procedure that creates an opening in the floor of the third ventricle in the brain, allowing trapped fluid to escape into its normal pathway.
  • Combined endoscopic third ventriculostomy/choroid plexus cauterization (ETV/CPC): This procedure can be used as the primary treatment for most infants with hydrocephalus. It combines ETV with CPC, which reduces the tissue in the ventricles (called choroid plexus) that pulsates with every heartbeat, creating pressure waves inside the brain’s ventricles, and also produces some of the cerebrospinal fluid. ETV/CPC is thought to work by reducing the rate of cerebrospinal fluid production and the strength of the pulsations, in addition to providing a new pathway for the fluid to escape. This surgery was pioneered by Benjamin Warf, MD, neurosurgeon at Boston Children's Hospital and director of Neonatal and Congenital Anomaly Neurosurgery.

How we care for hydrocephalus

The Boston Children's Hospital Hydrocephalus Program has been treating children with hydrocephalus for decades. Boston Children's was the first hospital in the world to treat children with hydrocephalus with shunts. And in the years since, our clinicians have pioneered and refined the use of minimally invasive surgical techniques to more effectively treat hydrocephalus while reducing the risk of complications.

Our clinicians have extensive experience in treating children, teens, and adults with all forms of the condition and can diagnose hydrocephalus before a baby is born.

Our areas of innovation for hydrocephalus

We try to avoid the life-long problems and risks associated with shunt dependence by treating most cases of hydrocephalus with a minimally invasive endoscopic procedure called endoscopic third ventriculostomy (ETV). For infants under age 2, we combine ETV with choroid plexus cauterization (CPC) because we have demonstrated this enhances the likelihood of success for ETV in that age group. Combined, this procedure is called ETV/CPC.

Hydrocephalus | FAQ

Frequently asked questions

Will my child be OK?

The severity of hydrocephalus can vary widely from child to child, but most children do well with treatment. Children who have advanced hydrocephalus at the time of diagnosis or who have another complication may need more long-term treatments.

Your clinician can give you a better sense of what your child will need over the long term, depending on his or her individual condition.

How common is hydrocephalus?

Experts estimate that as many as one in 500 children is born with hydrocephalus.

Does my child need to limit physical activity?

The amount of physical activity your child can do will depend on your child’s age and symptoms. Ask your child’s clinician about specific restrictions for your child.

Head trauma can make hydrocephalus worse, so your child should always wear a helmet for activities like bike riding or contact sports.

Is my child going to need surgery?

Since hydrocephalus is a progressive condition — the symptoms get more severe over time — most children eventually need some type of surgery.

What do I need to watch for if my child has hydrocephalus?

Tell your doctor if you notice a change in your child’s:

  • head shape or size
  • movement
  • activity level
  • temperament
  • appetite
  • cognitive functioning (memory, learning, speech, and language)

You should seek medical help right away if your child has:

  • headaches
  • poor appetite
  • difficulty or changes in standing, walking, or moving
  • nausea
  • vomiting
  • protruding veins in the scalp
  • sudden periods of irritability with no apparent cause
  • sudden personality changes
  • problems in mental functioning (memory or reasoning)
  • problems in speaking or communicating
  • incontinence
  • double vision
  • blurred vision
  • constant downward gaze or difficulty lifting the eyes to look up when the head is facing forward
  • periods of inconsolable, high-pitched crying
  • seizures
Can doctors diagnose hydrocephalus while a baby is still in the womb?

The Boston Children’s Maternal Fetal Care Center can diagnose babies with congenital problems like hydrocephalus before they are born.

Is there a cure for hydrocephalus?

While there is no cure for hydrocephalus, the treatments have an excellent success rate, especially with early diagnosis.

Hydrocephalus | Programs & Services