Pediatric Hydrocephalus

Pediatric hydrocephalus is a buildup of fluid in the brain at the time of birth or during infancy, childhood, or adolescence. Most often, the primary treatment for this condition is surgery to drain the fluid, and a child’s outcome is often excellent.

Hydrocephalus is one of the problems pediatric neurosurgeons see most frequently. It is also known as “water on the brain,” but that term is actually a misnomer. In reality, most cases of hydrocephalus represent a buildup of cerebrospinal fluid (CSF) inside the brain.

Everyone continuously produces CSF, a fluid very similar to the liquid portion of blood. It contains various salts as well as other products, such as sodium and glucose. Primarily produced in the ventricles, the fluid circulates through the ventricle system and around the brain and spinal cord. Eventually, the CSF is reabsorbed over the surface of the brain into large veins, where CSF mixes with blood and is transported to the heart. This orderly cycle of CSF production, flow, and absorption maintains a protective environment for the central nervous system.


During early infancy, hydrocephalus is usually detected by the family or pediatrician as macrocephaly; macrocephaly rarely occurs later in infancy and childhood.

Additional common symptoms for infants include:

  • Vomiting
  • Eye gaze pointed downward
  • Progressive weakness and spasticity
  • Poor feeding
  • Failure to thrive
  • Delay or loss of developmental milestones
  • Unusual sleepiness
  • Nystagmus
  • Irritability

Symptoms during childhood may include:

  • Headache
  • Vomiting and nausea
  • Failure to thrive
  • Visual disturbances, such as blurred vision or diplopia
  • Nystagmus
  • Irritability
  • Delay or loss of developmental milestones
  • Eye gaze pointed downward


A neurological examination is usually performed to identify alterations in brain function and mental status. This exam consists of assessing eye movements, vision, hearing, swallowing, motor function, sensation, balance, and coordination.

Depending on the child’s age at the time of discovery, various imaging techniques are available to confirm the diagnosis.

In the first six to 12 months of life, the diagnosis can often be made with an ultrasonography of the brain because the sutures in an infant’s skull have not yet fused. Plain X-rays of the skull and measurements of the head can also lead to a diagnosis for infants.

After the skull fuses, the diagnosis is best made with magnetic resonance imaging (MRI) or computed tomography (CT) scan; sometimes plain X-rays of the skull can lead to a diagnosis. Each of these tests has its strengths and weaknesses, but overall most pediatric neurosurgeons favor an MRI scan. While this test takes longer than a CT scan and usually requires sedation, it gives a much better picture of the brain and the possible cause of the hydrocephalus and avoids radiation exposure.

Together, all of this information helps guide the treatment plan for the child.

Risk Factors

Pediatric hydrocephalus occurs when the orderly balance of cerebrospinal fluid (CSF) in the brain is altered. This disruption can occur when CSF is overproduced, not properly absorbed or obstructed by a blockage.

Possible causes include bleeding, infection, trauma, tumors, vascular problems, and structural problems.

Hydrocephalus can occur during pregnancy, and when it does, it is labeled congenital hydrocephalus; about one to two per 1,000 babies are born with congenital hydrocephalus. Other instances of hydrocephalus arise after birth.

Hydrocephalus can occur at any age.


At Columbia, our pediatric neurosurgeons treat hundreds of patients each year and use the most sophisticated surgical techniques, resulting in the best possible outcomes.

If the diagnosis of hydrocephalus has been made, there are rarely options other than surgery for treatment. If a definable mass is causing the obstruction of cerebrospinal fluid flow, it may be possible to remove the mass and allow for normal flow and resolution of the hydrocephalus. However, more often than not, the blockage cannot be removed, and surgical intervention to reroute the fluid is needed.

Most surgeons use systems called shunts to channel the fluid from the ventricles to other sites in the body such as the abdominal cavity, chest cavity, or heart. Each of these sites has various advantages and disadvantages, but the most popular choice by far among neurosurgeons performing pediatric surgery is the abdominal cavity. Here, the CSF is absorbed onto the surface of the bowels to be returned to the bloodstream along with the vital salts and other products it contains.

There are many different shunt systems on the market. In its simplest form, a shunt is an inert plastic tube less than an eighth of an inch thick that allows fluid to flow through it in one direction. There is usually a valve system that regulates the volume of flow as well. The shunt is surgically placed in the brain by drilling a small hole in the skull; a reservoir or “bubble” can be felt through the scalp once the procedure is complete. This reservoir allows for sampling of the CSF with a tiny needle, if indicated, to test for function or infection. (Like all implanted devices, shunts can malfunction or become infected and need to be replaced.)

For certain types of hydrocephalus, endoscopic third ventriculostomy is preferred to shunt placement. The operation involves making a tiny hole inside the ventricle to reestablish normal flow. It is becoming very popular as a result of the ever-improving technology in surgical instruments and imaging techniques. To perform this procedure, a neurosurgeon guides an endoscope and microinstruments into the ventricle and makes a small opening. In addition, choroid plexus cauterization may be performed during ventriculostomy, reducing the production of CSF.

As with shunts, an endoscopic third ventriculostomy can fail over time, requiring further surgery. The risk of infection with a ventriculostomy is lower than with shunting, and this is one of the reasons it has become an attractive alternative to shunting in the appropriate patient.

It is important for the doctors taking care of a child with hydrocephalus to have expertise in determining whether the problem has resolved or requires additional treatment. Resolved hydrocephalus may leave behind enlarged ventricles that are stable. It can sometimes be difficult to distinguish between enlarged, stable ventricles and unstable ones. Often the decision about whether additional treatment is necessary will be based on many factors, including symptoms, neurological exam findings, changes in level of activity or school performance. In addition to this, often the child will have serial radiographic exams to look for changes in the ventricles.

Once identified, hydrocephalus itself is very treatable, and the prognosis for its successful management is excellent.

Unfortunately, sometimes the condition causes lasting damage before it is discovered. Our pediatric neurosurgeons advise each family how best to proceed, depending on the child’s individual situation, when this is the case.

It is difficult to generalize about the long-term consequences of the wide range of underlying conditions that can cause hydrocephalus. Some of these may pose greater challenges than the hydrocephalus.