Children's Hospital Colorado


What is hydrocephalus?

Hydrocephalus is a buildup of cerebrospinal fluid (CSF) in the brain. CSF is fluid that is made in the brain and surrounds the brain and spinal cord to cushion and support them. When there is a build-up of CSF, this can cause pressure on the brain, which can cause it to malfunction.

Why does the fluid build up on the brain?

Like the hole at the center of a strawberry, inside the brain are four cavities called ventricles that are filled with CSF. Cerebral spinal fluid is made by a tissue within the ventricles called the choroid plexus. CSF is made constantly by the choroid plexus, like the kidneys constantly make urine.

The CSF circulates through the ventricles, down around the spinal cord, and over the surface of the brain. Once on the surface of the brain, CSF is reabsorbed back into the blood stream by special structures called the arachnoid villi.

The making, circulating and reabsorbing of CSF is a constant and steady cycle. Any time there is a blockage of flow, a problem with re-absorption, or overproduction of CSF, the fluid builds up and hydrocephalus will result.

What causes hydrocephalus?

There are many causes of hydrocephalus. Some children are born with hydrocephalus and the exact cause is never known. Other times, the cause can be identified, such as when there is a physical blockage in the fluid cycle or an associated medical problem known to cause a blockage. Blockages can be congenital, meaning they are present at birth, or they can be caused by lesions such as brain tumors, infections or cysts. Hydrocephalus is also associated with certain birth defects such as spina bifida.

Problems with reabsorption can occur after such things as meningitis, bleeding in the brain or traumatic brain injuries. Over-production of CSF is very rare. It only occurs when there is a tumor in the choroid plexus.

Normal Pressure Hydrocephalus is a form of hydrocephalus that typically affects older adults.

Who gets hydrocephalus?

Anyone can develop hydrocephalus. Children who are born with hydrocephalus (congenital) are often diagnosed before birth or during infancy. Given that hydrocephalus can result from so many different problems, children of all ages and adults can develop it.

Get to know our pediatric experts.

Nina Robinson, PNP

Nina Robinson, PNP

Certified Pediatric Nurse Practitioner

Joanne Janas, MD

Joanne Janas, MD

Neurology - Pediatric

Richard Boada, PhD

Richard Boada, PhD