Hydrocephalus

What is hydrocephalus?

Hydrocephalus (PDF) is an abnormal accumulation of fluid within the brain where it does not belong. It is sometimes known as “water on the brain.”

In the center of our brains, each of us has two fluid-filled areas called cerebral ventricles. These cerebral ventricles make what is called cerebrospinal fluid, which is circulated over the brain and down the spinal cord. When the normal circulation of cerebrospinal fluid is blocked, or when too much fluid is being produced, fluid can accumulate within the ventricles in a harmful way. Excess fluid can widen ventricles, creating potentially harmful pressure on brain tissues.

Hydrocephalus can be caused by birth defects in the brain’s development. It may be present with other congenital (from birth) problems, such as spina bifida.

In other cases, hydrocephalus develops after a child is born. It can develop due to injury or disease. In prematurely born infants, the most common post-birth cause of hydrocephalus is intraventricular hemorrhage (PDF).

In children, there are two main types of hydrocephalus:

Communicating hydrocephalus. This occurs when the flow of cerebrospinal fluid is blocked after it has exited the ventricles. This form is called “communicating hydrocephalus” because cerebrospinal fluid still is able to flow between the ventricles.

Non-communicating hydrocephalus. This also is called “obstructive hydrocephalus” and occurs when cerebrospinal fluid is blocked from flowing in the passageways that connect the ventricles.

The causes of hydrocephalus are not well-understood. They may include inherited genetic abnormalities and inherited developmental disorders (such as defects of the neural tubes). Hydrocephalus that is acquired after birth may be caused by intraventricular hemorrhage. Other possible causes that are being explored are meningitis, tumors, traumatic head injury, or subarachnoid hemorrhage (bleeding in the area between the brain and the thin tissues that cover the brain.)

What are symptoms of hydrocephalus?

Usually, hydrocephalus is diagnosed when children are still infants. The accumulation of fluid causes the baby’s head to be larger than normal or leads to a bulging in the fontanelle “soft spot” on the top of the baby’s head. Sometimes, a baby with hydrocephalus has eyes that are fixed in a downward position. Hydrocephalus also can cause vomiting, seizures, sleepiness, irritability, and developmental delays.

Hydrocephalus sometimes is diagnosed in older children, too. Symptoms are often different in older children because their fontanelles already are closed, so their skulls cannot expand to accommodate the buildup of cerebrospinal fluid. Because every child is different, symptoms vary significantly from one child to the next but typical symptoms in older children include:

How is it treated?

Types of surgery that treat hydrocephalus include:

A ventriculo-peritoneal (VP) shunt. Currently, a shunt system is the most common treatment for hydrocephalus. A VP shunt is a plastic tube that is placed in the head and attached to a catheter, which directs the flow of cerebrospinal fluid away from the ventricles to another part of the body, usually the belly or sometimes the chest. From there, cerebrospinal fluid is harmlessly absorbed into the body.

Shunt systems are not perfect devices. They typically require monitoring and adjustments by physicians who check regularly for mechanical failures, infections, obstructions, or other issues. It is normal for children with hydrocephalus to require additional surgeries to replace the shunt when it is outgrown or becomes clogged.

Children’s was one of the first hospitals in the U.S. to perform shunt surgery.

An endoscopic third ventriculosotomy. In some cases, this minimally invasive surgery may be an option when the flow of cerebrospinal fluid is blocked. The surgeon uses an endoscope, a thin tube with a light on the end, to make a hole in the bottom of a ventricle. This allows cerebrospinal fluid to bypass the obstruction.

About surgery for hydrocephalus at Children’s

The neurosurgery team at Children’s provides next-generation care to neonatal infants, newborns, children, and adolescents from throughout the Upper Midwest. The team provides some of the most cutting-edge treatments available, including newborn surgery, surgery utilizing intra-operative MRI, and grid placement surgery for epilepsy. Neurosurgery is performed at Children’s - Minneapolis and Children’s - St. Paul.

If you are a family member looking for a Children’s specialist in neurosurgery, visit Find a Doctor.

If you are a health professional looking for a consultation or referral information, please call Children's Physician Access at 1-866-755-2121 (toll-free).

Return to Children’s neurosurgery home page.