Congenital Hydrocephalus

Topic Overview

What is congenital hydrocephalus?

Congenital hydrocephalus is a buildup of excess cerebrospinal fluid (CSF) within the brain that is present at birth. The excess fluid can increase pressure in the baby's brain, possibly resulting in brain damage and loss of mental and physical abilities. Prompt diagnosis and treatment is important to help limit serious long-term problems. But long-term effects of congenital hydrocephalus mostly depend on what causes it, how bad it gets, and how a baby responds to treatment.

See an illustration of congenital hydrocephalus .

Research shows that somewhere between 0.5 to 1.8 babies out of every 1,000 are born with the condition.¹ This means at least 998 babies out of every 1,000 are not born with hydrocephalus. The condition also occurs in about 80% to 90% of children who are born with open neural tube defects.²

Another form of hydrocephalus, called acquired hydrocephalus, may occur at any time after birth. This topic covers only congenital hydrocephalus.

What causes congenital hydrocephalus?

Congenital hydrocephalus is caused by an imbalance between the brain's production of cerebrospinal fluid (CSF) and the body's ability to distribute or absorb it properly. Normally, CSF flows through and out of chambers in the brain called ventricles, and then around the brain and spinal cord, providing nutrition and a protective cushion. It is then reabsorbed by the thin tissue that surrounds the brain and spinal cord.

Congenital hydrocephalus may result from either genetic or other causes, such as prenatal hemorrhage (bleeding in the fetus before birth) or infections, such as toxoplasmosis, chickenpox, rubella, or mumps. The condition is often associated with other birth defects, especially spina bifida.

What are the symptoms?

The most obvious symptom of hydrocephalus is an unusually large head that is noticed at birth or within the first 9 months of life. But keep in mind that babies' heads grow a lot during the first year. It is only when the head size grows faster than the normal rate for a baby's height and weight that doctors may become concerned. Also, the soft spot (fontanelle) may feel firm or bulge outward. Other symptoms in an infant may include irritability, excessive sleeping, vomiting, poor feeding, and eyes that gaze downward much of the time.

How is congenital hydrocephalus diagnosed?

Most cases of congenital hydrocephalus are diagnosed during a physical exam soon after birth based on the larger-than-normal size of the baby's head. In rare cases, a diagnosis is made later in childhood. There may be reasons other than congenital hydrocephalus for why a baby has a larger-than-normal head. Imaging tests are usually done to see whether congenital hydrocephalus is a possibility. A computed tomography (CT) scan, magnetic resonance imaging (MRI), or ultrasound may be done to help confirm the diagnosis or to provide a more detailed picture of the brain and its structures.

Images from a fetal ultrasound can sometimes indicate congenital hydrocephalus before birth.

How is it treated?

Early treatment—within a baby's first 3 to 4 months—is important to help limit or prevent brain damage. The long-term effects of congenital hydrocephalus depend largely on the cause of the condition, its severity, and the response to treatment.

Treatment generally consists of surgically inserting a flexible tube (shunt) in the brain to drain the cerebrospinal fluid. The shunt will remain in the brain permanently but may need to be repaired or replaced if a problem develops.

Endoscopic third ventriculostomy (ETV) is sometimes performed instead of surgical shunt placement. ETV is a surgical procedure in which a small hole is made in a ventricle in the brain, allowing CSF to flow freely. It is often done when hydrocephalus seems to be a result of a blockage between ventricles. If used as treatment for congenital hydrocephalus, it is more likely to be tried after a shunt malfunction or infection. ETV was once thought to be a permanent solution for redirecting CSF flow, but it has been shown to fail over time. Babies younger than 6 months of age usually are not good candidates for this procedure.

Children with congenital hydrocephalus are at increased risk for developmental disabilities and may require treatment such as speech therapy or physical therapy.

Frequently Asked Questions

Learning about congenital hydrocephalus:	What is congenital hydrocephalus? What are the symptoms? What are the different types of congenital hydrocephalus? What is the difference between communicating and noncommunicating hydrocephalus?
Being diagnosed:	What kinds of exams and tests are used to diagnose congenital hydrocephalus?
Getting treatment:	What is the treatment for congenital hydrocephalus?
Living with congenital hydrocephalus:	How can I help my child with congenital hydrocephalus?

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Author:	Amy Fackler, MA	Last Updated February 17, 2006
Medical Review:	Michael J. Sexton, MD - Pediatrics Mark G. Luciano, MD - Neurological Surgery
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