What is Congenital Hydrocephalus?

Congenital hydrocephalus, commonly referred to as water on the brain, is a congenital birth defect in which the brain is surrounded by too much cerebrospinal fluid, causing excess pressure on the brain. This pressure can damage the infant's brain, causing mental and physical problems. With early detection, treatment is available to limit long-term effects, although the success of treatment depends on how early the condition is diagnosed, what causes the excess fluid, how much excess fluid is present, and how well the infant responds to treatment. Only .1 percent of infants are afflicted with congenital hydrocephalus.

A number of factors can cause congenital hydrocephalus, such as fetal bleeding in utero, syphilis or other maternal infections present during pregnancy, and some birth defects, such as spina bifida. Symptoms of congenital hydrocephalus include a rate of head growth that is disproportionate to the baby's overall growth, bulging or firmness of the fontanel, or soft spot, in the baby's skull, irritability, a lack of appetite, vomiting, and sleeping more than normal. A computerized axial tomography (CAT) scan, magnetic resonance imaging (MRI) scan, or other imaging test can confirm diagnosis. If congenital hydrocephalus is suspected, it is important to seek treatment as soon as possible. Treatment within the first three to four months of life usually offers the best prognosis.

If an infant is diagnosed with congenital hydrocephalus, the infant's doctor will likely install a shunt in the baby's brain to drain the excess fluid. This may be a permanent fixture in the baby's brain, but it may need to be repaired or replaced over time. Outside the United States (US), surgery is sometimes performed in utero to drain the fluid before birth, but this procedure is no longer available in the US as many doctors feel that the benefits of this procedure are not great enough to warrant the risks to the fetus. In emergency situations, a lumbar puncture may be performed to relieve pressure until a shunt can be installed, or fluid may be drained into a bag from the infant's skull. Medications are available to temporarily slow or stop the production of cerebrospinal fluid, but the efficacy and safety of these medications is not well studied.

In cases where the fluid buildup is caused by an obstruction, the shunt may be waived in favor of a surgical procedure called endoscopic third ventriculostomy (ETV). ETV is not a treatment option for newborns, but rather is a part of ongoing treatment for older children with congenital hydrocephalus. In ETV, the surgeon creates a small hole in the brain's third ventricle, allowing fluid to drain from the skull. ETV is not always successful, however, and where the ETV fails, a shunt will need to be installed.

Children who have been diagnosed with congenital hydrocephalus will need ongoing treatment and monitoring for the rest of their lives. In addition to standard pediatric treatment, children with congenital hydrocephalus will need a neurologist, a neurological surgeon, and a developmental pediatrician in order to monitor progress and ensure the best prognosis with minimal complications. Developmental tests should be performed to make sure that the child is achieving appropriate developmental milestones, and imaging tests may be required throughout the child's growth to ensure that fluid is draining properly from the skull. The child should also be closely monitored for signs of shunt infection or failure, which can include vomiting, irritability, high-pitched crying, difficulty walking, confusion, seizures, having trouble tracking with the eyes or other vision problems, and neck pain.