Conditions Basics

What is congenital hydrocephalus?

Congenital hydrocephalus is a buildup of excess cerebrospinal fluid (CSF) in the brain at birth. The extra fluid can increase pressure in the baby's brain, causing a brain injury and mental and physical problems. This condition is rare.

Finding the condition early and treating it can help limit long-term problems. But long-term effects may depend on what caused the fluid buildup, how bad it gets, and how the baby responds to treatment.

What causes it?

This condition is caused by an imbalance between how much fluid the brain makes and how well the body is able to process it.

Normally, fluid flows through and out of chambers of the brain called ventricles, and then around the brain and spinal cord. The fluid is then absorbed by the thin tissue around the brain and spinal cord. But with hydrocephalus, the fluid can't move where it needs to or is not absorbed as it should be. And in rare cases the brain makes too much fluid.

Congenital hydrocephalus may happen because of:

• Bleeding in the fetus before birth.
• Certain infections in the birth parent, such as toxoplasmosis or syphilis.
• Conditions present at birth, like spina bifida.
• A genetic condition.

What are the symptoms?

The clearest symptom of hydrocephalus is a head that is larger than normal. You and your doctor may notice it when the baby is born or within the first several months of life. It's normal for a baby's head to grow a lot during the first year. But with congenital hydrocephalus, the head may grow faster than the normal rate for a baby's height and weight.

The condition may cause the soft spot (fontanelle) on your baby's head to feel firm or bulge out. Also, the areas between the skull bones (sutures) may be larger than normal.

If pressure builds in the brain, your baby may:

• Be irritable.
• Sleep too much.
• Vomit.
• Eat very little.

How is it diagnosed?

A fetal ultrasound can sometimes show the problem before birth. But it can be found during a physical examination soon after birth. Your doctor may suspect that your baby has congenital hydrocephalus if your baby's head is larger than normal.

Your baby may need imaging tests, such as a CT scan, an MRI, or an ultrasound, that can give a picture of the brain with more detail. Genetic tests may be done in some cases.

How is congenital hydrocephalus treated?

Early treatment can help limit or prevent injury to the brain. Treatment focuses on reducing the amount of fluid in the brain to relieve pressure.

The doctor may place a flexible tube, called a shunt, in the brain to drain the fluid. The shunt carries fluid to another part of the body (usually the belly or the heart), which then absorbs the fluid. The shunt may stay in the brain for life, though it may have to be fixed or replaced later if it becomes blocked or infected.

A surgery called endoscopic third ventriculostomy (ETV) may be used. In ETV, a small hole is made in the deep part of the brain so that the fluid in the brain can flow freely.

Sometimes emergency treatment is needed to reduce the fluid. This may include medicines, a lumbar puncture (sometimes called a spinal tap), or a procedure to drain fluid from the brain until a shunt can be put in.

If your child has any developmental problems or delays caused by an injury to the brain, your doctor can help you find the care you need. Treatment will focus on the specific problems your child has. For example, speech therapy can help with speech delays. Physiotherapy can help with motor skill problems.

What happens when your child has this condition?

No matter what kind of treatment your child has had, you and your child's doctors will need to watch your child closely to make sure that the fluid in the brain continues to drain. Pressure can build up in the brain again. Shunts can become blocked or infected. These problems need to be treated right away.

Symptoms such as irritability, poor appetite, sleeping too much, and vomiting may be signs that fluid has built up again. After early childhood, there may be other symptoms to watch for, such as headaches, vision problems, or problems walking. Shunt infections may also cause a fever and redness along the shunt tract or valve.

As your child grows, you'll need to watch for problems with brain development. These could include things like delayed learning, problems with motor skills, and speech problems. Talk to your doctor about any new problems or changes you see.