When is fetal hydrocephalus diagnosed

Congenital hydrocephalus is caused by a brain malformation or birth defect that causes excessive cerebrospinal fluid CSF to accumulate in brain cavities, called subarachnoid space. Cerebrospinal fluid is a clear, colorless liquid that surrounds the brain and spinal cord, protecting them from injury.

It carries nutrients to the brain and spinal cord and takes away waste. In a healthy person, the amount of this fluid produced by the brain is absorbed by the body. In hydrocephalus, the fluid fails to drain and accumulates, leading to pressure on the brain.

Congential hydrocephalus — from the Greek word for water hydro and head cephalus — affects one out of every 1, newborns. A less common type of hydrocephalus, called acquired hydrocephalus , occurs after birth, when a tumor, injury or disease blocks the absorption of cerebrospinal fluid.

The most common cause of congenital hydrocephalus is obstruction of the cerebral aqueduct — the long, narrow passageway between the third and fourth ventricle or cavity of the brain. This condition may result from a blockage, infection, hemorrhage, tumor or arachnoid cyst.

With sophisticated imaging technologies, congenital hydrocephalus can be detected in a fetus as early as the third or fourth month of pregnancy. By the fifth or sixth month, abnormal dilation of brain cavities is more clearly detectable. Tests to identify the condition before your baby is born include:. Congenital hydrocephalus can be detected before birth, but it is more often diagnosed at birth or shortly after.

To make a diagnosis, our experts thoroughly evaluate your child's physical condition. Your child's evaluation may include imaging techniques such as ultrasound , computed tomography CT scans , magnetic resonance imaging MRI or pressure-monitoring techniques. Congenital hydrocephalus generally isn't treated until after birth, even if diagnosed in the womb.

The condition most often is treated by removing the cause of the condition, such as a tumor or other blockage, or inserting a shunt. A shunt is a small flexible plastic tube that diverts excess cerebrospinal fluid CSF from the brain to another part of the body where the fluid can be reabsorbed. Learn more about our health system. MyChart Login. My Location.

Fetal Hydrocephalus. What Causes Hydrocephalus? How is Hydrocephalus Diagnosed During Pregnancy? Call For Info. Enter your location to receive information about nearby SSM Health services.

My location is: Why do we ask? Why do we ask? We will never share this information. Cancel Continue. This condition is rare. Finding the condition early and treating it quickly can help limit any long-term problems.

But long-term effects mostly depend on what caused the fluid buildup, how bad it gets, and how the baby responds to treatment. When hydrocephalus doesn't occur until later in life, it is called acquired hydrocephalus. This topic focuses on hydrocephalus that is present at birth congenital. 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. 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. A fetal ultrasound can sometimes show the problem before birth. But most cases are found during a physical exam 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. Early treatment—before age 4 months—is important to help limit or prevent brain damage. Treatment focuses on reducing the amount of fluid in the brain to relieve pressure. In most cases, the doctor places 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 instead of a shunt in some cases. 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 damage to the brain, your doctor can help you find the care you need.

Treatment will focus on the specific problems your child has.