What is Hydranencephaly

Hydranencephaly is a brain condition in which most or all of the upper parts of the brain, called the cerebral hemispheres, are missing at birth. Instead, a fluid called cerebrospinal fluid fills the space where the cerebral hemispheres should be.

After birth, the amount of this fluid may increase and cause enlargement of the baby’s head, which is known as hydrocephalus.

A baby with this condition may die in the womb (in utero) or may be born and live for a period of time. Most children with this condition die in the first year, but some can live for several years depending on how much of the brain is missing. A child with this condition will not be able to walk or crawl, eat normally, or learn and grow in the same way that a child without hydranencephaly would. Hydranencephaly is not curable, so treatment is focused on keeping the child as comfortable as possible.

What are the causes?

The cause of this condition is usually not known. It may be caused by:

• A major developmental problem after the 12th week of pregnancy, when the upper brain is forming.
• Reduced blood supply to the growing baby.
• Exposure to a toxin.
• An infection inside the womb.

What are the signs or symptoms?

Symptoms of this condition may be noted soon after birth or within a few weeks. Symptoms include:

• Irritability.
• Stiffness.
• Seizures.
• Lack of vision.
• Lack of growth.
• Lack of hearing.
• Inability to move the arms or legs.
• Enlargement of the head.

How is this diagnosed?

This condition may be diagnosed:

• Before birth, during a routine prenatal exam. Signs may be seen in images that are created using sound waves (fetal ultrasound).
• After birth, when the baby fails to develop normally in the first weeks of life. Your health care provider may suspect hydranencephaly based on your baby’s symptoms.

Imaging tests will be done to confirm the diagnosis. Tests may include:

• CT scans.
• MRI.

How is this treated?

There is no cure for this condition. The goal of treatment is to provide the best quality of life possible for your child. The main treatment for this condition may include:

• Placing a flexible tube (shunt) in the brain or spinal cord to drain the fluid into another part of the body. This may be done to reduce some symptoms and make your baby more comfortable.
• Placing a feeding tube.
• In some cases, medicines may be used to treat symptoms such as seizures.

Follow these instructions at home:

Managing hydranencephaly requires a team approach. You will work with a team of health care providers to provide the best quality of life possible for your baby. Depending on your baby’s needs, you may be told to:

• Give over-the-counter and prescription medicines only as told by your child’s health care provider.
• Talk with your child’s health care provider about your wishes to put a “do not attempt resuscitation” (DNAR) order in place for your child.
• Follow instructions from the health care provider on how to use and care for your child’s feeding tube, if your child has one.
• Talk with your child’s health care provider about palliative care services. Because this condition results in a short life for your child, palliative care services can help you plan for your child’s comfort and quality of life.
• Keep all follow-up visits as told by your child’s health care provider. This is important.

Contact a health care provider if your child:

• Has a fever.
• Is vomiting or has diarrhea that lasts longer than 24 hours.

Get help right away if your child:

• Has a seizure that lasts longer than 5 minutes or has many seizures without a period of recovery in between them.
• Has trouble breathing or turns blue.
• Is younger than 3 months and has a temperature of 100°F (38°C) or higher.

Summary

• Hydranencephaly is a condition that results in an underdeveloped brain.
• A child with this condition will have a shorter life and will not be able to do things that other children do.
• Because the brain is missing cerebral hemispheres, a child with this condition will not be able to walk or crawl, eat normally, or learn and grow in the same way that a child without hydranencephaly would.
• The goal of treatment is to provide the best quality of life possible for your child and to ensure that he or she is comfortable. A palliative care specialist may be able to help in planning how to do this.