Ventriculomegaly

Your child’s brain and spinal cord are covered in a clear protective liquid called cerebrospinal fluid (CSF). There are spaces within the brain (ventricles) that are also filled with CSF. Ventriculomegaly is a condition in which the ventricles appear larger than normal on a prenatal ultrasound. This can occur when CSF becomes trapped in the spaces, causing them to grow larger. Ventricles develop early in pregnancy and can be seen on a prenatal ultrasound in the second trimester, at about the 15th week.

This condition occurs in approximately one in 1,000 infants. Typically, ventriculomegaly only requires treatment if it causes hydrocephalus. Since the excessive pressure caused by the buildup of cerebrospinal fluid in hydrocephalus can lead to serious, long-term neurological damage, prompt treatment is a must.

Infants with mild ventriculomegaly usually don’t have any symptoms. If the ventriculomegaly progresses, the baby may have symptoms of hydrocephalus, including:

• An unusually large head
• A rapid increase in head size
• Extreme sleepiness
• Vomiting
• Trouble looking up when the head is facing forward
• Seizures with no known cause

Although there’s not always a single reason why a child develops ventriculomegaly, there are four main factors that can cause enlargement of the ventricles:

• A problem that prevents cerebrospinal fluid (CSF) fluid from circulating and being absorbed normally in the brain, which causes hydrocephalus
• A minor imbalance in fluid circulation and absorption
• Defects in brain development
• Damage or loss of brain tissue

Ventriculomegaly usually occurs spontaneously, which means that a child does not inherit the condition from the parents.

Ventriculomegaly can be detected on prenatal tests or after the baby is born.

Tests include:

• Prenatal ultrasound
• Amniocentesis
• Magnetic resonance imaging (MRI) – to test infants after birth

Ventriculomegaly only needs to be treated if the baby has hydrocephalus, a build-up of cerebrospinal fluid (CSF) in the brain.

Treatments for hydrocephalus include:

• Shunt placement: In this process a small tube is implanted in the brain while the child is under anesthesia. The tube provides internal drainage of CSF from the ventricles of the brain into the abdominal cavity.
• Endoscopic third ventriculostomy (ETV): This minimally-invasive procedure creates an opening in the floor of the third ventricle in the brain, allowing the trapped fluid to escape from the ventricles into its normal pathway.
• Combined endoscopic third ventriculostomy/choroid plexus cauterization (ETV/CPC)

Most infants with simple ventriculomegaly who have no other brain damage or developmental problems will have completely normal and healthy development.

With timely treatment, infants with hydrocephalus who do not have other serious brain damage have an excellent prognosis for normal development.

Clinicians in the Hydrocephalus Program here at Boston Children’s Hospital specialize in the diagnosis and treatment of ventriculomegaly and hydrocephalus. When surgery is necessary, we use minimally-invasive techniques to avoid placement of a shunt whenever we can. Our experts are highly experienced in all of these procedures, and will work with you and your family to determine which approach best suits your child.

Our approach is both patient-focused and family-centered. We never lose sight of the fact that your child is an individual, and we include your family at every stage of the treatment process.

Boston Children's was the first hospital in the world to treat children with hydrocephalus by shunting. In the years since this important milestone, our physicians have helped design and test the next generation of shunting devices, introduced and refined the use of minimally invasive surgical alternatives to shunt placement, and taught these potentially life-saving techniques to pediatric neurosurgeons around the world.