Ventriculomegaly | Symptoms & Causes

Infants who require evaluation for ventriculomegaly or possible hydrocephalus are generally seen in the Neonatal and Congenital Anomalies Neurosurgery Programat Boston Children’s Hospital. Here, members of the team work closely with specialists in other departments in the hospital, to develop individual care plans that meet each child’s medical needs.

Until you meet with our team of doctors, you may find it helpful to read the straightforward information about ventriculomegaly provided in the following pages.

What does it mean to have 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.
  • In the brain of a healthy fetus, the ventricles are about 10 millimeters wide. However, CSF may become trapped in the spaces, causing them to grow progressively larger.
  • Ventriculomegaly is a term that describes the actual image of the enlarged spaces as it appears on a prenatal ultrasound.

Are there any medical complications associated with ventriculomegaly?

  • Hydrocephalus is the main concern associated with ventriculomegaly. Hydrocephalus occurs when CSF builds up within the ventricles of the brain, causing them to grow progressively larger.
  • Benign macrocrania of infancy is a more common condition in which a baby can have mild ventriculomegaly and a large head, but not hydrocephalus. Although this condition causes the head to grow too fast, the baby is otherwise well, and the condition is self-limiting. It does not require treatment.


What causes ventriculomegaly?

Ventricles develop early in pregnancy and can be seen on a prenatal ultrasound in the second trimester, at about the 15th week.

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

  • a problem that prevents the CSF fluid from circulating and being absorbed normally, which causes the fluid to progressively build up in the ventricles  - the condition known as hydrocephalus.
  • a minor self-limiting imbalance in fluid circulation and absorption that becomes compensated
  • defects in brain development
  • damage or loss of brain tissue

Is ventriculomegaly inherited?

Ventriculomegaly usually occurs spontaneously, which means that a child does not inherit the condition from the parents. However, benign macrocephaly tends to run in families and there are some rare inherited causes of hydrocephalus. Congenital hydrocephalus can be associated with other anomalies of the brain, or other conditions such as spina bifida or heart defects.


What are the symptoms of ventriculomegaly?

Infants with mild self-limited ventriculomegaly usually don’t have any symptoms. If the ventriculomegaly is progressive the baby may show the signs and symptoms of hydrocephalus once it is born.

An infant with hydrocephalus may have:

  • abnormally rapid head growth
  • abnormally full fontanel
  • distended scalp veins
  • eyes that cannot look upward or appear to be staring downward (sunset sign)
  • developmental delays
  • irritability or abnormal sleepiness
  • poor feeding
  • vomiting

What is the long-term outlook?

Most infants with simple, nonprogressive ventriculomegaly in the absence of brain damage or developmental anomalies will have completely normal and healthy development. Likewise, infants with hydrocephalus who do not have other serious brain anomalies or damage have an excellent prognosis for normal development with timely treatment of the condition.