The ventricular system contains sac-like pockets that are filled with cerebrospinal fluid. When the ventricular system of the brain is enlarged, it is known as ventriculomegaly. The lateral ventricles of the brain are less than 10 mm wide in a healthy fetus. However, a fetus that suffers from ventriculomegaly has lateral ventricles measuring 10-15 mm wide. Sometimes they are even larger, in which the case is severe. Luckily, ventriculomegaly is not linked to other health conditions in most cases. Severe cases of ventriculomegaly can result in hydrocephalus, also known as water on the brain. In hydrocephalus cases, the cerebrospinal fluid builds up and puts pressure on the brain.
There are three major causes of ventriculomegaly. Improper brain development, destroyed brain tissue and insufficient absorption of cerebrospinal fluid are all factors that can make the ventricles in the brain larger. Sometimes chromosomal problems can cause ventriculomegaly.
Ventriculomegaly affects approximately 1 out of 1,000 live births and is normally nothing that the mother has done. The condition can be diagnosed before or after birth. Ventriculomegaly can be detected on ultrasound by the second trimester. An MRI can also be helpful in diagnosing the condition. A chromosomal analysis can be used to test for chromosomal problems that can cause the condition. The only time that ventriculomegaly needs to be treated is when there is water on the brain. Even if there is no water on the brain, regular exams should be done to monitor the condition. Once the baby has been born, doctors will do exams and measure the head circumference to make sure the baby is healthy. Usually, ventriculomegaly will resolve on its own and there are no neurological or developmental problems. As long as there are no other health conditions or chromosomal abnormalities present, the long-term prognosis for a child born with mild to moderate ventriculomegaly is great.