This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Congenital hydrocephalus is when a child is born with an excessive accumulation of cerebrospinal fluid (CSF) in the brain. CSF is a clear fluid that surrounds the brain and spinal cord. This excess fluid causes an abnormal widening of spaces in the brain called ventricles (ventriculomegalia) and can create a harmful pressure on brain tissue. Symptoms of hydrocephalus vary and may include an unusually large head with thin, transparent scalp, bulging forehead with increased spaces between the bones of the skull (fontanelles), and a downward gaze. Other symptoms may include seizures, abnormal reflexes, slow heartbeat and respiratory rate, headaches, vomiting, irritability, weakness, and visual problems.
It is caused by genetic and non-genetic factors. The most common cause of congenital hydrocephalus are variations (mutations) in the L1CAM gene, where there is a narrow passageway between the third and fourth ventricles (aqueductal stenosis). Other causes include mutations in many other genes, brain and/or spinal cord malformations, infections, bleeding inside the cavities of the brain (intraventricular hemorrhage), trauma, exposition to certain drugs (teratogens) or a congenital tumor of the brain. Congenital hydrocephalus can be an isolated malformation or be part of a syndrome where there are other associated malformations. It is most often treated by surgically inserting a shunt system to transport the excess CSF and allow for re-absorption. If left untreated, blindness and continuing mental deterioration may occur.
Hydrocephalus may be subdivided according to the particular defect that exists in the brain and whether the cerebrospinal fluid pressure is high or normal:
There are also 2 other forms of hydrocephalus that usually affect only adults:
Hydrocephalus may also be classified in congenital or acquired. Acquired hydrocephalus develops at the time of birth or at some point afterward and may be caused by injury or disease.
For more information, visit GARD.