The most common cause of congenital hydrocephalus is obstruction of the cerebral aqueduct — the long, narrow passageway between the third and fourth ventricle or cavity of the brain. This condition may result from a blockage, infection, hemorrhage, tumor or arachnoid cyst.
Other medical problems associated with congenital hydrocephalus may include:
- Chiari malformations, an abnormality at the base of brain where the spinal column joins the skull
- Craniosynostosis, when the bones in the skull fuse together before the brain has stopped growing
- Dandy-Walker syndrome, when the fourth ventricle is enlarged because of partial or complete closure of its outlets
- Hydranencephaly, a rare condition in which the brain's cerebral hemispheres are absent and replaced by sacs filled with cerebrospinal fluid
- Neural tube defects or spina bifida, when the spinal cord is exposed at birth and is often lacking cerebrospinal fluid
- Schizencephaly, an extremely rare disorder characterized by abnormal slits, or clefts, in the brain's cerebral hemispheres
- Vein of Galen malformations, abnormal connections between arteries and the deep draining veins of the brain that develop before birth
Symptoms in infants may include:
- Downward deviation of the eyes, called "sunsetting"
- Very large head or a head that's growing very quickly in relation to the rest of the body
Reviewed by health care specialists at UCSF Benioff Children's Hospital.