This condition is caused by an increased amount of cerebrospinal fluid (commonly called CSF) in the brain’s ventricles. The ventricles are a system of large, fluid-filled open spaces inside the brain. Too much CSF in the ventricles can elevate pressure in the skull. It can damage delicate brain tissue.


Cerebrospinal fluid is a colorless fluid that bathes the central nervous system. It carries nutrients and waste to and from cells. It also absorbs shocks and regulates pressure. CSF is produced in the brain. It normally flows through and around the brain and then down the spinal cord, where it is absorbed by the blood stream.


Hydrocephalus is caused by a disruption of this drainage system, or, in rare cases, by an overproduction of CSF. The ventricles swell with the excess fluid. This raises the fluid pressure within the skull.


Symptoms of hydrocephalus vary greatly with age. In infants, it can cause the head to swell rapidly and to unusually large proportions. This is because infants do not yet have rigid skulls. In addition to a swollen head, infants may experience symptoms such as vomiting, sleepiness, irritability and seizures. Their eyes may be fixed in a downward gaze.


In toddlers, hydrocephalus can also cause head swelling. Toddlers and children may experience headache, fever, irritability, and problems with coordination and balance. They may experience personality changes, problems with walking or talking, sleepiness, and other issues.