Hydrocephalus is a build-up of the cerebrospinal fluid (CSF) that surrounds the brain. This fluid generally nourishes the brain and cushions it from the skull. Normally, this fluid is produced and reabsorbed. However, if reabsorption is blocked or if too much CSF is produced, the fluid builds up and causes swelling of the brain's ventricles. When the brain is under such pressure, it is pushed against the skull and can result in injury to brain tissue. Symptoms of hydrocephalus can include headaches, seizures, and balance difficulties. Hydrocephalus can be diagnosed with a CT scan. Treatment depends on the cause of the hydrocephalus, if it can be defined. Typically, treatment involves medications or shunt placement to drain the extra CSF. Shunts, however, often need to be revised because of blockages or infections.