Hydrocephalus, once known as "water on the brain," is a condition in which extra fluid builds up in the brain, causing pressure. There are different forms of this condition, and symptoms vary according to the type. The age of the patient and the progression of the disease also play a part in the patient's symptoms. Hydrocephalus is usually treated with a shunt system. Left untreated, the disease is almost always fatal.
Hydrocephalus is a condition characterized by excessive fluid buildup in the brain. Although hydrocephalus was once known as "water on the brain," the "water" is actually cerebrospinal fluid (CSF) -- a clear fluid surrounding the brain and spinal cord. The extra accumulation of CSF causes the spaces in the brain, called ventricles, to expand. This expansion causes potentially harmful pressure on the tissues of the brain.
The ventricular system is made up of four ventricles connected by narrow pathways. Normally, CSF flows through the ventricles, exits into cisterns (closed spaces that serve as reservoirs) at the base of the brain, bathes the surfaces of the brain and spinal cord, and then is absorbed into the bloodstream.
CSF has three important life-sustaining functions:
- To keep the brain tissue buoyant
- To act as a cushion or "shock absorber"
- To deliver nutrients to the brain and remove waste
- To flow between the cranium and spine to compensate for changes in the amount of blood within the brain.
The balance between production and absorption of CSF is critically important. Ideally, the fluid is almost completely absorbed into the bloodstream as it circulates; however, there are circumstances that, when present, will prevent or disturb the production or absorption of CSF, or that will inhibit its normal flow. When this balance is disturbed, hydrocephalus is the result.