Hydrocephalus Definition

Hydrocephalus Definition

Hydrocephalus is a condition in which the flow of cerebrospinal fluid (CSF) in the central nervous system is interrupted or blocked. CSF is the liquid that circulates between the layers of tissue that cover the brain, within the ventricles (hollow cavities) of the brain, and around the spinal cord. It serves to cushion the structures of the central nervous system, deliver nutrients to the brain, and regulate the amount of blood within the brain. In normal circumstances, the CSF moves within the ventricles in the brain, exits through closed spaces at the base of the brain, flows over the surface of the brain and spinal cord, and is then reabsorbed into the bloodstream.

Hydrocephalus develops when there is an imbalance between the production of CSF and its reabsorption or when its flow is blocked. The cerebrospinal fluid builds up inside the brain, putting pressure on the tis- sues of the central nervous system and causing symptoms ranging from visual disturbances and headache to mental disturbances and difficulty walking.

Doctors classify hydrocephalus into several different categories:

• Congenital. This type of hydrocephalus is present at birth and may be caused by genetic disorders or problems that occur during the baby’s development before birth.

• Acquired. Acquired hydrocephalus develops later in life as the result of brain tumors, head injuries, infections of the brain, or other brain disorders.

• Communicating. This type of hydroce- phalus is one in which the CSF can flow between the ventricles of the brain but is blocked from leaving the brain.

• Noncommunicating or obstructive. In this type of hydrocephalus, the CSF cannot flow freely among the ventricles inside the brain.

• Normal pressure hydrocephalus (NPH). This is a form of communicating hydroce- phalus most commonly found in the elderly. It is a condition in which CSF builds up within the ventricles of the brain.