Normal Pressure Hydrocephalus
Normal pressure hydrocephalus is a condition in which excess cerebrospinal fluid builds up in the brain, causing pressure. It is most commonly seen in elderly people, but anyone can develop this condition. Because its symptoms vary and are similar to those of other conditions, it is often misdiagnosed. Early diagnosis and proper treatment are important in ensuring a good recovery.
Normal pressure hydrocephalus (NPH) is an abnormal increase of cerebrospinal fluid (CSF) in the brain's ventricles, or cavities. It occurs if the normal flow of CSF throughout the brain and spinal cord is blocked in some way. This causes the ventricles to enlarge, putting pressure on 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. It:
- Keeps the brain tissue buoyant
- Acts as a cushion or "shock absorber"
- Acts as the vehicle for delivering nutrients to the brain and removing waste
- Flows between the cranium and spine to compensate for changes in intracranial blood volume (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, normal pressure hydrocephalus is the result.