Hydrocephalus (fluid on the brain)
Head | Neurology | Hydrocephalus (fluid on the brain) (Disease)
The term hydrocephalus is derived from the Greek words hydro meaning water and cephalus meaning head. As the name implies, it is a condition in which the primary characteristic is excessive accumulation of fluid in the brain. Although hydrocephalus was once known as water on the brain, the water is actually cerebrospinal fluid (CSF) - a clear fluid that surrounds the brain and spinal cord.
The ventricular system is made up of four ventricles connected by narrow passages. 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 reabsorbs into the bloodstream.
CSF has three important life-sustaining functions: 1) to keep the brain tissue buoyant, acting as a cushion or shock absorber; 2) to act as the vehicle for delivering nutrients to the brain and removing waste; and 3) to flow between the cranium and spine and 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. Because CSF is made continuously, medical conditions that block its normal flow or absorption will result in an over-accumulation of CSF. The resulting pressure of the fluid against brain tissue is what causes hydrocephalus.
Causes and Risk factors
The excessive accumulation of CSF results in an abnormal widening of spaces in the brain called ventricles. This widening creates potentially harmful pressure on the tissues of the brain.
Diagnosis and Treatment
Hydrocephalus is most often treated by surgically inserting a shunt system. This system diverts the flow of CSF from the CNS to another area of the body where it can be absorbed as part of the normal circulatory process.