Conditions
and
Treatments of the
BRAIN
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HYDROCEPHALUS
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The term hydrocephalus is derived
from the Greek words "hydro" meaning water and "cephalus"
meaning head. As its 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 surrounding the brain and spinal cord. The excessive
accumulation of CSF results in an abnormal dilation of the spaces in
the brain called ventricles. This dilation 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: 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 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 which, when present, will prevent
or disturb the production or absorption of CSF, or which will
inhibit its normal flow. When this balance is disturbed,
hydrocephalus is the result.
SOURCE: National Institute of
Neurological Disorders and Stroke
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