The term hydrocephalus
is derived from the Greek words "hydro" meaning water
and "cephalus" meaning head. It is therefore a condition
in which the primary characteristic is excessive accumulation
of fluid in the brain. The fluid is actually cerebrospinal fluid,
a clear liquid surrounding the brain and spinal cord. The excessive
accumulation of this fluid 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.
Hydrocephalus may be congenital or acquired. Congenital hydrocephalus
is present at birth, and may be caused by either environmental
influences during fetal development or genetic predisposition.
Acquired hydrocephalus develops at the time of birth or at some
point afterward. This type of hydrocephalus can affect individuals
of all ages and may be caused by injury or disease.
Some disorders have similar symptoms. The clinician, therefore,
in his diagnostic attempt has to differentiate against the following
disorders which need to be ruled out to establish a precise diagnosis.
of hydrocephalus are not all well understood. Hydrocephalus may
result from genetic inheritance or developmental disorders such
as those associated with neural tube defects including spina bifida
and encephalocele. Other possible causes include complications
of premature birth such as intraventricular hemorrhage, diseases
such as meningitis, tumors, traumatic head injury, or subarachnoid
hemorrhage blocking the exit from the ventricles to the cisterns
and eliminating the cisterns themselves.
Hydrocephalus is most often
treated with the surgical placement of a shunt system. This system
diverts the flow of CSF from a site within the central nervous
system (CNS) to another area of the body where it can be absorbed
as part of the circulatory process.