Medical Definition of Hydrocephalus ex-vacuo
Hydrocephalus ex-vacuo: What is termed "hydrocephalus ex-vacuo" occurs when there is damage to the brain caused by stroke or injury, and there may be an actual shrinkage of brain substance. Although there is more CSF than usual, the CSF pressure itself is normal in hydrocephalus ex-vacuo.
Hydrocephalus can arise before birth or any time afterward. It may be due to many causes including a birth defect, hemorrhage into the brain, infection, meningitis, tumor, or head injury. Most forms of hydrocephalus are the result of obstructed CSF flow in the ventricular system. With birth defects, physical obstruction of CSF flow in the ventricular system is usually the cause of the hydrocephalus. Hydrocephalus is a common companion of spina bifida (meningomyelocele).
Normal pressure hydrocephalus (NPH) can occur due to a gradual blockage of the CSF drainage pathways in the brain. Although the ventricles enlarge, the pressure of the CSF remains within normal range. NPH is characterized by memory loss (dementia), balance disorder (ataxia), urinary incontinence and a general slowing of activity.
In old age or persons with Alzheimer's disease, the entire brain may shrink and the CSF fills up the space created by the shrinkage. This is not due to hydrocephalus.
The diagnostic signs and symptoms of hydrocephalus depend upon the age of the person:
Treatment of hydrocephalus involves the insertion of a shunt to let the excess fluid exit and relieve the pressure on the brain. The shunt is a flexible, plastic tube with a one-way valve. The shunt is inserted into the ventricular system of the brain to divert the flow of CSF into another area of the body, where the CSF can drain and be absorbed into the bloodstream.
The prognosis (outlook) with hydrocephalus depends the cause and the timing of the diagnosis and treatment. Many children treated for hydrocephalus are able to lead normal lives with few, if any, limitations. In some cases, cognitive impairments in language and non-language functions may occur. Problems with shunts such as infection or malfunction require revision of the shunt.
The word "hydrocephalus" in Greek means "watery head."
Last Editorial Review: 1/25/2017
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