Hydrocephalus is too much fluid in the brain. The fluid is called cerebrospinal fluid (CSF). It is a clear fluid that normally surrounds both the spinal cord and the brain. It is also in the ventricular system in the brain. With hydrocephalus the ventricles, or spaces, become enlarged.

You may be born with hydrocephalus, or it may develop after an injury or illness.

Hydrocephalus
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Hydrocephalus occurs when:

  • A blockage doesn't allow CSF to drain properly
  • Another condition, such as bleeding, inflammation, or infection, makes the brain unable to resorb fluid
  • An excess of CSF is produced

These problems with the CSF may be caused by: