Hydrocephalus is a build-up of cerebrospinal fluid (CSF) in the ventricles of the brain.

There are two main types of hydrocephalus:

  1. Obstructive hydrocephalus, where a tumour or developmental (for example, cerebral aqueduct stenosis) problem causes a blockage of CSF flow through the brain, resulting in a build-up of pressure inside the skull
  2. Communicating hydrocephalus, where CSF builds up because it is not being absorbed properly in the brain. This may occur following meningitis.


The symptoms of hydrocephalus often include headaches, nausea and vomiting, and altered consciousness.

Normal pressure hydrocephalus is a distinct condition which tends to affect those over 60 years of age. On CT and MRI, the appearances are similar to those seen with communicating hydrocephalus, but intracranial pressure is not elevated. Normal pressure hydrocephalus typically present with a triad of urinary incontinence, impaired gait (walking), and memory loss (dementia).


The treatment of hydrocephalus is usually undertaken by a neurosurgeon, and the exact procedure depends on the cause:

A ventriculoperitoneal shunt, whereby cerebrospinal fluid is diverted from the brain to the abdomen, where it can be absorbed.
Endoscopic third ventriculostomy, where a camera is inserted into the brain and a small hole is made to divert CSF around the blockage.