The Online Encyclopedia and Dictionary







Hydrocephalus ('water-head', in Greek) is the abnormal accumulation of cerebrospinal fluid in the ventricles of the brain. This usually leads to raised intracranial pressure.



Hydrocephalus can be broadly classified as being caused by disturbance to normal production, flow or absorption of cerebrospinal fluid.

The most common cause of hydrocephalus is disruption to cerebrospinal fluid circulation, which can be secondary to tumor, hemorrhage, infection or congenital malfomations. It can also be caused by overproduction of cerebrospinal fluid.

Hydrocephalus exists in two forms:

  • communicating
  • non-communicating

And can also be either:

  • congenital
  • acquired

Communicating hydrocephalus

Communicating hydrocephalus otherwise known as "non-obstructive hydrocephalus" is caused by inadequate absorption of cerebrospinal fluid when the ventricular pathways are not obstructed.

Non-communicating hydrocephalus

Non-communicating hydrocephalus, or "obstructive hydrocephalus", is caused by a blockage in the ventrical pathways through which the cerebrospinal fluid flows. Oftenly, this blockade is located at the level of the cerebral aqueduct between the third and fourth ventricle. In this case, an therapeutic option to shunting, is the surgical procedure third ventriculostomy.

Congenital hydrocephalus

In babies and infants with hydrocephalus, the head will enlarge because the bones are not joined together. One of the early symptoms of hydrocephalus in the newborn is that the fontanelles (soft spots) bulge and become firm.

Acquired hydrocephalus

Where the condition is acquired as the result of infection, brain tumors, cysts or head trauma.


Hydrocephalus was first described by Hippocrates but was not adequately treated until the 20th century, when appropriate shunts and neurosurgical techniques were developed.


Doctors treat hydrocephalus by putting a tube made of silastic, called a ventricular catheter , into the cerebral ventricles to help drain the excess fluid. Most shunts drain the fluid into the abdominal area but alternative sites include the vascular system, thoracic cavity, and gallbladder.

About 80-90% of fetuses or newborn infants with spina bifida (myelomeningocele) develop hydrocephalus. However, it is possible to have hydrocephalus without spina bifida.

Last updated: 09-12-2005 02:39:13