Hydrocephalus is commonly, but inaccurately known as "water on the brain". A watery fluid known as Cerebro Spinal Fluid (CSF) flows through narrow passageways from one ventricle to the next, out over the inside of the brain and down the spinal cord. CSF is continuously absorbed into the blood stream and the amount of pressure is kept within a narrow range. If the flow of fluid is obstructed at any point, it accumulates in the ventricles causing them to enlarge and compress surrounding brain tissue. In babies - but not older children or adults, the head will enlarge.

Treatment may be by insertion of a "shunt" (a piece of tubing with a pressure valve) to re-direct the excessive CSF or, in some cases, a third ventriculostomy. This will entail a hole being bored in the floor of the third ventricle to aid the impaired CSF flow. Symptoms caused by raised pressure usually improve, but other signs of brain damage may remain. These can include subtle learning difficulties.

Shunts can become blocked leading to headache, nausia, photophobia, inertia and irritability. Chronic infection may cause gradual deterioration in overall performance. Medical advice should be sought if a shunt blockage is suspected.

Inheritance Patterns:   Hydrocephalus is more likely to develop as a result of infections such as Meningitis or Toxoplasmosis; premature birth in infants; head injury, or a brain tumor; than to be genetically related, unless accompanies by Spina Bifida.

X-liked Hydrocephalus is the exception. Only boys are affected. Incidence is rare and is usually accompanied by abduction of the thumbs. It's presence is determined by genetic tests.

Pre-Natal Diagnosis: Often, but not always, seen pre-natally on ordinary ultrasound. Fetal anomaly scanning is recommended in suspected cases.

Further information available from:

Association of Spina Bifida and Hydrocephalus (ASBAH),
42 Park road
Peterborough
Cambridgeshire
PE1 2UQ
(Tel: 01733 555988   Fax: 01733 555985)

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ASBAH http://www.asbah.demon.co.uk is a Registered charity No.249388. The Hydrocephalus Network is part of ASBAH and supports families of children for whom Hydrocephalus is their main disability. It offers:

• Advice, information and support to affected families
• Education advice
• Service team for Assessment, Rehabilitation and Training (START)
• Medical information
• Mobility training
• Continence advisory service

Activities:

• Study days
• Residential courses for families of affected children

There are over 2000 children and adults with Hydrocephalus and there are also family self-help groups affiliated to ASBAH and some autonomous registered charities.