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Please note: This is a basic revision aid, not a comprehensive and reliable statement of medical fact. These notes should not be used to guide treatment. For reliable information and advice, consult a qualified practitioner.
Images on this page are used courtesy of the Association for Spina Bifida and Hydrocephalus (ASBAH)
Last updated: 05 March 2001
Hydrocephalus is an impairment of cerebrospinal fluid (CSF) drainage and resultant increase in intracranial pressure, causing enlargement of the ventricles and compression of surrounding tissues. If this develops in babies or infants, before the bones of the skull have knitted together, there can be an increase in head size. Head size is routinely monitored in infants to detect unusual rate of growth.
No data found. Incidence is approx 1:1000
Extremely variable, depending on the specific cause. May be present at birth, or can develop at any time due to infection, head injury. etc.
Hydrocephalus can be caused by either a blockage in CSF drainage or an overproduction of CSF, but the latter is very rare. Where overproduction does occur, it is usually due to a tumour of the choroid plexus, that produces CSF.
Congenital Causes:
Meningitis can cause an accumulation of infection debris and pus, impairing CSF drainage. Other causes include head injury, tumours, haemorrhage and Dandy-Walker cysts, which block the fourth ventricle, can impair CSF flow resulting in Hydrocephalus.
Cerebrospinal fluid (CSF), is produced in the ventricles of the brain and circulates through them and through the spinal cord and around the area between the brain and the meninges before being reabsorbed into the blood stream. If CSF is overproduced or its circulation or reabsorption are impaired, the pressure inside the brain will increase and there may be damage and distortion to the areas of the brain nearest the ventricles.
Both motor and cognitive problems may be seen. Motor problems tend to be those around hand-eye co-ordination and manual dexterity. Cognitive problems may include motivation, short term memory (recording rather than retrieval of information), concentration, perception of time, decision making, outcome prediction, difficulty with complex or abstract information. Some form of learning disability is common, but very variable in severity. There may also be difficulties with social skills: empathy, humour, reading nonverbal cues.
It is suggested that pathways in the brain that are heavily involved in motivation are situated very close to the ventricles, and may be damaged in ventricular dilation -- hence the commonly observed motivational difficulties.
There is relatively little knowledge about the implications of hydrocephalus, as shunting was invented only in the 1950s and widespread use only came about in the 1960s. Prior to this, the condition was usually fatal, so we are only now seeing the first generation of hydrocephalus survivors reaching late adulthood.
Assuming proper control of hydrocephalus and good management of shunts, there should be no major reduction in life expectancy. No real evidence is available on this as widespread shunting is less than forty years old.
The extent of disability is very variable, depending on how soon the condition was detected and treated.
In some cases, surgery may be used to clear the blockage, i.e. "Third Ventriculostomy" -- surgery to the ventricle to clear the blockage. More commonly, a shunt may be surgically inserted. This is a catheter that is surgically implanted to drain the CSF from the brain and discharge it into either the abdominal cavity (ventriculo-peritoneal or VP shunt) or the heart (ventriculo-atrial or VA shunt).
The Association for Spina Bifida and Hydrocephalus (ASBAH) has specialist advisors who can be a valuable source of advice for professionals, parents and later for the person themselves. Contact with ASBAH should be discussed with parents at an early stage.
Motivational difficulties are notoriously difficult for others to understand, and can cause lots of difficulties in assessment. The person may be physically and cognitively able to perform various activities of daily living, but lack the motivation to do so through no fault of their own. This must be carefully explained to family and carers, to avoid the person being unfairly labelled as lazy.
Cognition difficulties may require use of special learning techniques when acquiring new skills.
Onset of puberty may be significantly early and may be challenging for a mind that hasn't had time to attain the usual level of maturity. Specialist advice should be sought if necessary.
Shunt failure: Therapists, clients and all those involved in care of the person with hydrocephalus must be aware of the symptoms of shunt failure. If there is an indication of shunt failure, there should be an immediate referral to a neurosurgical unit. There are basically three shunt complications:
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Last updated: 7th November 2002
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