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Endoscopic Third Ventriculostomy (ETV)

Hydrocephalus in developing countries

Living with Hydrocephalus: testimonies




Hydrocephalus is sometimes referred to as 'water on the brain'. A watery fluid, known as cerebro-spinal fluid or CSF, is produced continuously inside each of the four spaces or ventricles inside the brain. The CSF normally flows through narrow pathways from one ventricle to the next, then out across the outside of the brain and down the spinal cord. The CSF is absorbed into the bloodstream and recirculates. The amount and pressure are normally kept within a fairly narrow range. If the drainage pathways are blocked at any point, the fluid accumulates in the ventricles inside the brain, causing them to swell - resulting in compression of surrounding tissue. In babies and infants, the head will enlarge. In older children and adults, the head size cannot increase as the bones which form the skull are completely joined together.

Treatment of Hydrocephalus

Hydrocephalus is usually treated by insertion of a drainage system (e.g. a shunt). A shunt is simply a drain that diverts or “shunts” the accumulated CSF from the obstructed drainage pathways and returns it to the bloodstream. Symptoms caused by raised pressure usually improve after successful shunting, but some problems will remain. Recently neuroendoscopy (telescopic surgery) makes treatment of hydrocephalus possible without shunting in two thirds of patients (the success rate depends on the aetiology of the hydrocephalus and varies between one quarter to nearly one hundred percent). Management of hydrocephalus by “Third Ventriculostomy” creates a natural bypass within the brain allowing the fluid to drain. This is a procedure that does not have the complications of shunt insertion. Infection is rare and morbidity is very low. This low morbidity operation is a valid treatment for hydrocephalus in the difficult conditions of developing countries where follow-up is inconsistent and retrieval of patients in case of complications is nearly impossible. 

A series of three articles by Dr Roger Bayston MMedSci MRCPath:

Causes of hydrocephalus  
Secondary effects 
Slit Ventricle Syndrome 
Treatment of Hydrocephalus 

Causes of hydrocephalus


The condition is caused by the inability of CSF to drain into the bloodstream. There are many reasons why this can happen:


Congenital Hydrocephalus

This means that hydrocephalus is present at birth. It is important to remember that this term does not imply that it is hereditary. Often the exact cause of congenital hydrocephalus cannot be determined.



Babies born prematurely are at risk of developing hydrocephalus. A baby born early is far more vulnerable than one which goes the full term since it is still developing. The area which lies just beneath the lining of the ventricles in the brain is particularly important - because of the activity in this area it has a plentiful of blood supply. Its blood vessels are very fragile and can easily burst if the baby suffers too large a swing in blood pressure or becomes severely ill from other causes.

If these complications do occur, then the baby is at risk of developing a haemorrhage from rupture of the fragile vessels. This can lead to a blood clot developing, which in some cases is big enough to break through the wall of the ventricle. Should the clot block the flow of CSF, the baby will develop hydrocephalus. The blockage may be temporary or permanent. Even if a blood clot does not develop, the blood cells from the haemorrhage can cause blockage.


Spina Bifida

Most babies born with spina bifida have hydrocephalus. In addition to the lesion in the spinal cord, there are abnormalities in the structure of certain parts of the brain which develop before birth. This prevents proper drainage of the CSF. The increase in pressure can compress the abnormal parts of the brain even further.


Other forms

of brain haemorrhage, including those occurring in adults ("stroke"), can result in this type of post-haemorrhagic hydrocephalus.



This is an infection of the membranes covering the brain. The inflammation and debris from this infection block the drainage pathways resulting in hydrocephalus. Meningitis can occur at any age but it is more common in children. The incidence of one form, haemophilus meningitis, has been drastically reduced by the HIB vaccine.


Dandy Walker Cysts

There is a particular group of disorders involving the formation of fluid-filled cysts in the CSF system (for example Dandy Walker cysts). In these cases, hydrocephalus is often developed due to the pressure on the surrounding tissues by the enlarging cyst.



Tumours of the brain cause compression and swelling of surrounding tissues, resulting in poor drainage of CSF. In the treatment of brain tumours, it is often necessary to include measures to control hydrocephalus, which may only be temporary.



In very rare circumstances, hydrocephalus is due to hereditary factors, which may affect future generations.


Other causes

There are many other very rare causes of hydrocephalus.


Secondary effects

There can be learning difficulties associated with hydrocephalus such as problems with concentration, reasoning and short-term memory. Hydrocephalus can also result in secondary effects: giving problems with co-ordination, motivation and organisational skills. Physical effects such as problems with vision, or early puberty, may also occur.

Many of these effects can be overcome with teaching strategies or treatment where relevant.

It must be stressed that the effects of hydrocephalus vary from one individual to the other. Some people will have very few, if any, problems.

Slit Ventricle Syndrome

Slit ventricle syndrome is a constellation of symptoms which, for example, can appear in patients with a functioning shunt and in whom the brain has lost part of its elasticity. The symptoms consist of headaches, vomiting, drowsiness etc. However, it should be noted that these symptoms resemble those of shunt malfuntion. The appearance of the symptoms is very cyclical, often with the regularity of a clock for example, the patient is well for three weeks, then violently ill and sleepy for 24 hours and then well again. There is more often than not no cause for the symptoms, although a minor viral illness can start the symptoms. Often the patient is taken to the hospital and imaging is done which shows the ventricles to be small, or even unchanged, compared to previous imaging.

Dr M. Vloeberghs explains what  a slit ventricles syndrome is and what can be done about it.

Treatment of Hydrocephalus

Some forms of hydrocephalus require no specific treatment. Other forms are temporary and do not require long-term treatment. However, most forms do require treatment, and this is usually surgical. Drugs have been used for many years but they may have unpleasant side effects and are often not successful.

The usual treatment is to insert a shunting device. It is important to note that this does not 'cure' the hydrocephalus and damage to the brain tissue remains. Shunting controls the pressure by draining excess CSF, so preventing the condition from becoming worse. Symptoms caused by raised pressure usually improve but other problems of brain damage will remain.

An alternative treatment may be third ventriculostomy. This treatment, if successful, avoids the need for a shunt. However, not all types of hydrocephalus can be treated by this method and it is not available in all neurosurgical units.

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