What is a shunt?
A shunt is simply a device which diverts the accumulated CSF around the obstructed pathways and returns it to the bloodstream. It consists of a system of tubes with a valve to control the rate of drainage and prevent back-flow. It is inserted surgically so that the upper end is in a ventricle of the brain and the lower end leads into the abdomen (ventriculo-peritoneal or VP shunt)
The device is completely enclosed so that all of it is inside the body.The fluid which is drained into the abdomen passes from there into the bloodstream. Other drainage sites such as the outer lining of the lungs or the heart can also be used, although this is rarely done now.
In most cases the shunts are intended to stay in place for life, although alterations or changing the shunt (called revisions) might become necessary from time to time.
» Are there any complications with this kind of treatment ?
Complications are usually caused either by blockage of the system, or by infection. They are only occasionally due to mechanical failure of the valve.
The tube (or catheter) may become too short as the individual grows and an operation to lengthen it might be necessary.
» Shunt Blockage
Symptoms usually develop gradually. In some cases blockage shows itself in a gradual deterioration in overall performance. Occasionally, symptoms are quite sudden and severe and may include headaches and vomiting. Various tests can be carried out to confirm the diagnosis. Medical advice should be sought if a shunt blockage is suspected.
If symptoms worsen rapidly, specialist attention (preferably at your neurosurgical unit) should be sought.
» Shunt Infection
Symptoms vary with the route of drainage. In ventriculo-peritoneal shunts the symptoms will often resemble those of blockage. This is because the shunt becomes infected and the lower catheter is very often then sealed off by tissue. There may be accompanying fever and abdominal pain or discomfort. The most usual time span for infection to appear is soon after the operation to insert the shunt.
Various tests can be carried out for shunt infections and medical advice should always be sought if an infection is suspected.
Symptoms of overdrainage are also similar to those of blockage. A severe headache, which is reduced when lying down, is a common symptom.
» What symptoms should be looked for ?
Whenever there is a possibility that hydrocephalus is causing problems, it is important to seek the correct help immediately.
Possible signs of ACUTE shunt blockage or infection may include:
Vomiting; headache; dizziness; photophobia (sensitivity to light) and other visual disturbances; drowsiness and fits.
Possible signs of CHRONIC shunt blockage may include: Fatigue; general malaise; visuo-perceptual problems; behavioural changes; decline in academic performance; being just 'not right' from the carer's point of view.
» How are shunt problems treated?
Shunt blockages that are causing illness usually require an operation to replace or adjust the affected part of the shunt. Shunt infections are usually treated by removal of the whole shunt and a course of antibiotics before insertion of a new system. Modern approaches to antibiotic therapy mean that such treatment in most cases can be expected to succeed.