Shunt complications

Shunts sometimes go wrong, and it may be due to infection, blockage, or malfunction. Occasionally your shunt may also need a revision (changing all or part of the shunt). Read on for more information.

Remember - if you know someone has a shunt and they're losing consciousness, call 999 immediately.

 

Shunt infections

Occasionally, bacteria from the skin can infect the shunt, at the time of surgery. Bacteria live within layers of the skin, no matter how clean it is or how thoroughly the skin is prepared for surgery. The bacteria are harmless when on unbroken skin but can cause infections in other parts of the body. The bacteria are released into the surgical cut onto the underlying tissue.

Signs of shunt blockage develop very quickly for infected VP shunts, but infected VA shunts do not block, and may not result in any symptoms for several years after insertion. It is not possible for a shunt to become infected through day-to-day illnesses, such as colds, flu or dental problems.

You will not need antibiotic cover for dental work. However, VP shunts can become infected following abdominal infections, like a burst appendix, or bladder or bowel surgery. Ensure your surgeons know you have a VP shunt if these situations arise.

If it is suspected that your VP shunt is infected, it will usually block, and you will need to seek medical attention straight away. The shunt will be removed and sent for testing, and an External Ventricular Drain (EVD) system will be inserted. This will allow the infected CSF to be drained into a bag outside the body, whilst antibiotics are used to clear the infection. It is important that blood or protein present in the CSF are allowed to clear before the new shunt is fitted, as these can block the new valve. 

 

Shunt blockages

Shunts can block for a number of reasons.

Proximal

The tiny drainage holes in the proximal catheter may become clogged with healthy brain cells as the catheter is passed through the brain on its way to the ventricle.

This may be a repeated problem for some people, leading to a shunt’s blocking within a few days of being inserted, even with no infection present. Some people are more prone to this, and at the moment we don’t know why that is. The drainage holes can become blocked with choroid plexus, a tissue in the ventricles that produces CSF.

The shunt can move slightly so the tip is no longer in the ventricle but in the brain tissue itself. The valve can become blocked with protein or blood from haemorrhage, although this is rare.

Distal

The bottom end of a VP shunt can become blocked by the tissue covering the bowel, especially if there is a lot of scar tissue (adhesions) in the abdominal cavity, or infections or blood in the abdomen. 

 

Shunt malfunctions

Shunts sometimes go wrong. There are various reasons why they may malfunction and need specialist medical intervention, and being able to recognise the possible signs and symptoms is vital.

It's also important to make sure those around you can spot the signs, and know what action to take if you display symptoms of a potential shunt malfunction. It would be a good idea to share this information with your family, friends, teachers, colleagues or anyone else you have regular contact with to ensure that they are able to support you in the case of an emergency.

Emergency signs of shunt malfunction

Emergency symptoms or signs to look for may include some, or all of the following:

  • Drowsiness / confusion
  • Vomiting / extreme nausea
  • Photophobia / sensitivity to light
  • Visual disturbances
  • Severe headaches

If you notice any of the emergency symptoms above, take action immediately:

  • Check their shunt alert card to get the contact details for their neurosurgical centre - call the centre for advice.
  • Be ready to call 999 - if the person is losing consciousness call 999 immediately.

Chronic symptoms of shunt malfunction

Chronic symptoms of malfunction may develop over weeks or even months. Symptoms that should be reviewed at a neurosurgery centre include:

  • Fatigue
  • Behaviour changes
  • General malaise
  • Decline in academic performance
  • Visual problems
  • Being "not right"

If a person with hydrocephalus has any of these symptoms, do not assume someone else has noticed, take action immediately.

 

Shunt revisions

If it is necessary to change part or all of your shunt, your neurosurgeon will aim to achieve this with the smallest risk of complications possible. Shunts may, over time, become attached to surrounding tissues, and it can be difficult to remove without causing complications. However, if the shunt is infected, it will usually be necessary to remove the whole shunt so that the infection can be treated effectively.

If the shunt needs changing for another reason, it may be possible to leave a non-functioning shunt in place and just add another shunt system, in another part of the head. If the proximal catheter is blocked but the distal catheter is working, it may be possible to just change the blocked component. Shunts which are under-or-over draining may be ‘tied off’ when another shunt is inserted, to stop them working.