Following SAH, the risk of a second bleed from the same aneurysm is very high within the first few weeks. Treatment of the aneurysm protects it from secondary rupture so there is an urgency to protect the aneurysm with treatment as soon as possible. This risk of another bleed from the ruptured aneurysm does decline with time if left untreated.
Vasospasm, or delayed cerebral ischaemia occurs in about 1 in 4 individuals following a subarachnoid haemorrhage. Following a reaction to the haemorrhage some of the blood vessels within the brain can become narrowed. When this happens the amount of blood reaching certain areas of the brain can be reduced, and patients may become less well. One of the aims of treatment in the Neurosurgical unit is to observe for and treat signs of 'spasm. Whilst the effects of a reduced blood supply to areas of the brain can be reversed in many cases, there is a risk that a stroke could occur. Vasospasm is a possible risk during the first couple of weeks following a subarachnoid haemorrhage; it is not a long-term risk that could occur in the future. Once the brain has recovered from the acute irritation caused by the bleed, the risk of vasospasm developing will also have passed.
The normal brain produces cerebrospinal fluid (CSF), which bathes the brain. Following subarachnoid haemorrhage this fluid continues to be made, but sometimes the blood from the haemorrhage can block the normal drainage pathways, resulting in a build up of CSF within the brain. If this occurs then patients may become less well, and the excess fluid will need to be drained. This can be done in three ways:
A lumbar puncture, whereby a needle is inserted into the spinal column in the lower back and fluid is taken off. This may be performed as one off procedure or on several occasions as needed.
An external ventricular drain. A catheter is passed into the fluid chambers of the brain, and attached to an external collection unit. Any excess fluid build up will flow out of the brain via the catheter. This method may be used in the early stages following a haemorrhage and may be kept in place for several days.
A permanent shunt, commonly ventriculoperitoneal (VP). A catheter is passed into the fluid chambers of the brain, tubing attached to this is passed internally into the cavity between the intestine and stomach wall (peritoneum). Excess fluid build up will be drained off the brain via a pressure-controlled valve and into the peritoneum where it will be absorbed by the body. This method is long term.
The development of hydrocephalus is most common in the first couple of weeks following a subarachnoid haemorrhage, but can sometimes occur at a later stage. In most cases it will be temporary, and normal circulation of CSF will resume once the blood from the haemorrhage has dispersed. On occasions the effects of the subarachnoid haemorrhage can lead to long-term difficulties with hydrocephalus, and a permanent shunt will be needed.
Seizures and Epilepsy
It is common to have a fit at the time of the haemorrhage due to the irritating effect the blood has on the brain. Having a fit at this time, or immediately after surgery does not mean you have epilepsy. Epilepsy is a term given to somebody who has a tendency to recurrent, unprovoked seizures. Following a subarachnoid haemorrhage you will be at a slightly increased risk of having a seizure, or fit. Depending on many factors, including the site of your haemorrhage, the risk will vary slightly. The risk of having a fit gets less as time elapses. In most cases a first fit would occur within the first year, and it would be unusual to happen after two years. If you have been prescribed anticonvulsant tablets, it is important to remember that you should not stop taking them until advised to, and you should always take them regularly.
What to do If you were to have a fit, you may not know anything about it, as often people lose consciousness. People around you should:
Move any sharp or hard objects that you might hurt yourself on.
Place something soft under your head, if you have collapsed.
Only move you if you are in danger e.g. in the road.
Do not put anything into your mouth,
Do not restrict any movements.
Once the fit has finished, you should be placed on your side e.g. the recovery position
It is advisable for somebody to stay with you during the fit and whilst recovering from it. Commonly people will sleep, or feel drowsy, for some time after a fit, and may notice that they have bitten their tongue, or been incontinent. Generally, once you have recovered from the fit you should inform your GP, or specialist nurse that you have had one. The only occasions an ambulance needs to be called are:
If the fit lasts for more than 5 minutes
If further fits occur, without regaining consciousness in-between
If the individual has been injured as a result of the fit or collapse.
You can contact the British Epilepsy Association if you need more information, the details can be found in Useful Links.