Stroke - haemorrhagic

In around 20% of cases, strokes are caused by ruptured blood vessels leaking blood into the brain - haemorrhagic strokes.

Both types of stroke - those caused by blood clots and those caused by burst blood vessels - interrupt the supply of blood to the brain, depriving the cells of oxygen and other nutrients. The cells are then damaged or die.

Strokes caused by the breakage or "blow-out" of a blood vessel in the brain are the result of a cerebral aneurysm - ballooning of a weakened blood vessel in the brain - which is left untreated, high blood pressure, or a cluster of abnormally formed blood vessels (arteriovenous malformation).

Aneurysms develop over a number of years and do not usually cause detectable problems until they break.

Types of haemorrhagic stroke

There are two types of haemorrhagic stroke - subarachnoid and intracerebral.

In an intracerebral haemorrhage bleeding occurs from vessels within the brain itself. Hypertension, or high blood pressure, is the primary cause of this type of haemorrhage.

In subarachnoid haemorrhage, an aneurysm bursts in a large artery on or near the delicate membrane surrounding the brain. Blood spills into the area around the brain which is filled with a protective fluid, causing the brain to be surrounded by blood-contaminated fluid.

The symptoms of stroke:

• Sudden numbness or weakness of the face, arm or leg, particularly if it is on one side of the body
• Sudden confusion, trouble speaking or understanding. Sudden difficulty with walking, dizziness, loss of balance or co-ordination
• Sudden trouble seeing in one or both eyes
• Sudden severe headache with no known cause

Anyone identifying themselves or friends or family as having a stroke should call emergency services, not a GP, as any delay reduces the chance of a full recovery.

Treatment

The speed of treatment after a stroke is extremely important as the longer the brain cells are deprived of oxygen, the more damage they will suffer.

Clot-busting drugs and aspirin must not be given to patients who have suffered a haemorrhagic stroke. A CT scan or MRI scan will identify the type of stroke suffered.

Treatment of haemorrhagic stroke is less developed than that of ischaemic stroke.

A Medical Research Council trial is currently underway into treatment to remove blood clots surgically and drugs which prevent damage to brain cells during haemorrhages are being tested.

Survival rates are better for patients in specialist stroke units, because of the expert nature of staff and early use of rehabilitation, but such units are not always available.

Rehabilitation programmes will be given to most stroke patients to help them recover lost mobility and speech.