What is a stroke?
A occurs when the blood supply to the brain is disturbed in some way. As a result, brain cells are starved of oxygen. This causes some cells to die and leaves other cells damaged.
Types of stroke
Most strokes happen when a blood clot blocks one of the arteries (blood vessels) that carries blood to the brain. This type of stroke is called an ischaemic stroke.
- Transient ischaemic attack (TIA) or 'mini-stroke' is a short-term stroke that lasts for less than 24 hours. The oxygen supply to the brain is quickly restored and symptoms disappear. A transient stroke needs prompt medical attention because it indicates a serious risk of a major stroke.
- Cerebral thrombosis is when a blood clot (thrombus) forms in an artery that supplies blood to the brain. Blood vessels that are furred up with fatty deposits (atheroma) make a blockage more likely. The clot prevents blood flowing to the brain and cells are starved of oxygen.
- Cerebral embolism is a blood clot that forms elsewhere in the body before travelling through the blood vessels and lodging in the brain. In the brain, it starves cells of oxygen. An irregular heartbeat or recent heart attack may make you prone to forming blood clots.
- Cerebral haemorrhage is when a blood vessel bursts inside the brain and bleeds (haemorrhages). With a haemorrhage, blood seeps into the brain tissue and causes extra damage.
What are the symptoms of a stroke?
Strokes usually happen suddenly. No two strokes are the same and people can be affected in quite different ways.
To an extent the symptoms of a stroke depend on which area of the brain is damaged, because different parts control different abilities such as speaking, memory, swallowing and moving.
The most common signs of a stroke are:
- Numbness or weakness in your face, arm, or leg, especially on one side
- Confusion or trouble understanding other people
- Trouble speaking
- Trouble seeing with one or both eyes
- Trouble walking or staying balanced or coordinated
- Severe headache that comes on for no reason
People who have had a severe stroke may lose consciousness. Unfortunately, the likelihood of such patients making a good recovery is poor.
Face-arm-speech test (FAST)
The Stroke Association says three simple checks can help you recognise whether someone has had a stroke or mini-stroke.
- Facial weakness: can the person smile? Has the mouth or eye drooped?
- Arm weakness: can the person raise both arms?
- Speech problems: can the person speak clearly and understand you?
- Test these symptoms.
If you see any of these signs, call 999 for an ambulance.
How is a stroke treated?
In hospital, brain scans are needed to find out what type of stroke you've had.
- If a blood clot is the cause, 'clot-busting' medication may be used to dissolve the clot, but this must be given within three hours of the stroke. Anti-clotting medication, such as aspirin may also be given to stop the stroke from getting worse.
- Anti-clotting medication is not given in strokes caused by haemorrhaging because it will make the bleeding worse.
Other treatment includes:
- tests on key functions like swallowing and movement
- checks on oxygen, glucose and blood pressure levels.
If swallowing is affected, you may be fed by a tube or given fluids into a vein (intravenously) to avoid food going into the lungs.
After a stroke
In the first few days after a stroke, treatment concentrates on making sure you are receive sufficient fluids and food.
The next phase of treatment is recovery through rehabilitation.
This involves a team of health professionals including physiotherapists, speech therapists, occupational therapists, nurses and doctors.
Family and friends will also have an important role to play in the recovery phase, which may last as long as one whole year, after which no further improvements can be hoped for.
Depression is common in patients during the first months after the event and its treatment might call for special attention.
If a stroke is caused by a blood clot in spite of a regular heart rhythm, then taking a low-dose aspirin (eg Nu-seals 75mg) once a day may help make the blood less sticky and less likely to cause clots.
Careful monitoring of the blood pressure is recommended.
What are the risk factors?
- Smokers have double the risk of stroke as non-smokers but those who dwell in surroundings where many people smoke are also at increased risk (second-hand smoke).
- High blood pressure does not cause any symptoms, so people over the age of 40 should have a regular blood pressure check, at least every five-years. A normal blood pressure is defined as the upper level (systolic pressure) below 140 mmHg, the lower level (diastolic pressure) below 90 mmHg.
- Irregular heart beat (atrial fibrillation) is fairly common in old age. It increases the risk of stroke by causing blood clots to form in the heart. Blood clots can be prevented from forming by taking Marevan (warfarin), a medicine that makes the blood less likely to clot. Warfarin treatment requires careful monitoring with regular blood checks and is an effective way to reduce the risk of stroke. Over the past years new medicines have been introduced for which careful monitoring no longer required. These include Pradaxa (dabigatran), etexilate, Xarelto (rivaroxaban) and Eliquis (apixaban).
- Diabetes mellitus is a common disease that can increase the risk of having a stroke. Good control of diabetes is important and requires attention to diet, regular urine tests or blood tests and, often, medication.
- Too much alcohol increases the risk of a stroke. The recommended safe limits for alcohol consumption are 21 units each week for women and 28 units each week for men. One unit of alcohol is equivalent to a measure of spirits, a 125ml glass of wine or half a pint of beer. People who drink more than this run a higher risk of stroke, high blood pressure, liver disease and dementia.
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