Acute Stroke Interventions
1. What is a stroke?
Most strokes happen when a blood clot blocks one of the arteries (blood vessels) that carries blood to the brain. A stroke happens 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 starve 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.
2. 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 it depends 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:
- weakness down one side of the body, ranging from numbness to paralysis that can affect the arm and leg
- weakness down one side of the face, causing the mouth to droop
- speech may be difficult or become difficult to understand
- swallowing may be affected
- loss of muscle coordination or balance
- brief loss of vision
- severe headache
People who have had a severe stroke may lose consciousness. Unfortunately, the likelihood of such patients making a good recovery is poor.
3. How is stroke diagnosed?
A stroke is a medical emergency, and anyone suspected of having a stroke should be taken to a hospital immediately so that tests can be run and the correct treatment can be provided as quickly as possible.
Physicians have several tools available to screen for stroke risk and diagnose an active stroke. These include:
- Physical assessment - blood pressure tests and blood tests to see cholesterol levels, blood sugar levels, and amino acid levels
- Ultrasound - a wand waved over the carotid arteries in the neck can provide a picture that indicates any narrowing or clotting
- Arteriography - a catheter is inserted into the arteries to inject a dye that can be picked up by X-rays
- Computerized tomography (CT) scan - a scanning device that creates a 3-D image that can show aneurysms, bleeding, or abnormal vessels within the brain
- Magnetic resonance imaging (MRI) - a magnetic field generates a 3-D view of the brain to see tissue damaged by stroke
- CT and MRI with angiography - scans that are aided by a dye that is injected into the blood vessels in order to provide clearer and more detailed images
- Echocardiography - an ultrasound that makes images of the heart to check for embolus
- Eye-movement analyzer may diagnose stroke - researchers from Johns Hopkins University School of Medicine in Baltimore created a device that can help diagnose stroke by expertly analyzing eye movements. They reported their findings in the journal Stroke. The electronic device is a small, portable, video-oculography machine. It detects eye movements that most doctors find hard to notice.
4. 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 well hydrated and nourished.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.
5. What are the risk factors?
High blood pressure does not cause any symptoms, so everyone over the age of 40 should have an annual blood pressure check.Smokers have double the risk of stroke as non-smokers.
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 warfarin (eg Marevan), a medicine that makes the blood less likely to clot. Warfarin treatment requires careful monitoring with regular blood checks and is a very effective way to reduce the risk of stroke.
Diabetes affects 1 in 20 older people and 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 probably some 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, liver disease and dementia.
6. What are the results of a stroke?
The effects of stroke vary widely depending on what part of your brain has been injured and how much brain tissue is involved. Even minor injury to certain areas can be serious, while other areas can be quite badly injured with little visible effect. The following effects are particularly common:
- Hemiplegia means half paralysis, this happens in about 80% of people who have had a stroke. The paralysis, on one side of the body, can be either partial or complete depending on how serious the stroke was. The paralysis happens because there is injury to that part of the brain which sends messages to the muscles in your arms and legs. Sometimes this loss of power affects not only your arm and your leg but also the side of your face. This can result in one side of your face drooping, with drooling from the side of your mouth. Due to the structure of the brain, if the right half of your brain is injured, the paralysis affects the left side of your body. If the left half of your brain is injured, the paralysis is on the right side. Balance may also be affected so that you are likely to fall or lean sideways in the bed or chair.
- Loss of sensation on one side of the body. This can be more than just loss of feeling in your skin. It can mean that, without looking, you will not know where an arm or leg is positioned. In the most severe cases, this loss of sensation can result in complete neglect of one side of your body. This sensory disturbance can also lead to difficulties with you knowing right from left and your judgement of depth and distance.
- Loss of vision. This affects half of your field of vision – nothing can be seen to one side of a central vertical line. If you have a weakness of the left side of your body you may find it difficult to see objects on the left side of the visual field. Often you can be unaware of this visual problem and may be surprised to keep bumping into furniture and door frames on the affected side.
- Difficulties communicating. The two major problems are: Not being able to express words and Not being able to understand the spoken word. Some people after a stroke have difficulty expressing words or may even lose the ability to speak completely, while at the same time still being able to understand what is being said to them. Never assume that because the person cannot speak that they cannot understand.
- Loss of intellectual or thinking ability. Loss of intellectual or thinking ability may follow a stroke and the person may have difficulty with attention, concentration, working out problems and grasping new information. If the person complains of memory difficulties it is usually for day to day events rather than long-term memory.
- Emotional changes. Experiencing a stroke can be very distressing and the person may experience a range of emotional changes and reactions. These emotional changes are often an expected response to a significant and upsetting life event. Sometimes emotional changes in the person are due to changes in the brain as a result of the stroke. These can lead to the person experiencing little or no control over their emotional responses. For example the person may laugh or cry out of context and for no apparent reason. This is often described as pathological laughter or crying. This can be very distressing for the person and their carers but fortunately this can usually be helped with medication