A stroke occurs when blood supply to a part of the brain is disrupted, causing brain cells to die.
Compromised blood flow to the brain can be due to lack of oxygen, blockage of blood flow, or rupture of an artery to the brain.
Another type of stroke is transient ischemic attack (TIA) which occurs when blood supply to the brain is briefly interrupted. These strokes almost always last for less than 24 hours.
Causes of Stroke
There are two common kinds of stroke. The most common, ischemic stroke, is caused by a blood clot that blocks a blood vessel in the brain or when cholesterol plugs and plaques in blood vessels narrow them, preventing blood from getting through. Ischemic strokes occur in 80 per cent of stroke patients.
The other kind, called haemorrhagic stroke, is caused by a blood vessel that ruptures and bleeds into the brain. Bleeding may lead to raised intracranial pressure, which further compromises other areas of the brain. Being more serious, death occurs in 30 to 50 per cent of people with this type of stroke.
The most common risk factors for strokes include high blood pressure, high blood cholesterol, smoking, diabetes, heavy alcohol consumption, drug abuse (cocaine and amphetamines), and ageing.
Signs and Symptoms
There are five major signs of stroke that most patients present with. They include;
• Sudden numbness or weakness of the face, arm, or leg, especially on one side of the body.
• Sudden confusion or difficulty speaking or understanding. Sometimes weakness in the muscles of the face can cause drooling.
• Sudden difficulty seeing in one or both eyes.
• Sudden difficulty walking, dizziness, and loss of balance or coordination.
• Sudden, severe headache with no known cause.
The symptoms of a stroke depend on the part of the brain and how much of the brain tissue is affected. These may appear within minutes or may take an hour.
They may not be associated with pain, but may resolve within 24 hours, indicating a TIA. Thirty per cent of stroke symptoms occur at night and symptoms noticed upon waking up.
Strokes are medical emergencies. The prognosis in part depends on how soon management begins; therefore it is important to get prompt treatment.
There are three steps that can confirm a stroke. These involve asking a patient to do the following:
1. Smile: the face should move symmetrically.
2. Raise both arms to look for weakness on one side of the body.
3. Say a simple sentence.
If these tasks cannot be performed properly, an ambulance should be summoned or the patient rushed to the hospital immediately.
The tests for stroke are highly specialised and conducted in a higher level medical facility and may include tests such as CT scans, MRI, CT angiograms, all of which will inform the doctors of the location of the stroke, the cause, and the extent.
This then determines treatment. Complications of strokes include heart attack, pneumonia, clots in the blood vessels due to immobility, loss of speech, as well as lack of bowel or urine control. Residual disability of some form occurs in over 75 per cent of the cases.
This may lead to lack of independence as well as inability to work, thus occasionally resulting in depression. Stroke patients, therefore, require a lot of counselling and rehabilitation through occupational, physical, and speech therapy.
Prevention of strokes is a major public health concern and must involve minimising and managing any of the present risk factors.
This article was first published in the Daily Nation.