A stroke is a very serious health condition, which must always be treated as a medical emergency. Strokes occur when there is a disruption in the supply of blood to the brain; this prevents the brain from gaining the necessary oxygen and nutrients contained in the blood, which can cause serious implications for a patient’s health. Strokes are one of the biggest killers in the UK, claiming thousands of lives each year; they are a common health condition and affect more than 100,000 people every year. Strokes are much more common in people aged over 55 but they can affect people of all ages.
What causes a stroke?
There are two different types of stroke; they are known as ischaemic strokes and haemorrhagic strokes.
- Ischaemic strokes are caused by a blood clot, which blocks the supply of blood to the brain. Blood clots commonly develop in areas where the arteries have become narrow as a result of atherosclerosis (this occurs when fatty deposits block the arteries). Arteries may become narrow as a result of:
- Being overweight or obese
- Smoking
- Having a poor diet
- Hypertension (high blood pressure)
- Family history of heart disease, strokes and diabetes
Ischaemic strokes may also be caused by an irregular heart rhythm (also known as atrial fibrillation), which may cause a clot to form in the brain; possible causes of atrial fibrillation include:
- Hypertension
- Cardiomyopathy (wearing of the muscle in the heart)
- Pericarditis
- Heart valve disease
- Overactive thyroid gland (known as hyperthyroidism)
- Excessive drinking
- High caffeine intake
- Haemorrhagic strokes happen when a blood vessel in the brain ruptures; most cases of this type of stroke are caused by hypertension (high blood pressure). High blood pressure can be caused by a number of factors, including:
- Having a poor diet that is high in cholesterol
- Being overweight or obese
- Smoking
- Living a sedentary lifestyle
- Excessive drinking
- Stress
- Family history
Haemorrhagic strokes may also occur as a result of an injury or accident which causes a direct blow to the head.
- Subarachnoid haemorrhage: rarely, strokes may result from a subarachnoid haemorrhage; this is the case in 5% of strokes. This condition results from defects that a person has from birth; however, these may never be identified.