What is stroke

The term stroke is used to describe an event during which the blood supply to a part of the brain is suddenly interrupted. The symptoms start abruptly and may slowly worsen over a few hours or days. Symptoms always last more than 24 hours and depend on which cerebral blood vessels and which part of the brain are affected.

• Weakness or paralysis of one side of the body
• Speech difficulties
• Sudden severe giddiness
• Nausea and vomiting
• Loss of sensation, e.g. numbness of the face
• Difficulty in swallowing
• Double vision
• Loss of vision in one eye
• Drooping of one upper eyelid with a small pupil and lack of sweating on that side of the face
• Sudden severe headache
• Confusion
• Coma

Symptoms

Transient Ischaemic Attacks (TIAs) are known as ‘mini stroke’. They occur when the blood supply to part of the body is temporarily interrupted, e.g. by a small blood clot or vascular spasm. The symptoms disappear within 24 hours, or even sooner.

Causes

About 80% of strokes are due to a blood clot blocking an artery in the brain while the rest are due to bleeding into brain tissue from a ruptured blood vessel. Either event causes the death of an area of brain tissue and the permanent loss of cells.

The underlying cause of a stroke is usually atherosclerosis (hardening of the arteries). In atherosclerosis, fatty plaques and scar tissue form in artery walls, restricting the blood flow; blood clot often form on the plaques, further blocking the arteries. Fragments of clot may detach and circulate in the bloodstream. If a fragment lodges in a smaller blood vessel in the brain, it may block it and cause a stroke.

Risk Factors

• Hypertension (high blood pressure)
• Heart disease
• Weakness in blood vessel walls in the brain
• Blood diseases
• Certain drugs

Diagnosis

• CT scanning – this confirms the presence of a cerebral infarct. In the first few days after stroke, it can differentiate between brain damage caused by bleeding and damage caused by an embolus.
• An MRI scan – this usually shown up abnormality within a few hours of the stroke.
• Lumbar puncture – blood in the cerebrospinal fluid that bathes the spinal cord, suggests a diagnosis of subarachnoid haemorrhage.
• Carotid Doppler and duplex scanning – this specialised form of ultrasound scanning is used to detect narrowing of the carotid arteries, the arteries that supply the brain.
• Angiography – this detects narrowing blood vessels.
• Blood tests – e.g. full blood count, erythrocyte sedimentation rate, blood electrolyte and glucose levels.
• Chest X-ray
• Electrocardiogram (ECG)

Treatment

• Anticoagulant drugs – these may be prescribed if the stroke is caused by a blood clot.
• Surgery – in server continued bleeding, surgery may be carried out to clip a bleeding vessel.
• Rehabilitation – this is essential as many patients are immobile following a stroke and are at risk of developing pressure sores and deep vein thromboses. Difficulty with swallowing is another problem as choking can occur and fluid or food may accidentally be inhaled into the airways. Blood control is vital for patients with hypertension, and readings are closely monitored.

Prevention

• Treat high blood pressure at an early stage
• smoking
• TIAs should be investigated in order to treat the underlying cause

Source: “Inside The Human Body”. Published by Bright Star Publishing PLC.