A stroke means that the blood supply to a part of the brain is suddenly cut off. The brain cells need a constant supply of oxygen from the blood. Soon after the blood supply is cut off, the cells in the affected area of brain become damaged, or die.
The blood supply to the brain comes mainly from four arteries – the right and left carotid arteries, and the right and left vertebrobasilar arteries (see diagram below). These branch into many smaller arteries which supply blood to all areas of the brain. The area of brain affected, and the extent of the damage, depends on which blood vessel is affected.
For example, if you lose the blood supply from a main carotid artery, then a large area of the brain is affected, which can cause severe symptoms, or death. In contrast, if a small branch artery is affected, then only a small area of brain is damaged which may cause relatively minor symptoms.
There are two main types of stroke – ischaemic and haemorrhagic.
Ischaemic stroke – caused by a blood clot
Ischaemic means a reduced blood and oxygen supply to a part of the body. It is usually caused by blood clot in an artery, which blocks the flow of blood. This occurs in about 7 in 10 cases.
• The blood clot often forms within the artery itself. This commonly occurs over a patch of fatty material called atheroma. Small patches of atheroma form on the inside of arteries in most older people. If a patch of atheroma becomes thick, it can trigger the blood to clot.
• In some cases, the blood clot forms in another part of the body, and then travels in the bloodstream – this is called an embolus. The most common example is a blood clot which forms in a heart chamber as a result of abnormal turbulent blood flow. This may occur in a condition called atrial fibrillation. The blood clot is then carried in the bloodstream until it gets stuck in an artery in the brain.
Haemorrhagic stroke – caused by bleeding
A damaged or weakened artery may burst and bleed inside the brain or in the narrow space between the brain and the skull (subarachnoid haemorrhage). The blood then spills into the nearby brain tissue. This can cause the affected brain cells to lose their oxygen supply and become damaged or die.
Who is affected by stroke?
J Neurol Neurosurg Psychiatry. 2014 Dec;85(12):1308-12. doi: 10.1136/jnnp-2013-306992. Epub 2014 Apr 25. Stroke in Asia: geographical variations and temporal trends. Mehndiratta MM, Khan M, Mehndiratta P, Wasay M
I cant access this paper. You might be able to through BMJ or athens. If we want to add Pakistani statistics.
What are the symptoms of a stroke?
The functions of the different parts of the body are controlled by different parts of the brain. So, the symptoms vary depending on which part of the brain is affected and on the size of the damaged area. Symptoms develop suddenly and usually include one or more of the following:
• Weakness of an arm, leg, or both. This may range from total paralysis of one side of the body, to mild clumsiness of one hand.
• Weakness and twisting of one side of the face. This may cause drooling of saliva.
• Problems with balance, co-ordination, vision, speech, communication, or swallowing.
• Dizziness or unsteadiness.
• Numbness in a part of the body.
• Loss of consciousness (occurs in severe cases).
What is a mini-stroke?
A mini-stroke is a set of symptoms similar to a stroke, but which last for less than 24 hours. It is due to a temporary lack of blood to a part of the brain. It is more correctly called a transient ischaemic attack (TIA). In most cases, a TIA is caused by a tiny blood clot that becomes stuck in a small blood vessel (artery) in the brain. This blocks the blood flow and a part of the brain is starved of oxygen. The affected part of the brain is without oxygen for just a few minutes, and soon recovers. This is because the blood clot either breaks up quickly, or nearby blood vessels are able to compensate.
Unlike a stroke, the symptoms of a TIA soon go. However, a doctor should be seen urgently in the case of a TIA as there is an increased risk of having a full stroke.
A quick guide for the general public to remember
Both a stroke and a TIA are medical emergencies and need immediate medical attention. As a way of helping the general public to become more aware of the symptoms of a stroke or TIA, a simple symptom checklist to remember is as follows :
Facial weakness. Can the person smile? Has their mouth or eye drooped?
Arm weakness. Can the person raise both arms?
Speech disturbance. Can the person speak clearly? Can they understand what you say?
If any of these symptoms suddenly develop, a doctor should be consulted urgently.
What are the long-term effects from having a stroke?
The type and extent of disability caused by a stroke can vary greatly. It depends on the extent of the damage to the brain.
A large stroke can cause death. A small stroke may cause minor problems, which may go completely over time. In many cases the effects are somewhere in between these two extremes.
The sort of problems that may occur include one or more of the following:
• Weakness of one side of the body. This may cause problems with walking if a leg is affected, or problems using an arm or hand properly.
• Problems with balance and co-ordination.
• Swallowing problems are common. In some cases this can be dangerous, as food may go down the windpipe rather than down the gullet during eating. Because of this, it is usual to do a swallow test on all people with a stroke before they are allowed to eat or drink to make sure that swallowing is safe. If there is severe difficulty with swallowing then they may need to have food and drinks passed into the stomach via a tube.
• Speech and communication difficulties. This may range from a difficulty in finding the correct words to say in the middle of a sentence, to being completely unable to speak. Also, understanding speech, reading, or writing may be affected.
• Difficulty with vision. If a part of the brain that deals with vision is affected then problems may arise. For example, some people who have had a stroke have double vision. Some people lose half of their field of vision.
• Difficulties with mental processes. For example, difficulty in learning, concentrating, remembering, etc.
• Inappropriate emotions. For example, following a stroke, some people cry or laugh at times for no apparent reason.
The above are just some examples of what may occur following a stroke. Every stroke is different and the problems and difficulties have to be assessed for each affected person.
In the first few weeks after a stroke the swelling and inflammation around the damaged brain tissue settles down. Some symptoms may then improve. In time, sometimes other parts of the brain can compensate for the damaged part of the brain. With rehabilitation and appropriate therapy, there may be a gradual improvement.
Of those people who survive a stroke, about 3 in 10 are fully independent within three weeks. This rises to about 5 in 10 within six months. However, it is common for some degree of disability to remain.
Are any tests needed?
A doctor can usually diagnose a stroke by the typical symptoms and signs which develop suddenly. Tests which are commonly done include:
• A brain scan (CT scan or MRI scan). This can determine the type of stroke (ischaemic or haemorrhagic
• Blood tests to check on su.ch things as blood sugar level and cholesterol level. High levels can increase the risk of a further stroke.
• Chest X-ray and ECG (a heart tracing) to check for heart or lung conditions which may be a cause of stroke (for example, atrial fibrillation).
• Ultrasound scan of the carotid arteries in the neck to check if there are large patches of atheroma in these arteries.
What treatment and care are usual for people who have a stroke?
A person who may be having a stroke should be admitted to hospital immediately.
A stroke patient should be assessed quickly by a doctor. A scan of the brain is organised as soon as possible to confirm the diagnosis and to tell whether the stroke is an ischaemic or haemorrhagic stroke. This is very important to know, as the initial treatment of the two is very different.
If an ischaemic stroke is diagnosed, and it has been less than four and a half hours since symptoms started clot breaking medication is injected directly into a vein to dissolve the blood clot. The medical word for this is thrombolysis. If the blood clot that caused the stoke can be dissolved shortly after symptoms begin, it can improve the eventual outcome. This is because brain cells that would have died, are able to survive.
A plan for any other treatments should be devised and started as soon as possible. Treatments are be tailored to the particular need of the individual. The treatment plan can depend on factors such as the severity of the stroke, the effects it has, the cause of the stroke, and other diseases that may be present. Treatments that may be considered include the following:
Antiplatelet medication. Platelets are tiny particles in the blood which help blood to clot. Antiplatelet medication is usually advised in the case of an ischaemic stroke (due to a blood clot). Antiplatelet medication reduces the stickiness of platelets. This helps to prevent blood clots forming inside arteries, which helps to prevent a further stroke.
Medication may be advised to reduce any risk factors for having a further stroke (as discussed later in this article). For example, medication to lower a raised blood pressure, sugar level, or cholesterol level.
In the case of atrial fibrillation, there is an increased risk of a blood clot forming in a heart chamber and travelling to the brain to cause a stroke. In such instances (or certain other heart conditions), anticoagulant medicine may be prescribed.
A stroke patient with carotid stenosis, ie., of one of your carotid arteries, due to atheroma have surgery to strip out the atheroma may be advised.
If a patient on anticoagulant medicine has a haemorrhagic (bleeding) stroke then treatment to reverse the effect of the anticoagulation is given.
If a subarachnoid haemorrhage is the cause of the stroke, an operation to fix the leaking artery is sometimes an option.
As soon as possible after having a stroke the patient should be helped to sit up in bed, and to get out of bed and move around if able to do so. This is to start the process of rehabilitation as soon as possible. Also, this reduces the risk of having a deep vein thrombosis (DVT) in a leg vein, which is a risk if a patient is inactive in bed for long periods.
The aim of rehabilitation is to maximise activity and quality of life following a stroke. Hospitals which deal with stroke patients have various specialists who help in rehabilitation. These include: physiotherapists, occupational therapists, speech therapists, dieticians, psychologists, specialist nurses and doctors. One or more of these may be required, depending on the effect of the stroke. Good-quality rehabilitation is vital following a stroke, and can make a big difference to the eventual outcome.
Can strokes be prevented?
A common reason why a blood clot forms is because it develops over a patch of atheroma on the lining of an artery. Certain risk factors increase the chance of atheroma forming – which increase the risk of having a stroke (and heart attack). This risk can be reduced if the risk factors are reduced.Briefly, risk factors that can be modified are:
• Smoking. If the stroke patient smokes, every effort should be made to stop. The chemicals in tobacco that carried in the bloodstream and can damage arteries.
• High blood pressure. Blood pressure should be checked at least once a year. If it is high it should be treated. High blood pressure usually causes no symptoms, but can be damaging to the arteries.
• If overweight, losing some weight is advised.
• A high cholesterol level. This can be treated if it is high.
• Inactivity. If able, moderate physical activity on most days of the week for at least 30 minutes should be done. For example, brisk walking, swimming, cycling, gardening, etc.
• Diet. A healthy diet is important.
• Diabetes. If diabetic, treatment to keep blood sugar as near normal as possible is important.