Every year, 15 million people worldwide suffer a stroke. Nearly six million die and another five million are left permanently disabled.
Stroke is the second leading cause of disability, after dementia. Disability may include loss of vision and/or speech, paralysis and confusion. Globally, stroke is the second leading cause of death above the age of 60 years, and the fifth leading cause of death in people aged 15 to 59 years old.
Stroke is less common in people under 40 years, although it does happen. In young people, the most common causes are high blood pressure or sickle cell disease. In many developed countries, the incidence of stroke is declining even though the actual number of strokes is increasing because of the ageing population.
A stroke occurs when the blood flow to the brain is suddenly interrupted or cut off. As a result, the brain is deprived of necessary oxygen and nutrients. The cells in the affected part of the brain then become damaged and the brain begins to die. A stroke is sometimes called a brain attack. Stroke affects people of all ages including children and young adults, but is more common as we age.
Are there different types of stroke?
There are two main types of strokes and they occur when blood flow to the brain is cut off by a blockage (Ischaemic Stroke) or if there is a sudden bleed in the brain (Haemorrhagic Stroke).
More than 80% of strokes are ischaemic strokes. An ischaemic stroke happens when something blocks an artery that carries blood to the brain, a blood clot for example or a narrowing of the arteries. The most common types of ischaemic strokes are:
- Embolic Stroke: this is where a clot forms in the heart or other major blood vessels. It is carried to the brain where it lodges in an artery and blocks the blood supply.
- Thrombotic Stroke: this occurs when a clot (also called a thrombus) forms in an already narrowed or damaged artery within the brain and blocks the supply of blood to that area. Atherosclerosis (the build-up of a fatty substance called plaque) is the most common cause of narrowing of the arteries.
A haemorrhagic stroke happens when a damaged or weakened blood vessel in the brain bursts and bleeds into the brain.
The most common types of haemorrhagic strokes are:
- Intracerebral Haemorrhage: this occurs when a blood vessel bursts inside the brain. The blood then spills into the surrounding brain tissue causing the brain cells to lose their oxygen supply.
- Subarachnoid Haemorrhage: this occurs when a blood vessel bursts near the surface of the brain and the blood leaks into the space between the brain and the skull.
A Transient Ischaemic Attack (TIA) or a mini-stroke is a temporary interruption in the blood flow to the brain. The affected part of the brain is without oxygen for just a few minutes and soon recovers. However, TIAs should be viewed as a warning sign. They may be an indication that a more serious stroke is about to happen. Most TIAs only last a few minutes, however the symptoms can occasionally last up to 24 hours. At first, it may not be possible to tell whether someone is having a TIA or stroke, as the signs and symptoms are the same. Therefore, all stroke-like symptoms require urgent medical care.
Without assessment and treatment, one in four people who have a TIA go on to have a full stroke within a few years.
Up to 90% of strokes are preventable so knowing your risk factors is the first step in preventing a stroke. The greater the number of risk factors, the greater the likelihood is of you getting a stroke. You may be at a higher risk if there is a family history of stroke or if you have had a TIA or heart attack. In addition, people from Asian, African and African-Caribbean communities are also more likely to have a stroke.
High blood pressure is the leading cause of stroke. One of the most important things you can do to reduce your stroke risk is to know your blood pressure reading and keep it under control (<140/90). Smoking damages the lining of blood vessels leading to blockages within the blood vessels in the brain. If you smoke, quitting reduces your risk of heart disease and stroke. It is also best to avoid second-hand smoke from other smokers.
Having diabetes almost doubles your risk of stroke. You can manage your diabetes and keep it well controlled with diet, exercise, weight control and medication.
An abnormal heart rhythm called atrial fibrillation can increase your risk of stroke five times. The irregular heartbeats can cause blood to collect in the heart and potentially form a clot, which can travel to the brain and block the blood supply (embolic stroke).
Other factors that can lead to stroke include, high cholesterol, being overweight and obese, sleep apnoea, excessive alcohol intake, having an inactive lifestyle, having other heart or artery disease and certain blood disorders.
Many of these risk factors can be reduced by making positive lifestyle changes.
Not all strokes are the same and no two people are affected by stroke in the same way. The effects of a stroke depend on the area of the brain affected and the extent of the damage to your brain. Recovery is different for each person too. Some people may recover completely whereas others may be left with more serious disabilities or even die. Recovery is usually a gradual process and can take months as the brain heals.
The brain has two sides and a stroke on the left side of the brain will affect the right side of the body and vice versa. Some functions that may be impaired as are follows:
- Damage to the left side of the brain means you may have problems moving the right side of your body, figuring out mathematical and science problems, difficulty with speech and language, or understanding what you hear and read.
- Damage to the right side of the brain means you may have problems moving the left side of your body. Doing creative things like painting, playing music, and making sense of what you see, hear and touch may be more challenging. In addition, you may find it difficult to recognise various types of emotions in others.
Someone who has had a stroke may also experience other physical and emotional changes depending on the part of the brain that was affected. These include:
- Weakness in the arm, leg, face or weakness on one side of the body which can affect movement.
- Problems with balance and coordination.
- Pain, numbness or altered sensations in the body.
- Interrupted vision.
- Difficulties with concentration, memory, understanding and communication.
- Issues with swallowing, continence, tiredness, behavioural changes and depression.
Some symptoms may improve in time and many people can make a good recovery following a stroke. Early treatment, appropriate medication and rehabilitation all have an impact on the final outcome.
Knowing the warning signs of stroke and seeking immediate medical help can improve the outcome of a stroke. The symptoms of a stroke appear suddenly and there is often more than one symptom at a time. These are some of the signs to watch out for if you or someone else may be having a stroke:
- Numbness, weakness or paralysis of an arm, leg or face, particularly on one side of the body
- Problems with balance or co-ordination
- Blurred vision or sudden loss of vision in one or both eyes
- Difficulty speaking, slurred speech or difficulty understanding other people
- Sudden severe headache which may be accompanied by dizziness or vomiting
- Loss of consciousness.
Stroke is a medical emergency. The longer a stroke goes untreated the greater the potential for brain damage and disability. If you suspect you or someone else is having a stroke, dial 999 or 112 to call an ambulance immediately. The quicker they get to a hospital, the quicker they can be treated. Early detection and treatment can prevent further damage to the brain and reduce the chances of long-term disability or even death. Every second counts.
Tip: Know your Eircode and keep it close to the phone.
- The Croí Galway Stroke Support Group meets at Croí House on the second Thursday of every month. Click to learn more.
- The Croí Mayo Stroke Support Group meets on the last Thursday of every month, alternating between Castlebar and Ballina. Click to learn more.
New members are always warmly welcomed. Please call Croí on 091 544310 for further information.
The above information is gathered from the World Stroke Organisation.