What are cerebrovascular diseases?
Cerebrovascular diseases are conditions caused by problems that affect the blood supply to the brain.
Types of cerebrovascular disease
There are a number of different types of cerebrovascular disease. The four most common types are:
- stroke – a serious medical condition where one part of the brain is damaged by a lack of blood supply or bleeding into the brain from a burst blood vessel
- transient ischaemic attack (TIA) – a temporary fall in the blood supply to one part of the brain, resulting in brief symptoms similar to stroke
- subarachnoid haemorrhage – a type of stroke where blood leaks out of the brain's blood vessels on to the surface of the brain
- vascular dementia – persistent impairment in mental ability resulting from stroke or other problems with blood circulation to the brain
These are discussed in more detail below.
To function properly, the brain needs oxygen and nutrients that are provided by the blood. However, if the blood supply is restricted or stopped, brain cells die, leading to brain damage and possibly death.
A stroke happens when the blood supply to part of the brain is blocked or interrupted – for example, by a blood clot (where the blood thickens and solidifies). This is the most common cause of stroke and is known as an ischaemic stroke.
The lack of blood causes part of the brain to die, a process known as cerebral infarction. About 10% of strokes are caused by bleeding from the arteries in the brain, which directly damages the brain's tissues and can also cause loss of blood supply. This is known as haemorrhagic stroke or cerebral haemorrhage.
The main symptoms of a stroke can be remembered using the acronym FAST, which describes the Face-Arms-Speech-Time test. Each part of the test is explained below.
- Face – the person's face may have fallen on one side, they may be unable to smile, or their mouth or eye may have drooped
- Arms – they may be unable to raise one or both arms and keep them up as a result of weakness
- Speech – they may have slurred speech and difficulty finding words or understanding what is said to them
- Time – it's time to dial 999 immediately if you see any of these signs or symptoms
Other common symptoms of stroke include sudden onset of:
- unsteadiness or inability to walk
- loss of vision in one eye or on one side of the field of vision
A stroke is a medical emergency – the sooner treatment is given in hospital, the less damage is likely to occur. Minutes count, so don't delay calling the emergency services.
Transient ischaemic attack (TIA)
A transient ischaemic attack (TIA) , or "mini-stroke", is caused by a temporary disruption in the blood supply to part of the brain. This results in a lack of oxygen and nutrition to that part of the brain, which stops it working until the blood supply is restored.
A TIA causes similar symptoms to a stroke, but only lasts for a short period of time – TIAs usually last from a few minutes up to an hour, but any ischaemic attack lasting less than 24 hours is officially classed as a TIA.
A TIA should always be taken seriously – if it's confirmed, TIA is an early warning sign of an impending stroke that could happen at any time, particularly in the next few days or weeks.
If you or someone you know has a TIA, contact your doctor, local hospital or out-of-hours service immediately to arrange for a specialist assessment.
A subarachnoid haemorrhage is a less common cause of a haemorrhagic stroke. It happens when blood leaks from blood vessels on to the surface of the brain.
The bleeding occurs in the arteries that run underneath a membrane in the brain known as the arachnoid, which is located just below the surface of the skull.
The bleeding can cause a sudden and very severe headache, often with neck stiffness. Someone who's had a subarachnoid haemorrhage may not have any other symptoms of stroke, although these may develop later as a result of complications of the bleeding.
A subarachnoid haemorrhage is a medical emergency and needs immediate medical treatment to prevent serious complications, brain damage and death.
Around three-quarters of all subarachnoid haemorrhages are the result of an aneurysm rupturing (bursting). An aneurysm is a bulge in a blood vessel caused by a weakness in the blood vessel wall.
Other causes of a subarachnoid haemorrhage include severe head injury and a rare type of birth defect called arteriovenous malformation, which affects normal blood vessel formation.
Vascular dementia is a common form of dementia that affects more than 138,000 people in the UK.
The term "vascular dementia" describes a widespread and persistent loss of mental ability caused by damage to brain cells as the result of a haemorrhage or a shortage of blood supply.
Vascular dementia can occur as the result of a single stroke or multiple strokes.
It can also be due to gradual narrowing of the blood vessels inside the brain which, unlike a stroke, may not cause any obvious symptoms at first.
Cerebrovascular diseases are much less common in children. However, stroke can sometimes affect children.
The Stroke Association estimate that childhood stroke affects around 5 out of every 100,000 children in the UK each year.
Children can have an ischaemic or haemorrhagic stroke, as well as a TIA. However, the common underlying causes are different in children.
In children, stroke is often the result of pre-existing conditions such as congenital heart disease or sickle cell disease. It can also be caused by infections or an injury to the arteries in the neck during vigorous activities.
The classic warning signs of a stroke are the same in adults and children.
Dial emergency services immediately to request an ambulance if you think your child has had a stroke.
Risks of cerebrovascular disease and how to prevent them
Certain things increase your risk of cerebrovascular disease.
- high blood pressure (hypertension)
- atrial fibrillation (a form of irregular heartbeat)
- poor diet
- high blood cholesterol
- lack of exercise
- being overweight or obese
- excessive alcohol consumption
Many of the risk factors for cerebrovascular disease are linked, which means if you have one, it's likely you'll also have others.
For example, someone who's overweight or obese is more likely to have high blood pressure, high cholesterol and diabetes.
To significantly reduce the risk of cerebrovascular disease, you need to look at your lifestyle as a whole. In particular, you need to consider:
- your weight
- your diet
- how active you are and the amount of regular exercise you do
- whether you need to stop smoking
- how much alcohol you drink
- your stress levels
As well as reducing your risk of developing cerebrovascular disease, making changes to your lifestyle will also lower your risk of getting other serious health conditions, such as coronary heart disease , heart attack and cancer.
High blood pressure
High blood pressure (hypertension) is a significant risk factor for cerebrovascular disease.
The increase in blood pressure damages the walls of the brain's blood vessels, increasing the risk of a blood clot forming or an artery rupturing (splitting). Both of these can trigger a stroke .
If you have high blood pressure, you're four times more likely to have a stroke than someone with healthy blood pressure.
You can prevent high blood pressure by exercising regularly, eating healthily, not smoking and drinking alcohol in moderation.
However, hypertension is still common, even in people who have a healthy lifestyle, and treatment with medication is usually required. It's therefore important to have your blood pressure checked from time to time.
Read more about preventing high blood pressure.
Atrial fibrillation is a common disorder that causes the heart to beat irregularly. It can occur without any symptoms, but clots can form in the heart, which can break off and travel to the brain and cause a stroke.
Atrial fibrillation can be treated to prevent stroke, so if you have a pulse that beats irregularly or you have undiagnosed palpitations, you should visit your doctor to test for the condition.
High blood cholesterol
High blood cholesterol can cause your arteries to narrow, increasing your risk of developing a blood clot.
The toxins in tobacco can damage and narrow the blood vessels that supply the brain. Smoking also causes high blood pressure.
It's estimated that a person who smokes 20 cigarettes a day is six times more likely to have a stroke than someone who doesn't smoke.
If you smoke, it's strongly recommended that you give up as soon as possible. Your doctor will be able to provide you with further information and advice, and they can prescribe medication to help you stop smoking .
A diet that contains a high amount of saturated fat and salt can lead to high blood pressure, high cholesterol and narrowing of the arteries, which all increase your risk of cerebrovascular disease.
A low-fat, high-fibre diet that includes wholegrains and at least five portions of fresh fruit and vegetables a day is recommended for a healthy heart and brain.
Limit the amount of salt in your diet to no more than 6g (0.2oz or 1 teaspoon) a day. Too much salt will increase your blood pressure. Check the salt content of processed foods and try not to add salt to your food.
Also, avoid eating foods high in saturated fat because they'll increase your cholesterol level. Foods that contain high levels of saturated fat include:
- meat pies
- sausages and fatty cuts of meat
- ghee – a type of butter often used in Indian cooking
- hard cheese
- cakes and biscuits
Foods high in unsaturated fat can help decrease your cholesterol level. These foods include:
- oily fish
- nuts and seeds
- olive oil
Not exercising regularly puts you at risk of developing high blood pressure and high cholesterol. Being physically inactive also increases your chances of becoming overweight.
To maintain a good level of health, the Department of Health recommends you do at least:
- 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity, such as cycling or fast walking, every week, and
- muscle-strengthening activities on two or more days a week that work all major muscle groups (the legs, hips, back, abdomen, chest, shoulders and arms)
Being overweight or obese increases your risk of developing a number of serious health conditions, such as diabetes and high blood pressure.
To lose weight, you need to combine regular exercise with a calorie-controlled diet. After you've reached your ideal weight, you should aim to maintain it by eating healthily and exercising regularly.
You can use the healthy weight calculator to calculate your body mass index (BMI) and get tips about how to lose weight. You can also read more about losing weight.
The high blood sugar levels associated with diabetes can damage the body's organs and arteries.
If you have type 1 diabetes , regular insulin treatment should keep your blood sugar levels normal.
If you have type 2 diabetes , it may be possible to control your symptoms by making simple lifestyle changes, such as exercising regularly and eating healthily. However, you may need medication (tablets or injections) to keep your blood glucose normal.
Read more about living with type 1 diabetes and living with type 2 diabetes.
Drinking excessive amounts of alcohol can increase your cholesterol and blood pressure levels, and increases the risk of bleeding into the brain.
You shouldn't exceed the recommended daily alcohol limits. These are:
- 3-4 units a day for men
- 2-3 units a day for women
One pint of ordinary strength beer, lager or cider contains two units of alcohol, and a single pub measure (25ml) of spirits contains one unit. A small glass of wine (125ml) contains 1.5 units of alcohol.
Visit your doctor if you're finding it difficult to moderate your drinking. Treatments such as counselling and medication are available to help you reduce your alcohol intake.
Read more about alcohol units and drinking excessively.
Reducing the amount of stress in your life may help you control your blood pressure, as well as keeping your blood sugar levels under control. Both of these will help reduce your risk of getting cerebrovascular disease.
Regular exercise has been shown to reduce stress levels, as have relaxation techniques such as deep breathing and yoga.