Cerebrovascular diseases are conditions caused by problems that affect the blood supply to the brain.
There are a number of different types of cerebrovascular disease. The four most common types are:
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.
Other common symptoms of stroke include sudden onset of:
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 999.
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 GP, 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 999 immediately to request an ambulance if you think your child has had a stroke.