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 999.
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.
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, or it can occur without any any other symptoms.
Cerebrovascular diseases are much less common in children. However, stroke can sometimes affect children. 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.