Stroke

What is a stroke?

A stroke is a medical emergency in which there is a disruption of the blood supply to part of the brain. It is a serious condition requiring immediate medical help.

There are two types of stroke:

• Ischaemic stroke – this is where there is a blockage of blood flow in the brain usually due to a blood clot.
  

• Haemorrhagic stroke, also known as brain haemorrhage – this is where there is bleeding in or around the brain from a burst blood vessel, such as from a burst brain aneurysm.

The main signs of stroke can be remembered using FAST:

F - Face. Part of the person's face starts to droop, making it difficult for them to smile.

A - Arms. The person is unable to fully lift their arms or keep them raised.

S - Speech. The person’s speech becomes slurred or hard to understand.

T - Time. It is time to call 999 and ask for an ambulance.

A person may not have all of these signs. Call 999 as soon as any of them develop.

Other symptoms can include the sudden onset of:

• headache

• confusion

• dizziness

• speech difficulties such as slurred speech or difficulty understanding speech

• vision problems, such as blurred vision or loss of sight.

What is a transient ischaemic attack (TIA)?

A transient ischaemic attack (TIA) happens when there is a temporary disruption to the blood supply to part of the brain due to a blocked blood vessel. A TIA is sometimes called a ‘mini-stroke’.

A TIA causes the same types of symptoms as a stroke, but they only last for a few minutes or hours. However, medical attention should always be sought as soon as these symptoms are recognised, as a TIA can be a warning that the person is at increased risk of having a stroke.

Call 999 immediately if you or someone else develops symptoms of a TIA or stroke, even if the symptoms begin to improve.

What causes a stroke?

Strokes are caused by a disruption of the blood supply to part of the brain.

Sometimes this disruption can be due to natural causes, such as weakening of blood vessels over time or a genetic condition that increases the risk of having a stroke.

However, there are some factors that can increase the risk of having a stroke; these include:

• smoking

• drinking too much alcohol

• being overweight

• being physically inactive

• having an unhealthy diet

There are some health conditions that also increase the risk of having a stroke. These include:

• diabetes

• high blood pressure

• atrial fibrillation

• high cholesterol

Managing health conditions such as high blood pressure, atrial fibrillation, diabetes and high cholesterol can help to reduce the risk of stroke.

In rare cases, a person may be born with an abnormal formation of blood vessels in their brain, which can put them at greater risk of blood flow disruption. The two main types of blood vessel malformations are:

• Arteriovenous malformation (AVM) – a tangle of blood vessels that can cause problems with the connection between arteries and veins. Blood can flow at a high pressure within an AVM, increasing the risk of bleeding.
  

• Cavernoma – a cluster of blood vessels that resembles a raspberry. The walls of a cavernoma can be weak, increasing the risk of bleeding.

What happens in a stroke?

The brain relies on a rich supply of oxygen to keep brain cells working. This is supplied by an intricate network of blood vessels that carry oxygen-rich blood to and through the brain. When this blood flow is disrupted, for instance by a blood clot or a burst blood vessel, the brain cells do not receive enough oxygen and they begin to die. This results in brain injury.

How are strokes treated?

Upon arrival at a hospital, a person suspected of having a stroke will usually undergo a number of tests to confirm the diagnosis. Tests can include:

• Brain scans - these can help to confirm the type of stroke that has occurred and its location in the brain. This can help with guiding treatment at the next stage. The most common types of brain scans used are computerised tomography (CT) and magnetic resonance imaging (MRI) scans.
  

• Blood tests - these may be used to check factors such as blood sugar and cholesterol levels. The person’s blood pressure will also be measured. These checks can help the medical team identify possible causes of the stroke and decide on treatment.
  
  

• Heart tests - these tests may be used to check the heart’s rhythm and structure or to look for narrowing in the blood vessels to identify the cause of the stroke. Tests may include an electrocardiogram, which checks the heart’s rhythm, and an echocardiogram, which produces images of the heart.
  
  

• Swallowing tests - a person having a stroke may have difficulty with swallowing. Swallowing tests can check whether the person can swallow safely.
  
  

• Other assessments - a stroke can lead to a number of different issues, such as problems with mobility and cognitive issues (difficulties with thinking, memory or concentration. A range of other assessments can be used to identify which particular problems the person is having, which can help with treatment at the next stage.

Treatment depends on whether the stroke was caused by a clot or bleeding, how much time has passed and the person’s individual circumstances. It may include clot-dissolving medicine in a treatment called thrombolysis, or physically removing the clot in a procedure called thrombectomy. In some circumstances, both treatments may be used. These treatments are most effective when given as soon as possible after the stroke.

Medication can be used to reduce the chance of future blood clots forming, or to lower blood pressure or blood cholesterol levels. Alternatively, a surgical procedure known as carotid endarterectomy can be performed to remove a narrowing caused by fatty deposits in a carotid artery in the neck – this improves blood flow and reduces the risk of future blockages leading to ischaemic stroke.

Haemorrhagic strokes are often caused by burst brain aneurysms. Treatments for a ruptured aneurysm may include endovascular treatment or surgical clipping.

Endovascular treatment

Tiny coils can be inserted into the aneurysm, helping to seal it and stopping blood from flowing into it. A mesh device may instead be used to divert blood flow away from the aneurysm. The coils or mesh device are placed through a thin tube called a catheter, which is passed through an artery and guided to the aneurysm.

Surgical clipping

A section of the skull is removed (called a craniotomy) to reach the aneurysm. A metal clip is then attached to the ‘neck’ of the aneurysm to stop blood from flowing into it.

Both procedures are carried out under general anaesthetic, which means the person is asleep during the procedure. The medical team will discuss details of the chosen procedure with the person beforehand, including what may happen during the recovery phase.

A surgical procedure known as a craniotomy might be performed to relieve pressure within the skull, remove leaked blood from the brain and treat the source of bleeding.

Medicines may be used to control blood pressure or reverse the effects of blood-thinning medicines, depending on the type and cause of the stroke.

What happens after a stroke is treated?

Following treatment for a stroke, a person will usually need to stay in hospital to recover. They will continue to be monitored by the medical team. The length of the hospital stay will depend on the type and severity of the stroke, the treatment provided and the person’s individual needs.

The person may have rehabilitation to help manage the physical, cognitive or emotional impact of the stroke. This can take place within the hospital, at a specialist brain injury rehabilitation unit or through community-based teams.

A person may be able to return directly home from hospital, but they will need to continue resting. The time needed to recover and return to usual activities varies from person to person.

For more information on these next stages, visit Treatment and rehabilitation.