What is a stroke?

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A stroke is an attack on brain tissue.

It happens when the blood supply to a part of the brain is cut off, killing the brain cells in that area. In turn, this damage affects how the body works. And… it can also change how you think and feel. The effects of a stroke depend on where the damage takes place in the brain, and how big that damage is.

There are three types of stroke
(( also called CerebroVascular Accident / CVA ))

Ischaemic Stroke

• An ischaemic stroke – this is caused by a clot. It forms a blockage in an artery, cutting off the blood supply to the brain – which in turn reduces the amount of oxygen supplied to the brain. Without these, brain tissue is suffocated and gradually dies. This type of stroke is the most common.

Causes of ischaemic stroke:

The main cause of an ischaemic stroke is when a blood clot forms in an artery leading to the brain. Alternatively, this may occur inside one of the small blood vessels, found deep inside the brain. 

These blockages/clots may either occur in the brain or be caused by a clot that forms elsewhere in the body and moves through the circulatory system, to the brain.

Clots/blockages form for a variety of reasons. These include:

• Atherosclerosis: fatty deposits build up on the inside walls of the arteries. They cause hardening and narrowing of the arteries, and in turn, this makes them more likely to become blocked. Sometimes, a blood clot forms on the fatty deposit somewhere in the body, and if this clot breaks away it can travel to the brain and cause a stroke. Hypertension causes the heart to push harder to get blood to circulate around the body. If there is a clot or fatty build-up in an artery, it is much easier for this to become dislodged when the pressure required to push blood around the body, is higher.
  
• Small vessel disease: the tiny blood vessels deep within the brain are damaged.
  
• Atrial fibrillation and other heart conditions: the heart flutters and beats irregularly, which in turn can cause blood clots to form. From the heart, they can easily move to the brain via the blood stream, especially if there is also hypertension (high blood pressure).
  
• Arterial dissection: which happens when tears develop in the lining of an artery and allow blood to get between the layers of your artery walls. This can happen for no clear reason or it can happen because of an injury to the neck.

Haemorrhagic Stroke

• A haemorrhagic stroke – this is caused by a bleed in or around the brain. It can occur for a variety of underlying reasons and often results in sub-arachnoid haemorrhage – or a ‘blow out’ of the artery, causing a large bleed under the skull, within the brain tissue. This can be fatal.
  

TIA – Transient Ischaemic Attack

• A transient ischaemic attack or TIA – this is also known as a mini-stroke and is the same as an ischaemic stroke. However, the symptoms only last for a short while and the person recovers fairly quickly. That is because the blockage that stopped the blood getting to the brain just happens temporarily. It can be scary until it’s understood.