Ischaemic strokes occur when the arteries supplying blood to the brain are blocked due to a build-up of cholesterol waxy deposits, known as plaques, in the walls of the arteries. This causes the arteries to narrow, or they can burst and lead to the formation of a blood clot, which then block blood flow to the brain.
Haemorrhagic strokes occur when the arteries in the brain burst due to high blood pressure and a brain aneurysm (balloon-like swelling in the wall of the artery), the bleeding occurs from the arteries within the brain itself.
Different factors increase the risk of a stroke, like a smoking habit and ageing. Other conditions including high blood pressure, high cholesterol level and diabetes mellitus increase the risk of a stroke. Some heart complications including irregular heartbeat, recent heart attacks, and previous strokes or TIA (mini-stroke) further increase the risks.