A stroke happens when blood flow through the brain is disrupted and the brain stops working properly. This causes problems with coordination and language, for example. Similar symptoms may also be caused by an injury, tumour or inflammation of the brain.
A person’s activity is regulated by the brain. Since a stroke damages brain tissue, it has many effects on what a person is able to do. The effects vary from one case to another and depend on the size and location of the damaged area.
An ischaemic stroke (cerebral infarction) happens when an artery in the brain is suddenly blocked, stopping the flow of blood and oxygen to the area it supplies. Brain tissue in the area dies as a result. The blockage is often formed by clotting in the artery itself, but a clot may also travel to the brain from other parts of the body, such as the heart or a neck artery.
A haemorrhagic stroke happens when an artery in the brain bursts, bleeding into the brain tissue (intracerebral haemorrhage, ICH) or into the space between the brain and the surrounding membrane (subarachnoid haemorrhage, SAH). SAH is usually caused by the rupture of a natural bulge (aneurysm) in an artery at the surface of the brain. The bleeding causes tissue damage, although the leaked blood is eventually reabsorbed.
A transient ischaemic attack (TIA) is a ‘mini-stroke’ that happens when blood flow in the brain is temporarily blocked. The blockage causes a TIA but does not continue long enough to cause permanent brain damage. TIA symptoms are similar to those of an ischaemic stroke, but they pass quickly. Typically, the symptoms last 2–15 minutes (usually less than an hour). When a TIA first occurs, you should consider it a warning signal and call the emergency number 112 immediately. The factors that caused it can then be investigated promptly, in the best case making it possible to prevent a full-fledged stroke. An ischaemic stroke occurs within 90 days after a patient’s first TIA in 10–20 percent of cases, and within 48 hours in as many as half of these cases.
Negative impacts of stroke
A person’s activity is regulated by the brain. Since a stroke damages brain tissue, it has many effects on a person’s physical, mental and social capacity. The effects always vary from one case to another and depend on the size and location of the damaged area. A stroke can result in permanent or temporary symptoms of paralysis, diminished sensation, and impaired language and other mental functions.
One in two people who experience a stroke are left with permanent impairment, which is severe in half of these cases. One in four recover fully and have no remaining symptoms, more than half recover enough to function independently, and one in seven needs institutional care.
Frequency of stroke
There were estimated to be about 100,000 stroke survivors in Finland in 2015. About 18,000 people each year have an ischaemic stroke and about 1,800 have a haemorrhagic stroke. About 2,500 people experience another stroke within a year. About 5,000 people have a transient ischaemic attack (TIA). All in all, strokes occur in about 25,000 people in Finland each year, or 68 people each day. Strokes cause about 4,500 deaths in Finland each year, making them the third-highest cause of mortality.