Some cells die and others are damaged. If the patient survives, the degree of disability depends on the area of the brain affected. As damaged cells recover, the patient may gradually improve, but brain tissue that has died is gone forever. This may be either a cerebral thrombosis, when a clot forms at the site of the blockage, or a cerebral embolism, when the clot forms elsewhere in the body and travels to the brain. In the latter, the embolus may start in the heart after a heart attack or as a result of irregular heart rhythm or heart valve problems.
Lacunar stroke happens when small blood vessels deep in the brain become blocked over the long term.
Typical symptoms of stroke are numbness, weakness or paralysis down one side of the body and difficulty with swallowing, speaking, reading and writing. Other symptoms are disturbed vision, incontinence, headache, tiredness and confusion. A stroke in the right side of the brain affects the left side of the body and vice versa. Cerebral oedema, a serious complication occurring in the days immediately afterwards, can cause swelling of the brain tissue and increased intracranial pressure leading to further damage to blood vessels and bleeding. Again there is weakness or numbness in an arm, leg or one side of the face or body, possibly with disturbances of vision and speech.