Cerebral infarction, also known as ischemic stroke, occurs when the blood vessels supplying the brain are altered to interrupt blood flow. There are two common types of ischemic stroke: atherothrombotic and embolic, as well as other less common causes. The cause of an ischemic stroke cannot be determined in about 40% of cases.
heart attack is a medical term that describes necrosis that occurs when the blood supply to tissues is interrupted. The blood supply can be interrupted in a number of ways, such as blockage of a supplying artery, mechanical compression of an artery by a tumor or hernia, or rupture of an artery due to trauma. Cerebral infarction is often associated with atherosclerosis or high blood pressure.
Stroke occurs when the blood supply to the brain is interrupted. Within minutes, a series of reactions known as the ischemic cascade begins, which can continue for several hours and can even last for days. The brain remains vulnerable even when the blood supply is restored, due to the possibility of reperfusion injury.
During the ischemic cascade, oxygen deprivation leads to the absence of ATP in brain tissues. ATP proton pumps fail, allowing a massive influx of calcium ions into cells. This results in the generation of reactive oxygen species, free radicals, and other harmful chemicals. Eventually cells begin to die, some through necrosis, triggering an inflammatory response that can cause further damage to brain tissue. The ischemic cascade can occur in any type of tissue, but the brain is considered most vulnerable due to its complete reliance on aerobic metabolism.
Stroke can occur for several different reasons. The formation of a thrombosis, or blood clot, in an artery or blood vessel that feeds the brain can lead to an interrupted blood supply. Embolism, in which a part of the thrombosis ruptures and causes a blockage, is another common cause of heart attack. Cerebral venous sinus thrombosis, in which blood vessels draining the brain become blocked, can lead to a stroke because blood cannot recirculate in the body.
The symptoms of cerebral infarction are quite distinctive. Interrupted blood supply to the brain can cause muscle weakness in the face and other parts of the body, tingling or numbness, inability to speak or understand speech, confusion, and memory disturbances. Diagnosis is usually made on the basis of symptom assessment and neurological examinations, as well as medical imaging tests such as CT or MRI.
Treatment of ischemic stroke may involve breaking down or removing a thrombosis or embolus, and giving medications to prevent clots from forming. Much of stroke treatment is supportive in nature, as many people suffer from brain tissue damage that requires rehabilitative therapy. Some people find that they must relearn how to walk, talk, and perform other daily activities, while others may have to adjust to the permanent loss of these skills.