Ischemisk

Ischemia, or ischemic (ischemisk in some languages), is a medical condition characterized by an insufficient blood supply to a tissue or organ. The reduced perfusion leads to a shortage of oxygen and nutrients, which can cause cellular injury and, if prolonged, tissue necrosis. The term derives from Greek roots meaning to hold back or restrain.

Causes of ischemia include obstruction of arteries by atherosclerotic plaque, thrombosis, or embolism, as well as arterial vasospasm or systemic hypoperfusion from shock, severe dehydration, or heart failure. Microvascular dysfunction can also contribute to impaired tissue perfusion. Reperfusion after a period of ischemia can sometimes cause additional injury through inflammatory and oxidative processes.

Common forms of ischemia affect different organs. Myocardial ischemia involves the heart muscle and is central to conditions such as angina and myocardial infarction. Cerebral ischemia affects the brain and can cause stroke or transient ischemic attacks. Mesenteric, renal, and limb ischemias reflect reduced blood flow to the intestines, kidneys, or extremities, respectively. Acute ischemia is a medical emergency requiring rapid restoration of blood flow; chronic ischemia results from long-standing, partial reductions in perfusion.

Symptoms depend on the affected tissue. Heart-related ischemia often presents as chest pain or dyspnea; cerebral ischemia can cause sudden neurological deficits; intestinal ischemia may cause severe abdominal pain; limb ischemia can present with pain, pallor, pulselessness, and cold extremities.

Treatment focuses on restoring perfusion and preventing further injury. This may involve antiplatelet or anticoagulant therapy, thrombolysis, endovascular revascularization, or surgical intervention, along with management of underlying risk factors and supportive care. Prognosis varies with cause, extent, and the speed of treatment.