acute limb ischemia definition
Brain ischemia is insufficient blood flow to the brain, and can be acute or chronic. Acute ischemic stroke is a neurologic emergency that may be reversible if treated rapidly. Chronic ischemia of the brain may result in a form of dementia called vascular dementia. Acute limb ischemia is a sudden decrease in limb perfusion that threatens limb viability and requires urgent evaluation and management. Causes of acute limb ischemia include acute thrombosis of a limb artery or bypass graft, embolism from the heart or a diseased artery, dissection, and trauma. Events that can lead to acute limb ischemia include an acute thrombosis at the site of an atherosclerotic plaque or bypass graft, an arterial embolism that originates in the heart or elsewhere, arterial dissections or aneurysms, and trauma. These etiologies of acute limb ischemia are worth a closer look. Critical limb ischemia (CLI) Critical limb ischemia (CLI) is a severe blockage in the arteries of the lower extremities, which markedly reduces blood-flow. It is a serious form of peripheral arterial disease, or PAD, but less common than claudication. The Clinical Problem. Acute limb ischemia is defined as a sudden decrease in limb perfusion that threatens the viability of the limb.1 The incidence of this condition is approximately 1.5 cases per 10,000 persons per year. The most prominent features of critical limb ischemia (CLI) are called ischemic rest pain — severe pain in the legs and feet while a person is not moving, or non-healing sores on the feet or legs. 1  Pain or numbness in the feet.  Shiny, smooth, dry skin of the legs or feet. Clinical events that cause acute limb ischemia include acute thrombosis of a limb artery or bypass graft, embolism from the heart or a diseased artery, dissection, and trauma (from severing of an artery or thrombosis). Acute thrombosis of a limb artery is most likely to occur at the site of an atherosclerotic plaque. Paralysis is a very late sign of acute arterial ischemia and signals the death of nerves supplying the extremity. Foot drop may occur as a result of nerve damage. Because nerves are extremely sensitive to hypoxia, limb paralysis or ischemic neuropathy may persist after revascularization and may be permanent. Ischemia is a restriction in blood supply to tissues, causing a shortage of oxygen and glucose needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems with blood vessels, with resultant damage to or dysfunction of tissue. It also means local anemia in a given part of a body sometimes resulting from congestion (such as vasoconstriction, thrombosis or embolism). Acute limb ischemia is defined as a sudden decrease in limb perfusion leading to failure to meet the oxygen and nutrient requirements of limb tissue, resulting in tissue ischemia. Ischemic tissue is characterized by hypoxia (decreased oxygen levels) and the accumulation of metabolic wastes such as lactic acid.
It is a sudden decrease in limb perfusion that threatens limb viability and requires urgent evaluation and management.