Ischemia

Ischemia is one of the most studied medical conditions. It is associated with various infectious and non-infectious medical conditions. The term ischemia is derived from the Greek word Icheim (restrain) referring to the lack of blood supply to a respective tissue. The occurrence of ischemia in the body triggers many biochemical abnormalities in the body therefore creating insufficiency of metabolites to the tissue.

Studies indicate that almost fifty percent of deaths around the world happen because of ischemia. The most prevalent forms of ischemia are associated with the cardiovascular system and brain. Ischemia progresses itself in to metabolic disorders such as hypoxia. Hypoxia is a fatal condition in which there is oxygen deficiency to the cells causing cellular damage and death. The predisposing factors for hypoxia may include blockage of arteries in a respective circulatory region preventing the blood supply. Ischemia gradually results in tissue necrosis and damage to blood vessels restricting the flow of blood into the tissues.

Biochemical changes such as accumulation of metabolized waste products occur as a result of ischemia in relation to conditions such as embolism, atherosclerosis, thrombosis and compression. This metabolic waste accumulation eventually leads to increase in toxin levels in the body. Cell death is one of the main outcomes of ischemia. The complications of ischemia range from reversible forms to irreversible forms depending on the type of organ damage.

Physiological studies indicate the significance of parenchyma cells in the occurrence of ischemia. Parenchyma cells located in each organ have a specific threshold. In the cardiac muscle, the threshold levels are 20-30 min whereas in the neural cells it is only 3-4 min. Parenchyma cells are more prone to damage than the cells of the stoma and hence the difference in these threshold values indicate the exact etiology of ischemia.

Ischemia occurring in the cardiac region is predominantly because of the hypoxia present in the sub endocardial region. Simultaneously in the central nervous system, it is because of the watershed infarcts. Hence the effect of ischemia is directly proportional to the micro vascular anatomy of the organ systems. Another form of ischemia is silent ischemia. It is an asymptomatic condition often found in people who are old, women and have a history of diabetes. Silent ischemia does not present any visible clinical signs of illness, however through diagnostic examinations such as electrocardiogram and stress testing; the insufficient blood supply to the cardiac muscle can be identified.

Mesenteric Ischemia

Acute mesenteric ischemia is caused due to inadequate blood flow the the mesentery artery and results in tissue hypoxemia. Symptoms such as acute abdominal pain, nausea, diarrhea and vomiting are noticed. Some feel acute pain on eating - 'abdominal angina'. The narrowed mesenteric artery is usually a result of chronic atherosclerosis. Anticoagulation and vasodilation are resorted to. Often surgery is done to treat mesenteric ischemia due to embolus or thrombosis.

Treatment

Ischemia is treated by administering blood thinning drugs such as aspirin. This is done to prevent the clot formation in the blood vessels. Temporary opening of the arterial walls is done by using nitro-glycerine medication. Since ischemia is the precursor for the occurrence of tachycardia, beta blockers are used to relax the heart muscle. Other medications include calcium channel blockers and cholesterol lowering drugs.