pernicious anemia [L, perniciosus, destructive; Gk, a + haima, not blood] , a rare autoimmune form of megaloblastic anemia that results from autoantibodies to parietal cells and intrinsic factor essential for the absorption of cyanocobalamin (vitamin B12). The maturation of red blood cells in bone marrow becomes disordered, the white blood cell count is reduced, and the polymorphonuclear neutrophils become hypersegmented. Weakness, numbness and tingling in the extremities, fever, pallor, anorexia, and weight loss may occur. The condition is usually treated with cyanocobalamin injection and with folic acid and iron therapy. Also called Addison anemia. See also atrophic gastritis, intrinsic factor, nutritional anemia.
