Leukocyte function is impaired in diabetes. The leukocytes show reduced ability for phagocytosis and microbicidal activity, thus assisting the development of infection.
In both forms of long-standing diabetes, atherosclerotic events such as myocardial infarction, cerebrovascular accidents, gangrene of the leg, and renal insufficiency are the most threatening and most frequent complications. Diabetic patients are also plagued by enhanced susceptibility to infections with certain microbes. Contrary to popular belief, there is no generalized increase in susceptibility to all infections. Common infections include those affecting skin, lung, and urinary tract. Infections with certain microbes, such as those causing mucormycosis, occur principally in people with diabetes. Such infections cause the deaths of about 5% of diabetic patients. The basis for this susceptibility is probably multifactorial; impaired leukocyte function and poor blood supply secondary to vascular disease are involved. Phagocytosis and the bactericidal activity of neutrophils are impaired. A trivial infection in a toe may be the first event in a long succession of complications (gangrene, bacteremia, and pneumonia) that ultimately lead to death.
