Diabetes mellitus. Diabetes mellitus is caused by an underproduction of insulin, a resistance of insulin receptors in end-organs to the effects of ins-ulin, or both. Diabetes commonly is divided into Insulin-dependent and
non-insulin-dependent diabetes. Insulin-dependent diabetes usually begins during childhood or adolescence. The major problem in this form of diabetes is an underproduction of insulin, which results in the inability of
the patient to use glucose properly. The serum glucose rises above the level at which renal reabsorption of all glucose can take place, causing glucosuria. The osmotic effect of the glucose solute results in polyuria, stimulating patient thirst and causing polydipsia (frequent consumption of liquids). In addition, carbohydrate metabolism is altered, leading to fat breakdown and the
production of ketone bodies. This can produce ketoacidosis and the attendant tachypnea with somnolence and eventually coma.