diabetes mellitus (DM) /məlī″təs/ , a complex disorder of carbohydrate, fat, and protein metabolism that is primarily a result of a deficiency or complete lack of insulin secretion by the beta cells of the pancreas or resistance to insulin. The disease is often familial but may be acquired, as in Cushing’s syndrome, as a result of the administration of excessive glucocorticoid. The various forms of diabetes have been organized into categories developed by the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus of the American Diabetes Association. Type 1 diabetes mellitus in this classification scheme includes patients with diabetes caused by an autoimmune process, dependent on insulin to prevent ketosis. This group was previously called type I, insulin-dependent diabetes mellitus, juvenile-onset diabetes, brittle diabetes, or ketosis-prone diabetes. Patients with type 2 diabetes mellitus are those previously designated as having type II, non–insulin-dependent diabetes mellitus, maturity-onset diabetes, adult-onset diabetes, ketosis-resistant diabetes, or stable diabetes. Those with gestational diabetes mellitus are women in whom glucose intolerance develops during pregnancy. Other types of diabetes are associated with a pancreatic disease, hormonal changes, adverse effects of drugs, or genetic or other anomalies. A fourth subclass, the impaired glucose tolerance group, also called prediabetes, includes persons whose blood glucose levels are abnormal although not sufficiently above the normal range to be diagnosed as having diabetes. Contributing factors to the development of diabetes are heredity; obesity; sedentary lifestyle; high-fat, low-fiber diets; hypertension; and aging. See also impaired glucose tolerance, potential abnormality of glucose tolerance, previous abnormality of glucose tolerance. ▪ OBSERVATIONS: The onset of type 1 diabetes mellitus is sudden in children. Type 2 diabetes often begins insidiously. Characteristically, the course is progressive and includes increased urination, increased thirst, weight loss, polyphagia, hyperglycemia, and glycosuria. The eyes, kidneys, nervous system, skin, and circulatory system may be affected by the long-term complications of either type of diabetes. Infections are common. Atherosclerosis often develops. In type 1 diabetes mellitus, when no endogenous insulin is being secreted, ketoacidosis is a constant danger. The diagnosis is confirmed by fasting plasma glucose and history. ▪ INTERVENTIONS: The goal of treatment is to maintain insulin glucose homeostasis. Type 1 diabetes is controlled by insulin, meal planning, and exercise. Studies have demonstrated that tight control of blood glucose levels (i.e., frequent monitoring and maintenance at as close to normal as possible to the level of nondiabetics) significantly reduces complications such as eye disease, kidney disease, and nerve damage. Type 2 diabetes is controlled by meal planning, weight loss, exercise, one or more oral agents, and insulin. Stress of any kind may require medication adjustment in both type 1 and type 2 diabetes.
