DIABETES MELLITUS

Scientists consider the diabetes mellitus to occur as a result of inadequate secretion of insulin or the inability of tissues to respond to insulin. Thus, when body's cells are unable to use the glucose in the bloodstream because of a lack of insulin activity, diabetes mellitus occurs. Insulin hyposecretion is usually caused by degeneration of the beta cells in the pancreatic islets. There are two types of diabetes mellitus: insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM). Insulin-dependent diabetes mellitus is also known as type I, juvenile or juvenile-onset diabetes. Terms used for NIDDM include adult-onset, stable, and type II diabetes. Juvenile-onset diabetes usually develops in young people. It is caused by diminished insulin secretion. It is not clear if heredity plays a major role in its onset, but viral infection of the pancreatic islets may be involved. NIDDM develops in older people and often does not result from a lack of insulin but from the inability of the tissues to respond insulin.

The symptoms associated with diabetes mellitus are increased thirst, increased urination, fatigue, nausea, vomiting, skin infections, and bladder infections. These symptoms are the consequence of the abnormal metabolism of nutrients, which is caused by diminished insulin secretion or a decreased number of insulin receptors. In patients with diabetes mellitus nutrients are absorbed from the intestine after a meal, but without insulin skeletal muscle, adipose tissue, the liver and other target tissues do not readily take glucose into their cells. Consequently, blood level of glucose increases dramatically.

Diabetes mellitus often is treated by administration of insulin by injection. Insulin is extracted from sheep or pork pancreatic tissue. Genetic engineering currently is used to synthesize human insulin. In some cases diabetes mellitus can be treated by administering drugs that stimulate beta cells to secrete more insulin. This treatment is effective only if an adequate number of functional beta cells is present in the islets of Langerhans.

Too much insulin or too little food intake after an injection of insulin by a diabetic patient causes insulin shock. The high level of insulin causes target tissues to take up glucose at a very high rate. As a result, blood glucose levels rapidly fall to a low level. Since the nervous system depends on glucose as its major source of energy, neurons malfunction because of a lack of metabolic energy. As the blood glucose level decreases, the concentration of fatty acids increases in the blood, resulting in a decrease in the blood pH, which also causes nerve cells to malfunction. The result is a series of nervous system malfunctions that include disorientation, confusion, and convulsions