n. [ NL., from Gr. &unr_;, fr. &unr_; to pass or cross over. See Diabase. ] (Med.) Any of several diseases which is attended with a persistent, excessive discharge of urine; when used without qualification, the term usually refers to diabetes mellitus. The most common form is diabetes mellitus, in which the urine is not only increased in quantity, but contains saccharine matter, and the condition if untreated is generally fatal. [ 1913 Webster ]

☞ The two major subtypes recognized are
diabetes insipidus and
diabetes mellitus. In diabetes insipidus there is excretion of large amounts of urine of relatively low density, accompanied by extreme thirst, but the urine contains no abnormal constituent. The more serious form diabetes mellitus (from Latin mellitus, sweetened with honey) is a metabolic disease in which the utilization of carbohydrate is reduced and that of lipids and proteins is increased. This form is caused by a deficiency in insulin (which is mostly formed in the pancreas), and may be accompanied by glucosuria, hyperglycemia, elecrolyte loss, ketoacidosis, and sometimes coma. It has severe long-term effects, including damage to the nerves, the retina, and the kidney, and degeneration of blood vessels which may lead to poor circulation, especially in the limbs, subsequent infection, and eventual loss of limbs.
Diabetes mellitus itself has recognized variants, being divided into insulin-dependent diabetes mellitus and non-insulin-dependent diabetes mellitus. Non-insulin-dependent diabetes mellitus is also called adult-onset diabetes (abbreviated NIDDM), and is the less severe form of diabetes mellitus, occurring mostly in obese individuals over the age of 35. It may be treated by diet and oral hypoglycemic agents, though occasionally serious degenerative effects may develop. Insulin-dependent diabetes mellitus (abbreviated IDDM), also called type I diabetes, is a severe form of the disease, usually starting when the affected person is young (hence also called juvenile-onset diabetes). In addition to the increased urine (polyuria) common to all forms of diabetes, this form is characterized by low levels of insulin in the blood, ketoacidosis, increased appetite, and increased fluid intake, and may lead to weight loss and eventually the severe degenerative effects mentioned above. Treatment requires administration of insulin and careful regulation of the diet. Stedman [ PJC ]

‖Diabetes mellitus [ NL., sweet diabetes ], that form of diabetes in which the urine contains saccharine matter. --
‖Diabetes insipidus [ NL., lit., diabetes ], the form of diabetes in which the urine contains no abnormal constituent.