diabetic coma, a life-threatening condition occurring in persons with diabetes mellitus. It is caused by undiagnosed diabetes; inadequate treatment; failure to take prescribed insulin; excessive food intake; or, most frequently, infection, surgery, trauma, or other stressors that increase the body’s need for insulin. Without insulin to metabolize glucose, fats are used for energy, resulting in ketone waste accumulation and metabolic acidosis. The body’s effort to counteract acidosis depletes the alkali reserve; causes a loss of sodium, chloride, potassium, and water; increases respiratory exhalation of carbon dioxide (Kussmaul breathing) and urinary excretion; and leads to dehydration and generalized hypoxia. Warning signs of diabetic coma include a dull headache, fatigue, inordinate thirst, epigastric pain, nausea, vomiting, parched lips, flushed face, and sunken eyes. The temperature usually rises and then falls, the systolic blood pressure drops, and circulatory collapse may occur. Immediate treatment consists of administering short-acting insulin and replacing electrolytes and fluids to correct the acidosis and dehydration. Nonketotic coma may occur in patients with poorly controlled type 2 diabetes mellitus and high levels of blood glucose but no fatty acid breakdown. The plasma hyperosmolarity causes water to leave cells, and the dehydration of cerebral cells results in coma. See also diabetic ketoacidosis, insulin shock.
