[Ketoacidotic diabetic metabolic dysregulation: pathophysiology, clinical aspects, diagnosis and therapy]

When glucose utilisation is impaired due to decreased insulin effect, ketones are produced by the liver from free fatty acids to supply an alternate source of energy. This adaptation may be associated with severe metabolic acidosis and tends to occur in patients with type I (insulin-dependent) diabetes mellitus. In addition, hypovolemia is an almost invariable finding with marked hypoglycemia and is primarily induced by the associated glucosuria. Ketoacidosis stimulates both the central and peripheral chemoreceptors controlling respiration, resulting in alveolar hyperventilation (Kussmaul's respiration). With the ensuing fall in pCO2 the patient tries to raise the extracellular pH. A fruity odor of acetone on the patient's breath sometimes suggests that ketoacidosis is present. The classical triad of symptoms associated with hyperglycemia are polyuria, polydipsia, and weight loss. Circulatory insufficiency with hypotension is not uncommon due to the marked fluid loss and acidemia. In more severely affected patients, neurologic abnormalities may be seen, including lethargy, seizures or coma. Some patients also have marked vomiting and abdominal pain. The history and physical examination may provide important clues to the presence of uncontrolled diabetes mellitus. Once suspected, the diagnosis can be easily confirmed by measuring the plasma glucose concentration. Glucosuria and ketonuria can be semiquantitatively detected with reagent sticks. Blood gas analysis and anion gap give objective information as to the severity of the metabolic acidosis. Therapy must be directed toward each of the metabolic disturbances: hyperosmolality, ketoacidosis, hypovolemia and potassium, and phosphate depletion. The mainstays of therapy are the administration of low-dose insulin and volume repletion.(ABSTRACT TRUNCATED AT 250 WORDS)