Hyperglycemic crises in diabetes mellitus: diabetic ketoacidosis and hyperglycemic hyperosmolar state.

Diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar state (HHS) potentially are fatal but largely preventable acute metabolic conditions of uncontrolled diabetes, the incidence of which continues to increase. Mortality from DKA has declined remarkably over the years because of better understanding of its pathophysiology and treatment. The mortality rate of HHS remains alarmingly high, however, owing to older age and mode of presentation of patients and associated comorbid conditions. DKA and HHS also are economically burdensome; therefore, any resources invested in their prevention would be rewarding.