Type II Diabetes Mellitus

Abstract

Hyperosmotic hyperglycemic nonketotic (HHNK) state (also known as hyperosmolar hyperglycemic state) is a significant acute complication of type 2 diabetes mellitus, especially for those over 65 years of age. It is characterized by extreme hyperglycemia and hyperosmolarity with little ketosis. The main clinical effect of extreme hyperosmolarity is somnolence or confusion. The absence of severe ketonemia is attributed to residual insulin secretion that is sufficient to restrain lipolysis. HHNK state is marked by extreme dehydration, with both a marked deficit of free water and serious compromise of intravascular volume and tissue perfusion. Most patients with HHNK state have hypotension, extremely dry mucous membranes, and gross elevation of urea nitrogen and creatinine. Urinary tract infection, pneumonia, stroke, myocardial infarction, and sepsis may precipitate HHNK state. Elderly patients are particularly vulnerable because their thirst mechanisms are less sensitive to a rising serum osmolality. Fluid replacement is the most important component of therapy for HHNK state. Restoration of circulating volume is an urgent first priority and is accomplished by relatively rapid intravenous infusion of 2 L of 0.9% normal saline followed by 0.45% normal saline. Later, when plasma glucose levels have declined to 250 to 300 mg/dL, 5% dextrose in water is given. Insulin treatment is started soon after administration of isotonic saline. Potassium must be added to intravenous fluids to prevent hypokalemia caused by insulin action but should not be started until hypokalemia is proven, because potassium levels can be high initially. The mortality from the HHNK state is high, ranging from 10 to 20%, and is most often from the precipitating illness. This review contains 6 figures, 7 tables, and 73 references. Key words: dehydration, fluid deficit, hyperglycemia, hyperglycemic nonketotic state, hyperosmolar, hyperosmotic insulin, potassium, type 2 diabetes mellitus