Diabetic Hyperglycemic Hyperosmolar coma

Alternative names:

NKHHC; nonketotic hyperglycemic coma

Definition:

A complication of noninsulin-dependent diabetes mellitus that results in extremely high glucose levels without the presence of ketones, a by-product of fat metabolism.

Causes, incidence, and risk factors:

Diabetic hyperglycemic hyperosmolar coma is a condition characterized by decreased consciousness, extreme dehydration, and extremely high blood-glucose levels that is not accompanied by ketoacidosis. The condition is usually seen in noninsulin-dependent diabetes mellitus and usually occurs in those previously undiagnosed, or those who have neglected their diabetes. The condition could be precipitated by an infection or by certain medications that impair glucose tolerance or increase fluid loss.

Normally the kidneys compensate for high glucose levels in the blood by excreting excess glucose in the urine. However, when dehydration occurs, the kidneys conserve fluid and glucose levels become higher, which results in greater dehydration. Hyperosmolarity is a condition in which the blood is much more concentrated with sodium, glucose, and other molecules which, in turn, attracts water into the blood stream. This creates a vicious cycle of increasing dehydration and increasing blood-glucose levels. Risk factors are older age; underlying kidney insufficiency; congestive heart failure; recent discontinuation of insulin or oral hypoglycemic agents; and a precipitating event such as infection, stroke, or recent surgery.