Hyperglycemic hyperosmolar nonketotic coma (HHNKC) is an extremely serious complication of type 2 diabetes, most often occurring in those who are non-insulin dependent.
HHNKC is caused by severely elevated blood glucose levels, usually over 600 mg/dl. Symptoms can include weakness, increased thirst, nausea, lethargy, confusion and ultimately, convulsions, and coma. Onset of these symptoms can be slow and insidious, building over a period of days or weeks.
HHNKC frequently happens in the elderly and is usually precipitated by another illness, such as infection or flu, or sometimes a chronic condition such as congestive heart failure or renal failure. HHNKC is an emergency that requires immediate medical care.
Source:
Phipps, W. (Ed.). (1995). In Medical-Surgical Nursing - Concepts and Clinical Practice (5th ed.), St. Louis: Mosby.
