A helpful clue to differentiate diabetic ketoacidosis (DKA) from hyperosmolar nonketotic hyperglycemia (HONK) is:
Serum glucose of 500 mg/dL is most consistent with the diagnosis of HONK.
Fluid deficits are typically greater in DKA.
Most patients who develop HONK have a prior history of complications of their IDDM.
HONK most commonly presents as an acute event with illness developing over several hours, and coma is required to make the diagnosis.
Focal neurologic symptoms occur more frequently in HONK.
HONK and DKA have similar features: hyperglycemia (patients with HONK usually have a serum glucose >800 mg/dL), hyperosmolality, and dehydration; however, no ketoacidosis. HONK most commonly occurs in patients with non–insulin-dependent diabetes, usually the elderly. Precipitating illnesses include myocardial infarction, stroke, upper GI bleeding, sepsis, and renal failure. Some drugs that can cause HONK include thiazide diuretics, calcium channel blockers, phenytoin, and propranolol. There are no specific signs on physical examination, although neurologic pathology is most prominent and may present as hemisensory or hemiparesis, altered mental status, and focal motor seizures. Treatment for HONK includes correction of hypovolemia—the average fluid deficit is between 8 and 12 L—and hyperglycemia.