Hyperglycemic Hyperosmolar Nonketotic Coma
This is a rarer condition than DKA and a slower process, usually occurring in
the elderly diabetic patient. The degree of volume contraction is generally
greater in HHNK than DKA.
■ Hyperglycemia and stress →insulin resistance →increased insulin →glu-
coneogenesis and glycogenolysis → hyperglycemia without ketosis →
chronic osmolality and dehydration →dehydration without acidosis.
SYMPTOMS
■ Weakness and fatigue
■ Thirst
■ Anorexia
EXAM
■ Most patients have some altered mental status but are not comatose (despite
the name).
■ Focal neurologic signs
■ Dehydration
DIAGNOSIS
■ Extremely elevated blood glucose (>400 mg/dL but often >800 mg/dL)
■ Negative ketones
■ No acidosis on ABG
TREATMENT
■ IV fluids
■ Patients have incredibly large water deficits averaging 8–12 L. Hydra-
tion should be initiated as in DKA.
■ Approximately half of the estimated water deficit should be replaced
during the first 8 hours and the rest during the next 24 hours.
■ Insulin
■ Initiating 0.1 units/kg/hour is a safe and effective dose and should be
continued until the patient’s glucose reaches approximately 300 mg/dL.
■ Aggressively replete potassium and magnesium as in DKA.
COMPLICATIONS
■ HNNK carries a high mortality rate of 8–25%.
A 50-year-old homeless man is brought in altered and dehydrated with a
history of chronic alcohol use. His labs are negative for alcohol or ketones,
but he has an anion gap of 22 mEq/L and a glucose of 150 mg/dL. What
is his diagnosis?
Likely alcoholic ketoacidosis. Check an osmolar gap to exclude the possibility
of methanol or ethylene glycol poisoning.ENDOCRINE, METABOLIC, FLUID, ANDELECTROLYTE DISORDERS