HHS
Formal Definition
Hyperosmolar Hyperglycemic State; a life-threatening hyperglycemic emergency predominantly in type 2 diabetes characterized by extreme hyperglycemia (glucose typically >600 mg/dL), hyperosmolarity (>320 mOsm/kg), severe dehydration, and altered mental status, but WITHOUT significant ketoacidosis (distinguishing it from DKA).
How It's Used on the Ward
"HONK" (Hyperosmolar Non-Ketotic) — the older term that stuck clinically. "HHS" in formal documentation.
Example
""82-year-old nursing home resident with type 2 diabetes, 3 days of decreased PO intake: glucose 1,140, serum osm 342, bicarb 22, no ketonemia — HHS. 6 liters free water deficit. Aggressive fluid resuscitation with NS initially, then switch to 0.45% NS, cautious insulin correction.""
Clinical Context
HHS vs DKA: HHS has higher glucose, more severe dehydration, no acidosis, predominantly type 2, older patients, higher mortality. Treatment: fluid resuscitation is paramount (total free water deficit can be 8–10L). Use NS initially for hemodynamic stabilization, then 0.45% NS to correct hypertonicity. Insulin: lower rate than DKA (0.05 units/kg/hr), add dextrose when glucose <300 (not <250 as in DKA). Cerebral edema risk if corrected too fast — aim to lower glucose by 50–75 mg/dL/hr. Mortality 10–20% (higher than DKA) due to older, sicker population.