A 62-year-old woman with type 2 diabetes mellitus presents with severe hyperglycemia (blood glucose 680 mg/dL), osmolality 340 mOsm/kg, and altered mental status. Serum ketones are negative and arterial pH is 7.32. She is diagnosed with hyperglycemic hyperosmolar state (HHS). What is the first-line pharmacological agent for management of her hyperglycemia?

## Pharmacological Management of HHS: Insulin Choice ### Why IV Regular Insulin is First-Line **Key Point:** Although HHS is less ketotic than DKA, intravenous regular insulin remains the drug of choice because it rapidly lowers blood glucose, reduces osmolality, and restores intracellular fluid shifts. The severe hyperglycemia (often >600 mg/dL) and hyperosmolality demand rapid correction. **High-Yield:** In HHS: - Initial insulin bolus: 0.1 unit/kg IV (same as DKA) - Continuous infusion: 0.05–0.1 unit/kg/hour (often lower than DKA because ketogenesis is not the primary problem) - Goal: reduce glucose by 50–100 mg/dL/hour initially - Insulin suppresses hepatic glucose production and enhances peripheral uptake ### Comparison of Insulin Routes and Formulations in HHS | Agent | Route | Onset | Titratability | Suitability in HHS | |-------|-------|-------|---------------|-------------------| | **Regular insulin** | IV | 15 min | Excellent | ✓ First-line | | **Insulin aspart** | SC | 15–30 min | Moderate | ✗ Slower absorption in dehydration | | **Insulin detemir** | SC | 1–2 hours | Poor | ✗ Too slow; long-acting | | **SGLT-2 inhibitor** | Oral | Hours | N/A | ✗ Contraindicated (euglycemic DKA risk) | **Clinical Pearl:** HHS typically occurs in elderly patients with residual beta-cell function; they mount enough endogenous insulin to prevent ketosis but insufficient to prevent hyperglycemia. IV insulin rapidly corrects the osmotic gradient, reducing neurological complications and restoring consciousness. **Mnemonic: OSMOL** — **O**smolality (>320 mOsm/kg in HHS), **S**evere hyperglycemia (>600 mg/dL), **M**inimal ketosis, **O**lder patients, **L**ow insulin (relative, not absolute). ### Concurrent Fluid & Electrolyte Management - Hypotonic saline (0.45%) preferred in HHS (vs. isotonic in DKA) to correct hyperosmolality - Aggressive potassium monitoring and replacement - Phosphate and magnesium repletion - Thromboprophylaxis (HHS carries high thrombotic risk) [cite:Harrison 21e Ch 397]