A 78-year-old patient with type 2 diabetes is brought to the ED with progressive lethargy and dehydration over five days. Glucose 720 mg/dL, serum osmolality 322 mOsm/kg, sodium 152, BUN 56, creatinine 1.8, pH 7.34, bicarbonate 22, small ketones. Which intervention should the nurse anticipate first?

This patient has hyperosmolar hyperglycemic state (HHS), characterized by very high glucose (>600), high serum osmolality (>320), profound dehydration, mild or absent ketosis, and altered mental status — distinct from DKA, where ketosis and acidosis dominate. The first priority is aggressive isotonic IV fluid resuscitation (0.9% NS at 15–20 mL/kg in the first hour, often 1–1.5 L) to restore circulating volume and renal perfusion. Insulin is started AFTER fluids have begun and AFTER serum potassium is verified — giving insulin first can precipitate cardiovascular collapse and severe hypokalemia. Bicarbonate is rarely needed in HHS because acidosis is mild. Subcutaneous insulin and oral hydration are inadequate for an unstable, dehydrated, altered patient.

In-depth explanation

HHS treatment core: initial priority is fluid. The average deficit is 8–12 L, and restoring renal perfusion is the prerequisite for every subsequent intervention. Use 0.9% NS at 15–20 mL/kg (typically 1–1.5 L) in the first hour, then transition to 0.45% NS once hemodynamics stabilize. Insulin starts only after fluids have begun AND serum potassium is ≥3.3; if K is lower, replace potassium first. If insulin precedes fluids, glucose rapidly enters cells and further depletes intravascular volume (causing shock), and potassium co-shifts intracellularly (causing severe hypokalemia). Oral hydration is contraindicated in altered mental status because of aspiration risk. The HHS-vs-DKA distinction is core NCLEX content: HHS occurs in older T2DM patients with mild or absent ketones and minimal acidosis, whereas DKA occurs in younger T1DM patients with prominent ketones and acidosis. Both follow the same order: fluids → insulin → potassium replacement.

Clinical scenario

<p>A <strong>78-year-old patient</strong> with <strong>type 2 diabetes</strong> presents with progressive <strong>lethargy and dehydration over 5 days</strong>. Labs: <strong>glucose 720 mg/dL</strong>, <strong>osmolality 322 mOsm/kg</strong>, <strong>Na 152</strong>, <strong>BUN 56</strong>, <strong>Cr 1.8</strong>, <strong>pH 7.34</strong>, <strong>HCO3 22</strong>, <strong>small ketones</strong>.</p>

Key concepts

• Hyperosmolar Hyperglycemic State (HHS) — A diabetic emergency typically in older adults with type 2 diabetes. Defined by glucose >600 mg/dL, serum osmolality >320 mOsm/kg, profound dehydration (often 8–12 L deficit), minimal or absent ketosis, and altered mental status. Mortality is higher than DKA — closer to 5–15%.
• HHS vs DKA — DKA: glucose typically 250–600, marked acidosis (pH <7.30), large ketones, type 1 diabetes more common. HHS: glucose >600, mild/absent acidosis, minimal ketones, type 2 diabetes more common, dehydration more severe. Both require fluids first, then insulin, with potassium replacement.
• Fluid Resuscitation Priority — Aggressive 0.9% NS at 15–20 mL/kg (1–1.5 L) in the first hour, then transition to 0.45% NS once intravascular volume is restored. Insulin is held until fluids begin and potassium is verified; potassium replacement begins when serum K is below 5.2.