Chart — Med-Surg
DKA vs HHS Comparison Chart
Diabetic ketoacidosis and hyperosmolar hyperglycemic state are both acute hyperglycemic emergencies that require rapid recognition. This chart compares them across all critical parameters to support rapid differentiation in clinical practice and NCLEX preparation.
Educational use only. Both conditions are medical emergencies requiring immediate provider notification and ICU-level monitoring. Treatment protocols are institution-specific and provider-ordered. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
DKA vs HHS — Side-by-Side Comparison
| Parameter | DKA | HHS |
|---|---|---|
| Diabetes type | Type 1 (primarily) | Type 2 (primarily) |
| Glucose | ≥ 200 mg/dL (often 300–600) | > 600 mg/dL (often 800–1200+) |
| Ketones | Moderate to large (serum and urine) | Absent or trace |
| Arterial pH | < 7.30 (often 7.0–7.24) | > 7.30 (near normal) |
| HCO₃ (Bicarbonate) | < 18 mEq/L (often < 10) | > 18 mEq/L (normal to near-normal) |
| Anion gap | Elevated (>12) — high anion gap metabolic acidosis | Normal or mildly elevated |
| Serum osmolality | Variable (may be normal) | > 320 mOsm/kg (markedly elevated) |
| Dehydration | Moderate (3–6 L deficit) | Profound (8–12+ L deficit) |
| Mental status | Alert to confused (variable) | Severely altered — stupor to coma |
| Kussmaul respirations | Present (respiratory compensation for acidosis) | Absent |
| Fruity breath | Present (acetone from ketosis) | Absent |
| Nausea/vomiting | Common | Less common |
| Onset speed | Hours to days (rapid) | Days to weeks (gradual) |
| Mortality | < 1–5% with treatment | 10–20% (higher mortality) |
Treatment Priority Comparison
| Intervention | DKA | HHS |
|---|---|---|
| First priority | IV fluid resuscitation + potassium replacement + insulin | Aggressive fluid resuscitation (most critical intervention) |
| IV fluids | 0.9% NS 1 L/hour initially; switch to 0.45% NS | 0.9% NS — 8–12+ L total over 24–48 hours |
| Insulin | Regular insulin IV infusion (after K⁺ ≥ 3.5 mEq/L) | Low-dose insulin after fluid resuscitation; less aggressive than DKA |
| Potassium | Critical replacement — hold insulin if K⁺ < 3.5 | Replace as needed — typically less severe |
| Add dextrose when | Glucose 200–250 mg/dL (to continue insulin safely) | Glucose 300 mg/dL |
| Resolution criteria | Glucose < 200, HCO₃ ≥ 15, pH > 7.3, gap closed | Glucose < 300, osmolality normal, mental status restored |
Key Differentiating Facts
Why DKA Has Ketones but HHS Does Not
In DKA (typically Type 1), absolute insulin deficiency allows unopposed lipolysis. Free fatty acids flood the liver and are converted to ketone bodies. In HHS (Type 2), residual insulin secretion is enough to suppress significant lipolysis, preventing ketone production — despite extreme hyperglycemia.
Why HHS Has More Profound Dehydration
HHS develops slowly over days to weeks. The sustained extreme hyperglycemia drives relentless osmotic diuresis, depleting 8–12+ liters of fluid before the condition is recognized. The gradual onset and preserved mental status (until very late) allow the patient to continue losing fluids without triggering an early emergency response.
Potassium in DKA — The Critical Trap
Acidosis drives potassium out of cells, making serum K⁺ appear normal or elevated. However, total body potassium is severely depleted from urinary losses. When insulin is given and acidosis corrects, potassium rapidly shifts back into cells — precipitating dangerous hypokalemia. Never start insulin if K⁺ < 3.5 mEq/L. Replace aggressively with IV KCl.
NCLEX Quick Tips
- DKA = ketones + acidosis. HHS = no significant ketones, near-normal pH.
- HHS glucose is always higher than DKA glucose (> 600 mg/dL)
- Kussmaul respirations + fruity breath = DKA. Neither in HHS.
- HHS = more profound dehydration and more severe mental status changes
- Hold insulin in DKA if K⁺ < 3.5 mEq/L — replace first
- Regular insulin is the only insulin given IV (used in DKA infusion)
- Priority: IV fluid resuscitation in BOTH conditions
- Monitor glucose hourly, electrolytes every 1–2 hours during treatment
Related Resources
Standards & sources
Fact-checked Jun 21, 2026This page is written to align with Academy of Medical-Surgical Nurses (AMSN) · Current medical-surgical nursing standards. It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →