Both are emergencies caused by very high blood sugar. The big difference: DKA has ketones and acidosis. HHS has extreme blood sugar and severe dehydration, with few or no ketones.
Side by side
| DKA | HHS | |
|---|---|---|
| Who | Usually type 1, often younger | Usually type 2, often older |
| Onset | Fast (hours to a day) | Slow (days) |
| Blood sugar | Usually over 250 mg/dL | Often over 600 mg/dL |
| Ketones | Present | None or small |
| pH | Under 7.30 (acidosis) | Usually normal (over 7.30) |
| Key signs | Deep, fast Kussmaul breathing, fruity breath, nausea, belly pain | Severe dehydration, confusion, sometimes seizures |
Treatment order
- IV fluids first, usually normal saline.
- Check potassium before insulin. If it is low (often under 3.3 mEq/L), replace it first.
- Regular insulin IV drip. Insulin pushes potassium into the cells, so potassium often drops.
- Add dextrose to the IV fluids as blood sugar comes down (around 200 mg/dL in DKA, per protocol), so insulin can keep running.
- Check blood sugar every hour and potassium often.
Watch for
- Low potassium and dangerous rhythms
- Blood sugar dropping too fast
- Brain swelling, especially in children with DKA (headache, confusion)
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Quick answers
What is the main difference between DKA and HHS?
DKA has ketones and acidosis and usually affects people with type 1 diabetes. HHS has extremely high blood sugar and severe dehydration with few or no ketones, and usually affects people with type 2 diabetes.
Why check potassium before starting insulin in DKA?
Insulin moves potassium into the cells and can drop it dangerously low, so low potassium is replaced before insulin is started.
Evidence & Clinical Sources
- ADA Standards of Care in Diabetes
- Hinkle & Cheever, Brunner & Suddarth's Textbook of Medical-Surgical Nursing, Wolters Kluwer
Reviewed against current guidelines and drug labels. Always follow your program, a current drug reference, and facility policy. Our sources policy
For learning only. Lab ranges and policies vary. Always follow your nursing program, a current drug reference, and your facility's policies.