DKA vs HHS: The Two Hyperglycemic Emergencies Compared
How diabetic ketoacidosis and the hyperosmolar hyperglycemic state differ, the laboratory criteria the hospital will use, euglycemic DKA, and what EMS can do for either in the field.
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Diabetic ketoacidosis (DKA) and the hyperosmolar hyperglycemic state (HHS) are the two hyperglycemic emergencies. Both come from too little insulin and both leave the patient badly dehydrated. What separates them is ketones and acid. In DKA the body, starved of insulin, burns fat for fuel and floods the blood with ketoacids. In HHS there is usually just enough insulin to prevent that, so the glucose climbs higher and more slowly and the patient dries out further, often until the brain is affected.
Side by side
| Feature | DKA | HHS |
|---|---|---|
| Typical patient | Type 1 diabetes, often younger, sometimes the first sign of diabetes; also occurs in type 2 | Type 2 diabetes, usually older, often with another illness such as an infection |
| Onset | Hours to a day or two | Days to weeks |
| Blood glucose | High, but can be only modestly raised | Typically very high, often reading HIGH on a field meter |
| Ketones and acid | Present: the defining feature | Minimal or absent |
| Breathing | Deep, rapid Kussmaul respirations as the body blows off acid; fruity or acetone breath odor | Usually no Kussmaul pattern |
| Abdominal pain, nausea, vomiting | Common | Less common |
| Dehydration | Severe | Often more severe |
| Mental status | Often alert or mildly drowsy; altered in severe cases | Often altered, from confusion to coma; seizures and stroke-like deficits can occur |
Mixed presentations are common. A patient can have features of both, and the hospital sorts that out with blood tests. In the field the job is the same for either: recognize a hyperglycemic emergency, support the patient and look for what set it off.
What the hospital will measure
These are the laboratory criteria from the 2024 consensus report on hyperglycemic crises in adults, published by the ADA with other diabetes and endocrine societies. They are not field criteria; most of them need a blood gas or a chemistry panel. They are here so the terms in a report or a handoff make sense.
| Measure | DKA | HHS |
|---|---|---|
| Glucose | 200 mg/dL or more, or a known history of diabetes | 600 mg/dL or more |
| Ketones | Beta-hydroxybutyrate 3.0 mmol/L or more, or urine ketones 2+ or more | Beta-hydroxybutyrate below 3.0 mmol/L (urine below 2+) |
| Acid | pH below 7.3 or bicarbonate below 18 mEq/L | pH 7.3 or above and bicarbonate 15 mEq/L or more |
| Osmolality | Variable | Effective serum osmolality above 300 mOsm/kg, or total above 320 |
What sets them off
Infection and missed or inadequate insulin are the most common triggers. Others include missed or inadequate insulin, an insulin pump failure, a heart attack or stroke, pancreatitis, trauma, alcohol or drug use, and medications such as steroids. Ask about all of them, because the trigger may need treating as urgently as the glucose.
Prehospital priorities
- Airway, breathing and circulation first. A patient in HHS may be unable to protect the airway.
- Check the blood glucose. A field meter often reads simply HIGH above its upper limit; report it that way rather than guessing a number.
- Do not try to slow Kussmaul breathing. It is the body compensating for acid. If you must assist ventilation, the patient needs a high rate to keep compensating, and your protocol and medical direction should guide it.
- Give fluids as your protocol directs. Dehydration is profound in both, and fluid is the main prehospital treatment.
- Put the patient on the cardiac monitor. Total body potassium is depleted even when the blood level is normal or high, and both high and low potassium can change the ECG.
- Look for the trigger: fever, a source of infection, chest pain, a pump that has stopped delivering.
- Insulin is outside the scope of most EMS systems and is started in hospital once potassium is known.
Score the Glasgow Coma Scale for an altered patient
The short version
- DKA and HHS are both insulin deficiency with severe dehydration; DKA adds ketones and acid.
- DKA: often younger, faster onset, Kussmaul breathing and fruity breath. HHS: often older, slower onset, higher glucose, more dehydration and more confusion.
- A normal-looking glucose does not rule out DKA in a patient taking an SGLT2 inhibitor.
- In the field: support the ABCs, check glucose, monitor the heart, give fluids per protocol and look for the trigger.
- Do not slow a patient's Kussmaul breathing; it is compensation.