Phys · endocrine
Diabetic Ketoacidosis and Hyperosmolar Hyperglycaemic State
Also known as DKA · diabetic ketoacidosis · hyperosmolar hyperglycaemic state · HHS · hyperosmolar hyperglycemic state · HONK · hyperosmolar non-ketotic coma · hyperglycaemic emergency · ketoacidosis · euglycaemic DKA · euglycemic diabetic ketoacidosis · fixed-rate intravenous insulin infusion · FRIII · beta-hydroxybutyrate · Kussmaul breathing · ketogenesis
Consultant-physician-depth guide to the two hyperglycaemic emergencies, built on the 2024 ADA/EASD/JBDS/AACE/DTS consensus and the 2023 JBDS HHS guideline: DKA and HHS diagnostic criteria, severity grading, pathophysiology, precipitants, fluid, insulin, potassium and bicarbonate management, resolution criteria, transition to subcutaneous insulin, complications and euglycaemic DKA on SGLT2 inhibitors. Structured for FRACP DWE and DCE preparation.
Checked against its sources on 23 Oct 2026
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Target exams
Red flags
- A person on an SGLT2 inhibitor with nausea, vomiting, malaise or a metabolic acidosis — test promptly for urine or serum ketones, because euglycaemic DKA lacks significant hyperglycaemia
- Potassium below 3.5 mmol/L on admission in DKA — replace potassium and delay insulin until it is above 3.5 mmol/L
- Severe DKA (pH below 7.0, bicarbonate below 10 mmol/L, stupor or coma) — intensive care unit
- HHS with osmolality above 350 mOsm/kg, sodium above 160 mmol/L or GCS below 12 — these should prompt discussion of high-dependency care, and immediate senior review should be considered
- Abdominal pain that does not settle as dehydration and acidosis resolve — look for a precipitating cause
Diabetic Ketoacidosis and Hyperosmolar Hyperglycaemic State
The answer first
DKA and HHS share one pathogenesis: insulin deficiency, raised counterregulatory hormones, and loss of fluid and electrolytes. Management is the same four things for both: intravenous fluids, insulin, electrolytes, and identifying and treating the precipitating cause. [1]
They differ in degree. In DKA the insulin deficiency is severe, so ketones accumulate. In HHS there is enough insulin to prevent ketogenesis but not hyperglycaemia. Appropriate treatment has reduced DKA mortality to below 1 percent, while mortality in HHS remains 5- to 10-fold higher. [1]
Three rules carry most exam marks: [1]
- Measure blood beta-hydroxybutyrate. For diagnosis and monitoring of the response to therapy, the consensus recommends direct measurement of venous or capillary beta-hydroxybutyrate, the main ketoacid in DKA. [1]
- Check potassium before insulin. If it is below 3.5 mmol/L, replace potassium and delay insulin until it is above 3.5 mmol/L. [1]
- Keep the insulin running until the ketoacidosis has resolved. Once glucose falls below 13.9 mmol/L, add 5 to 10 percent dextrose rather than stopping insulin. [1]
References6ShowHide
- [1]Umpierrez GE, Davis GM, ElSayed NA, et al. Hyperglycemic Crises in Adults With Diabetes: A Consensus Report. Diabetes care, 2024.PMID 39052901
- [2]Mustafa OG, Haq M, Dashora U, et al. Management of Hyperosmolar Hyperglycaemic State (HHS) in Adults: An updated guideline from the Joint British Diabetes Societies (JBDS) for Inpatient Care Group. Diabetic medicine : a journal of the British Diabetic Association, 2023.PMID 36370077
- [3]Kitabchi AE, Umpierrez GE, Miles JM, et al. Hyperglycemic crises in adult patients with diabetes. Diabetes care, 2009.PMID 19564476
- [4]Peters AL, Buschur EO, Buse JB, et al. Euglycemic Diabetic Ketoacidosis: A Potential Complication of Treatment With Sodium-Glucose Cotransporter 2 Inhibition. Diabetes care, 2015.PMID 26078479
- [5]Glaser N, Barnett P, McCaslin I, et al. Risk factors for cerebral edema in children with diabetic ketoacidosis. The Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics. The New England journal of medicine, 2001.PMID 11172153
- [6]Van Zyl DG, Rheeder P, Delport E Fluid management in diabetic-acidosis--Ringer's lactate versus normal saline: a randomized controlled trial. QJM : monthly journal of the Association of Physicians, 2012.PMID 22109683