Diabetic Ketoacidosis

Key points

• DKA: uncontrolled lipolysis → excess free fatty acids → ketone bodies; precipitants: infection, missed insulin, MI; mortality now < 1%.
• Diagnostic criteria (JBDS-IP, current guideline is the 2021/22 update — the 2013 version is SUPERSEDED): glucose ≥ 11 mmol/L OR known diabetes · ketones ≥ 3 mmol/L (or urine ketones ++) · pH ≤ 7.3 OR bicarbonate ≤ 15 mmol/L. All three domains are needed — D, K and A.
• Features: abdominal pain · polyuria/polydipsia/dehydration · Kussmaul respiration · acetone ('pear drops') breath.
• Management: IV 0.9% sodium chloride (most patients are 5–8 litres depleted) plus a FIXED-RATE IV insulin infusion at 0.1 units/kg/hour · CONTINUE the usual long-acting basal insulin throughout.
• KEY 2021/22 CHANGE: once blood glucose falls below 14 mmol/L, ADD 10% glucose AND CONSIDER DE-ESCALATING the insulin infusion from 0.1 to 0.05 units/kg/hour — this was introduced because of the high observed rates of hypoglycaemia and hypokalaemia on the older fixed 0.1 units/kg/h regimen.
• RESOLUTION is defined as ketones < 0.6 mmol/L AND venous pH > 7.3. Do NOT use bicarbonate as the marker of resolution — large volumes of 0.9% sodium chloride cause a hyperchloraemic acidosis that keeps bicarbonate low despite the ketoacidosis having resolved. This is a classic exam trap.
• EUGLYCAEMIC DKA: the current guideline added a section on SGLT2 inhibitors, which can precipitate ketoacidosis with normal or only mildly raised glucose — check ketones in any unwell patient on an SGLT2 inhibitor and stop the drug. Mortality has fallen from around 8% to under 1% over recent decades.
• ADA 2009 criteria differ slightly: glucose > 13.8 mmol/l · pH < 7.30 · HCO3 < 18 · anion gap > 10 · ketonaemia.