Diabetic ketoacidosis (DKA) is an acute, life-threatening metabolic emergency characterised by the biochemical triad of hyperglycaemia, ketonaemia, and high anion gap metabolic acidosis resulting from absolute or relative insulin deficiency and excess counter-regulatory hormones 1,2.
Diagnostic criteria (UK JBDS Guidelines)
All three criteria must be present to establish the diagnosis of DKA 1:
ketonaemia: blood beta-hydroxybutyrate ≥3.0 mmol/L (or significant ketonuria >2+ on standard urine sticks)
hyperglycaemia: blood glucose >11.0 mmol/L (200 mg/dL) or known diabetes mellitus (note: euglycaemic DKA occurs with SGLT2 inhibitors and pregnancy) 1,2
acidaemia: venous bicarbonate (HCO3-) <15.0 mmol/L and/or venous pH <7.3
Clinical presentation
polyuria, polydipsia, profound dehydration, nausea, vomiting, and generalized abdominal pain
Kussmaul respiration (deep, sighing hyperventilation compensating for metabolic acidosis) and sweet "pear-drop" acetone breath odour
Management (UK JBDS Protocol)
1. Fluid resuscitation: restore circulating volume using 0.9% sodium chloride (average deficit 100 mL/kg); once blood glucose falls below 14.0 mmol/L, add 10% intravenous glucose at 125 mL/hr alongside 0.9% NaCl to allow continuation of fixed-rate insulin for ketone clearance 1
2. Fixed-rate intravenous insulin infusion (FRIII): administer soluble human insulin at 0.1 units/kg/hour; continue the patient's usual long-acting basal insulin subcutaneously 1,2
3. Potassium replacement: insulin drives potassium intracellularly; omit potassium if serum K+ >5.5 mmol/L, add 40 mmol/L KCl if serum K+ is 3.5–5.5 mmol/L, and delay insulin until K+ is corrected if initial K+ <3.5 mmol/L 1