Diabetic ketoacidosis (DKA) is not just "high blood sugar" — it's a hormonal storm caused by absolute insulin deficiency and a surge of counter-regulatory hormones. The result is a triad of hyperglycaemia, dehydration, and metabolic acidosis.
We follow Sophie, a 23-year-old with type 1 diabetes who arrives with vomiting, Kussmaul breathing, glucose 28 mmol/L, ketones 5.6 mmol/L, and pH 7.08.
No insulin → cells can't use glucose → liver produces more.
Glucose spills into urine → osmotic diuresis → 6–8L fluid + electrolyte loss.
Fat breakdown produces ketones → metabolic acidosis.
Potassium appears normal or high, but total body stores are low.
Fluids first – 1L 0.9% NaCl over 30 mins (slower if frail/cardiac issues). Restores perfusion, lowers stress hormones.
Potassium next – replace before insulin if K⁺ <3.5 mmol/L; add to fluids if 3.5–5.5.
Insulin third – fixed-rate 0.1 units/kg/h to stop ketone production, not to chase glucose.
Add 10% dextrose when glucose falls to ~14 mmol/L to safely continue insulin.
Treat the trigger – infection, missed insulin, MI, etc.
DKA isn't chaotic when understood physiologically. Fluids, potassium, insulin — in that order. You're not treating the number; you're fixing the metabolic storm.
