FFinalistSouthampton · 2027
Acute care
AKT · Acute care/Metabolic & endocrine

Diabetic ketoacidosis (DKA)

Insulin deficiency → ketoacidosis + osmotic diuresis

Overview

A medical emergency of insulin deficiency: hyperglycaemia, ketosis and metabolic acidosis. Defined by the triad of ketonaemia ≥3 (or ketonuria ++), glucose >11 (or known diabetes) and acidosis (bicarbonate <15 or pH <7.3). Treated with fluids then a fixed-rate insulin infusion.

Recognise

  • Polyuria/polydipsia, vomiting, abdominal pain, Kussmaul breathing, ketotic (acetone) breath
  • Dehydration, tachycardia, hypotension; drowsiness
  • Often a precipitant: infection, missed insulin, new diagnosis, MI

Red flags

  • Reduced consciousness, shock, K+ <3.5 before insulin, severe acidosis (pH <7.1) → HDU/ICU

Differentials & how to tell them apart

Hyperosmolar hyperglycaemic state (HHS)type 2, very high glucose + osmolality, minimal ketones/acidosis, profound dehydration
Starvation/alcoholic ketoacidosisglucose normal/low; alcohol history
Sepsis/acute abdomenmay precipitate DKA or mimic the abdominal pain
Lactic acidosisraised lactate, no significant ketones

Investigations

Capillary/blood ketones, glucose, venous gas (pH/bicarbonate), U&E (potassium!), FBC/CRP, cultures/ECG to find the precipitant.

Management

IV 0.9% saline first, then fixed-rate insulin 0.1 units/kg/h + careful potassium replacement

  1. 1IV 0.9% saline resuscitation FIRST; then fixed-rate IV insulin 0.1 units/kg/h; continue basal insulin; monitor ketones/glucose/K+ hourly.Gate: If potassium is <3.5 do NOT start insulin until potassium is being replaced — insulin drives K+ intracellularly and can cause fatal hypokalaemia
  2. 2Add 10% glucose alongside saline once glucose <14 (to keep insulin running and clear ketones); treat the precipitant.
IV 0.9% sodium chloride — fluid replacement FIRST; restore circulating volume
Fixed-rate IV insulin (0.1 units/kg/h) — continue long-acting/basal insulin
Potassium replacement — add to fluids once K+ <5.5 and urine output adequate

Key points

Fluids before insulin; watch potassium obsessively (it falls as insulin acts). Cerebral oedema is the feared complication in children — cautious fluids.

Monitor & prognosis

Hourly glucose/ketones/K+, venous pH/bicarbonate, fluid balance, GCS.

Good with prompt protocolised care; mortality from hypokalaemia/cerebral oedema if mismanaged.

Source: JBDS-IP (Joint British Diabetes Societies) DKA guideline