Non-anion-gap metabolic acidosis
Type 1 distal: can't excrete acid, urine pH >5.5, ↓K, stones (amphotericin) → oral bicarbonate/citrate
Type 2 proximal: ↓HCO₃ reabsorption, ↓K, Fanconi → bicarbonate
Type 4: hypoaldosteronism, ↑K, diabetes → fludrocortisone / low-K diet
Order set
- VBG (NAGMA)
- Urine pH
- K⁺
- Urine anion gap
Criteria
AdmitSevere electrolyte disturbance
DischargeAcidosis/K⁺ corrected, replacement + cause addressed
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
- Severe hypokalaemia (type 1/2)
- Hyperkalaemia (type 4)
Differentials
- GI bicarbonate loss (diarrhoea)
- Other NAGMA causes
Common mistakes
- Mislabelling type
- Missing drug cause
Disposition & follow-up
Bicarbonate/citrate replacement; treat cause.
Discharge package
MedicationsBicarbonate/citrate; potassium as needed
Follow-upNephrology; electrolyte monitoring
Warning symptomsWeakness, palpitations
💊 Treatment detail — doses & preparation
Sodium bicarbonate POoral alkali
Dose600 mg–1.2 g TDS, titrate to HCO₃ (RTA, CKD)
Preparation600 mg tablets or 8.4% solution measured doses
MonitorHCO₃, K⁺, BP/oedema (sodium load)
Potassium chlorideelectrolyte
DosePO 40–100 mmol/day divided. IV: 10 mmol/h peripheral, 20 mmol/h central with cardiac monitor
PreparationIV: NEVER undiluted push — 10 mmol in 100 mL or 40 mmol/L bag via pump
MonitorK⁺ q4–6 h during replacement, ECG, urine output >0.5 mL/kg/h
📖 expert consensusReviewed July 2026