A diagnostic approach to metabolic alkalosis

The diagnostic algorithm for metabolic alkalosis can be reduced into a flowchart. The following easy-to-follow algorithm has been gratefully adopted from the contribution by Dr V. Wakade. 

Metabolic alkalosis algorithm

The approach to metabolic alkalosis

Background history

  • History of congential adrenal hypoplasia
  • History of cystic fibrosis
  • History of CCF (suggesting chronic exposure to diuretics)
  • History of uncontrolled hypertension (malignant hypertension or renal artery stenosis)

Recent history

  • Recent antacic consumption
  • Recent use of calcium supplements
  • β-lactam antibiotic use
  • Massive abuse of licorice
  • History of diarrhoea (villous adenoma) or vomiting (chloride loss)
  • History of recent hypercapneic respiratory failure


  • Clinically, findings consistent with severe hypertension (eg. retinal changes)
  • Renal artery stenosis bruit
  • Peripheral oedema (suggesting chronic exposure to diuretics)


  • Serum potassium
  • Serum magnesium
  • Urinary chloride
  • Serum renin levels
  • Serum aldosterone levels