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. 

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

Examination

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

Biochemistry

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