Differential Diagnosis for Metabolic Alkalosis

Single Most Likely Diagnosis

• Volume contraction with chloride depletion: This is often due to excessive vomiting or nasogastric suction, leading to loss of hydrogen and chloride ions, which in turn increases bicarbonate levels in the blood.

Other Likely Diagnoses

• Excessive bicarbonate intake: Ingestion of large amounts of bicarbonate can directly increase blood bicarbonate levels.
• Mineralocorticoid excess: Conditions like primary aldosteronism lead to increased sodium reabsorption and potassium excretion, resulting in metabolic alkalosis.
• Diuretic use: Loop and thiazide diuretics can cause loss of potassium and chloride, leading to metabolic alkalosis.

Do Not Miss Diagnoses

• Milk-alkali syndrome: Although less common, this condition, caused by excessive intake of calcium and alkali, can lead to severe metabolic alkalosis and is important not to miss due to its potential for significant morbidity.
• Severe potassium deficiency: Potassium depletion can lead to metabolic alkalosis and is critical to identify and treat to prevent cardiac arrhythmias and muscle weakness.

Rare Diagnoses

• Liddle's syndrome: A rare genetic disorder characterized by excessive sodium reabsorption and potassium excretion, leading to metabolic alkalosis.
• Bartter syndrome and Gitelman syndrome: These are rare genetic disorders affecting the kidneys' ability to reabsorb or secrete electrolytes, which can result in metabolic alkalosis among other electrolyte imbalances.
• Licorice ingestion: Glycyrrhizin in licorice can mimic the effects of aldosterone, leading to mineralocorticoid excess and metabolic alkalosis in some cases.