Differential Diagnosis for Metabolic Alkalosis
Single Most Likely Diagnosis
- Gastrointestinal bicarbonate loss: This is often due to prolonged vomiting, which leads to the loss of hydrogen ions and chloride, resulting in a metabolic alkalosis. The body compensates by increasing bicarbonate reabsorption in the kidneys.
Other Likely Diagnoses
- Volume contraction: Often seen in conjunction with gastrointestinal bicarbonate loss, volume contraction can exacerbate metabolic alkalosis by increasing the reabsorption of bicarbonate in the proximal tubule of the kidneys.
- Mineralocorticoid excess: Conditions like primary aldosteronism can lead to increased sodium reabsorption and potassium excretion, resulting in metabolic alkalosis due to the increased hydrogen ion excretion in the distal tubules.
- Diuretic use: Loop and thiazide diuretics can cause loss of potassium and hydrogen ions, leading to metabolic alkalosis.
Do Not Miss Diagnoses
- Milk-alkali syndrome: Although less common, this condition, caused by excessive ingestion of calcium and alkali (often in the form of antacids), can lead to severe metabolic alkalosis and is potentially life-threatening if not recognized and treated promptly.
- Severe hypokalemia: Potassium levels below 2.5 mEq/L can lead to respiratory muscle weakness and failure, making prompt recognition and treatment critical.
Rare Diagnoses
- Liddle's syndrome: A rare genetic disorder characterized by excessive sodium reabsorption and potassium excretion, leading to metabolic alkalosis.
- Bartter syndrome: A rare genetic disorder affecting the kidneys' ability to reabsorb sodium and chloride, leading to metabolic alkalosis, hypokalemia, and hypercalciuria.
- Gitelman syndrome: Similar to Bartter syndrome but typically presents later in life with hypokalemia, metabolic alkalosis, and hypomagnesemia.