From the Guidelines
Metabolic alkalosis is primarily caused by excessive loss of hydrogen ions or gain of bicarbonate in the body, with the main causes including diuretic use, vomiting or nasogastric suction, excessive alkali administration, severe potassium depletion, and certain endocrine disorders. The causes of metabolic alkalosis can be categorized into several key areas, including:
- Diuretic use, particularly loop and thiazide diuretics like furosemide and hydrochlorothiazide, which increase renal bicarbonate reabsorption 1
- Vomiting or nasogastric suction, which removes acidic gastric contents
- Excessive alkali administration, such as sodium bicarbonate or antacids containing calcium carbonate
- Severe potassium depletion, which promotes hydrogen ion movement into cells
- Certain endocrine disorders like hyperaldosteronism or Cushing's syndrome
- Contraction alkalosis, which can occur with volume depletion, as the kidneys retain sodium and bicarbonate
- Milk-alkali syndrome from excessive calcium and absorbable alkali intake
- Bartter and Gitelman syndromes, genetic disorders affecting renal tubular function, can lead to chronic metabolic alkalosis 1 It's worth noting that the body typically compensates for metabolic alkalosis through decreased respiratory rate to retain carbon dioxide, but severe cases may require addressing the underlying cause, administering chloride-containing solutions like normal saline, correcting potassium deficiencies, or using carbonic anhydrase inhibitors like acetazolamide in specific situations. Some rare tubulopathies exhibiting metabolic alkalosis are listed in Table 4 of the study by 1, and urinary chloride excretion assessed by either fractional chloride excretion or urinary sodium/chloride ratio is helpful to distinguish renal from extrarenal salt losses. In patients with suspected Bartter syndrome, genetic analysis has surpassed diuretic tests, and routine tubular function testing is not recommended 1.
From the FDA Drug Label
Supplemental potassium chloride and, if required, an aldosterone antagonist are helpful in preventing hypokalemia and metabolic alkalosis The causes of metabolic alkalosis include:
- Hypokalemia
- Aldosterone excess 2
From the Research
Causes of Metabolic Alkalosis
Metabolic alkalosis is a condition characterized by an increase in plasma bicarbonate levels and blood arterial pH. The causes of metabolic alkalosis can be divided into several categories:
- Generation of alkalosis: This can occur due to excessive hydrogen ion loss through the gastrointestinal tract (e.g., vomiting) or the kidney (e.g., use of loop diuretics), or due to exogenous base gain 3, 4, 5.
- Maintenance of alkalosis: This reflects the inability of the kidney to excrete excess bicarbonate due to factors such as hypovolemia, chloride depletion, hypokalemia, hyperaldosteronism, renal failure, or a combination of these factors 3, 4, 5.
- Clinical states associated with metabolic alkalosis: These include vomiting, aldosterone or cortisol excess, licorice ingestion, chloruretic diuretics, excess calcium alkali ingestion, and genetic diseases such as Bartter syndrome, Gitelman syndrome, and cystic fibrosis 4, 6, 5.
- Categories of metabolic alkalosis: These can be divided into chloride depletion alkalosis, mineralocorticoid excess syndromes, apparent mineralocorticoid excess syndromes, and excess alkali administration 6, 7.
Key Factors Contributing to Metabolic Alkalosis
Some key factors that contribute to the development and maintenance of metabolic alkalosis include: