Differential diagnosis of metabolic alkalosis
Differential diagnosis of metabolic alkalosis
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Normal blood pressure or hypotension |
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Low spot urine [Cl] (<20 mEq/L) Generally chloride (saline) responsive |
High spot urine [Cl] (>20 mEq/L) Generally chloride (saline) unresponsive |
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Vomiting/nasogastric tube suction |
Bartter syndrome |
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Congenital chloride wasting diarrhea (chloridorrhea) |
Gitelman syndrome |
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Villous adenoma* |
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Chronic laxative abuse* |
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Cystic fibrosis |
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Status post reversal of chronic hypercapnia |
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Loop or thiazide diuretics – remote treatment (effect has dissipated) |
Loop or thiazide diuretics – recent treatment (effect persists) |
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Hypertension (all have high spot urine [Cl] [>20 mEq/L]) |
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Renin |
Aldosterone |
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Primary hyperaldosteronism |
Low |
High |
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Renovascular and malignant hypertension¶ |
High |
High |
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Exogenous mineralocorticoids |
Low |
Low |
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Apparent mineralocorticoid excess |
Low |
Low |
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Use of substances made with licorice root |
Low |
Low |
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Liddle's syndromeΔ |
Low |
Low |
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Cushing syndrome (usually ectopic ACTH) |
Low |
Low |
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Low or normal |
Low |
Cl: chloride; ACTH: adrenocorticotropic hormone.
* May present with metabolic acidosis, metabolic alkalosis, or both.
¶ Some forms of renovascular hypertension (bilateral renal arterial stenosis) may generate volume expansion with reduced renin and aldosterone levels.
Δ The findings in Liddle's syndrome are probably generally similar to those that occur with the syndrome of apparent mineralocorticoid excess, but published data are limited. Liddle's syndrome responds to amiloride but not spironolactone, whereas the syndrome of apparent mineralocorticoid excess responds to both drugs.
Harrison's 20th edition
REF. UpToDate 2020.06.17
Harrison's 20th edtion