Differential diagnosis of metabolic alkalosis

Differential diagnosis of metabolic alkalosis

Normal blood pressure or hypotension
Low spot urine [Cl] (<20 mEq/L) Generally chloride (saline) responsive	High spot urine [Cl] (>20 mEq/L) Generally chloride (saline) unresponsive
Vomiting/nasogastric tube suction	Bartter syndrome
Congenital chloride wasting diarrhea (chloridorrhea)	Gitelman syndrome
Villous adenoma*
Chronic laxative abuse*
Cystic fibrosis
Status post reversal of chronic hypercapnia
Loop or thiazide diuretics – remote treatment (effect has dissipated)	Loop or thiazide diuretics – recent treatment (effect persists)
Hypertension (all have high spot urine [Cl] [>20 mEq/L])
	Renin	Aldosterone
Primary hyperaldosteronism	Low	High
Renovascular and malignant hypertension¶	High	High
Exogenous mineralocorticoids	Low	Low
Apparent mineralocorticoid excess	Low	Low
Use of substances made with licorice root	Low	Low
Liddle's syndromeΔ	Low	Low
Cushing syndrome (usually ectopic ACTH)	Low	Low
	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