What are the diagnostic hallmarks of metabolic alkalosis resulting from depletion of HCl?
Because of the deficit of Cl − , the urine should be virtually free of Cl − . Despite a contracted ECF volume, Na + may be excreted if the urine contains bicarbonate, or anions other than Cl − .
This is particularly the case in the generation phase when bicarbonaturia occurs, urine pH is higher than 6.0, and urinary Na + and K + losses are occurring.
The secret here is that the fractional excretion of sodium may be high in the context of volume depletion secondary to loss of gastric acid. In addition, the urine may contain K + even though the patient has chronic hypokalemia.