Occult causes of hypokalemia.

Most causes of hypokalemia are obvious from the clinical picture and the values for plasma electrolytes. In cases with obscure etiology, a pretreatment estimation of urinary potassium and chloride often helps lead the clinician into new and fruitful avenues of clinical investigation. Here we present four cases of hypokalemia in which the pathogenesis was initially enigmatic but was clarified somewhat by the determination of the urinary electrolytes. These simple, inexpensive investigations were initiated by the clinical chemistry laboratory in each case. The results encouraged the physicians to consider further clinical investigations, which led to a definitive diagnosis, before invoking expensive hormonal analyses.