Pseudohypoaldosteronism: case report and discussion of the syndrome.

A 41-year-old man, complaining of leg cramps, was found to have persistent hyperkalemia. Except for mild hypertension, his physical examination and laboratory values to exclude connective tissue diseases and diabetes mellitus were normal. Renal function testing revealed a normal glomerular filtration rate and tubular capacity to acidify and dilute, as well as near-normal ability to concentrate his urine. Hormonal evaluation revealed a normal cortisol, as well as normal resting and stimulated renin and aldosterone levels. A selective defect in tubular potassium secretion was demonstrated. In the absence of aldosterone deficiency or renal dysfunction, it was assumed that the patient had primary renal resistance to aldosterone, known as pseudohypoaldosteronism. Treatment with hydrochlorothiazide controlled his hyperkalemia and hypertension. His case emphasizes the diagnostic and therapeutic factors that should be considered in evaluating and treating a non-hospitalized patient with sustained hyperkalemia.