Pseudohypoaldosteronism with normal blood pressure

In adults, persistent hyperkalemic distal renal tubular acidosis in the absence of impaired renal function is an unusual abnormality usually associated with the syndromes of aldosterone deficiency or resistance. Herein, we present an adult with a clinical picture consisting of a normal blood pressure of 125/80 mmHg, normal blood volume, and glomerular filtration rate, with hyperkalemic distal renal tubular acidosis. The patent could spontaneously lower her urine pH to less than 5.5. Plasma renin activity was normal. Serum aldosterone level was appropriately elevated for the level of serum potassium. Following alkalinization of the urine, she was able to generate a urinary to blood PCO2 gradient [U-B PCO2] of 55 mmHg, and had a ten fold increased potassium secretion. After salt restriction and furosemide administration, her potassium secretion rate increased only twofold despite correction of he acidosis. The acidosis, as well as the hyperkalemia, was completely corrected after 9-alpha-Fluorohydrocortisone administration. Hydrochlorothiazide corrected the acidosis and hyperkalemia. Collectively, this picture suggests an underlying chloride shunt as the possible pathophysiological mechanism. Our case in unique in that it is not associated with hypertension.