PSEUDOHYPOALDOSTERONISM WITH NORMAL BLOOD-PRESSURE

In adults, persistent hyperkalemic distal renal tubular acidosis in th e 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 glomeru lar filtration rate, with hyperkalemic distal renal tubular acidosis. The patient could spontaneously lower her urine pH to less than 5.5. P lasma renin activity was normal. Serum aldosterone level was appropria tely elevated for the level of serum potassium. Following alkalinizati on of the urine, she was able to generate a urinary to blood PCO2 grad ient [U-B PCO2] of 55 mmHg, and had a ten fold increased potassium sec retion. After salt restriction and furosemide administration, her pota ssium secretion rate increased only twofold despite correction of her acidosis. The acidosis, as well as the hyperkalemia, was completely co rrected after 9-alpha-Fluorohydrocortisone administration. Hydrochloro thiazide corrected the acidosis and hyperkalemia. Collectively, this p icture suggests an underlying chloride shunt as the possible pathophys iological mechanism. Our case is unique in that it is not associated w ith hypertension.