EFFECT OF HYDROCHLOROTHIAZIDE IN PSEUDOHYPOALDOSTERONISM WITH HYPERCALCIURIA AND SEVERE HYPERKALEMIA

Severe hyperkalemia resistant to treatment with sodium chloride (NaCl) supplements plus cation exchange resins can be found in pseudohypoald osteronism type I. In a patient with the multiple target organ variant of this condition, hyperkalemia persisted at dangerous levels (8.5 mm ol/l) despite large doses of NaCl (50 mmol/kg per day) and cation exch ange resins (6 g/kg per day). Hypercalciuria was also present. The tot al volume of fluids and supplements required was not tolerated orally. Indomethacin (2 mg/kg per day) and later hydrochlorothiazide (2 mg/kg per day) were tried to further correct imbalance. Plasma potassium (K ) and Na levels, the urinary Na/K ratio, transtubular potassium gradie nt (TTKG), and urinary calcium/creatinine (Ca/Cr) ratio were used to e valuate the effect of hydrochlorothiazide. Under treatment, plasma Na was stable (137-144 mmol/l), K levels decreased from 8.5 to 5 mmol/l, urinary Na/K from 90 to 24, and TTKG increased from 0.3 to 1.8. Ca/Cr decreased from 3.5 to 1.5 mmol/mmol. The dosage of cation exchange res ins was decreased, oral fluids were tolerated, and the patient's gener al condition improved. Hence: hydroclorothiazide can be useful in the treatment of severe hyperkalemia and hypercalciuria of pseudohypoaldos teronism type I.