Gouty diathesis and sarcoidosis in patient with recurrent calcium nephrolithiasis

We describe a patient who initially formed calcium-containing renal stones owing to gouty diathesis and hypocitraturia. On therapy with 300 mg. allopurinol and 60 mEq. potassium citrate daily serum uric acid decreased from 9.2 to 5.8 mg. per dl., urinary pH increased from less than 5.5 to 6.6 and urinary citrate increased from 223 to 1,005 mg. per day. Four months later while still on this medical regimen, the patient presented with hypercalcemia (13.4 mg. per dl.), high serum 1,25-dihydroxyvitamin D (65 pg. per ml.) and hypercalciuria (598 mg. per day), which subsequently were found to result from sarcoidosis. Prednisone therapy normalized the disturbances in calcium metabolism. During 33 months of combined treatment with 7.5 to 10 mg. prednisone a day, allopurinol and potassium citrate, the patient was free of stones and he had normal urinary calcium, pH and citrate. However, a calcium stone formed 1 month after discontinuation of prednisone therapy, although treatment with allopurinol and potassium citrate was continued. The patient had marked hypercalciuria of 447 to 465 mg. per day, despite normal urinary pH, citrate and uric acid. This case represents calcium stone formation in a patient with 2 separate etiologies for stone disease, that is gouty diathesis and sarcoidosis. Therapeutic regimens directed at the correction of both metabolic disturbances were required to control renal stone formation.