[Medullary sponge kidney. Diagnosis and course in 12 cases]

12 adult patients with medullary sponge kidney (MSK), followed up for 1 to 14 years (mean 7 years) are presented. MSK was initially diagnosed in 4 cases. In 8 cases the initial diagnosis included pyelonephritis, nephrocalcinosis, and nephrolithiasis. Renal calculi (4 patients), urinary tract infection (8) and hematuria (5) were the most frequent symptoms. Renal tubular acidosis was documented in 2 patients and hypercalciuria without hyperparathyroidism in 2. Over the years renal calculi increased in size in 4 patients. Renal function was stable in 11. In one patient with associated, well controlled hypertension, serum creatinin rose from 141 to 298 mumol/l over 14 years.