A man with bilateral loin pain

A 65 year old man presented with a 12 month history of bilateral flank pain but no fever or lower urinary tract symptoms. Over the preceding 10 years he had had multiple interventions, including extracorporeal shock wave lithotripsy and ureteroscopic laser stone fragmentation, for cystine renal stones. He had type 2 diabetes and hypertension, and he was also obese.

A plain radiograph showed a large renal pelvic calculus measuring 3.4 cm in the right kidney and a 4.4 cm partial staghorn calculus projected over the left kidney. A dimercaptosuccinic acid scan showed a relative function of 47.5% for the right kidney and 52.5% for the left kidney.

A staged percutaneous nephrolithotomy was performed successfully on the simpler right stone, but postoperatively he developed pain in the right loin. A nephrostogram showed debris partially occluding the right ureter, which resulted in a filling defect; this was thought to be a clot and it later passed. Stone analysis confirmed cystine stones. Three months later a percutaneous nephrolithotomy was undertaken on the left side. Postoperative recovery was uneventful and radiography showed no residual stones.