[Incidence and treatment of urinary lithiasis in renal transplantation]

Urinary calculi is an uncommon complication in kidney transplantation; several stone risk factors are found in transplanted patients, but in most cases there is not a relationship between these risk factors and stone formation. The treatment of these patients is complex due to their both immunosuppressive status and border-line renal function.

From 1980 to February 2000, 1198 kidney transplant have been performed in our institution. We describe our series consisting in 22 urinary calculi (15 in the graft, 3 in the urether and 4 in the bladder) in 18 patients, including 7 stones detected in cadaveric donor patients.

We performed external shock wave lithotripsy in 7 patients, bench surgery in 4, endoscopic mechanic lithotripsy in 5, open surgery in 1 and observation in 6. Calcium oxalate (mono and dihidrate) was found in 9 of 13 calculi. Metabolic changes were found in 15 of the 18 patients, the most common was hiperuricemia. There were not complications of every treatment applied and 9% of them needed a savage treatment. We found recurrence in 4 cases (22.2%). Now 12 of the patients are stone-free (66.7%) and three have non-significative stones (83.3% without symptoms).

Detection of renal calculi in cadaveric renal donors is not a reason to refuse the graft for further transplantation. In both renal calculi up to 2 cm and uretheric calculi surgical treatment is assessed as first option. In caliceal stones smaller than 5 mm observations is the best treatment.