[Lithiasis of the transplanted kidney: therapeutical potential].

OBJECTIVES: The formation of calculus in the transplanted kidney is an uncommon complication. Metabolic derangements, infectious or obstructive processes, factors related with the surgical technique and the presence of ureteral catheters have been implicated in its etiopathogenesis. The therapeutic possibilities have changed in the last decade. The different factors related with stone formation in the transplanted kidney, the indications and treatment utilized in each case are analyzed. METHODS: We analyzed the cases of lithiasis following renal transplantation in our series of 800 renal transplants. The metabolic anomalies and other associated lithogenic factors in 5 cases that required treatment are described. RESULTS: All 5 patients were treated by ESWL. Complete resolution of the lithiasis was achieved in 4 cases whose kidney graft is currently stone free with preserved renal function, except one patient with hyperuricemia and hyperuricosuria who is again on hemodialysis for chronic rejection. In the fifth case fragmentation of the caliceal stone was not achieved after 4 sessions of ESWL. Subsequem ultrasound control evaluations have disclosed no changes in stone size or location. CONCLUSIONS: In our view, the approach to renal lithiasis in the transplanted kidney is similar to that of patients with solitary kidney, although stone size for treatment by ESWL should be limited to 2 cms. If stone size is between 1 and 2 cms, placement of a double-J catheter prior to ESWL is recommended, whenever possible. For stones larger than 2 cms, percutaneous nephrolithotomy is more effective and has less complications. Surgery is reserved for those patients in whom these techniques are unamenable or have failed.