In Reply to "The Presence of Kidney Cyst Infections in ADPKD Patients After Kidney Transplantation: Need for Urological Analysis?"

The Author Replies:

We agree with Geertsema et al. when they point out that prophylactic unilateral nephrectomy in case of a history of cyst infection before kidney transplantation may be an overtreatment. As they stated, prophylactic nephrectomy did not prevent cyst infection recurrence in the post-transplantation period in our retrospective cohort. Among the 43 patients with a history of cyst infection, 11 had prophylactic unilateral nephrectomy (6 for recurrent cyst infection and 5 for insufficient place for renal allograft) and 32 patients did not receive pre-emptive transplantation nephrectomy. One (1 of 11, 9.1%) patient in the prophylactic unilateral nephrectomy group and 4 (4 of 32, 12.5%) in the group without prophylactic nephrectomy developed a cyst infection after kidney transplantation. Whether a significant difference could be reached in a larger study needs to be investigated but seems unlikely. Moreover, although we found out that a history of cyst infection is a risk factor for cyst infection occurrence in the post-transplantation period, only 7 of 43 (16.3%) patients’ cyst infection recurred after the transplantation within a median follow-up of 4 (2–7) years. When we focused on renal cyst infection determined by imaging, that proportion was even lower with 5 of 43 patients (11.6%). Putting it in another way, performing systematic prophylactic unilateral nephrectomy in patients with a history of cyst infection before renal transplantation would not be beneficial for most of them. Furthermore, the risk related to the remaining polycystic kidney lingers as illustrated in a patient who underwent a prophylactic nephrectomy but developed a cyst infection of the contralateral native kidney in the post-transplantation period. Finally, cyst infection, also in a transplanted patient, is rarely life-threatening or even severe (1 of 12, 8% in the cyst infection determined by imaging) because their management in recent years has been improved with the use of lipophilic antibiotics for a long duration. Therefore, balancing the surgical risk of prophylactic nephrectomy and the drawbacks mentioned above, do not plead for its implementation in all patients with a history of cyst infection but rather to confine it in the rare cases of frequently relapsing or persistent infection.

We also agree with the suggestion made by Geertsema et al that complete urological evaluation should be performed after a renal cyst infection (in patients with preserved urine output) to investigate the presence, for example, of vesicoureteral reflux or postvoid residual volume that may be accessible to surgical procedure and thus, alleviate the risk of cyst infection recurrence. Because no patient in our study underwent such examination, we were not able to evaluate its practical use for that purpose. Further studies is required to address this specific point.