Supplementary Material for: Xanthogranulomatous Pyelonephritis in Peritoneal Dialysis

Abstract
Introduction: Xanthogranulomatous pyelonephritis (XGP) is a rare illness that consists of a destructive chronic inflammatory process of the renal parenchyma associated with recurrent infection and obstructions of the urinary tract. Peritoneal dialysis (PD) is a form of renal replacement therapy (RRT) used in advanced kidney disease. PD patients demonstrate a systemic inflammatory state, secondary to the increase in uraemic toxins, decreased filtration of proinflammatory cytokines, as well as constant exposure to bioincompatible dialysis solutions or a foreign body reaction from the catheter, among other factors, as peritoneal infections (infection of the catheter exit site, subcutaneous pathway, or effluent).
Case presentation: We present the clinical case of a 74-year-old woman, with a history of recurrent urinary tract infections associated with nephrolithiasis and stage 5D chronic kidney disease, on a PD program. The patient presented a non-specific 3-month state of progressive asthenia, with increased inflammatory parameters in the analytical controls. After presenting multiple negative urine cultures and peritoneal fluid cultures, she was hospitalized to study the constitutional syndrome. The imaging test revealed bilateral staghorn lithiasis with severe dilatation of the right renal pelvis and great cortical thinning. Given the suspicion of XGP, it was decided to perform right renal nephrectomy, which was confirmed after the anatomopathological study. Prior to the intervention, she was transferred to hemodialysis. Over the following months significant clinical and analytical improvement was observed.
Conclusion: The systemic inflammatory state and the risk of infections in PD, can mask the diagnose of XGP in PD patients. There are no reported cases of XGP in patients in PD.

摘要
引言：黄色肉芽肿性肾盂肾炎（Xanthogranulomatous pyelonephritis, XGP）是一种罕见疾病，以肾实质破坏性慢性炎症过程为特征，常与复发性尿路感染及尿路梗阻相关。腹膜透析（Peritoneal dialysis, PD）是终末期肾病患者采用的一种肾脏替代治疗（renal replacement therapy, RRT）方式。腹膜透析患者会出现全身性炎症状态，其诱因包括尿毒症毒素蓄积、促炎细胞因子清除减少、长期接触生物不相容性透析液，或导管引发的异物反应等，此外还包括腹膜感染（如导管出口部位感染、皮下隧道感染或透析液引流液感染）。

病例报告：本文报告1例74岁女性患者，既往有复发性尿路感染伴肾结石病病史，患有5D期慢性肾脏病，接受腹膜透析治疗。患者出现为期3个月的非特异性进行性乏力症状，实验室检测显示炎症指标升高。多次尿培养及腹膜液培养结果均为阴性，随后患者入院以排查全身性综合征。影像学检查提示双侧鹿角形肾结石，伴右侧肾盂重度扩张及肾皮质显著变薄。鉴于疑似黄色肉芽肿性肾盂肾炎，遂行右侧肾切除术，术后病理组织学检查证实了诊断。术前患者转为血液透析治疗。后续数月随访可见患者临床症状及实验室指标显著改善。

结论：腹膜透析患者的全身性炎症状态及感染风险可能会掩盖黄色肉芽肿性肾盂肾炎的诊断。目前尚无腹膜透析患者并发黄色肉芽肿性肾盂肾炎的相关病例报道。