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.