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 used in advanced kidney disease. PD patients demonstrate a systemic inflammatory state, secondary to the increase in uremic 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. 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 diagnosis of XGP in PD patients. There are no reported cases of XGP in patients in PD.

Xanthogranulomatous pyelonephritis (XGP) is a granulomatous inflammation characterized by the destruction and replacement of the renal parenchyma by masses of lipid-laden macrophages, associated with infections and recurrent obstructive processes of the urinary tract [1]. Peritoneal dialysis (PD) is a widely used home renal replacement therapy (RRT) that makes it possible to replace the excretory function in kidney failure cases.

Different factors such as the greater presence of uremic toxins and proinflammatory cytokines that present less renal filtration, the exposure to bioincompatible dialysis solutions, and a foreign body reaction from the catheter cause an inflammatory state in PD patients [23]. Peritoneal infections are frequent in PD patients (infection of the catheter exit site, subcutaneous pathway, or effluent). The chronic elevation of inflammatory parameters, in the exposed context, sometimes makes the diagnosis of this infrequent clinical manifestation difficult.

We present the clinical case of a 74-year-old woman with recurrent infections and bilateral lithiasis with a staghorn appearance in the right kidney which required pyelolithotomy in January 2016. She was diagnosed with advanced chronic kidney disease secondary to chronic interstitial nephritis, which required urgent hemodialysis after deterioration of renal function in relation to indicated urological intervention. She was later transferred to PD in February 2016, continuous ambulatory PD with three exchanges of 2,000 cc: two with glucose 1.36% and one nocturnal with icodextrin. She presented good residual diuresis, around 1,000–1,500 cc. She was receiving treatment with subcutaneous erythropoietin 3,000 IU every 15 days, barnidipine, atorvastatin, furosemide, omeprazole, and sertraline.

In April 2020, the patient presented a non-specific symptomatology, with asthenia, impairment of the general condition, anorexia including a weight loss of 7 kg over the previous 6 months, as well as cloudy urine without dysuria or pollakiuria. Repeatedly negative urine cultures and peritoneal fluid cultures were performed. She received empirical antibiotic therapy with ciprofloxacin and later with amoxicillin/clavulanate. However, at the beginning she suffered from diffused abdominal pain, but with clear peritoneal fluid during exchanges. Hospitalization for study in nephrology was decided to rule out a possible underlying neoplastic disease.

Analytically, she presented progressive worsening of inflammatory parameters in the previous 4 months (Table 1). On admission, she presented hyperchromic macrocytic anemia despite increasing the dose of erythropoietin (with 5,000 IU/70 kg/week), leukocytosis with neutrophilia and thrombocytosis. In addition, she has elevated ferritin and C-reactive protein levels. In the urinary sediment, she presented proteinuria, leukocyturia, and hematuria. The autoimmunity study with anti-nuclear and anti-neutrophil cytoplasmic antibodies, tumor markers (Ca 125, Ca 15.3, Ca 19.9, CEA, alpha-fetoprotein), and viral serology (HIV, HBV, HCV) was normal. Urine and peritoneal fluid cultures were repeated and were negative.

Table 1.

Analytical parameters, 4 months before hospitalization, at hospitalization and 1 month after

4 months before admissionHospitalization1 month post-interventionReference values
Blood count 
 Hemoglobin, g/dL 10.1 7.3 10.2 12–16 
 Leukocytes, ×103/μL 13.20 16.15 9.24 4–11 
 Neutrophils, ×103/μL 9.56 12.04 5.620 1.7–7.5 
 Lymphocytes, ×103/μL 2.35 2.68 2.56 1–4 
 Platelets, ×103/μL 555 775 370 140–450 
 ESR, mm/h 141 0–20 
Blood count 
 Urea, mg/dL 88 90 84 10–50 
 Creatinine, mg/dL 4.9 4.71 5.28 0.7–1.2 
 GFR, CKD-EPI, mL/min 60–999 
 Serum total protein, g/dL 5.7 7.1 6–8 
 Albumin, g/dL 2.1 3.6 3.5–5 
 CRP, mg/L 50 196.2 26.1 0–5 
 β2-microglobulin, mg/L 28.29 0.8–2.2 
Iron profile 
 Iron 45 26 63 50–170 
 Ferritin, ng/mL 981 4,074 731 10–190 
 Transferrin, mg/dL 173 116 171 250–380 
 Transferrin saturation, % 16.8 17.6 16.6 15–45 
Proteinogram, % 
 Albumin  30.2 50.2 58–66 
 Alpha-1-globulins  11.0 5.2 3–5 
 Alpha-2-globulins  19.3 10 7–12 
 Beta-globulins  14.7 18.1 8.4–13 
 Gamma-globulins  24.8 16.5 11–18 
Autoimmunitya  Negative   
Complement  Normal   
Viral serologyb  Negative   
Tumor markersc  Negative   
4 months before admissionHospitalization1 month post-interventionReference values
Blood count 
 Hemoglobin, g/dL 10.1 7.3 10.2 12–16 
 Leukocytes, ×103/μL 13.20 16.15 9.24 4–11 
 Neutrophils, ×103/μL 9.56 12.04 5.620 1.7–7.5 
 Lymphocytes, ×103/μL 2.35 2.68 2.56 1–4 
 Platelets, ×103/μL 555 775 370 140–450 
 ESR, mm/h 141 0–20 
Blood count 
 Urea, mg/dL 88 90 84 10–50 
 Creatinine, mg/dL 4.9 4.71 5.28 0.7–1.2 
 GFR, CKD-EPI, mL/min 60–999 
 Serum total protein, g/dL 5.7 7.1 6–8 
 Albumin, g/dL 2.1 3.6 3.5–5 
 CRP, mg/L 50 196.2 26.1 0–5 
 β2-microglobulin, mg/L 28.29 0.8–2.2 
Iron profile 
 Iron 45 26 63 50–170 
 Ferritin, ng/mL 981 4,074 731 10–190 
 Transferrin, mg/dL 173 116 171 250–380 
 Transferrin saturation, % 16.8 17.6 16.6 15–45 
Proteinogram, % 
 Albumin  30.2 50.2 58–66 
 Alpha-1-globulins  11.0 5.2 3–5 
 Alpha-2-globulins  19.3 10 7–12 
 Beta-globulins  14.7 18.1 8.4–13 
 Gamma-globulins  24.8 16.5 11–18 
Autoimmunitya  Negative   
Complement  Normal   
Viral serologyb  Negative   
Tumor markersc  Negative   

ESR, erythrocyte sedimentation rate; GFR, glomerular filtration rate; CRP, C-reactive protein; ANA, anti-nuclear antibody; ANCA, anti-neutrophil cytoplasmic antibody. aANA, ANCA. bHBV, HCV, HIV. cCa 125, Ca 15.3, Ca 19.9, CEA, alpha-fetoprotein.

A CT scan of the abdomen and pelvis was performed (Fig. 1) where bilateral staghorn lithiasis was observed, with marked cortical thinning and hydronephrosis, more severe in the left kidney, showing an image resembling a bear paw sign. Urology was contacted and decided to place a percutaneous nephrostomy, on which purulent drainage was carried out (Fig. 2), and posterior nephrectomy was scheduled. Empirical antibiotic therapy was started with piperacillin/tazobactam 2 g every 8 h, with slight clinical improvement and a slight decrease in acute phase reactants. Multisensitive Proteus mirabilis was isolated in the percutaneous drainage cultures. They were negative for mycobacteria and fungi.

Fig. 1.

CT of the abdomen and pelvis: staghorn lithiasis in the right renal pelvis with calyceal dilation, with bear’s paw sign.

Fig. 1.

CT of the abdomen and pelvis: staghorn lithiasis in the right renal pelvis with calyceal dilation, with bear’s paw sign.

Close modal
Fig. 2.

Purulent drainage obtained by percutaneous nephrostomy.

Fig. 2.

Purulent drainage obtained by percutaneous nephrostomy.

Close modal

Before the intervention, due to the laparotomy approach required, a transfer to hemodialysis was necessary. Therefore, the peritoneal catheter was removed by general surgery, and a temporary right femoral catheter was implanted to start hemodialysis, with good tolerance.

Initially, a bilateral nephrectomy was scheduled, given the suspicion of bilateral XGP; however, only left nephrectomy was performed after a difficult surgery presented itself, with a laceration of the spleen. She required hemodynamic stabilization via anesthesiology and transfusion of two packed red blood cells. After surgery, the patient was admitted to the intensive care unit recovering well during the 3 days that followed. Faced with clinical improvement, she was referred to urology, monitoring and scheduling intermittent hemodialysis sessions by nephrology.

The surgical piece showed a dilation of the pyelocalyceal system replaced, practically the entire parenchyma, with greenish-gray content and multiple orange calculi (Fig. 3). Large areas of necrosis with gigantocellular granulomatous reaction were observed.

Fig. 3.

Left kidney after nephrectomy, observing (a) cortical thinning, without appreciating renal parenchyma, and (b) dilation of calyceal systems with (c) greenish-yellowish content.

Fig. 3.

Left kidney after nephrectomy, observing (a) cortical thinning, without appreciating renal parenchyma, and (b) dilation of calyceal systems with (c) greenish-yellowish content.

Close modal

The patient continued with a good clinical and analytical evolution, with improvement of inflammatory parameters and anemia. Hospital discharge accompanied by scheduled right nephrectomy was decided. The CARE Checklist has been completed by the authors for this case report, attached as online supplementary material (for all online suppl. material, see https://doi.org/10.1159/000536489).

XGP is a granulomatous inflammation characterized by the destruction and replacement of the renal parenchyma by masses of lipid-laden macrophages, associated with infections and recurrent obstructive processes of the urinary tract [1]. The most frequently associated pathogens are P. mirabilis and Escherichia coli, although up to 10–40% of cases do not present microbiological isolation [1]. It is characterized by the presence in histology of inflammatory granulomas, with macrophages containing lipids, which gives a macroscopic yellowish appearance. It is frequently associated with renal lithiasis and metabolic syndrome, particularly with diabetes and obesity, and has a higher prevalence in women around 50 years of age [2], as in our case.

PD is an RRT that makes it possible to replace the excretion function in the case of renal failure. According to the Spanish Registry of Renal Patients, the PD technique was used in 26,683 patients, which represents 5% of the patients on RRT. PD is the most widely used home therapy in our country.

In PD patients, there are factors that favor an inflammatory state, such as decreased renal filtration of uremic toxins and proinflammatory cytokines, exposure to bioincompatible dialysis solutions, and foreign body reaction from the catheter [3]. The chronic elevation of inflammatory parameters in this context makes the diagnosis of this rare clinical case difficult. The symptoms described in clinical series, as in Kim SW et al. [4] and Addison B et al. [5], like anemia, impaired renal function, or clinical signs, such as the presence of a palpable mass, are not assessable in these patients.

In conclusion, XGP is a rare clinical case [6‒8], whose diagnosis requires the gathering of clinical, analytical, and imaging results, in addition to the anatomopathological study, which also needs a differential diagnosis with paraneoplastic syndrome. The presence of possible PD-associated infections in PD patients, such as peritonitis, peritoneal fluid infections, in addition to altered analytical parameters, such as the presence of anemia, impaired renal function, and elevated inflammatory parameters, can mask and complicate the diagnosis.

Ethical approval is not required for this study in accordance with local or national guidelines. Written informed consent was obtained from the patient for publication of the details of their medical case and any accompanying images.

The authors have no conflicts of interest to declare.

This study was not supported by any sponsor or funder.

J.B.M.: edition and development of the case report. M.A.T.: analysis and interpretation of the data. F.A.G.: draft of the article or the critical review of the intellectual content. F.J.P.A.: conception and design of the study. M.S.L.: correction and final approval of the version presented. Contributors to the paper fulfill the ICMJE Criteria.

All data generated or analyzed during this study are included in this article and its online supplementary material files. Further inquiries can be directed to the corresponding author.

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