UROLOGY ANZJSurg.com
Analysis of 35 cases of Xanthogranulomatous pyelonephritis Ben Addison,* Homayoun Zargar,† Nikola Lilic,‡ David Merrilees† and Michael Rice† *Department of General Surgery, North Shore Hospital, Auckland, New Zealand †Department of Urology, Auckland City Hospital, Auckland, New Zealand and ‡Department of Otolaryngology Head and Neck Surgery, Middlemore Hospital, Auckland, New Zealand
Key words chronic inflammation, Maori, stone, Xanthogranulomatous pyelonephritis. Correspondence Dr Ben Addison, 1e/10 Beaumont Street, Freemans Bay, Auckland 1010, New Zealand. Email: [email protected] B. Addison MBBS; H. Zargar FRACS; N. Lilic MBChB; D. Merrilees FRACS; M. Rice FRACS. Accepted for publication 21 January 2014. doi: 10.1111/ans.12581
Abstract Background: To retrospectively determine key demographic and clinical features of 35 patients with Xanthogranulomatous pyelonephritis (XGP) in a New Zealand setting and to compare it with the existing literature. Methods: A retrospective review of patients having a confirmed diagnosis of XGP on histopathology examination was performed. Key clinical and demographic features were analysed and compared with the published literature. Results: XGP was diagnosed in 35 patients over a 12-year (2001–2013) period in Auckland Public Hospital. Ninety-one percent of the patients were female. The population had significantly higher numbers of Maori and Pacific Island patients compared with the general population (74%). Staghorn calculi were the most common cause (51.4%) with obstructing ureteric calculi as the next most common (22.9%) cause. Twenty percent of cases were not thought to be XGP prior to nephrectomy (suspicious renal mass). Thirteen (38%) patients suffered serious complications post-operatively (Clavien 3–5). Conclusion: XGP is a rare chronic inflammatory condition that appears to be overrepresented by Maori and Pacific islanders in our cohort when compared with the overall patient pool. Surgical treatment is associated with significant morbidity but remains the only definitive option. Obesity and other conditions associated with metabolic syndrome may coexist at the time of presentation and may be contributing factors to the development of XGP and poor outcomes associated with it.
Introduction Xanthogranulomatous pyelonephritis (XGP) is an uncommon distinctive chronic inflammatory disease that is associated with chronic infection and obstruction. It is named because of its pathological appearance; that of a granulomatous inflammatory process with lipid filled macrophages, which appear yellow, hence ‘xantho’ which is Greek for yellow. Previous reports have shown that XGP is associated with a high prevalence of renal calculi (Fig. 1) and metabolic syndrome, particularly obesity and diabetes, which is more common in females and patients aged over 50.1–3 There is a paucity of data regarding demographics and clinical features of XGP in a New Zealand setting. In addition, there have been no ethnic demographic data reported in relation to this condition. XGP may be a life-threatening condition and generally the best management is radical surgery,1,4–7 as conservative measures with antibiotics fail to treat the underlying pathological process. In its ANZ J Surg 85 (2015) 150–153
most severe form, XGP can involve the surrounding structures, such as liver, duodenum and colon as well as great vessels.8,9 Given this and resulting nephron loss (Fig. 2) and its chronic complications, any predictive factors such as patient demographics or clinical findings that can aid in the early identification and treatment of patients at risk would be valuable. The aim of our study was to retrospectively determine key demographic and clinical features of XGP in a New Zealand setting.
Methods Diagnosis was confirmed by histopathology examination and the list of patients for the review was obtained from Auckland City Hospital’s central pathology database. Records of all patients diagnosed with XGP between 2001 and 2013 in the Auckland region were reviewed. All patients underwent nephrectomy, apart from one patient who was treated conservatively with antibiotics. © 2014 Royal Australasian College of Surgeons
Analysis of 35 cases of XGP
151
Data from electronic hospital database including demographics, co-morbidities, operative data, complications and 30 days mortality were obtained. Post-operative complications were graded according to the Clavien-Dindo classification of surgical complications.10,11 Analysis of differences of our sample population to the general population (greater Auckland population demographics at most recent census12) was performed with a binomial exact test using R version 3.0.1 (two-tailed) (R Foundation for Statistical Computing, Vienna, Austria).
Table 1 Patient’s demographics Mean age at diagnosis year (range) Gender, No. (%) Ethnicity, No. (%)
Cause of Xanthogranulomatous pyelonephritis, No. (%)
Smoking, No. (%)
Co-morbidities, No. (%)
46.6 (12–81) Female Male New Zealand Maori Pacific Islanders New Zealand European Indian Staghorn calculus Ureteric calculus Congenital pelviureteric junction Other Current Ex-smoker Non-smoker Ischaemic heart disease Diabetes mellitus Hypertension
32 (91) 3 (9) 11 (31.4) 15 (42.8) 8 (22.9) 1 (2.9) 18 (51.4) 8 (22.9) 4 (11.4) 5 (14.3) 15 (42.9) 5 (14.3) 15 (42.9) 3 (8.6) 11 (31.4) 12 (34.3)
Results A total of 35 patients with histologically confirmed XGP were identified. One patient was identified after a renal biopsy and was treated conservatively with antibiotics. This was due to the fact that patient resided outside of New Zealand and post-operative care and follow-up would not have been possible upon returning home. Mean age of patients was 46.6 years (12–81); 91% of patients were female (n = 32). Pacific Islanders (42.8%) and Maori (31.4%) were the largest ethnic groups in the cohort. Mean body mass index of the population was 29.5 kg/m2. Staghorn calculi were the most common cause of XGP (51.4%) and overall, 74.3% of patients had stone disease (Table 1). Of the patients without clear obstruction (stone disease or congenital pelviureteric junction), one had polycystic kidney disease and four had chronic pyelonephritis without any evidence of stone or obstruction. Twenty percent of cases were not identified to be XGP prior to nephrectomy and were treated as a suspicious renal mass. Escherichia coli was the most common isolated organism (45.7%) followed by Proteus mirabilis (20.0%). Median operative time was 186 min (65–570) and 54.5% (n = 18) required blood transfusion. Median estimated blood loss was Table 3 Comparison of cohort demographics to normal population using binomial exact test Comparison Sex Ethnicity Smoking Obesity
P value Female predominance Maori and Pacific Island predominance Current smoker Maori Pacific Islander
Analysis of 35 cases of Xanthogranulomatous pyelonephritis Ben Addison,* Homayoun Zargar,† Nikola Lilic,‡ David Merrilees† and Michael Rice† *Department of General Surgery, North Shore Hospital, Auckland, New Zealand †Department of Urology, Auckland City Hospital, Auckland, New Zealand and ‡Department of Otolaryngology Head and Neck Surgery, Middlemore Hospital, Auckland, New Zealand
Key words chronic inflammation, Maori, stone, Xanthogranulomatous pyelonephritis. Correspondence Dr Ben Addison, 1e/10 Beaumont Street, Freemans Bay, Auckland 1010, New Zealand. Email: [email protected] B. Addison MBBS; H. Zargar FRACS; N. Lilic MBChB; D. Merrilees FRACS; M. Rice FRACS. Accepted for publication 21 January 2014. doi: 10.1111/ans.12581
Abstract Background: To retrospectively determine key demographic and clinical features of 35 patients with Xanthogranulomatous pyelonephritis (XGP) in a New Zealand setting and to compare it with the existing literature. Methods: A retrospective review of patients having a confirmed diagnosis of XGP on histopathology examination was performed. Key clinical and demographic features were analysed and compared with the published literature. Results: XGP was diagnosed in 35 patients over a 12-year (2001–2013) period in Auckland Public Hospital. Ninety-one percent of the patients were female. The population had significantly higher numbers of Maori and Pacific Island patients compared with the general population (74%). Staghorn calculi were the most common cause (51.4%) with obstructing ureteric calculi as the next most common (22.9%) cause. Twenty percent of cases were not thought to be XGP prior to nephrectomy (suspicious renal mass). Thirteen (38%) patients suffered serious complications post-operatively (Clavien 3–5). Conclusion: XGP is a rare chronic inflammatory condition that appears to be overrepresented by Maori and Pacific islanders in our cohort when compared with the overall patient pool. Surgical treatment is associated with significant morbidity but remains the only definitive option. Obesity and other conditions associated with metabolic syndrome may coexist at the time of presentation and may be contributing factors to the development of XGP and poor outcomes associated with it.
Introduction Xanthogranulomatous pyelonephritis (XGP) is an uncommon distinctive chronic inflammatory disease that is associated with chronic infection and obstruction. It is named because of its pathological appearance; that of a granulomatous inflammatory process with lipid filled macrophages, which appear yellow, hence ‘xantho’ which is Greek for yellow. Previous reports have shown that XGP is associated with a high prevalence of renal calculi (Fig. 1) and metabolic syndrome, particularly obesity and diabetes, which is more common in females and patients aged over 50.1–3 There is a paucity of data regarding demographics and clinical features of XGP in a New Zealand setting. In addition, there have been no ethnic demographic data reported in relation to this condition. XGP may be a life-threatening condition and generally the best management is radical surgery,1,4–7 as conservative measures with antibiotics fail to treat the underlying pathological process. In its ANZ J Surg 85 (2015) 150–153
most severe form, XGP can involve the surrounding structures, such as liver, duodenum and colon as well as great vessels.8,9 Given this and resulting nephron loss (Fig. 2) and its chronic complications, any predictive factors such as patient demographics or clinical findings that can aid in the early identification and treatment of patients at risk would be valuable. The aim of our study was to retrospectively determine key demographic and clinical features of XGP in a New Zealand setting.
Methods Diagnosis was confirmed by histopathology examination and the list of patients for the review was obtained from Auckland City Hospital’s central pathology database. Records of all patients diagnosed with XGP between 2001 and 2013 in the Auckland region were reviewed. All patients underwent nephrectomy, apart from one patient who was treated conservatively with antibiotics. © 2014 Royal Australasian College of Surgeons
Analysis of 35 cases of XGP
151
Data from electronic hospital database including demographics, co-morbidities, operative data, complications and 30 days mortality were obtained. Post-operative complications were graded according to the Clavien-Dindo classification of surgical complications.10,11 Analysis of differences of our sample population to the general population (greater Auckland population demographics at most recent census12) was performed with a binomial exact test using R version 3.0.1 (two-tailed) (R Foundation for Statistical Computing, Vienna, Austria).
Table 1 Patient’s demographics Mean age at diagnosis year (range) Gender, No. (%) Ethnicity, No. (%)
Cause of Xanthogranulomatous pyelonephritis, No. (%)
Smoking, No. (%)
Co-morbidities, No. (%)
46.6 (12–81) Female Male New Zealand Maori Pacific Islanders New Zealand European Indian Staghorn calculus Ureteric calculus Congenital pelviureteric junction Other Current Ex-smoker Non-smoker Ischaemic heart disease Diabetes mellitus Hypertension
32 (91) 3 (9) 11 (31.4) 15 (42.8) 8 (22.9) 1 (2.9) 18 (51.4) 8 (22.9) 4 (11.4) 5 (14.3) 15 (42.9) 5 (14.3) 15 (42.9) 3 (8.6) 11 (31.4) 12 (34.3)
Results A total of 35 patients with histologically confirmed XGP were identified. One patient was identified after a renal biopsy and was treated conservatively with antibiotics. This was due to the fact that patient resided outside of New Zealand and post-operative care and follow-up would not have been possible upon returning home. Mean age of patients was 46.6 years (12–81); 91% of patients were female (n = 32). Pacific Islanders (42.8%) and Maori (31.4%) were the largest ethnic groups in the cohort. Mean body mass index of the population was 29.5 kg/m2. Staghorn calculi were the most common cause of XGP (51.4%) and overall, 74.3% of patients had stone disease (Table 1). Of the patients without clear obstruction (stone disease or congenital pelviureteric junction), one had polycystic kidney disease and four had chronic pyelonephritis without any evidence of stone or obstruction. Twenty percent of cases were not identified to be XGP prior to nephrectomy and were treated as a suspicious renal mass. Escherichia coli was the most common isolated organism (45.7%) followed by Proteus mirabilis (20.0%). Median operative time was 186 min (65–570) and 54.5% (n = 18) required blood transfusion. Median estimated blood loss was Table 3 Comparison of cohort demographics to normal population using binomial exact test Comparison Sex Ethnicity Smoking Obesity
P value Female predominance Maori and Pacific Island predominance Current smoker Maori Pacific Islander
