Original Paper
Urologia Internationalis
Received: December 21, 2012 Accepted after revision: June 14, 2013 Published online: October 15, 2013
Urol Int 2014;93:29–33 DOI: 10.1159/000353798
Emphysematous Pyelonephritis: Patient Characteristics and Management Approach Wun-Rong Lin a Marcelo Chen a–c Jong-Ming Hsu a–c Chien-Hsiang Wang d a
Department of Urology, Mackay Memorial Hospital and b Mackay Nursing, Medicine and Management College, Taipei, School of Medicine, Mackay Medical College, New Taipei City, and d Division of Urology, Department of Surgery, Show-Chwan Memorial Hospital, Changhua, Taiwan c
Abstract Introduction: Emphysematous pyelonephritis (EPN) is an acute, severe, necrotizing infection of the renal parenchyma and perirenal tissue that requires immediate treatment. However, the ideal approach to its management remains controversial. We conducted this study to determine the appropriate treatment modalities. Materials and Methods: A retrospective review of EPN cases revealed 10 consecutive cases from July 2003 to June 2012. Clinical and demographic data were collected from each patient. Results: All patients had diabetes mellitus, 5 presented with urinary tract obstruction by urolithiasis. Seven patients had type I disease and 3 had type II disease. Six of the type I patients underwent emergent nephrectomy and 1 of these died, the remaining patient refused surgical intervention and died after receiving medical management only. The type II patients underwent percutaneous drainage, and 2 of them subsequently underwent elective nephrectomy; all 3 survived. Conclusion: Our results suggest that emergency nephrectomy may be considered the initial management for type I EPN, while percutaneous drainage may be an effective initial treatment option for type II EPN. © 2013 S. Karger AG, Basel
© 2013 S. Karger AG, Basel 0042–1138/13/0931–0029$38.00/0 E-Mail [email protected] www.karger.com/uin
Introduction
Emphysematous pyelonephritis (EPN) is an acute, severe, necrotizing infection of the renal parenchyma and perirenal tissue, which results in the presence of gas within the renal parenchyma, collecting system or perinephric tissue [1]. While medical management may be attempted, several authors suggest early nephrectomy [1–3]. Therefore, treatment for EPN has historically consisted of nephrectomy and/or open surgical drainage with antibiotic therapy [4], yielding a mortality rate of 40–50% [5]. Percutaneous drainage for the treatment of EPN, first described by Hudson et al. [6] in 1986, has become another treatment option used in addition to medical management, and this approach has resulted in a significant reduction in mortality rates [7, 8]. Given the aggressive nature of EPN and the different approaches available for its management, we conducted this study to determine appropriate treatment modalities.
Materials and Methods A retrospective review of EPN cases at our institution revealed 10 consecutive cases from July 2003 to June 2012. Diagnoses were based on symptoms and signs of sepsis of renal origin and radiological evidence of gas accumulation in the renal parenchyma, perinephric or pararenal space.
Marcelo Chen, MD, PhD or Jong-Ming Hsu, MD Department of Urology, Mackay Memorial Hospital No. 92, Sec. 2, Zhong-shan North Road Taipei 104, Taiwan E-Mail mchen4270 @ yahoo.com or jmhsu7 @ yahoo.com.tw
Downloaded by: Universitätsbibliothek Giessen 134.176.129.147 - 5/12/2015 4:16:17 PM
Key Words Emphysematous pyelonephritis · Emergency nephrectomy · Percutaneous drainage
a
b
Fig. 1. a Nonenhanced CT showing type I EPN (dry type) in right kidney. b Enhanced CT showing type II EPN (wet type) in right kidney.
Table 1. Demographic and clinical characteristics of patients with EPN
Patient
Age
Sex
Laterality
Obstructiona
Leukocytosis
Thrombocytopenia
Renal impairmentb
1 2 3 4 5 6 7 8 9 10
47 50 54 59 63 66 61 84 55 59
M F M F F M M F F F
left right left left left left right right left right
+ – – + + – – + – +
+ + + + + + + + – +
– + – – – – – – – –
– + + – + + + + – –
a
Obstruction of the urinary tract by calculi. as serum creatinine level >1.2 mg/dl.
b Defined
30
Urol Int 2014;93:29–33 DOI: 10.1159/000353798
presence of renal or perirenal fluid accompanied by a bubbly gas pattern or the presence of gas in the collecting system (fig. 1b). This study was approved by the institutional review board of Mackay Memorial Hospital.
Results
Table 1 shows patient demographic and clinical characteristics. The mean age of EPN patients was 59.8 years (range 47–84 years). Six of the patients were female and 4 Lin/Chen/Hsu/Wang
Downloaded by: Universitätsbibliothek Giessen 134.176.129.147 - 5/12/2015 4:16:17 PM
Clinical and demographic data collected from each patient included age, gender, history of diabetes mellitus, laterality of disease, presence of obstructive uropathy, serum glucose level, glycosylated hemoglobin A1c (HbA1c) level, serum creatinine level, white blood cell count, platelet count, urine and blood culture results, imaging studies, treatment modality and outcome. Radiographic images were reviewed and cases were then classified as either type I or type II EPN as proposed by Wan et al. [9]. In this radiological classification system based on computed tomography (CT) findings, EPN was divided into 2 types: type I EPN (dry type) was characterized by renal parenchymal necrosis with an absence of fluid content or the presence of a streaky/mottled gas pattern (fig. 1a) and type II EPN (wet type) was characterized by the
Discussion
EPN is an uncommon, potentially life-threatening, infectious process requiring prompt diagnosis and management. The most common associated factor is diabetes mellitus [10], and this was present in all of our EPN cases. Urinary tract obstruction is another common associated factor [11], and the most common reported cause of obstruction was urinary calculi [1]. This was seen in 5 of our cases. Other factors reported to be associated with EPN include neurogenic bladder, alcoholism, drug abuse and anatomic anomaly [4, 12, 13]. Emphysematous Pyelonephritis Management
Table 2. Management and outcome of EPN patients
Patient
EPN type
Management
Outcome
1 2 3 4 5 6 7 8 9 10
II I I I I I II I I II
MM + PCD + N MM + EmN MM + EmN MM + EmN MM MM + EmN MM + PCD MM + EmN MM + EmN MM + PCD + N
survived survived died survived died survived survived survived survived survived
EmN = Emergency nephrectomy; MM = medical management; N = elective nephrectomy; PCD = percutaneous drainage.
Table 3. Causative pathogens and antibiotics used
Patient
Pathogen
Fluoroquinolone resistance
Antibiotics
1
E. coli
–
2
E. coli
–
3
E. aerogenes
–
4
E. coli
N/A
5
E. coli
N/A
6
E. coli
–
7
–
8
Coagulasenegative staphylococci K. pneumoniae
+
9
E. coli
+
E. coli/P. mirabilis
+/–
flomoxef sodium + amikacin cefotaxime + metronidazole piperacillin/ tazobactam + ciprofloxacin ceftazidime + amikacin + metronidazole flomoxef sodium + amikacin + metronidazole flomoxef sodium + amikacin + metronidazole flomoxef sodium + amikacin piperacillin/ tazobactam flomoxef sodium + metronidazole piperacillin/ tazobactam + metronidazole
10
N/A = Data not available.
Urol Int 2014;93:29–33 DOI: 10.1159/000353798
31
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were male. The left kidney was affected in 6 patients and the right kidney in 4 patients. All the patients were diabetic, the mean serum glucose level was 372.9 mg/dl (range 194–700 mg/dl) and the mean HbA1c was 10.9% (range 7.8–16.6%). The mean white blood cell count was 20,194/μl (range 5,100–48,600/μl), and only 1 patient presented with thrombocytopenia (platelet count 56,000/μl). The mean serum creatinine level was 2.6 mg/dl (range 0.6–7.0 mg/dl), and 5 of the patients had impaired renal function. Five patients presented with obstruction of the urinary tract: 2 had ureteropelvic stones, 2 had renal staghorn stones and 1 had a midureteral stone (table 1). All diagnoses were based on radiological exams. Kidney, ureter and bladder radiography aided the diagnosis in 5 of 9 patients, and renal ultrasonography aided the diagnosis in only 1 of 3 patients. Single-phase CT was diagnostic in all 10 patients. Contrast-enhanced CT was performed in patients with a serum creatinine level ≤1.2 mg/dl. Nonenhanced CT was performed if the serum creatinine level was >1.2 mg/dl. Classification of EPN revealed 7 cases of type I EPN and 3 cases of type II EPN (table 2). Six of the type I patients underwent emergent nephrectomy, while 1 refused surgical intervention and received medical management only. This patient and 1 of the patients undergoing emergent nephrectomy eventually died. All the type II patients underwent percutaneous drainage, 2 of them subsequently underwent elective nephrectomy and all 3 survived. Blood and urine cultures grew Escherichia coli in 7 patients (table 3). Other causative pathogens included Klebsiella pneumoniae, Proteus mirabilis, Enterobacter aerogenes and coagulase-negative Staphylococcus. Antimicrobial susceptibility tests showed fluoroquinolone resistance in 3 of 9 pathogens. Highly potent antibiotics were given.
32
Urol Int 2014;93:29–33 DOI: 10.1159/000353798
kidney [5]. In inoperable cases, percutaneous drainage combined with medical therapy may be attempted [19]. In our series, 3 patients with type II EPN received percutaneous drainage as initial management. Two of them subsequently underwent elective nephrectomy. All type II EPN patients survived. In a series of 24 EPN cases, Kuzgunbay et al. [20] reported that 6 patients (25%) with mild EPN recovered with antibiotic treatment only. However, it has been reported that medical management alone is a significant risk factor for mortality in patients with EPN [10]. In our series, only 1 patient received medical treatment alone, and this was because her family refused invasive treatment. This patient eventually died. Other risk factors for poor prognosis include hypotension, impaired renal function, disturbance of consciousness, thrombocytopenia, type I EPN and bilateral EPN [16]. The main limitation of this study was that the case number was small. Cases differed in severity and were treated by five different urologists with different amounts of experience. Another limitation was the long recruitment period (9 years), during which a trend towards a less invasive, kidney-sparing initial approach was seen. While changes in the intensive care options and antimicrobials used were not significant in the study period, all these could be potential confounders of the outcomes in these patients. Larger studies are therefore necessary to confirm our findings that percutaneous drainage may be safely attempted first in type II EPN cases and that a more aggressive approach is needed in type I EPN cases.
Conclusions
EPN is a urological emergency with serious consequences if not adequately managed. Our small series suggests that emergency nephrectomy should be considered the initial management for type I EPN, while percutaneous drainage may be an effective initial treatment option for type II EPN. Larger studies are needed to corroborate our results before such a recommendation is made.
References
1 Shokeir AA, El-Azab M, Mohsen T, El-Diasty T: Emphysematous pyelonephritis: a 15-year experience with 20 cases. Urology 1997;49:343–346. 2 Ahlering TE, Boyd SD, Hamilton CL, et al: Emphysematous pyelonephritis: a 5-year experience with 13 patients. J Urol 1985; 134: 1086–1088.
Lin/Chen/Hsu/Wang
Downloaded by: Universitätsbibliothek Giessen 134.176.129.147 - 5/12/2015 4:16:17 PM
While a few small series have reported that EPN was 6 times more common in females than in males [5, 11, 14], our small series showed only a slight female preponderance. This is in agreement with the fact that urinary tract infections are more frequent in females. EPN usually presents in the fourth and fifth decades of life [7, 8, 15], but as seen in our series, it can present even later (our oldest patient was 84 years old). For some unexplained reason, while EPN has been reported worldwide, it is more common in Asia [16]. Analysis of causative pathogens revealed that E. coli was isolated in 7 of our 10 EPN cases, which was in agreement with previous reports which showed that this pathogen was responsible for nearly 70% of the reported cases [7, 8]. Mallet et al. [17] found that K. pneumoniae, P. mirabilis, Pseudomonas aeruginosa and E. aerogenes also cause EPN, albeit to a lesser extent than E. coli. Therefore, initial antimicrobial therapy should target Gram-negative bacteria as they are the most common causative organisms. Fluoroquinolone resistance was only detected for 3 pathogens, so fluoroquinolones could be considered in the initial antimicrobial regimen. CT is the most useful and reliable imaging modality for the early diagnosis of EPN. Kidney, ureter and bladder radiography and renal ultrasonography, although more cost-effective, are only accurate in roughly two thirds of the cases [16]. Therefore, CT should be performed in all suspected EPN cases to confirm the diagnosis. The ideal treatment modality for EPN remains controversial [5]. While historically, emergent nephrectomy was the conventional treatment of choice [4], percutaneous drainage has increasingly been used because the kidney can be preserved and there may be the possibility of renal function recovery [5]. Sugandh [18] suggested that type I EPN be treated immediately with nephrectomy. The mortality rate from emergency nephrectomy ranges from 25 to 50% [5]. In our series, 6 patients with type I EPN underwent emergency nephrectomy. The mortality rate of the patients receiving emergency nephrectomy was 17% (1/6). Percutaneous drainage should be part of the initial management strategy for EPN. This strategy is associated with a lower mortality than medical treatment or emergency nephrectomy. Somani et al. [5] reported that mortality from percutaneous drainage (13.5%) was significantly lower than that from medical treatment (50%) or emergency nephrectomy (25%) alone. Delayed elective nephrectomy may be required in some patients after percutaneous drainage, especially in those with prolonged fever, sepsis and a nonfunctioning
Emphysematous Pyelonephritis Management
9 Wan YL, Lee TY, Bullard MJ, Tsai CC: Acute gas-producing bacterial renal infection: correlation between imaging findings and clinical outcome. Radiology 1996;198:433–438. 10 Falagas ME, Alexiou VG, Giannopoulou KP, Siempos II: Risk factors for mortality in patients with emphysematous pyelonephritis: a meta-analysis. J Urol 2007;178:880–885. 11 Huang JJ, Tseng CC: Emphysematous pyelonephritis: clinicoradiological classification, management, prognosis, and pathogenesis. Arch Intern Med 2000;160:797–805. 12 Godec CJ, Cass AS, Berkseth R: Emphysematous pyelonephritis in a solitary kidney. J Urol 1980;124:119–121. 13 Morehouse HT, Weiner SN, Hoffman JC: Imaging in inflammatory disease of the kidney. Am J Roentgenol 1984;143:135–141. 14 Abdul-Halim H, Kehinde EO, Abdeen S, Lashin I, Al-Hunayan AA, Al-Awadi KA: Severe emphysematous pyelonephritis in diabetic patients: diagnosis and aspects of surgical management. Urol Int 2005;75:123–128.
Urol Int 2014;93:29–33 DOI: 10.1159/000353798
15 Narlawar RS, Raut AA, Nagar A, Hira P, Hanchate V, Asrani A: Imaging features and guided drainage in emphysematous pyelonephritis: a study of 11 cases. Clin Radiol 2004;59:192–197. 16 Ubee SS, McGlynn L, Fordham M: Emphysematous pyelonephritis. BJU Int 2011; 107: 1474–1478. 17 Mallet M, Knockaert DC, Oyen RH, Van Poppel HP: Emphysematous pyelonephritis: no longer a surgical disease? Eur J Emerg Med 2002;9:266–269. 18 Sugandh S: Emphysematous pyelonephritis. Medscape Reference (updated 1 May 2008). http://emedicine.medscape.com/article/ 457306-overview (accessed 1 October 2012). 19 Park SB, Lee SJ, Kim YW, Huh JS, Kim JI, Chang SG: Outcome of nephrectomy and kidney-preserving procedures for the treatment of emphysematous pyelonephritis. Scand J Urol Nephrol 2006;40:332–338. 20 Kuzgunbay B, Turunc T, Tokmak N, Turunc T, Dirim A, Aygun C, Ozkardes H: Tailored treatment approach for emphysematous pyelonephritis. Urol Int 2011;86:444–447.
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3 Pontin AR, Barnes RD, Joffe J, Kahn D: Emphysematous pyelonephritis in diabetic patients. Br J Urol 1995;75:71–74. 4 Michaeli J, Mogle P, Perlberg S, Heiman S, Caine M: Emphysematous pyelonephritis. J Urol 1984;131:203–208. 5 Somani BK, Nabi G, Thorpe P, et al: Is percutaneous drainage the new gold standard in the management of emphysematous pyelonephritis? Evidence from a systematic review. J Urol 2008;179:1844–1849. 6 Hudson MA, Weyman PJ, van der Vliet AH, Catalona WJ: Emphysematous pyelonephritis: successful management by percutaneous drainage. J Urol 1986;136:884–886. 7 Tang HJ, Li C, Yen MY, et al: Clinical characteristics of emphysematous pyelonephritis. J Microbiol Immunol Infect 2001;34:125–130. 8 Khaira A, Gupta A, Rana DS, Gupta A, Bhalla A, Khullar D: Retrospective analysis of clinical profile, prognostic factors and outcomes of 19 patients of emphysematous pyelonephritis. Int Urol Nephrol 2009; 41: 959– 966.
Urologia Internationalis
Received: December 21, 2012 Accepted after revision: June 14, 2013 Published online: October 15, 2013
Urol Int 2014;93:29–33 DOI: 10.1159/000353798
Emphysematous Pyelonephritis: Patient Characteristics and Management Approach Wun-Rong Lin a Marcelo Chen a–c Jong-Ming Hsu a–c Chien-Hsiang Wang d a
Department of Urology, Mackay Memorial Hospital and b Mackay Nursing, Medicine and Management College, Taipei, School of Medicine, Mackay Medical College, New Taipei City, and d Division of Urology, Department of Surgery, Show-Chwan Memorial Hospital, Changhua, Taiwan c
Abstract Introduction: Emphysematous pyelonephritis (EPN) is an acute, severe, necrotizing infection of the renal parenchyma and perirenal tissue that requires immediate treatment. However, the ideal approach to its management remains controversial. We conducted this study to determine the appropriate treatment modalities. Materials and Methods: A retrospective review of EPN cases revealed 10 consecutive cases from July 2003 to June 2012. Clinical and demographic data were collected from each patient. Results: All patients had diabetes mellitus, 5 presented with urinary tract obstruction by urolithiasis. Seven patients had type I disease and 3 had type II disease. Six of the type I patients underwent emergent nephrectomy and 1 of these died, the remaining patient refused surgical intervention and died after receiving medical management only. The type II patients underwent percutaneous drainage, and 2 of them subsequently underwent elective nephrectomy; all 3 survived. Conclusion: Our results suggest that emergency nephrectomy may be considered the initial management for type I EPN, while percutaneous drainage may be an effective initial treatment option for type II EPN. © 2013 S. Karger AG, Basel
© 2013 S. Karger AG, Basel 0042–1138/13/0931–0029$38.00/0 E-Mail [email protected] www.karger.com/uin
Introduction
Emphysematous pyelonephritis (EPN) is an acute, severe, necrotizing infection of the renal parenchyma and perirenal tissue, which results in the presence of gas within the renal parenchyma, collecting system or perinephric tissue [1]. While medical management may be attempted, several authors suggest early nephrectomy [1–3]. Therefore, treatment for EPN has historically consisted of nephrectomy and/or open surgical drainage with antibiotic therapy [4], yielding a mortality rate of 40–50% [5]. Percutaneous drainage for the treatment of EPN, first described by Hudson et al. [6] in 1986, has become another treatment option used in addition to medical management, and this approach has resulted in a significant reduction in mortality rates [7, 8]. Given the aggressive nature of EPN and the different approaches available for its management, we conducted this study to determine appropriate treatment modalities.
Materials and Methods A retrospective review of EPN cases at our institution revealed 10 consecutive cases from July 2003 to June 2012. Diagnoses were based on symptoms and signs of sepsis of renal origin and radiological evidence of gas accumulation in the renal parenchyma, perinephric or pararenal space.
Marcelo Chen, MD, PhD or Jong-Ming Hsu, MD Department of Urology, Mackay Memorial Hospital No. 92, Sec. 2, Zhong-shan North Road Taipei 104, Taiwan E-Mail mchen4270 @ yahoo.com or jmhsu7 @ yahoo.com.tw
Downloaded by: Universitätsbibliothek Giessen 134.176.129.147 - 5/12/2015 4:16:17 PM
Key Words Emphysematous pyelonephritis · Emergency nephrectomy · Percutaneous drainage
a
b
Fig. 1. a Nonenhanced CT showing type I EPN (dry type) in right kidney. b Enhanced CT showing type II EPN (wet type) in right kidney.
Table 1. Demographic and clinical characteristics of patients with EPN
Patient
Age
Sex
Laterality
Obstructiona
Leukocytosis
Thrombocytopenia
Renal impairmentb
1 2 3 4 5 6 7 8 9 10
47 50 54 59 63 66 61 84 55 59
M F M F F M M F F F
left right left left left left right right left right
+ – – + + – – + – +
+ + + + + + + + – +
– + – – – – – – – –
– + + – + + + + – –
a
Obstruction of the urinary tract by calculi. as serum creatinine level >1.2 mg/dl.
b Defined
30
Urol Int 2014;93:29–33 DOI: 10.1159/000353798
presence of renal or perirenal fluid accompanied by a bubbly gas pattern or the presence of gas in the collecting system (fig. 1b). This study was approved by the institutional review board of Mackay Memorial Hospital.
Results
Table 1 shows patient demographic and clinical characteristics. The mean age of EPN patients was 59.8 years (range 47–84 years). Six of the patients were female and 4 Lin/Chen/Hsu/Wang
Downloaded by: Universitätsbibliothek Giessen 134.176.129.147 - 5/12/2015 4:16:17 PM
Clinical and demographic data collected from each patient included age, gender, history of diabetes mellitus, laterality of disease, presence of obstructive uropathy, serum glucose level, glycosylated hemoglobin A1c (HbA1c) level, serum creatinine level, white blood cell count, platelet count, urine and blood culture results, imaging studies, treatment modality and outcome. Radiographic images were reviewed and cases were then classified as either type I or type II EPN as proposed by Wan et al. [9]. In this radiological classification system based on computed tomography (CT) findings, EPN was divided into 2 types: type I EPN (dry type) was characterized by renal parenchymal necrosis with an absence of fluid content or the presence of a streaky/mottled gas pattern (fig. 1a) and type II EPN (wet type) was characterized by the
Discussion
EPN is an uncommon, potentially life-threatening, infectious process requiring prompt diagnosis and management. The most common associated factor is diabetes mellitus [10], and this was present in all of our EPN cases. Urinary tract obstruction is another common associated factor [11], and the most common reported cause of obstruction was urinary calculi [1]. This was seen in 5 of our cases. Other factors reported to be associated with EPN include neurogenic bladder, alcoholism, drug abuse and anatomic anomaly [4, 12, 13]. Emphysematous Pyelonephritis Management
Table 2. Management and outcome of EPN patients
Patient
EPN type
Management
Outcome
1 2 3 4 5 6 7 8 9 10
II I I I I I II I I II
MM + PCD + N MM + EmN MM + EmN MM + EmN MM MM + EmN MM + PCD MM + EmN MM + EmN MM + PCD + N
survived survived died survived died survived survived survived survived survived
EmN = Emergency nephrectomy; MM = medical management; N = elective nephrectomy; PCD = percutaneous drainage.
Table 3. Causative pathogens and antibiotics used
Patient
Pathogen
Fluoroquinolone resistance
Antibiotics
1
E. coli
–
2
E. coli
–
3
E. aerogenes
–
4
E. coli
N/A
5
E. coli
N/A
6
E. coli
–
7
–
8
Coagulasenegative staphylococci K. pneumoniae
+
9
E. coli
+
E. coli/P. mirabilis
+/–
flomoxef sodium + amikacin cefotaxime + metronidazole piperacillin/ tazobactam + ciprofloxacin ceftazidime + amikacin + metronidazole flomoxef sodium + amikacin + metronidazole flomoxef sodium + amikacin + metronidazole flomoxef sodium + amikacin piperacillin/ tazobactam flomoxef sodium + metronidazole piperacillin/ tazobactam + metronidazole
10
N/A = Data not available.
Urol Int 2014;93:29–33 DOI: 10.1159/000353798
31
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were male. The left kidney was affected in 6 patients and the right kidney in 4 patients. All the patients were diabetic, the mean serum glucose level was 372.9 mg/dl (range 194–700 mg/dl) and the mean HbA1c was 10.9% (range 7.8–16.6%). The mean white blood cell count was 20,194/μl (range 5,100–48,600/μl), and only 1 patient presented with thrombocytopenia (platelet count 56,000/μl). The mean serum creatinine level was 2.6 mg/dl (range 0.6–7.0 mg/dl), and 5 of the patients had impaired renal function. Five patients presented with obstruction of the urinary tract: 2 had ureteropelvic stones, 2 had renal staghorn stones and 1 had a midureteral stone (table 1). All diagnoses were based on radiological exams. Kidney, ureter and bladder radiography aided the diagnosis in 5 of 9 patients, and renal ultrasonography aided the diagnosis in only 1 of 3 patients. Single-phase CT was diagnostic in all 10 patients. Contrast-enhanced CT was performed in patients with a serum creatinine level ≤1.2 mg/dl. Nonenhanced CT was performed if the serum creatinine level was >1.2 mg/dl. Classification of EPN revealed 7 cases of type I EPN and 3 cases of type II EPN (table 2). Six of the type I patients underwent emergent nephrectomy, while 1 refused surgical intervention and received medical management only. This patient and 1 of the patients undergoing emergent nephrectomy eventually died. All the type II patients underwent percutaneous drainage, 2 of them subsequently underwent elective nephrectomy and all 3 survived. Blood and urine cultures grew Escherichia coli in 7 patients (table 3). Other causative pathogens included Klebsiella pneumoniae, Proteus mirabilis, Enterobacter aerogenes and coagulase-negative Staphylococcus. Antimicrobial susceptibility tests showed fluoroquinolone resistance in 3 of 9 pathogens. Highly potent antibiotics were given.
32
Urol Int 2014;93:29–33 DOI: 10.1159/000353798
kidney [5]. In inoperable cases, percutaneous drainage combined with medical therapy may be attempted [19]. In our series, 3 patients with type II EPN received percutaneous drainage as initial management. Two of them subsequently underwent elective nephrectomy. All type II EPN patients survived. In a series of 24 EPN cases, Kuzgunbay et al. [20] reported that 6 patients (25%) with mild EPN recovered with antibiotic treatment only. However, it has been reported that medical management alone is a significant risk factor for mortality in patients with EPN [10]. In our series, only 1 patient received medical treatment alone, and this was because her family refused invasive treatment. This patient eventually died. Other risk factors for poor prognosis include hypotension, impaired renal function, disturbance of consciousness, thrombocytopenia, type I EPN and bilateral EPN [16]. The main limitation of this study was that the case number was small. Cases differed in severity and were treated by five different urologists with different amounts of experience. Another limitation was the long recruitment period (9 years), during which a trend towards a less invasive, kidney-sparing initial approach was seen. While changes in the intensive care options and antimicrobials used were not significant in the study period, all these could be potential confounders of the outcomes in these patients. Larger studies are therefore necessary to confirm our findings that percutaneous drainage may be safely attempted first in type II EPN cases and that a more aggressive approach is needed in type I EPN cases.
Conclusions
EPN is a urological emergency with serious consequences if not adequately managed. Our small series suggests that emergency nephrectomy should be considered the initial management for type I EPN, while percutaneous drainage may be an effective initial treatment option for type II EPN. Larger studies are needed to corroborate our results before such a recommendation is made.
References
1 Shokeir AA, El-Azab M, Mohsen T, El-Diasty T: Emphysematous pyelonephritis: a 15-year experience with 20 cases. Urology 1997;49:343–346. 2 Ahlering TE, Boyd SD, Hamilton CL, et al: Emphysematous pyelonephritis: a 5-year experience with 13 patients. J Urol 1985; 134: 1086–1088.
Lin/Chen/Hsu/Wang
Downloaded by: Universitätsbibliothek Giessen 134.176.129.147 - 5/12/2015 4:16:17 PM
While a few small series have reported that EPN was 6 times more common in females than in males [5, 11, 14], our small series showed only a slight female preponderance. This is in agreement with the fact that urinary tract infections are more frequent in females. EPN usually presents in the fourth and fifth decades of life [7, 8, 15], but as seen in our series, it can present even later (our oldest patient was 84 years old). For some unexplained reason, while EPN has been reported worldwide, it is more common in Asia [16]. Analysis of causative pathogens revealed that E. coli was isolated in 7 of our 10 EPN cases, which was in agreement with previous reports which showed that this pathogen was responsible for nearly 70% of the reported cases [7, 8]. Mallet et al. [17] found that K. pneumoniae, P. mirabilis, Pseudomonas aeruginosa and E. aerogenes also cause EPN, albeit to a lesser extent than E. coli. Therefore, initial antimicrobial therapy should target Gram-negative bacteria as they are the most common causative organisms. Fluoroquinolone resistance was only detected for 3 pathogens, so fluoroquinolones could be considered in the initial antimicrobial regimen. CT is the most useful and reliable imaging modality for the early diagnosis of EPN. Kidney, ureter and bladder radiography and renal ultrasonography, although more cost-effective, are only accurate in roughly two thirds of the cases [16]. Therefore, CT should be performed in all suspected EPN cases to confirm the diagnosis. The ideal treatment modality for EPN remains controversial [5]. While historically, emergent nephrectomy was the conventional treatment of choice [4], percutaneous drainage has increasingly been used because the kidney can be preserved and there may be the possibility of renal function recovery [5]. Sugandh [18] suggested that type I EPN be treated immediately with nephrectomy. The mortality rate from emergency nephrectomy ranges from 25 to 50% [5]. In our series, 6 patients with type I EPN underwent emergency nephrectomy. The mortality rate of the patients receiving emergency nephrectomy was 17% (1/6). Percutaneous drainage should be part of the initial management strategy for EPN. This strategy is associated with a lower mortality than medical treatment or emergency nephrectomy. Somani et al. [5] reported that mortality from percutaneous drainage (13.5%) was significantly lower than that from medical treatment (50%) or emergency nephrectomy (25%) alone. Delayed elective nephrectomy may be required in some patients after percutaneous drainage, especially in those with prolonged fever, sepsis and a nonfunctioning
Emphysematous Pyelonephritis Management
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Urol Int 2014;93:29–33 DOI: 10.1159/000353798
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