Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities and follow-up
Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities...
El-Nahas, Ahmed R.; Shokeir, Ahmed A.; Eziyi, Amogu Kalu; Barakat, Tamer S.; Tijani, Kehinde Habeeb; El-Diasty, Tarek; Abol-Enein, Hassan
2011-09-01 00:00:00
Arab Journal of Urology (2011) 9, 185–189 Arab Journal of Urology (Official Journal of the Arab Association of Urology) www.sciencedirect.com STONES/ENDOUROLOGY ORIGINAL ARTICLE Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities and follow-up a, a a Ahmed R. El-Nahas , Ahmed A. Shokeir , Amogu Kalu Eziyi , a a b Tamer S. Barakat , Kehinde Habeeb Tijani , Tarek El-Diasty , Hassan Abol-Enein Urology Department, Urology and Nephrology Center, Mansoura University, Mansoura, Egypt Radiology Unit, Urology and Nephrology Center, Mansoura University, Mansoura, Egypt Received 25 August 2011, Received in revised form 24 September 2011, Accepted 25 September 2011 Available online 17 November 2011 KEYWORDS Abstract Objectives: To present treatments for kidney preservation in the management of emphy- sematous pyelonephritis (EPN), and to evaluate the functional outcome of preserved kidneys during Emphysematous the follow-up. pyelonephritis; Infection; Patients and methods: The computerized files of patients with EPN from 2000 to 2010 were Obstruction; reviewed. After initial resuscitation, ultrasonography-guided percutaneous tubes were placed for Diabetes mellitus drainage of infected fluid and gas. A radio-isotopic renal scan was done after stabilization of the patients’ condition. Preservation of the affected kidney was attempted when the differential func- ABBREVIATIONS tion was >10%. A renal isotopic scan was taken during the follow-up to evaluate renographic EPN, emphysematous pyelo- changes in preserved kidneys. nephritis; Results: The study included 33 kidneys in 30 consecutive patients (mean age 51.7 years, SD 10.9). NCCT, non-contrast CT; Kidney preservation was applicable for 23 kidneys (20 patients). Preservation methods included US, ultrasonography; percutaneous nephrostomy for 12, percutaneous tube drain for two and conservative treatment PCN, percutaneous for nine kidneys (six patients). Nephrectomy was performed for 10 kidneys (emergency in three nephrostomy; and delayed in seven). The frequency of post-treatment septic shock after kidney preservation PCD, percutaneous tube (10%) was significantly lower than after nephrectomy (20%, P = 0.005). The overall mortality rate drain Corresponding author. Tel.: +20 50 2262222; fax: +20 50 2263717 E-mail address: ar_el_nahas@yahoo.com (A.R. El-Nahas). 2090-598X ª 2011 Arab Association of Urology. Production and hosting by Elsevier B.V. All rights reserved. Production and hosting by Elsevier Peer review under responsibility of Arab Association of Urology. doi:10.1016/j.aju.2011.09.002 186 El-Nahas et al. was 7% (two patients). The follow-up was completed for 13 patients with 15 preserved kidneys for a mean duration of 21 months. During the follow-up, differential renographic clearance of the affected kidney was stable in 13 of 15 while two kidneys showed improvement. Conclusions: Kidney preservation should be the primary goal in the treatment of EPN when the differential renal clearance is >10%. It was associated with fewer complications than nephrectomy and the follow-up showed a favourable functional outcome of the preserved kidneys. ª 2011 Arab Association of Urology. Production and hosting by Elsevier B.V. All rights reserved. Introduction culture, serum creatinine estimation, complete blood count, and random blood sugar and liver function tests. Radiological Emphysematous pyelonephritis (EPN) is a rare, severe infec- investigations included abdominal US and NCCT, done to con- tion of the kidney that results in formation of gas in the collect- firm the diagnosis and for classification. ing system, renal parenchyma, or perinephric tissue [1].Itis Patients were classified according to Huang and Tseng [1], most commonly seen in diabetics and immunocompromised who classified EPN as: Class I, gas in the collecting system patients [2]. The clinical features of EPN are indistinguishable only; class II, gas inside the renal parenchyma with no exten- from those of severe acute pyelonephritis and the diagnosis can sion into the extrarenal space; class IIIa, extension of gas into be suspected after a poor response to conventional antibiotic the perinephric space; class IIIb, extension of gas into the para- treatment [3]. It is a life-threatening condition, with mortality renal space; and class IV, bilateral disease or EPN in a solitary rates of 11–42% [1–4]. kidney. The radiological diagnosis depends on detecting gas in or Treatment started by resuscitation of patients in shock, and around the kidney by plain X-ray film of the abdomen or by blood sugar control for diabetic patients. Intravenous antibiot- ultrasonography (US), which can also diagnose obstruction ics (third-generation cephalosporins) were administered for all and associated stones or collections. Non-contrast CT (NCCT) patients at time of presentation. In patients with obstruction can be used to confirm the diagnosis and various radiological or extensive gaseous collections, the infected fluid and gas were classifications have been suggested based on CT. Wan et al. [3] drained using an US-guided percutaneous nephrostomy (PCN) described two distinct radiological classifications of EPN, or percutaneous tube drain (PCD). The response to treatment while Huang and Tseng [1] classified EPN into four categories. was monitored using a plain abdominal film and US for some The treatment of EPN has been a subject of controversy. patients, or NCCT in others. After stabilising the patient’s con- 99m Emergency nephrectomy after medical control of septicaemia dition, a renal radio-isotopic scan using Tc MAG3 was ta- and diabetes was reported [5,6]. The availability of effective ken to estimate the differential function of the affected kidney. antibiotics and advances in image-guided procedures resulted Preservation of the affected kidney was attempted when the dif- in the use of less aggressive surgical approaches such as percu- ferential function was >10% [13]. taneous drainage [7–9]. Moreover, some authors suggested Patients with preserved kidneys were recruited for follow-up; medical treatment alone [10]. In recent years the goals of treat- they had a clinical examination, urine analysis, plain film, US ment included improving the survival rate and preserving the and renal isotopic scan to evaluate changes in differential func- affected kidney whenever possible [11]. tion of the affected kidney. A change in renographic clearance of Risk factors for death from EPN were previously assessed >5% of the pretreatment value was considered as improvement in a meta-analysis [2], but studies discussing risk factors for or deterioration, while changes within 5% were defined as stable nephrectomy are scarce [12] and, to the best of our knowledge, function [13]. there is no study evaluating differential renal functional The data were analysed using standard methods; to deter- changes after preserving the affected kidney. The current study mine significant prognostic factors for nephrectomy, univari- was conducted to present kidney preservation protocols for ate analysis (chi-square test) and multivariate (logistic managing EPN, to determine risk factors predicting the need regression analysis) were used, with P < 0.05 taken to indicate for nephrectomy, and to show differential renographic changes statistical significance. during the follow-up of patients with preserved kidneys. Results Patients and methods The study included 33 renal units in 30 consecutive patients, as The computerized files of patients with acute pyelonephritis who three patients had bilateral EPN. The mean (SD, range) patient were treated in our centre from January 2000 to December 2010 age was 51.7 (10.9, 22–80) years. The patients’ demographics, were reviewed retrospectively. The study included patients with presentations, predisposing factors and CT classes are shown EPN who had evidence of gas in the kidney, perinephric or para- in Table 1. Six patients needed admission to the intensive care renal spaces by NCCT. We excluded patients with possible unit to manage septic shock and three presented with acute renal external introduction of gas into the urinary system (e.g. fistula failure. Urine cultures were positive in 18 patients (60%); the with gastrointestinal system, recent ureteric catheterization or most frequently isolated organism was Escherichia coli in 11 pa- recent percutaneous renal procedures). tients (60%), while Klebsiella species were responsible for the The patients’ files were reviewed for medical and surgical his- remaining positive cultures. tory, clinical presentation, predisposing factors, laboratory and Kidney preservation was attempted for 23 kidneys in 20 pa- radiological investigations, treatments, complications and out- tients; preservation methods included PCN for 12 kidneys, comes. Laboratory investigations included urine analysis and conservative (medical) treatment for nine (six patients) and Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities 187 tion in two of 20 patients (10%); the difference was statistically Table 1 Demographics, presentations and predisposing significant; P = 0.005). The overall mortality rate was 7% (two factors of 30 patients with EPN. patients); the first presented with septic shock after a trial med- Variable N (%) ical treatment of acute pyelonephritis for many days before pre- sentation to our centre, and trial resuscitation in the intensive Gender Male 8 (27) care unit failed. The second death was due to failed treatment Female 22 (73) of septic shock after emergency nephrectomy of the affected kidney. Affected side Among patients who survived, the kidney was preserved in Right 12 (40) 23 of 31 affected kidneys (74%). Any calculi were treated after Left 15 (50) 2 weeks of infection control and stabilization of the general Bilateral 3 (10) condition, with percutaneous nephrolithotomy in two and Presentation ureteroscopy in three patients. The follow-up was completed Fever and loin pain 21 (70) for 13 patients with 15 preserved kidneys for a mean (range) Shock 6 (20) of 21 (3–55) months. The function of the affected kidney was Acute renal failure 3 (10) stable in 13 of 15 while two kidneys showed an improvement Predisposing factors: in selective clearance from 25% and 50% before treatment Diabetes mellitus 23 (77) to 37% and 60% during the follow-up, respectively. Renal calculi 2 (7) Ureteric calculi 3 (10) Discussion Immunocompromise 2 (7) CT Class: EPN is a life-threatening infection characterized by the pres- I 7 (23) ence of gas in the renal parenchyma and the surrounding tis- II 8 (27) sues. Diabetes mellitus was the most frequently reported IIIa 7 (23) predisposing factor for developing EPN, as it constituted IIIb 3 (10) 80–100% of patients [5,14,15]. Of the present patients, 77% IV 5 (17) were diabetic, and the second predisposing factor was urolith- Three patients had bilateral disease and two had solitary iasis; the same was reported by Kapoor et al. [12]. kidneys. The clinical presentations of EPN among the present patients were similar to those reported previously, with loin pain and fever (70%) being the predominant symptom PCDs for extensive para-renal gaseous collection in two [7,8,16]. Patients who had delayed treatment presented with (Fig. 1). Nephrectomy was used for 10 kidneys (emergency septic shock, and those with a solitary kidney presented with in three and delayed after PCN in seven). Table 2 summarizes acute renal failure. Urine culture was positive in 60% of the the results of the univariate statistical analysis of risk factors present cases, unlike the value of 98% reported by Huang for nephrectomy. Thrombocytopenia was the only statistically and Tseng [1]. With the virtually unlimited access of patients significant factor (P = 0.009) on univariate analysis, but there to antibiotics without prescription, most were likely to have was no significant factor on multivariate analysis. tried self-medication or would have received antibiotics from Post-treatment septic shock developed after emergency the referring doctor. This ultimately might give false-negative nephrectomy in two of 10 patients, and after kidney preserva- cultures. E. coli was the predominant organism in cases with positive cultures, and these findings were consistent with the other reports [4,9,17]. Radiological detection of gas in and around the kidney is diagnostic for EPN; US is a good screening method, and it is useful in the diagnosis of stone disease and upper urinary tract obstruction. A plain X-ray of the abdomen can also detect gas in the renal region. NCCT was reported to have the highest diagnostic accuracy (100%) for EPN [9]. Therefore, NCCT was the investigation of choice, not only for diagnosing EPN but also for classifying patients into different categories [1,3,9]. Previously EPN was considered as a surgical emergency be- cause of the high mortality rate. Falagas et al. [2] conducted a meta-analysis of seven reports including 175 patients with EPN to identify risk factors for mortality. They found an over- all mortality rate of 25% (11–42%). Factors associated with increased mortality rate were conservative treatment alone, bilateral EPN, type I EPN according to the classification of Wan et al., and thrombocytopenia. More recently, Kapoor Figure 1 NCCT (axial scan) showing extensive gaseous collec- et al. [12] reported a mortality rate of 13% of 39 patients with tion affecting the parenchyma of the left kidney and extending to EPN. They concluded that altered mental status, thrombocy- the para-renal space (class IIIb). topenia, renal failure and severe hyponatraemia at presenta- 188 El-Nahas et al. Table 2 Univariate statistical analysis of risk factors for nephrectomy in 33 kidneys with EPN. Factor Preserved kidney n/N (%) Nephrectomy, n/N (%) P Odds ratio (95% CI) Gender 0.396 2.133 (0.363–12.54) Male 8/10 2/10 Female 15/23 (65) 8/23 (35) Age, years 0.441 0.533 (0.119–2.408) <50 8/13 5/13 >50 15/20 (75) 5/20 (25) Side 0.779 1.250 (0.263–5.936) Right 11/15 4/15 Left 12/18 6/18 Diabetes mellitus 0.911 1.111 (0.177–6.990) No 5/7 2/7 Yes 18/26 (69) 8/26 (31) Obesity 0.909 1.091 (0.247–4.817) Not obese (BMI < 30) 12/17 5/17 Obese (BMI > 30) 11/15 5/15 Renal obstruction 0.853 1.154 (0.255–5.223) No 10/14 4/14 Yes 13/19 (68) 6/19 (32) CT class 0.730 0.769 (0.174–3.409) I or II 10/15 5/15 III or IV 13/18 5/18 Serum creatinine, mg/dL 0.198 0.325 (0.056–1.880) <2 13/21 (62) 8/21 (38) P2 10/12 2/12 Leukocytosis 0.383 1.950 (0.431–8.828) No 13/17 4/17 Yes 10/16 6/16 Thrombocytopenia 0.009 14.67 (1.371–156.9) No 22/28 (79) 6/28 (21) Yes 1/5 4/5 a 1 Blood leukocyte count >12,000 dL . b 1 Platelet count <140,000 dL . tion were significantly associated with death. In the present mortality (6.6%) was reported with percutaneous drainage study the mortality rates were significantly lowered to 7%. then elective nephrectomy. They concluded that percutaneous The better mortality rate in our series and that of Aswathaman drainage should be part of the initial management for EPN be- et al. [11] was the result of efficient resuscitation followed by cause it was associated with a lower mortality rate than med- early percutaneous drainage if there was obstruction or no ical management or emergency nephrectomy. The advantages improvement of the patient’s condition on conservative treat- of percutaneous drainage include stabilization of patients’ con- ment alone. dition, treatment of underlying contributory factors, and a de- Emergency nephrectomy was considered by some authors creased risk associated with nephrectomy should surgery later as the surgical treatment of choice and a life-saving procedure be required. Our results support these conclusions, as there for treating EPN [5,6]. This taboo was also rejected in recent was one death due to prolonged medical management and an- years and a new treatment strategy of kidney preservation other after emergency nephrectomy. emerged [8–11]. The reasons for this change were the high mor- Conservative (medical) treatment for EPN was suggested by tality rates of emergency nephrectomy (17.6–40%) [5,6] and some authors [7,10,11]. Aswathaman et al. [11] reported com- advances in image-guided procedures for drainage of the gas plete success for conservative treatment in patients who had and infected fluids, using PCDs [9,10]. Chen et al. [8], in their no risk factors such as thrombocytopenia, shock, altered senso- experience with 25 patients, suggested that percutaneous drain- rium, and haemodialysis. Among the present patients, it was age is safe and effective for EPN, and that can result in cure. successful in six patients with nine diseased kidneys. We recom- Moreover, surgical intervention often poses a substantial risk mend considering this method for patients with localized disease for patients with haemodynamic instability. In the present pa- (class I or II in the Huang classification) who have no renal tients, methods of kidney preservation were associated with a obstruction. When patients have EPN in a solitary kidney or significantly lower complication rate (10%) than for nephrec- bilateral EPN, conservative treatment, and drainage if there is tomy (20%), whether these nephrectomies were early or de- a poor response, should be tried before embarking on nephrec- layed after drainage. tomy; this might help to obviate life-time renal dialysis [8]. Somani et al. [9] published a systematic review of 10 studies Risk factors for nephrectomy were studied by Kapoor et al. [12] on 210 patients with EPN. They found that the highest mortal- in a retrospective study of 39 patients. They found that extensive ity rate (50%) was with medical treatment alone, followed by renal parenchymal destruction of >50% (based on CT) signifi- emergency nephrectomy (25%), while percutaneous drainage cantly predicted the need for nephrectomy (P < 0.001). In the was associated with a 13.5% mortality rate and the lowest present series there was no statistically significant factor (on multi- Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities 189 [6] Ahlering TE, Boyed SD, Hamilton CL, Bragin SD, Chandrasoma variate analysis), possibly because there were too few nephrecto- G, Lieskovsky G, et al. Emphysematous pyelonephritis: 5-year mies (10 kidneys) or failure of all preoperative factors to affect experience with 13 patients. J Urol 1985;134:1086–8. the decision for nephrectomy. Based on our observations, we be- [7] Knockaert MM, Oven RH, Van Poppel HP. Emphysematous lieve that the primary goal in treating EPN should be preservation pyelonephritis: no longer a surgical disease? Eur J Emerg Med of the affected kidney unless its renographic clearance is <10%. 2002;9:266–9. The main limitation of our study is the retrospective nature, [8] Chen MT, Huang CN, Chou YH, Huang CH, Chiang CP, Liu but this was the main limitation of all previously published ser- GC. Percutaneous drainage of emphysematous pyelonephritis: 10- ies of EPN. The main advantage of this study is that it con- year experience. J Urol 1997;157:1569–73. firmed objectively, for the first time, that kidney preservation [9] Somani BK, Nabi G, Thorpe P, Hussey J, Cook J, N’Dow J. in patients with EPN is beneficial because the preserved kid- ABACUS research group is percutaneous drainage the new gold neys maintained their function during the follow-up. standard in the management of emphysematous pyelonephritis? Evidence from a systematic review. J Urol 2008;179:1844–9. In conclusion, kidney preservation should be the primary goal [10] Nagappan R, Kletchko S. Bilateral emphysematous pyelonephri- in treating EPN when the differential renal clearance is >10%, be- tis resolving to medical therapy. J Intern Med 1992;232:77–80. cause it was associated with fewer complications than nephrec- [11] Aswathaman K, Gopalakrishnan G, Gnanaraj L, Chacko NK, tomy. The kidney-preservation protocol includes adequate Kekre NS, Devasia A. Emphysematous pyelonephritis: outcome resuscitation, diabetic control and antibiotic coverage, followed with conservative management. Urology 2008;71:1007–9. by early drainage of obstructed systems or para-renal infected fluid [12] Kapoor R, Muruganandham K, Gulia AK, Singla M, Agrawal S, and gas. The follow-up showed a favourable functional outcome of Mandhani A, et al. Predictive factors for mortality and need for the preserved kidneys. nephrectomy in patients with emphysematous pyelonephritis. BJU Int 2010;105:986–9. [13] Shokeir AA, Provoost AP, Nijman RJ. Recoverability of renal References function after relief of chronic partial upper urinary tract obstruction. BJU Int 1999;83:11–7. [1] Huang J-J, Tseng C-C. Emphysematous pyelonephritis: clinico- [14] Addul-Halim H, Kehinde EO, Abdeen S, Lashin I, Al-Hunayan radiological classification, management, prognosis, and patho- KA, Al-Awadi KA. Severe emphysematous pyelonephritis in genesis. Arch Intern Med 2000;160:797–805. diabetic patients: diagnosis and aspects of surgical management. [2] Falagas ME, Alexiou VG, Giannopoulou KP, Siempos II. Risk Urologia Int 2005;75:123–8. factors for mortality in patients with emphysematous pyelone- [15] Park BS, Lee S, Kim YW, Huh JS, Kim JI, Chang S. Outcome of phritis: a meta-analysis. J Urol 2007;178:880–5. nephrectomy and kidney-preserving procedures for the treatment [3] Wan YL, Lee TY, Bullard MJ, Tsai CC. Acute gas-producing of emphysematous pyelonephritis. Scand J Urol Nephrol bacterial renal infection correlation between imaging findings and 2006;40:332–8. clinical outcome. Radiology 1996;198:433–8. [16] Wan YL, Lo SK, Bullard MJ, Chang PL, Lee TY. Predictors of [4] Kumar A, Turney JH, Brownjohn AM, McMahon MJ. Unusual outcome in emphysematous pyelonephritis. JUrol 1998;159:369–73. bacterial infections of the urinary tract in diabetic patients-rare [17] Khaira A, Gupta A, Rana DS, Gupta A, Bhalla A, Khullar D. but frequently lethal. Neph Dial Transplant 2001;16:1062–5. Retrospective analysis of clinical profile prognostic factors and [5] Shokeir AA, El-Azab M, Mohsen T, El-Diasty T. Emphysema- outcomes of 19 patients of emphysematous pyelonephritis. Int tous pyelonephritis: a 15-year experience with 20 cases. Urology Urol Nephrol 2009;41:959–66. 1997;49:343–6.
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Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities and follow-up
Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities and follow-up
Abstract
AbstractObjectives: To present treatments for kidney preservation in the management of emphysematous pyelonephritis (EPN), and to evaluate the functional outcome of preserved kidneys during the follow-up.Patients and methods: The computerized files of patients with EPN from 2000 to 2010 were reviewed. After initial resuscitation, ultrasonography-guided percutaneous tubes were placed for drainage of infected fluid and gas. A radio-isotopic renal scan was done after stabilization of the...
Arab Journal of Urology (2011) 9, 185–189 Arab Journal of Urology (Official Journal of the Arab Association of Urology) www.sciencedirect.com STONES/ENDOUROLOGY ORIGINAL ARTICLE Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities and follow-up a, a a Ahmed R. El-Nahas , Ahmed A. Shokeir , Amogu Kalu Eziyi , a a b Tamer S. Barakat , Kehinde Habeeb Tijani , Tarek El-Diasty , Hassan Abol-Enein Urology Department, Urology and Nephrology Center, Mansoura University, Mansoura, Egypt Radiology Unit, Urology and Nephrology Center, Mansoura University, Mansoura, Egypt Received 25 August 2011, Received in revised form 24 September 2011, Accepted 25 September 2011 Available online 17 November 2011 KEYWORDS Abstract Objectives: To present treatments for kidney preservation in the management of emphy- sematous pyelonephritis (EPN), and to evaluate the functional outcome of preserved kidneys during Emphysematous the follow-up. pyelonephritis; Infection; Patients and methods: The computerized files of patients with EPN from 2000 to 2010 were Obstruction; reviewed. After initial resuscitation, ultrasonography-guided percutaneous tubes were placed for Diabetes mellitus drainage of infected fluid and gas. A radio-isotopic renal scan was done after stabilization of the patients’ condition. Preservation of the affected kidney was attempted when the differential func- ABBREVIATIONS tion was >10%. A renal isotopic scan was taken during the follow-up to evaluate renographic EPN, emphysematous pyelo- changes in preserved kidneys. nephritis; Results: The study included 33 kidneys in 30 consecutive patients (mean age 51.7 years, SD 10.9). NCCT, non-contrast CT; Kidney preservation was applicable for 23 kidneys (20 patients). Preservation methods included US, ultrasonography; percutaneous nephrostomy for 12, percutaneous tube drain for two and conservative treatment PCN, percutaneous for nine kidneys (six patients). Nephrectomy was performed for 10 kidneys (emergency in three nephrostomy; and delayed in seven). The frequency of post-treatment septic shock after kidney preservation PCD, percutaneous tube (10%) was significantly lower than after nephrectomy (20%, P = 0.005). The overall mortality rate drain Corresponding author. Tel.: +20 50 2262222; fax: +20 50 2263717 E-mail address: ar_el_nahas@yahoo.com (A.R. El-Nahas). 2090-598X ª 2011 Arab Association of Urology. Production and hosting by Elsevier B.V. All rights reserved. Production and hosting by Elsevier Peer review under responsibility of Arab Association of Urology. doi:10.1016/j.aju.2011.09.002 186 El-Nahas et al. was 7% (two patients). The follow-up was completed for 13 patients with 15 preserved kidneys for a mean duration of 21 months. During the follow-up, differential renographic clearance of the affected kidney was stable in 13 of 15 while two kidneys showed improvement. Conclusions: Kidney preservation should be the primary goal in the treatment of EPN when the differential renal clearance is >10%. It was associated with fewer complications than nephrectomy and the follow-up showed a favourable functional outcome of the preserved kidneys. ª 2011 Arab Association of Urology. Production and hosting by Elsevier B.V. All rights reserved. Introduction culture, serum creatinine estimation, complete blood count, and random blood sugar and liver function tests. Radiological Emphysematous pyelonephritis (EPN) is a rare, severe infec- investigations included abdominal US and NCCT, done to con- tion of the kidney that results in formation of gas in the collect- firm the diagnosis and for classification. ing system, renal parenchyma, or perinephric tissue [1].Itis Patients were classified according to Huang and Tseng [1], most commonly seen in diabetics and immunocompromised who classified EPN as: Class I, gas in the collecting system patients [2]. The clinical features of EPN are indistinguishable only; class II, gas inside the renal parenchyma with no exten- from those of severe acute pyelonephritis and the diagnosis can sion into the extrarenal space; class IIIa, extension of gas into be suspected after a poor response to conventional antibiotic the perinephric space; class IIIb, extension of gas into the para- treatment [3]. It is a life-threatening condition, with mortality renal space; and class IV, bilateral disease or EPN in a solitary rates of 11–42% [1–4]. kidney. The radiological diagnosis depends on detecting gas in or Treatment started by resuscitation of patients in shock, and around the kidney by plain X-ray film of the abdomen or by blood sugar control for diabetic patients. Intravenous antibiot- ultrasonography (US), which can also diagnose obstruction ics (third-generation cephalosporins) were administered for all and associated stones or collections. Non-contrast CT (NCCT) patients at time of presentation. In patients with obstruction can be used to confirm the diagnosis and various radiological or extensive gaseous collections, the infected fluid and gas were classifications have been suggested based on CT. Wan et al. [3] drained using an US-guided percutaneous nephrostomy (PCN) described two distinct radiological classifications of EPN, or percutaneous tube drain (PCD). The response to treatment while Huang and Tseng [1] classified EPN into four categories. was monitored using a plain abdominal film and US for some The treatment of EPN has been a subject of controversy. patients, or NCCT in others. After stabilising the patient’s con- 99m Emergency nephrectomy after medical control of septicaemia dition, a renal radio-isotopic scan using Tc MAG3 was ta- and diabetes was reported [5,6]. The availability of effective ken to estimate the differential function of the affected kidney. antibiotics and advances in image-guided procedures resulted Preservation of the affected kidney was attempted when the dif- in the use of less aggressive surgical approaches such as percu- ferential function was >10% [13]. taneous drainage [7–9]. Moreover, some authors suggested Patients with preserved kidneys were recruited for follow-up; medical treatment alone [10]. In recent years the goals of treat- they had a clinical examination, urine analysis, plain film, US ment included improving the survival rate and preserving the and renal isotopic scan to evaluate changes in differential func- affected kidney whenever possible [11]. tion of the affected kidney. A change in renographic clearance of Risk factors for death from EPN were previously assessed >5% of the pretreatment value was considered as improvement in a meta-analysis [2], but studies discussing risk factors for or deterioration, while changes within 5% were defined as stable nephrectomy are scarce [12] and, to the best of our knowledge, function [13]. there is no study evaluating differential renal functional The data were analysed using standard methods; to deter- changes after preserving the affected kidney. The current study mine significant prognostic factors for nephrectomy, univari- was conducted to present kidney preservation protocols for ate analysis (chi-square test) and multivariate (logistic managing EPN, to determine risk factors predicting the need regression analysis) were used, with P < 0.05 taken to indicate for nephrectomy, and to show differential renographic changes statistical significance. during the follow-up of patients with preserved kidneys. Results Patients and methods The study included 33 renal units in 30 consecutive patients, as The computerized files of patients with acute pyelonephritis who three patients had bilateral EPN. The mean (SD, range) patient were treated in our centre from January 2000 to December 2010 age was 51.7 (10.9, 22–80) years. The patients’ demographics, were reviewed retrospectively. The study included patients with presentations, predisposing factors and CT classes are shown EPN who had evidence of gas in the kidney, perinephric or para- in Table 1. Six patients needed admission to the intensive care renal spaces by NCCT. We excluded patients with possible unit to manage septic shock and three presented with acute renal external introduction of gas into the urinary system (e.g. fistula failure. Urine cultures were positive in 18 patients (60%); the with gastrointestinal system, recent ureteric catheterization or most frequently isolated organism was Escherichia coli in 11 pa- recent percutaneous renal procedures). tients (60%), while Klebsiella species were responsible for the The patients’ files were reviewed for medical and surgical his- remaining positive cultures. tory, clinical presentation, predisposing factors, laboratory and Kidney preservation was attempted for 23 kidneys in 20 pa- radiological investigations, treatments, complications and out- tients; preservation methods included PCN for 12 kidneys, comes. Laboratory investigations included urine analysis and conservative (medical) treatment for nine (six patients) and Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities 187 tion in two of 20 patients (10%); the difference was statistically Table 1 Demographics, presentations and predisposing significant; P = 0.005). The overall mortality rate was 7% (two factors of 30 patients with EPN. patients); the first presented with septic shock after a trial med- Variable N (%) ical treatment of acute pyelonephritis for many days before pre- sentation to our centre, and trial resuscitation in the intensive Gender Male 8 (27) care unit failed. The second death was due to failed treatment Female 22 (73) of septic shock after emergency nephrectomy of the affected kidney. Affected side Among patients who survived, the kidney was preserved in Right 12 (40) 23 of 31 affected kidneys (74%). Any calculi were treated after Left 15 (50) 2 weeks of infection control and stabilization of the general Bilateral 3 (10) condition, with percutaneous nephrolithotomy in two and Presentation ureteroscopy in three patients. The follow-up was completed Fever and loin pain 21 (70) for 13 patients with 15 preserved kidneys for a mean (range) Shock 6 (20) of 21 (3–55) months. The function of the affected kidney was Acute renal failure 3 (10) stable in 13 of 15 while two kidneys showed an improvement Predisposing factors: in selective clearance from 25% and 50% before treatment Diabetes mellitus 23 (77) to 37% and 60% during the follow-up, respectively. Renal calculi 2 (7) Ureteric calculi 3 (10) Discussion Immunocompromise 2 (7) CT Class: EPN is a life-threatening infection characterized by the pres- I 7 (23) ence of gas in the renal parenchyma and the surrounding tis- II 8 (27) sues. Diabetes mellitus was the most frequently reported IIIa 7 (23) predisposing factor for developing EPN, as it constituted IIIb 3 (10) 80–100% of patients [5,14,15]. Of the present patients, 77% IV 5 (17) were diabetic, and the second predisposing factor was urolith- Three patients had bilateral disease and two had solitary iasis; the same was reported by Kapoor et al. [12]. kidneys. The clinical presentations of EPN among the present patients were similar to those reported previously, with loin pain and fever (70%) being the predominant symptom PCDs for extensive para-renal gaseous collection in two [7,8,16]. Patients who had delayed treatment presented with (Fig. 1). Nephrectomy was used for 10 kidneys (emergency septic shock, and those with a solitary kidney presented with in three and delayed after PCN in seven). Table 2 summarizes acute renal failure. Urine culture was positive in 60% of the the results of the univariate statistical analysis of risk factors present cases, unlike the value of 98% reported by Huang for nephrectomy. Thrombocytopenia was the only statistically and Tseng [1]. With the virtually unlimited access of patients significant factor (P = 0.009) on univariate analysis, but there to antibiotics without prescription, most were likely to have was no significant factor on multivariate analysis. tried self-medication or would have received antibiotics from Post-treatment septic shock developed after emergency the referring doctor. This ultimately might give false-negative nephrectomy in two of 10 patients, and after kidney preserva- cultures. E. coli was the predominant organism in cases with positive cultures, and these findings were consistent with the other reports [4,9,17]. Radiological detection of gas in and around the kidney is diagnostic for EPN; US is a good screening method, and it is useful in the diagnosis of stone disease and upper urinary tract obstruction. A plain X-ray of the abdomen can also detect gas in the renal region. NCCT was reported to have the highest diagnostic accuracy (100%) for EPN [9]. Therefore, NCCT was the investigation of choice, not only for diagnosing EPN but also for classifying patients into different categories [1,3,9]. Previously EPN was considered as a surgical emergency be- cause of the high mortality rate. Falagas et al. [2] conducted a meta-analysis of seven reports including 175 patients with EPN to identify risk factors for mortality. They found an over- all mortality rate of 25% (11–42%). Factors associated with increased mortality rate were conservative treatment alone, bilateral EPN, type I EPN according to the classification of Wan et al., and thrombocytopenia. More recently, Kapoor Figure 1 NCCT (axial scan) showing extensive gaseous collec- et al. [12] reported a mortality rate of 13% of 39 patients with tion affecting the parenchyma of the left kidney and extending to EPN. They concluded that altered mental status, thrombocy- the para-renal space (class IIIb). topenia, renal failure and severe hyponatraemia at presenta- 188 El-Nahas et al. Table 2 Univariate statistical analysis of risk factors for nephrectomy in 33 kidneys with EPN. Factor Preserved kidney n/N (%) Nephrectomy, n/N (%) P Odds ratio (95% CI) Gender 0.396 2.133 (0.363–12.54) Male 8/10 2/10 Female 15/23 (65) 8/23 (35) Age, years 0.441 0.533 (0.119–2.408) <50 8/13 5/13 >50 15/20 (75) 5/20 (25) Side 0.779 1.250 (0.263–5.936) Right 11/15 4/15 Left 12/18 6/18 Diabetes mellitus 0.911 1.111 (0.177–6.990) No 5/7 2/7 Yes 18/26 (69) 8/26 (31) Obesity 0.909 1.091 (0.247–4.817) Not obese (BMI < 30) 12/17 5/17 Obese (BMI > 30) 11/15 5/15 Renal obstruction 0.853 1.154 (0.255–5.223) No 10/14 4/14 Yes 13/19 (68) 6/19 (32) CT class 0.730 0.769 (0.174–3.409) I or II 10/15 5/15 III or IV 13/18 5/18 Serum creatinine, mg/dL 0.198 0.325 (0.056–1.880) <2 13/21 (62) 8/21 (38) P2 10/12 2/12 Leukocytosis 0.383 1.950 (0.431–8.828) No 13/17 4/17 Yes 10/16 6/16 Thrombocytopenia 0.009 14.67 (1.371–156.9) No 22/28 (79) 6/28 (21) Yes 1/5 4/5 a 1 Blood leukocyte count >12,000 dL . b 1 Platelet count <140,000 dL . tion were significantly associated with death. In the present mortality (6.6%) was reported with percutaneous drainage study the mortality rates were significantly lowered to 7%. then elective nephrectomy. They concluded that percutaneous The better mortality rate in our series and that of Aswathaman drainage should be part of the initial management for EPN be- et al. [11] was the result of efficient resuscitation followed by cause it was associated with a lower mortality rate than med- early percutaneous drainage if there was obstruction or no ical management or emergency nephrectomy. The advantages improvement of the patient’s condition on conservative treat- of percutaneous drainage include stabilization of patients’ con- ment alone. dition, treatment of underlying contributory factors, and a de- Emergency nephrectomy was considered by some authors creased risk associated with nephrectomy should surgery later as the surgical treatment of choice and a life-saving procedure be required. Our results support these conclusions, as there for treating EPN [5,6]. This taboo was also rejected in recent was one death due to prolonged medical management and an- years and a new treatment strategy of kidney preservation other after emergency nephrectomy. emerged [8–11]. The reasons for this change were the high mor- Conservative (medical) treatment for EPN was suggested by tality rates of emergency nephrectomy (17.6–40%) [5,6] and some authors [7,10,11]. Aswathaman et al. [11] reported com- advances in image-guided procedures for drainage of the gas plete success for conservative treatment in patients who had and infected fluids, using PCDs [9,10]. Chen et al. [8], in their no risk factors such as thrombocytopenia, shock, altered senso- experience with 25 patients, suggested that percutaneous drain- rium, and haemodialysis. Among the present patients, it was age is safe and effective for EPN, and that can result in cure. successful in six patients with nine diseased kidneys. We recom- Moreover, surgical intervention often poses a substantial risk mend considering this method for patients with localized disease for patients with haemodynamic instability. In the present pa- (class I or II in the Huang classification) who have no renal tients, methods of kidney preservation were associated with a obstruction. When patients have EPN in a solitary kidney or significantly lower complication rate (10%) than for nephrec- bilateral EPN, conservative treatment, and drainage if there is tomy (20%), whether these nephrectomies were early or de- a poor response, should be tried before embarking on nephrec- layed after drainage. tomy; this might help to obviate life-time renal dialysis [8]. Somani et al. [9] published a systematic review of 10 studies Risk factors for nephrectomy were studied by Kapoor et al. [12] on 210 patients with EPN. They found that the highest mortal- in a retrospective study of 39 patients. They found that extensive ity rate (50%) was with medical treatment alone, followed by renal parenchymal destruction of >50% (based on CT) signifi- emergency nephrectomy (25%), while percutaneous drainage cantly predicted the need for nephrectomy (P < 0.001). In the was associated with a 13.5% mortality rate and the lowest present series there was no statistically significant factor (on multi- Kidney preservation protocol for management of emphysematous pyelonephritis: Treatment modalities 189 [6] Ahlering TE, Boyed SD, Hamilton CL, Bragin SD, Chandrasoma variate analysis), possibly because there were too few nephrecto- G, Lieskovsky G, et al. Emphysematous pyelonephritis: 5-year mies (10 kidneys) or failure of all preoperative factors to affect experience with 13 patients. J Urol 1985;134:1086–8. the decision for nephrectomy. Based on our observations, we be- [7] Knockaert MM, Oven RH, Van Poppel HP. Emphysematous lieve that the primary goal in treating EPN should be preservation pyelonephritis: no longer a surgical disease? Eur J Emerg Med of the affected kidney unless its renographic clearance is <10%. 2002;9:266–9. The main limitation of our study is the retrospective nature, [8] Chen MT, Huang CN, Chou YH, Huang CH, Chiang CP, Liu but this was the main limitation of all previously published ser- GC. Percutaneous drainage of emphysematous pyelonephritis: 10- ies of EPN. The main advantage of this study is that it con- year experience. J Urol 1997;157:1569–73. firmed objectively, for the first time, that kidney preservation [9] Somani BK, Nabi G, Thorpe P, Hussey J, Cook J, N’Dow J. in patients with EPN is beneficial because the preserved kid- ABACUS research group is percutaneous drainage the new gold neys maintained their function during the follow-up. standard in the management of emphysematous pyelonephritis? Evidence from a systematic review. J Urol 2008;179:1844–9. In conclusion, kidney preservation should be the primary goal [10] Nagappan R, Kletchko S. Bilateral emphysematous pyelonephri- in treating EPN when the differential renal clearance is >10%, be- tis resolving to medical therapy. J Intern Med 1992;232:77–80. cause it was associated with fewer complications than nephrec- [11] Aswathaman K, Gopalakrishnan G, Gnanaraj L, Chacko NK, tomy. The kidney-preservation protocol includes adequate Kekre NS, Devasia A. Emphysematous pyelonephritis: outcome resuscitation, diabetic control and antibiotic coverage, followed with conservative management. Urology 2008;71:1007–9. by early drainage of obstructed systems or para-renal infected fluid [12] Kapoor R, Muruganandham K, Gulia AK, Singla M, Agrawal S, and gas. The follow-up showed a favourable functional outcome of Mandhani A, et al. Predictive factors for mortality and need for the preserved kidneys. nephrectomy in patients with emphysematous pyelonephritis. BJU Int 2010;105:986–9. 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Scand J Urol Nephrol bacterial renal infection correlation between imaging findings and 2006;40:332–8. clinical outcome. Radiology 1996;198:433–8. [16] Wan YL, Lo SK, Bullard MJ, Chang PL, Lee TY. Predictors of [4] Kumar A, Turney JH, Brownjohn AM, McMahon MJ. Unusual outcome in emphysematous pyelonephritis. JUrol 1998;159:369–73. bacterial infections of the urinary tract in diabetic patients-rare [17] Khaira A, Gupta A, Rana DS, Gupta A, Bhalla A, Khullar D. but frequently lethal. Neph Dial Transplant 2001;16:1062–5. Retrospective analysis of clinical profile prognostic factors and [5] Shokeir AA, El-Azab M, Mohsen T, El-Diasty T. Emphysema- outcomes of 19 patients of emphysematous pyelonephritis. Int tous pyelonephritis: a 15-year experience with 20 cases. Urology Urol Nephrol 2009;41:959–66. 1997;49:343–6.
Emphysematous pyelonephritis: clinico-radiological classification, management, prognosis, and pathogenesis
Risk factors for mortality in patients with emphysematous pyelonephritis: a meta-analysis
Acute gas-producing bacterial renal infection correlation between imaging findings and clinical outcome
Unusual bacterial infections of the urinary tract in diabetic patients-rare but frequently lethal
Emphysematous pyelonephritis: a 15-year experience with 20 cases
Emphysematous pyelonephritis: 5-year experience with 13 patients
Emphysematous pyelonephritis: no longer a surgical disease?
Percutaneous drainage of emphysematous pyelonephritis: 10-year experience
ABACUS research group is percutaneous drainage the new gold standard in the management of emphysematous pyelonephritis? Evidence from a systematic review
Bilateral emphysematous pyelonephritis resolving to medical therapy
Emphysematous pyelonephritis: outcome with conservative management
Predictive factors for mortality and need for nephrectomy in patients with emphysematous pyelonephritis
Recoverability of renal function after relief of chronic partial upper urinary tract obstruction
Severe emphysematous pyelonephritis in diabetic patients: diagnosis and aspects of surgical management
Outcome of nephrectomy and kidney-preserving procedures for the treatment of emphysematous pyelonephritis
Predictors of outcome in emphysematous pyelonephritis
Retrospective analysis of clinical profile prognostic factors and outcomes of 19 patients of emphysematous pyelonephritis
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