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Saudi Journal of Kidney Diseases and Transplantation
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Year : 2014  |  Volume : 25  |  Issue : 4  |  Page : 823-829
Emphysematous infections of the kidney and urinary tract: A single-center experience

1 Department of Internal Medicine, Armed Forces Medical College, Pune, India
2 Department of Nephrology, Armed Forces Medical College, Pune, India

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Date of Web Publication24-Jun-2014


Emphysematous pyelonephritis (EPN) is a group of potentially life-threatening conditions seen particularly in diabetics, leading to high morbidity and mortality. Our aim was to study the profile of emphysematous infections of the kidney and urinary tract and evaluate the effect of early surgical intervention on mortality. This is an observational study conducted in a tertiary care hospital between January 2009 and January 2013, in which the clinical, laboratory, microbiological and radiological profiles of patients with EPN (diagnosed based on clinical, laboratory and imaging findings) was studied. A total of 12 patients were studied, including 10 with diabetes. A total of 66.6% had pyelonephritis, 25% had both cystitis and pyelonephritis and 8.3% had only cystitis; involvement of the left kidney was more common and bilateral involvement was seen in two cases. The clinical features seen in the patients included fever (100%), features of urinary infection (66.6%) and flank pain (50%). Culture positivity was seen in only 50% of the cases. Ten patients underwent percutaneous drainage (PCD) within 24 h, and two of these patients required nephrectomy subsequently. All patients were followed-up for one month. There was one death (mortality 8.3%), and all other patients responded well and reco­vered. Our study suggests that EPN is a potentially life-threatening condition that requires aggressive and prompt medical therapy with early PCD to reduce morbidity and mortality. Nephrectomy should be reserved for cases that do not respond to PCD.

How to cite this article:
Behera V, Vasantha Kumar R S, Mendonca S, Prabhat P, Naithani N, Nair V. Emphysematous infections of the kidney and urinary tract: A single-center experience. Saudi J Kidney Dis Transpl 2014;25:823-9

How to cite this URL:
Behera V, Vasantha Kumar R S, Mendonca S, Prabhat P, Naithani N, Nair V. Emphysematous infections of the kidney and urinary tract: A single-center experience. Saudi J Kidney Dis Transpl [serial online] 2014 [cited 2022 May 18];25:823-9. Available from: https://www.sjkdt.org/text.asp?2014/25/4/823/135164

   Introduction Top

Emphysematous pyelonephritis (EPN) is a severe and life-threatening infection of the renal parenchyma, collecting system or peri-nephric tissue, which is characterized by the presence of gas in the parenchymal tissue. [1] The out­come of this condition has significantly im­proved over the years due to early diagnosis by better imaging modalities and a change in treatment strategies from nephrectomy to a more conservative nephron-sparing approach. We present a clinico-radio-pathological profile of a series of patients with EPN in which the patients were aggressively managed and early percutaneous surgical drainage (PCD) was performed.

   Subjects and Methods Top

Settings and design

This is an observational study conducted in a tertiary care hospital between January 2009 and January 2013. All patients with emphyse-matous infections of the kidney and urinary tract were studied.

Definition of EPN

For the purpose of this study, EPN was de­fined by the presence of fever, chills, flank pain or tenderness; imaging findings of gas in the renal parenchyma, peri-nephric tissue, bladder or other areas of the urinary tract [de­monstrated by X-ray abdomen/ultrasonography (USG)/computerized tomography (CT) scan or magnetic resonance imaging (MRI) of the abdomen], evidence of pyuria and/or hema-turia or urine culture growing an organism. The clinical, laboratory, microbiological and radiological profile of the cases was studied.

All patients were managed with (a) empirical broad-spectrum intravenous (i.v.) antibiotics (carbapenems or fourth-generation cephalos-porins or ureidopenicillins) followed by the antibiotics as per sensitivity pattern, (b) aggres­sive glycemic control in diabetics (with i.v. insulin infusion to keep the blood sugar below 200 mg/dL followed by insulin in basal bolus regimen till recovery), (c) supportive therapy including fluid administration guided by monitoring the central venous pressure (CVP), electrolyte correction and hemodialysis (if re­quired) or (d) PCD using a pigtail nephros-tomy catheter under USG or CT guidance within 24 h of diagnosis. The patients were observed for the next 48 h. Nephrectomy was considered if the patient failed to improve despite PCD. Patients who had minimal gas restricted to the collecting system (stage I Huang and Tseng class, discussed later) did not follow this protocol and were managed with only medical treatment.

All patients were followed-up for one month and the clinical, laboratory and radiological response to therapy was noted.

   Statistical Analysis Top

The data collected was studied and appro­priate statistical analysis was performed using the SPSS software version 17.

   Results Top

A total of 12 cases were included over a four-year period. Ten patients had pre-existing diabetes, among whom eight patients (66.6%) had uncontrolled hyperglycemia at presenta­tion and two patients had diabetic ketoaci-dosis; the mean blood sugar of the patients at presentation was 252 mg/dL. One patient had associated neurogenic bladder due to under­lying post-traumatic paraplegia and another was positive for human immunodeficiency virus (HIV) antibody. The mean age of the study patients was 56.5 years (range 39-75 years) and there were seven females (58.3%).

Fever was seen in all patients, features of urinary infection (dysuria, pyuria) in eight pa­tients (66.6%) and flank pain was seen in six patients (50%), as shown in [Table 1]. Leuko-cytosis was seen in eight patients (66.6%) (mean TLC 14,350/mm [3] ) and elevated serum creatinine was seen in six patients (50%), as shown in [Table 2]. Eight patients (66.6%) had pyelonephritis, three (25%) had both cystitis and pyelonephritis and one (8.3%) had only cystitis. The left urinary tract was more com­monly involved (58.3%) than the right side (25%), and two patients had bilateral involve­ment, as shown in [Table 3]. Features of hydro-nephrosis were present in eight patients (66%). Urine culture was positive in six cases with growth of E. coli in three, Klebsiella in two and Proteus in one patient. The poor prognostic markers included presence of bila­teral disease, thrombocytopenia, hypotension, elevated creatinine and altered sensorium which were seen in seven patients.
Table 1: Clinical presentation of emphysematous pyelonephritis in the study patients.

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Table 2: Mean investigation reports among the patients with emphysematous pyelonephritis.

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Table 3: Summary of the study patients with emphysematous pyelonephritis.

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Empirical i.v. antibiotics were administered to all patients as per our protocol and, subse­quently, the antibiotics were changed based on the culture sensitivity. Three patients required dialysis support. Of the 12 patients studied, 10 patients underwent PCD within 24 h. One patient had only cystitis and was managed with medical therapy alone and the second patient expired, before PCD could be attempted. Among the 10 patients who underwent PCD, two patients had to undergo subsequent nephrectomy due to failure of proper drainage by PCD or extensive involvement of the renal system not improving with PCD.

One death occurred among the 12 patients studied (mortality 8.3%). This patient presented with fulminant bilateral pyelonephritis, septic shock and multi-organ dysfunction and died within six hours of admission despite immediate medical and other resuscitative measures. One patient who required dialysis after one month, was followed-up for three months and was found to be dialysis dependent due to under­lying diabetic nephropathy. All other patients responded well and recovered completely.

   Discussion Top

EPN is an acute necrotizing infection of the kidney or urinary system caused by gas-for­ming organisms. The first such case was re­ported by Kelly and MacCullum in 1898. [2] The term "emphysematous pyelonephritis" was first used in 1962 by Schultz and Klorfein because it stresses the relationship between acute renal infection and gas formation. [3]

EPN is commonly seen in diabetics and immune-compromised patients, with other re­ported risk factors being i.v. drug abuse, neu-rogenic bladder, alcoholism, malnutrition or anatomic anomalies of the urinary tract. [4],[5] As in our study, diabetes mellitus is the single most common predisposing factor. [6] With the gradual increase in the population with HIV, this may also be considered as an emerging risk factor.

EPN is mostly caused by gram negative orga­nisms, and E. coli is the most commonly iso­lated organism. The other causative organisms are Proteus, Klebsiella, coagulase negative Staphylococcus and anaerobes like anaerobic Streptococcus and Clostridium septicum. [7]

Candida albicans, Cryptococcus neoformans and Pneumocystis jiroveci have also been reported as causative pathogens. [8]

Factors involved in the pathogenesis include high levels of glucose within the tissues, the presence of gas-forming micro-organisms, im­paired vascular supply, reduced host immunity and the presence of obstruction within the uri­nary tract. [9] It is hypothesized that a high level of tissue glucose in association with impaired blood supply to the kidneys, which is prevalent in patients with diabetes, facilitates the process of anaerobic metabolism of glucose and lactate by the micro-organisms, leading to production of gases like carbon dioxide, nitrogen, hydro­gen, oxygen and methane. [10]

Clinical features of EPN include features of pyelonephritis such as dysuria, fever/rigors, nausea, vomiting and flank pain. Fever is seen in over 80% of the affected patients. [11] Loin tenderness is a common finding and, rarely, a crepitus may be felt around the renal area and the scrotum. [12] The common laboratory abnor­malities include leukocytosis, azotemia, hyper-glycemia and urinary findings like pyuria and hematuria. [13] In a study by Kumar et al, fever, dysuria and abdominal pain were noted in all, vomiting in 30%, palpable abdominal mass in 20% and hypotension in 10%, while leuko-cytosis and pyuria were found in all patients. [14]

Radiological evaluation is required for the diagnosis. Plain X-ray of the abdomen may re­veal mottled gas shadows in the renal region followed by the development of a crescent of gas surrounding the kidneys. Based on plain X-ray and intravenous pyelogram, Michaeli et al [5] suggested a classification as shown in [Table 4]. Ultrasonography reveals strong focal echoes in the renal area. The interpretation of X-ray and USG may be limited in the presence of bowel gas or in obese patients. CT scan or MRI are better imaging modalities, and are diagnostic of EPN. Huang and Tseng classified EPN based on CT scan features of location and extent of gas in the renal and urinary systems [Table 4]. [12]
Table 4: Classification of emphysematous pyelonephritis.

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Wan et al identified two distinct pathological types of EPN. [15] In individuals with poor immunity, type I EPN is seen, which is charac­terized by parenchymal destruction, absence of fluid collection and presence of streaky or mottled gas. Individuals with good host immu­nity develop type II EPN, characterized by re­nal or peri-renal fluid collections with bubbly or loculated gas in the collection system. Thus, Wan's type I EPN is associated with more extensive parenchymal necrosis and fulminant clinical course than type II EPN.

The diagnosis of EPN is based on a high index of suspicion and by imaging techniques. Treatment involves institution of appropriate antibiotic support, control of diabetes with in­sulin, correction of fluid and electrolyte imba­lance, hemodialysis (if required) and establish­ment of drainage for the infected and obs­tructed systems. Presence of bilateral disease, uncontrolled diabetic state, findings of type I EPN, thrombocytopenia, hypotension, altered sensorium and impaired renal function are predictors of poor outcome and carry a bad prognosis. [4],[7]

The medical management includes early use of broad-spectrum parenteral antibiotics. As gram-negative bacteria remain the common causative organisms, the initial empirical anti­biotic regimen includes fourth-generation cepha-losporins or carbapenems or ureidopenicillins with aminoglycosides. [7] Once the culture report is available, the antibiotics can be changed according to the culture sensitivity report. Aminoglycosides should be used with caution with appropriate monitoring as patients with EPN often have associated azotemia.

Drainage procedures or surgery have been the cornerstone of therapy in EPN. [16] The accepted treatment of EPN until the late 1980s was emergency nephrectomy or open surgical drai­nage, which carried a high morbidity and mortality. During the last decade, there has been a gradual shift toward a nephron-sparing approach with CT or USG-guided PCD. [17],[18] The advantages of PCD include drainage of pus, relief of gas under pressure and lesser morbidity to the patient. [7] The mortality asso­ciated with medical management alone was 50%, medical management combined with emergency nephrectomy was 25% and medical management combined with PCD was 13.5%. [18] Since the first use of percutaneous catheters by Hudson et al, [19] significant advances have been made in PCD techniques, which has led to a gradual decline in mortality of EPN. [20] The average overall mortality in EPN is about 25%, ranging from as high as 42% in the nephrectomy era to about 11% after the advent of PCD and better antibiotics. [4]

In our study, aggressive medical therapy and early PCD improved the prognosis of the illness; there was only one death, yielding a mortality of 8.3%. Based on our study, we pro­pose a treatment protocol for EPN. The pa­tients should be given aggressive medical ma­nagement in the form of broad-spectrum antibiotics, strict glycemic control and other supportive therapy like dialysis, if required. In cases where gas collection is seen in the kid­neys or surrounding peri-renal tissue, prompt PCD should be performed. Nephrectomy should be reserved only for cases in whom PCD fails or those who have extensive disease not ame­nable to PCD.

   Conclusion Top

EPN is a potentially life-threatening condi­tion commonly associated with diabetes and immune-suppressed states. It requires a high index of suspicion for an early radiological confirmation of diagnosis. Aggressive and prompt medical therapy with early PCD the­rapy is the key for reducing morbidity and mortality. A combined team approach by a nephrologist, urologist, endocrinologist, inten-sivist, radiologist and pathologist may be adopted for achieving better outcomes of this condition.

   References Top

1.Pontin AR, Barnes RD, Joffe J, Kahn D. Emphysematous pyelonephritis in diabetic patients. Br J Urol 1995;75:71-4.  Back to cited text no. 1
2.Kelly HA. Pneumaturia. JAMA 1898;31:375-81.  Back to cited text no. 2
3.Schultz EH Jr, Klorfein EH. Emphysematous pyelonephritis. J Urol 1962;87:762-6.  Back to cited text no. 3
4.Falagas ME, Alexiou VG, Giannopoulou KP, Siempos II. Risk factors for mortality in patients of emphysematous pyelonephritis: A meta-analysis. J Urol 2007;178:880-5.  Back to cited text no. 4
5.Michaeli J, Mogle P, Perlberg S, Heiman S, Caine M. Emphysematous pyelonephritis. J Urol 1984;131:203-8.  Back to cited text no. 5
6.Shokeir AA, El-Azab M, Mohsen T, El-Diasty T. Emphysematous pyelonephritis: A 15-year experience with 20 cases. Urology 1997;49: 343-6.  Back to cited text no. 6
7.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;41:959-66.  Back to cited text no. 7
8.Kamaliah MD, Bhajan MA, Dzarr GA. Emphy-sematous pyelonephritis caused by Candida infection. Southeast Asian J Trop Med Public Health 2005;36:725-7.  Back to cited text no. 8
9.Wan YL, Lee TY, Bullard MJ, Tsai CC. Acute gas-producing bacterial renal infection: corre­lation between imaging findings and clinical outcome. Radiology 1996;198:433-8.  Back to cited text no. 9
10.Turney JH. Renal conservation for gas forming infections. Lancet 2000;355:770-1.  Back to cited text no. 10
11.Tang HJ, Li CM, Yen MY, et al. Clinical characteristics of emphysematous pyelo-nephritis. J Microbiol Immunol Infect 2001; 34:125-30.  Back to cited text no. 11
12.Huang JJ, Tseng CC. Emphysematous pyelo­nephritis: Clinical radiological classification, management, prognosis and pathogenesis. Arch Intern Med 2000;160:797-805.  Back to cited text no. 12
13.Ubee SS, McGlynn L, Fordham M. Emphyse-matous pyelonephritis. BJU Int 2011;107: 1474-8.  Back to cited text no. 13
14.Kumar VS, Lakshmi AY. Emphysematous pyelonephritis. Indian J Nephrol 2004;14:192-4.  Back to cited text no. 14
15.Wan YL, Lo SK, Bullard MJ, Chang PL, Lee TY. Predictors of outcome in emphysematous Pyelonephritis. J Urol 1998;159:369-73.  Back to cited text no. 15
16.Soo Park B, Lee SJ, Wha Kim Y, Sik Huh J, Il Kim J, Chang SG. Outcome of nephrectomy and kidney-preserving procedures for the treatment of emphysematous pyelonephritis. Scand J Urol Nephrol 2006;40:332-8.  Back to cited text no. 16
17.Chen MT, Huang CN, Chou YH, Huang CH, Chiang CP, Liu GC. Percutaneous drainage in the treatment of Emphysematous Pyeloneph­ritis: 10 year experience. J Urol 1997;157: 1569-73.  Back to cited text no. 17
18.Somani BK, Nabi G, Thorpe P Hussey J, Cook J, N'Dow J; ABACUS Research Group. Is percutaneous drainage the new gold standard in the management of emphysematous pyelo­nephritis? Evidence from a systematic review. J Urol 2008;179:1844-9.  Back to cited text no. 18
19.Hudson MA, Weyman P, Van der Vliet AH, Catalona WJ. Emphysematous pyelonephritis: successful management by percutaneous drai­nage. J Urol 1986;136:884-6.  Back to cited text no. 19
20.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;59:192-7.  Back to cited text no. 20

Correspondence Address:
Vineet Behera
Department of Internal Medicine, Armed Forces Medical College, Pune, Maharashtra, 411 040
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1319-2442.135164

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