|CASE IN POINT - CLINICS IN NEPHROLOGY
|Year : 2016 | Volume
| Issue : 2 | Page : 114-117
Emphysematous pyelonephritis: Retrospective analysis of 12 patients over a 2-year period
Midhun Ramesh1, Ashutosh Mungi2, Jayakrishnan Cherakkarakuzhiyil Peethambaran2, Praveen Murlidharan1, Satish Balan1
1 Department of Nephrology, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India
2 Department of Medicine, Kerala Institute of Medical Sciences, Trivandrum, Kerala, India
|Date of Web Publication||30-Dec-2016|
Department of Nephrology, Kerala Institute of Medical Sciences, P.B. No. 1, Anayara P. O., Trivandrum - 695 029, Kerala
Source of Support: None, Conflict of Interest: None
Emphysematous pyelonephritis (EPN) is a life threatening infection of the renal parenchyma with gas formation, usually caused by the organism Escherichia coli and carries significantly high mortality rates. This study is a retrospective analysis of all cases of EPN admitted to our institute over a two year period. The clinical details, demographics, associations with co-morbid illnesses and urinary tract obstruction have been considered. The outcomes to treatment were assessed. Twelve patients of EPN were studied during the period of January 2013 to December 2014. The majority of them were females (male:female = 3:9) with a mean age of 51 years. Left sided EPN was more common than the right side. Three cases (25%) had bilateral EPN. Eleven patients were diabetics and ten cases had renal dysfunction. E. coli was the most common organism detected in urine culture and blood culture was sterile in most of the cases. Mean duration of hospital stay was 13 ± 4.86 days. The majority of patients responded to medical management and only one patient required unilateral nephrectomy. The literatures on EPN management suggest vigorous resuscitation and appropriate medical treatment, followed by immediate nephrectomy. However, with advancement of critical care nephrology, we conclude that aggressive management with appropriate antibiotics, strict diabetic control along with other supportive measures like renal replacement therapies will yield satisfactory results. Surgical intervention is required for urinary obstruction and nephrectomy should be reserved for the few patients who continue to deteriorate despite medical management and correction of obstruction.
Keywords: Emphysematous pyelonephritis, pyelonephritis emphysematousa, renal emphysema
|How to cite this article:|
Ramesh M, Mungi A, Peethambaran JC, Murlidharan P, Balan S. Emphysematous pyelonephritis: Retrospective analysis of 12 patients over a 2-year period. Astrocyte 2016;3:114-7
|How to cite this URL:|
Ramesh M, Mungi A, Peethambaran JC, Murlidharan P, Balan S. Emphysematous pyelonephritis: Retrospective analysis of 12 patients over a 2-year period. Astrocyte [serial online] 2016 [cited 2019 Jun 15];3:114-7. Available from: http://www.astrocyte.in/text.asp?2016/3/2/114/197253
| Introduction|| |
Emphysematous pyelonephritis (EPN) is a life threatening infection, characterized by gas formation within or around the kidney and is associated with high mortality rates. 
The first case of EPN was reported in 1898 by Kelly and Mac Callum.  It has been described under various terminologies since then such as renal emphysema, pyelonephritis emphysematousa and pneumonephritis.  Schultz and Klorfein proposed the term "EPN" in 1962. 
EPN has preponderance for diabetics with poor glycemic control. The exact incidence of EPN is unknown. Hardly 300 cases have been reported till date, with varying treatment success rate. It is commonly a unilateral disease with the left kidney affected more than the right. Bilateral involvement is reported in approximately 5% of cases. Female to male ratio is 2:1. The pathogenesis, classifications, prognostic factors, appropriate therapeutic regimen are all controversial.  It has been hypothesized that reduced state of immunity and high blood glucose levels in diabetics makes them susceptible to anaerobic gas forming micro organisms resulting in EPN.  In the absence of any early therapeutic intervention these cases rapidly progress to Sepsis. 
The management strategy suggested by various authors include vigorous resuscitation and aggressive medical management followed by immediate nephrectomy. ,, Overall, mortality rates is about 11%. 
| Case Series|| |
The purpose of this report is to highlight the changes in the management strategies and outcome of EPN cases with advancement of renal medicine. We conclude that aggressive medical management with broad spectrum antibiotics and strict diabetic control along with other supportive measures including timely renal replacement therapies (RRT) in indicated cases yields satisfactory results. Surgical intervention is needed only for urinary obstruction and nephrectomy should be reserved only for very severe involvement.
| Discussion|| |
Twelve patients of EPN were studied during the period January 2013 to December 2014. The majority of them were females (M:F = 3:9) with mean age of 50.67 ± 13.9 years. Women outnumbered men probably due to their increased susceptibility to urinary tract infections [Table 1]. These patients presented with vague clinical symptoms such as fever, abdominal pain, nausea, vomiting with rapid clinical deterioration. Diabetes was present 91.67% (11) of the cases. Fever and abdominal pain was present in 91.67% (11) of patients. Most patients with EPN had deranged renal function and hyponatremia at presentation [Table 2].
A history of renal intervention in form of D-J stenting or lithotripsy was present in 6 (50%) cases and history of urinary tract infection was present in 25% (3) cases. Five (41.6%) cases were hypertensive and two cases had history of coronary artery disease.
Blood culture was sterile in majority (58%) of patients. Pyuria was present in almost all cases. Ultrasound was insensitive for the diagnosis of renal gas, but useful in diagnosing urinary tract obstruction. The sensitivity of USG in picking up EPN was 41.5% and that of non contrast CT was 100% in our study. Non-contrast CT scan remains the diagnostic method of choice. In addition to showing the presence of gas, it was useful to define the extent of the infection and also detected urinary tract obstructions [Figure 1]. Left sided EPN was more common than right side. Three cases had bilateral EPN [Table 2].
|Figure 1: Non-contrast abdominal CT coronal section. A crescent of air is visible as low attenuation lucency inferior to the right renal margin. The patient also has a double J stent in situ to negotiate the obstruction|
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E. Coli (5 cases) was the commonest organism detected in culture, followed by Enterococci, Klebsiella and mixed growth in one case each [Figure 2]. Almost all species of E coli isolated were extended spectrum beta-lactamases producers. Majority of patients responded to medical management. Only one patient, in the present study required unilateral nephrectomy
The main predisposing factors of EPN are diabetes mellitus (DM) and obstruction of urinary tract. Escherichia More Details coli and Klebsiella pneumonia are the two most common bacteria resulting in EPN.
Mixed acid fermentation and alcoholic fermentation of glucose by gram negative facultative anaerobes is the major pathway of formation of gas which is mainly composed of nitrogen, carbon dioxide and hydrogen. The gas formation further results in septicemia by compression or destruction of the normal renal parenchyma.
Wan et al.  classified EPN into two categories:
The role of percutaneous drainage (PCD) of abscess in the management of EPN was emphasized by Huang et al.,  based on their experience on class 1 and 2 of EPN patients. These patients were treated with PCD/ureteral catheterization and antibiotics; with high survival rates. They advocated surgical intervention in the first line of management of EPN.
- Type I EPN characterized by parenchyma destruction with either absence of fluid or presence of streaky or mottled gas
- Type II EPN characterized with either renal or perirenal fluid collection with bubbly, loculated gas or gas in the collecting system.
The present study is in concordance to the observations in similar studies done worldwide in terms of commonest pathogen,  co-morbidities and sex ratio, but the mortality rate of EPN in this study was nil. A hundred percent survival rate was achieved with prompt initiation of broad spectrum antibiotics and supportive care. Aggressive management in form of optimal glycemic control and use of appropriate antibiotic yielded satisfactory results [Figure 3]. All patients were initially put on Ertapenem in doses adjusted for degree of renal function; based on our institutional policy, suspecting ESBL infection. Later, de-escalation was done to Piperacillin-Tazobactam or to a sensitive oral antibiotic (Nitrofurantoin/Septran), if culture and sensitivity patterns were favorable and patient showed significant clinical improvement so as to complete a total course of 14 days to 21 days. Immediate surgical intervention in form of double J stenting was sought when there was evidence of ureteric obstruction in CT and nephrectomy was done in one case of very severe involvement where medical management failed and kidney was replaced with pus.
|Figure 3: Sensitivity pattern of the microorganism in emphysematous pyelonephritis|
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The spectrum of antibiotic sensitivity is different from that seen in literature. This might be because of a referral bias to a tertiary care center, as most of our cases were referred from peripheral hospitals after a short course of antibiotics and may be due to the fact that there has been a steep rise in antibiotic resistance in recent years.
| Conclusion|| |
We recommend early diagnosis, and aggressive management in the form of strict diabetic control and use of broad spectrum antibiotics in all EPN cases. Surgical intervention is needed where obstruction exists and nephrectomy is required only in very severe cases which are refractory to medical management.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]