eMedicine Specialties > Urology > Infections and Related Inflammatory Conditions
Emphysematous Pyelonephritis: Workup
Updated: May 1, 2008
Workup
Laboratory Studies
- A high index of suspicion is important when attempting to diagnose emphysematous pyelonephritis (EPN) promptly.
- Laboratory data reveal leukocytosis with a left shift, pyuria, infected urine, thrombocytopenia, an elevated creatinine level, and positive blood culture results.
- Patients with urosepsis and shock should undergo cardiac and pulmonary function assessment as needed.
Imaging Studies
- Patients should be stabilized with intravenous fluids and intravenous antibiotics prior to radiologic intervention.
- Kidneys, ureter, and bladder imaging often reveals gas distribution over the region of the kidneys, as depicted in the images below. In patients with emphysematous pyelitis, the collecting system may be filled with gas. An ileus pattern may be seen, suggesting retroperitoneal inflammation.
Kidneys, ureter, and bladder imaging showing a streaky gas pattern over the entire right kidney in a patient with emphysematous pyelonephritis.
Emphysematous pyelonephritis. Kidneys, ureter, and bladder imaging showing gas over the region of the right kidney. White arrows outline the area. The faint outline of a staghorn calculus can be seen in the right kidney.
- Renal sonograms often reveal high echogenic areas with dirty shadowing. Hydronephrosis and perinephric fluid may also be seen, as depicted in the image below.
Emphysematous pyelonephritis. Renal sonogram showing hyperechoic shadows suggestive of gas along the lower pole of the kidney.
- CT scanning is the definitive test. Several patterns have been described, including streaky, streaky and mottled, and streaky and bubbly. Gas can be rimlike or crescent-shaped in the perinephric area. Gas can also be seen in the renal vein or inferior vena cava,as depicted in the images below. Gas can be seen along the psoas muscle. Perinephric abscess may also lead to significant gas accumulation in the perinephric space. A stone may be seen in the collecting system.
Emphysematous pyelonephritis. CT scan showing gas in the left kidney, with stones and xanthogranulomatous pyelonephritis.
CT scan showing right renal and perinephric gas in a patient with emphysematous pyelonephritis.
CT scan showing gas in both kidneys and the inferior vena cava in a patient with bilateral emphysematous pyelonephritis.
- Radiological classification
- In 1970, Langston and Pfister described 3 main radiographic patterns, as follows:13
- Diffuse mottling of the renal parenchyma
- Bubbly renal parenchyma surrounded by crescent-shaped gas in the perinephric space
- Extension of gas through the Gerota fascia
- In 1984, Michaeli et al suggested 3 stages of EPN, as follows:14
- Stage I - Gas within the renal parenchyma or the perinephric tissue
- Stage II - Presence of gas in the kidney and its surroundings
- Stage III - Extension of gas through Gerota fascia or bilateral EPN
- In 1996, Wan et al described 2 distinct types of EPN, as follows:15
- Type I - Characterized by parenchymal destruction with streaky or mottled parenchymal gas with an absence of fluid collection, which has a fulminant course and high risk of mortality
- Type II - Characterized by renal or perirenal fluid collection with bubbly gas collection in the perinephric space or in the collecting system and a mortality rate of 18% (According to Wan et al, the compromised immune state of the host leads to fulminant and dry-type EPN, which is fatal.)
- In 2000, Huang et al modified the staging proposed by Michaeli et al, as follows:1
- Class 1 - Gas confined to the collecting system
- Class 2 - Gas confined to the renal parenchyma alone
- Class 3A - Perinephric extension of gas or abscess
- Class 3B - Extension of gas beyond the Gerota fascia
- Class 4 - Bilateral EPN or EPN in solitary kidney
- Note that the classifications are not comparable.
- In 1970, Langston and Pfister described 3 main radiographic patterns, as follows:13
Staging
See Imaging Studies.
More on Emphysematous Pyelonephritis |
| Overview: Emphysematous Pyelonephritis |
 Workup: Emphysematous Pyelonephritis |
| Treatment: Emphysematous Pyelonephritis |
| Follow-up: Emphysematous Pyelonephritis |
| Multimedia: Emphysematous Pyelonephritis |
| References |
| Further Reading |
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References
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Michaeli J, Mogle P, Perlberg S, Heiman S, Caine M. Emphysematous pyelonephritis. J Urol. Feb 1984;131(2):203-8. [Medline].
Wan YL, Lee TY, Bullard MJ, Tsai CC. Acute gas-producing bacterial renal infection: correlation between imaging findings and clinical outcome. Radiology. Feb 1996;198(2):433-8. [Medline].
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. May 1997;157(5):1569-73. [Medline].
Aswathaman K, Gopalakrishnan G, Gnanaraj L, Chacko NK, Kekre NS, Devasia A. Emphysematous Pyelonephritis: Outcome of Conservative Management. Urology. Mar 25 2008;[Medline].
Ahlering TE, Boyd SD, Hamilton CL, Bragin SD, Chandrasoma PT, Lieskovsky G, et al. Emphysematous pyelonephritis: a 5-year experience with 13 patients. J Urol. Dec 1985;134(6):1086-8. [Medline].
Ahmad M. Emphysematous pyelonephritis due to Aspergillus fumigatus: a case report. J Nephrol. May-Jun 2004;17(3):446-8. [Medline].
George J, Chakravarthy S, John GT, Jacob CK. Bilateral emphysematous pyelonephritis responding to nonsurgical management. Am J Nephrol. 1995;15(2):172-4. [Medline].
Guvel S, Kilinc F, Kayaselcuk F, Tuncer I, Ozkardes H. Emphysematous pyelonephritis and renal amoebiasis in a patient with diabetes mellitus. Int J Urol. Jul 2003;10(7):404-6. [Medline].
Roy C, Pfleger DD, Tuchmann CM, Lang HH, Saussine CC, Jacqmin D. Emphysematous pyelitis: findings in five patients. Radiology. Mar 2001;218(3):647-50. [Medline].
Wheeler LD. Cystitis emphysematosa: case report. J Urol. Jan 1954;71(1):43-8. [Medline].
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Further Reading
For additional information, visit Medscape’s Diabetic Microvascular Complications Resource Center and Stone Disease Resource Center.
Keywords
emphysematous pyelonephritis, emphysematous pyelitis, gas-forming infection of the urinary tract, EPN, renal parenchyma infection, urinary tract infection, UTI, pneumaturia, renal emphysema, pneumo-nephritis, pneumonephritis, diabetes, xanthogranulomatous pyelonephritis
