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 (see Images 1-2). In patients with emphysematous pyelitis, the collecting system may be filled with gas. An ileus pattern may be seen, suggesting retroperitoneal inflammation.
- Renal sonograms often reveal high echogenic areas with dirty shadowing. Hydronephrosis and perinephric fluid may also be seen (see Image 3).
- 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 (see Images 4-6). 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.
- 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.
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Workup: Emphysematous Pyelonephritis |
| Treatment: Emphysematous Pyelonephritis |
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| Multimedia: Emphysematous Pyelonephritis |
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References
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Wan YL, Lo SK, Bullard MJ, Chang PL, Lee TY. Predictors of outcome in emphysematous pyelonephritis. J Urol. Feb 1998;159(2):369-73. [Medline].
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Huang JJ, Chen KW, Ruaan MK. Mixed acid fermentation of glucose as a mechanism of emphysematous urinary tract infection. J Urol. Jul 1991;146(1):148-51. [Medline].
Yang WH, Shen NC. Gas-forming infection of the urinary tract: an investigation of fermentation as a mechanism. J Urol. May 1990;143(5):960-4. [Medline].
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Gaither K, Ardite A, Mason TC. Pregnancy complicated by emphysematous pyonephrosis. J Natl Med Assoc. Oct 2005;97(10):1411-3. [Medline].
Langston CS, Pfister RC. Renal emphysema. A case report and review of the literature. Am J Roentgenol Radium Ther Nucl Med. Dec 1970;110(4):778-86. [Medline].
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].
Wu VC, Fang CC, Li WY, Hsueh PR, Chu TS. Candida tropicalis-associated bilateral renal papillary necrosis and emphysematous pyelonephritis. Clin Nephrol. Dec 2004;62(6):473-5. [Medline].
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
Workup: Emphysematous Pyelonephritis