Fact-sheet: Emphysematous pyelonephritis
Updated on 08/23/2017 at 7:13 AM
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Definition
Rare necrotizing infection of the kidney characterized by the
presence of gas within the renal parenchyma, excretory
cavities, or perirenal spaces.
Occurs in diabetic patients
Severe, life-threatening condition.
The causative organism is most often Escherichia coli (93%).
Clinical features
Renal colic, chills, fever, nausea and vomiting
Radiography
Lucencies in the renal area, interpretation of which may be hindered by bowel gas superimposition.
Ultrasound
At the early stage: heterogeneous nephromegaly. Clusters of microbubbles appear as hyperechoic areas with reverberation and posterior attenuation and may be mistaken for calculi
At the advanced stage: dense, heterogeneous, highly echogenic mass in the renal fossa, mimicking a bowel loop.
CT
Reference examination
Presence of gas within the renal parenchyma and assessment of parenchymal destruction. It allows evaluation of the perirenal spaces and thus defines the extent of the lesions.
Classification
•
Hung and Tseng CT classification:
-Stage 1: gas confined to the collecting system
-Stage 2: gas in the renal parenchyma without extension into the extrarenal space
-Stage 3A: extension of gas or abscess into the perinephric space
-Stage 3B: extension of gas or abscess into the pararenal space
-Stage 4: bilateral emphysematous pyelonephritis or emphysematous pyelonephritis in a solitary kidney