A 45-year-old woman presented to our hospital complaining of fever, leukocytosis, elevated serum creatinine and requested CT KUB.

CT KUB was performed and shows features suggestive of emphysematous pyelitis or reflux emphysematous cystitis rather than emphysematous pyelonephritis.

The patient responded poorly to antibiotics alone then the double J stent was inserted with a continuous antibiotic. CT KUB examination was then performed and showed a persistently swollen and edematous left kidney and total resolution of the previously noted multiple gas pockets seen within the collecting system as well as the upper cortical parenchyma.

Huang and Tseng defined four classes of emphysematous pyelonephritis; our patient had class 1 emphysematous pyelonephritis (so-called emphysematous pyelitis), which is a milder form with a better prognosis.

Emphysematous pyelitis is a term representing gas-forming urinary tract infection that is associated with gas localized in only the renal collecting system.