Definition and Key Features Emphysematous pyelitis is a condition where gas is confined to the pelvicalyceal system. Importantly, there is no involvement of the renal parenchyma. This condition is most commonly linked with obstructive urinary tract infections, such as those caused by stones. Gas-producing bacteria, particularly E. coli, are often responsible. It's worth noting that this condition frequently occurs in diabetic patients. Radiological Findings Plain Radiograph O