INTRODUCTION

Emphysematous pyelonephritis is an acute severe necrotizing infection of the renal parenchyma; it causes gas formation within the collecting system, renal parenchyma, and/or perirenal tissues. It is caused by gas forming organisms E coli (68%), Klebsiella spp (9%) and Proteus mirabilis most commonly. It typically occurs in immunocompromised patients especially diabetics (85–90%) and patients with obstructive uropathy (3). Diagnosis is made radiologically and clinically. It is bilateral in approximately 10% of cases (8). Radiologically, it is recognized by the presence of gas either within the renal parenchyma, the collecting system or perinephric tissues. This is seen as lucencies on plain radiographs, high amplitude echoes on ultrasound, mottled areas of low attenuation on CT and signal void on T1WI and T2WI on magnetic resonance imaging (MRI).