DEFINITION Emphysematous pyelonephritis is an acute necrotizing infection characterized by gas formation. It is characterized by the presence of gas in and around the kidney. ETIOLOGY E. coli (58%) and K. pneumoniae (21%) are the organisms most commonly isolated. Clostridium and Enterobacter spp may also be responsible, 7% each. RISK FACTORS 1) Diabetes mellitus (70-90%)- usually patients with poor glucose control. High levels of glucose in the urine serve as a substrate for these bacteria and large amounts of gas are generated through natural fermentation 2) Obstruction (25-40%)- it is another common predisposing factor for emphysematous pyelonephritis. For non-diabetics, protein fermentation is a proposed source of gas formation. CLINICAL FEATURES 7% of cases may be asymptomatic. If symptomatic, patients may complain of pneumaturia, irritative lower tract voiding symptoms, flank pain or may present in a severe septic condition with an acute abdomen and hig