Emphysematous pyelonephritis (EPN) is an acute, severe necrotizing infection of the renal parenchyma and perirenal tissue. A 72-year-old female patient with uncontrolled diabetes mellitus was admitted to a hospital with loss of consciousness and, fever. Laboratory data suggested acute inflammation and hyperosmolar hyperglycemic syndrome. The left EPN was accurately diagnosed after abdominal computed tomographic (CT) scan revealed renal parenchymal gas and fluid within the subcutaneous tissue and mediastinum. The patient was transferred to our institution and underwent emergent open surgical drainage. However, a CT scan performed 3 days after the drainage revealed the presence of fluid in the left perinephric space. CT-guided drainage of the left perinephric fluid was performed. The patient was finally discharged after complete recovery from severe inflammation.