Rationale: Emphysematous pyelonephritis is a life-threatening infectious disease that requires early diagnosis and treatment. The disease is often misdiagnosed due to its diversity of clinical manifestations. Patient\'s concern: A 62-year-old woman was admitted to the emergency department following a 12-hour history of abdominal pain and dyspnea. Physical examination showed percussion pain on the right costovertebral angle. Besides, she had a history of diabetes mellitus and urinary calculus. Diagnosis: Emphysematous pyelonephritis. Intervention: The patient accepted antishock therapy, tight glucose control, and broad-spectrum anti-infective therapy. After stabilization of the general condition, an ultrasound-guided percutaneous nephrostomy was performed. Outcome: Her conditions became stable over the following days. She presented a favorable clinical course, with normalization of renal function and positive improvements in imaging findings in a month. Lessons: Early diagnosis and rapid medical management are the keys to successful treatment. CT is an important method for the diagnosis of emphysematous pyelonephritis. For patients with severe lesions, percutaneous renal drainage combined with active anti-infection should be given in time.