Computed tomography in emphysematous pyelonephritis.

A 44-year-old woman presented to our emergency department with fever, right flank and abdominal pain for one week. Her past medical history depicted that she had asthma and newly diagnosed diabetes. Direct abdominal X-ray revealed hyperlucent areas in the right kidney lodge (A). Abdominal computed tomography (CT) with contrast showed free gas collection with fatty infiltration outlining the right perirenal space (B). Right kidney also had increased attenuation comparing to the left one. The patient was admitted to the urology department with the diagnose of sepsis due to emphysematous pyelonephritis. Right nephrectomy was recommended to the patient with intravenous antibiotics and drainage. Several classification systems have been proposed to correlate imaging findings with subsequent prognosis and management in patients with emphysematous pyelonephritis. The mildest forms are confined to collecting system or form loculated air-fluid collections in or adjacent kidneys. This may be amenable to percutenous drainage. The more severe infections are characterized by spread of gas into the renal paranchyma and can extend into the perinephric and paranephric spaces and often require emergency nephrectomy as occured in our case. Conventional radiographs may demonstrate a cluster of mottled lucencies within the kidneys.