Emphysematous Pyelonephritis From a Perinephric Hematoma Complicated by Fournier's Gangrene: A Case Report.

Fournier's gangrene and emphysematous pyelonephritis are rare necrotizing infections of the genitourinary system. Many cases of this rapidly progressive infection occur from abscesses and urinary tract infections; however, Fournier's gangrene secondary to emphysematous pyelonephritis is seldom discussed in the literature. Emphysematous pyelonephritis is defined as a gas-forming, necrotizing infection of the renal parenchyma or its surrounding tissue. Emphysematous pyelonephritis has been observed in high-risk individuals, including those with poor glycemic control and urinary tract obstruction. We present a 61-year-old male with emphysematous pyelonephritis arising from a perinephric hematoma with tracking of the infection to the scrotum, resulting in Fournier's gangrene. The perinephric hematoma most likely developed from increased intrarenal hydrostatic pressure during nephroureteral stent placement. Broad-spectrum antibiotic therapy and surgical debridement of the retroperitoneum, groin, and scrotum were performed ultimately requiring left orchiectomy. We conclude that an existing hematoma can precipitate emphysematous pyelonephritis with tracking from the retroperitoneum to scrotum, causing Fournier's gangrene. High-risk patients with perinephric hematomas can be susceptible to this pathologic transformation.