IS Case 121: Fournier gangrene
Imaging Sciences URMC 2008
Publication Date: 2009-05-20
Patient is a 64-year-old paraplegic male presenting with 4 days of fever and scrotal swelling.
The diagnosis of Fournier gangrene is primarily based upon clinical findings, however there are several characteristic imaging findings. Ultrasound examination shows gas within the scrotal wall, perineal or perirectal areas. Additionally, scrotal wall edema may be present. The testes and epididymes are usually normal. CT evaluation also demonstrates gas collections within the scrotal wall or perineal tissues. There is associated soft-tissue inflammation and fat stranding. Occasionally a perirectal abscess or focal fluid collection may also be present.
Fournier gangrene is a polymicrobial necrotizing fasciitis of the perineal, perianal, or genital region. The inciting event is usually a localized infection adjacent to the perineal region. The multiple forms of bacteria involved invade and destroy fascial planes and cause an obliterative endarteritis which leads to cutaneous and subcutaneous vascular necrosis. This extremely aggressive infection has been reported to destroy tissue and spread as fast as 2-3 cm/hour. Extension into the penis, perineum, anterior abdominal wall or urogenital diaphragm can occur. Testicular involvement is rare due to an alternate blood supply. The incidence of Fournier gangrene is not clearly known, but it appears to be quite rare. The mortality ranges from 4-75%. Factors that are associated with an increased mortality include advanced age, extent of disease, anorectal source, and development of systemic symptoms such as renal or hepatic failure. Clinical symptoms include the slow onset of pruritus and pain. Later erythema, swelling, fever and crepitus may develop. The pain may subside as necrosis occurs leading to blisters, feculent odor and necrotic tissue. Fournier gangrene occurs more frequently in males (10:1 M:F) and is also more common in patients with HIV, chronic steroid use or diabetes melitus. Fournier gangrene is a surgical emergency and urgent diagnosis and consultation is imperative for patient survival.
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