Post-traumatic perineal necrotizing fasciitis.

Sir,

Necrotizing fasciitis of the perineum and external genital area, also known as Fournier's Gangrene, is an infection with a polymicrobial etiology and with rapid progression that causes severe tissue destruction.

It represents an important surgical emergency, with early diagnosis and early instauration of a treatment being essential.[12] We report an unusual case of a patient who developed perianal necrotizing fasciitis extending to lower extremities and chest wall, due to a laceration in the anoderm after trauma.

A 54-year-old male who met a traffic accident was admitted. A full body computerized tomography (CT) scan was performed that showed a stable fracture with coining in the body of the fourth lumbar vertebra and comminuted fracture of tibia and right perone, without pathological findings at the thoracic-abdominal level. After 48 hours of admission, the patient developed fever, hypotension, testicular edema, and smelly anal secretions. An abdominal CT scan was performed that showed air at subcutaneous tissue in the perianal area, right gluteus, scrotum, and right thoracic-abdominal wall and, free liquid in presacral space and right ischiorectal fossa [Figure 1]. With the diagnosis of Fournier's Gangrene, broad-spectrum antibiotics were prescribed and he was taken to the operating room, where multiple surgical incisions were made (in perineum and abdominal wall) to drain purulent material [Figure 2]. During the intervention, the point of origin of the infection, a laceration in anoderm, located at 10 o’clock in gynecological position, was observed and laparoscopic colostomy was made on left flank. Cultures with isolated Escherichia coli producing broad-spectrum beta-lactamases were reported. The patient remained in the ICU in a septic shock clinical situation, but with good clinical outcome. He was transferred five days later at the Trauma Department and discharged 30 days after the trauma.

Figure 1

Images of abdominal computerized tomography (CT) scan where air is observed at subcutaneous tissue in the perianal region, right gluteus, scrotum, and right thoracic-abdominal wall, and free liquid in presacral space, right ischiorectal fossa

Figure 2

Multiple surgical incisions performed to drain purulent material and the extensive dissection of the perineum

Necrotizing fasciitis after rectal perforation due to trauma is not widely reported in the literature.[3] Most cases described are secondary to perianal diseases, such as complicated abscesses, complex fistulas, and fissures. Other causes include genitourinary infections as those postoperative of the urogenital area. The diagnosis is imminent clinically, which can be supported by imaging, where CT scan shows subcutaneous emphysema as hypodense areas, subcutaneous collections, and also provides excellent information of the locoregional extension of the disease. The most frequently isolated bacteria is Gram negative E. coli, among aerobes, and Bacteroides, among anaerobes. The treatment should be introduced early and be based on empirical antibiotic therapy, together with aggressive removal of necrotic tissue, and even the use of other therapies such as hyperbaric oxygen.[4]

Colostomy should be considered in those cases where the origin is colo-proctological; in those patients with extensive lesions to prevent contamination of infected lesions or of drainage incisions made. In doubtful cases it will be preferred to be performed the procedure as both the absence and the delay in its implementation are factors shown to increase mortality.[5]