Fournier Gangrene

Fournier gangrene is a rapidly progressive necrotising soft tissue infection involving the perineum, genitalia or perianal tissues.

It is usually polymicrobial, with synergistic aerobic and anaerobic organisms causing thrombosis of small subcutaneous vessels and fascial necrosis.

Diabetes, obesity, immunosuppression, renal disease, anorectal sepsis and urogenital infection increase risk, but absence of these factors does not exclude disease.

This is a surgical emergency.

Early findings can be deceptively mild.

High value warning signs are:

• Pain disproportionate to superficial appearance
• Rapid progression
• Perineal oedema and induration
• Skin discoloration or bullae
• Crepitus
• Skin anaesthesia
• Necrosis
• Severe systemic toxicity

Shock may occur before extensive skin necrosis becomes visible.

Diagnosis is clinical.

CT pelvis: useful in a stable uncertain patient to define extent and identify anorectal or urogenital source, but imaging must not delay debridement.

Laboratory scores cannot reliably exclude Fournier gangrene.

Begin resuscitation, antibiotics and operative preparation simultaneously.

Empirical adult therapy can use:

Piperacillin tazobactam 4.5 g IV every 8 hours by extended infusion

plus

Vancomycin IV, weight and renal function adjusted with AUC guided monitoring.

If streptococcal or clostridial toxin mediated disease is strongly suspected, add:

Clindamycin 900 mg IV every 8 hours.

Perform immediate aggressive surgical debridement of all necrotic skin, subcutaneous tissue and fascia until healthy bleeding tissue is reached.

Do not preserve visibly nonviable tissue for cosmetic reasons.

Return to theatre within approximately 24 to 36 hours, and repeatedly thereafter, until no further necrosis remains.

Identify and treat the source, such as perianal abscess, rectal perforation or urogenital infection.

Urinary diversion is required when urethral injury or extensive periurethral disease prevents safe urethral drainage.

Faecal diversion is selective rather than automatic. Consider a colostomy with major anal sphincter involvement, rectal perforation or uncontrollable faecal contamination of the wound.

Hyperbaric oxygen, where available, must never delay operative debridement.

Definitive reconstruction with skin grafts or flaps occurs only after infection has been eradicated and a healthy granulating wound remains.