Fournier gangrene is a genital and perineal necrotizing fasciitis secondary to polymicrobial synergistic infection
Risk Factors– immunocompromised, alcoholics, diabetics, smoking, hypertension,
Pathophysiology
Infection from 4 sources
- 21% colorectal- appendicitis(ruptured), diverticulitis, colon cancer, peri-rectal abscess
- 19%genitourinary- urethral fistula, stones or strictures
- 24 %dermatological
- 36%idiopathic
Clinical Features
- Pruritus of sudden onset that quickly progresses to erythema, oedema and necrosis of scrotal skin, perianal area and phallus in hours
- Malaise, fever and chills
- Tissue crepitus in the case of organisms that form gas
Diagnosis
Primarily clinical
Other tests to help with diagnosis include
- Complete blood count- RBC cell mass, thrombocytopenia due to sepsis
- Coagulation profile- coagulopathy due to sepsis
- Urine and blood cultures –septicemia and to determine the type of bacteria
- Arterial blood gases- hyperglycemia or hypoglycemia acidosis
- Blood glucose- glucose intolerance due to diabetes or sepsis
- UECs- electrolyte imbalances secondary to dehydration
- Plain x-ray- extent and presence of disease
- CT- Preferred to x-ray since it is more specific in defining disease extent
- Incisional biopsy- during surgery to differentiate cellulitis from necrotizing fasciitis as the source of Fournier gangrene
Management
1. Broad-spectrum antibiotics for coverage of both aerobic and anaerobic bacteria since infection is polymicrobial. Use penicillin + Beta lactamase inhibitor metronidazole. For MRSA, use Vancomycin
2. Wide debriding followed by aggressive support post-operatively
Note- often testes are not affected as they have a different blood supply
Differential Diagnosis
- Cellulitis
- Epididymitis
- Gas gangrene
- Balanitis
- Testicular torsion
- Orchitis
