What is the etiology of Fournier's gangrene?

Etiology of Fournier's Gangrene

Fournier's gangrene is primarily a polymicrobial infection with three main sources of origin: perineal skin (24%), colorectal region (21%), and genitourinary tract (19%), with 36% of cases having an unknown origin. 1

Microbiology

• Typically polymicrobial infection involving both aerobic and anaerobic bacteria 1
• Common aerobic organisms include:
  • Streptococcus species 1
  • Staphylococcus species 1
  • Escherichia coli 1
• Anaerobic organisms are also frequently involved, contributing to the rapid tissue destruction 1, 2

Pathophysiology

• The disease process begins with a localized infection that allows entry of commensal bacteria into the perineum 1
• Inflammatory response leads to obliterative endarteritis with thrombosis of surrounding vessels 1
• Vascular compromise causes tissue ischemia, promoting further anaerobic bacterial proliferation 1
• The resulting fascial necrosis and tissue digestion spread rapidly along fascial planes 1, 3
• Infection can extend cranially to the abdominal wall and caudally to the legs via superficial perineal fascia 1
• Testicular involvement is rare due to their non-perineal blood supply 1

Risk Factors

• Diabetes mellitus is a major predisposing factor 1, 4
• Obesity is commonly associated 1
• Conditions causing impaired host resistance and reduced cellular immunity:
  • Alcoholism 1, 5
  • HIV infection 1, 5
  • Leukemia and other immunocompromising conditions 1
• Local tissue trauma or surgery can serve as entry points 4, 6
• Hidradenitis suppurativa may predispose to infection 4
• Inflammatory bowel disease has been reported as a rare predisposing condition 6

Epidemiology

• Predominantly affects males with a male to female ratio of 42:1 1
• Mean age of presentation is 51 years 1
• Overall incidence is approximately 1.6 cases per 100,000 males annually 1
• Accounts for less than 0.02% of all hospital admissions 1
• Mortality rates vary widely, ranging from 7.5% to as high as 88% in some studies 1

Unusual Etiologies

• Streptococcus anginosus has been reported as a causative organism in some cases 4, 2
• Rare organisms such as Actinomyces turicensis and Peptoniphilus harei have been isolated in immunocompetent patients 2
• Inflammatory bowel disease complications can rarely lead to Fournier's gangrene 6

The aggressive nature of Fournier's gangrene requires prompt recognition and immediate intervention with surgical debridement and broad-spectrum antibiotics to reduce the high associated mortality 1, 7.