What is Fournier gangrene?

What is Fournier Gangrene

Fournier gangrene is a life-threatening necrotizing fasciitis of the genital, perineal, and perianal regions caused by polymicrobial infection that requires immediate recognition and emergency surgical intervention to prevent mortality rates that can reach 20-50%. 1, 2

Definition and Pathophysiology

Fournier gangrene is a rapidly progressive polymicrobial infection involving both aerobic organisms (Streptococcus species, Staphylococcus species, Escherichia coli) and anaerobic bacteria that causes necrotizing fasciitis of the external genitalia and perineum 1, 3.

The disease process follows a specific pathophysiologic cascade:

• Localized infection allows commensal bacteria to enter the perineum, triggering an inflammatory response 1
• Obliterative endarteritis with thrombosis of surrounding vessels occurs, causing tissue ischemia 1
• Vascular compromise promotes anaerobic bacterial proliferation and rapid tissue destruction 1
• Infection can extend cranially to the abdominal wall and caudally to the legs via superficial perineal fascia 1

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 range from 7.5% to as high as 88% in some studies, with contemporary series showing 20-50% mortality 1, 2, 4

Risk Factors

The most important predisposing conditions include:

• Diabetes mellitus is the major risk factor 1, 3
• Obesity is commonly associated 1, 3
• Immunocompromising conditions (leukemia, HIV, chronic alcoholism) that cause impaired host resistance and reduced cellular immunity 1, 4

Anatomic Sources and Portals of Entry

• Perianal and perirectal abscesses represent the most common etiology at 45.8% of cases 1
• Urethral damage provides a portal of entry for bacteria 1
• Anal sphincter involvement with fecal contamination can serve as an infection source 1
• Local cutaneous sources may also be involved 2

Clinical Presentation

The World Journal of Emergency Surgery recommends assessing for the following cutaneous manifestations:

• Erythema and tenderness to palpation 2
• Subcutaneous crepitations (indicating gas in tissues) 2
• Patches of gangrene 2
• Foul smell 2
• Purulence or wound discharge 2

The infection can present with systemic manifestations including septic shock and multiple organ dysfunction syndrome 5.

Diagnostic Approach

Laboratory investigations should include:

• Complete blood count with differential looking for leukocytosis 2
• Inflammatory markers (C-reactive protein and procalcitonin) to guide diagnostic and therapeutic decisions 2
• Blood cultures obtained before initiating antibiotics 2

Imaging studies:

• Contrast-enhanced CT scan is the preferred imaging modality with 90% sensitivity and 93.3% specificity for evaluating disease extent and identifying underlying causes 2
• Bedside ultrasound is an alternative when CT is not available, demonstrating marked scrotal skin thickening, soft tissue inflammation, collections/abscesses, and subcutaneous gas 2

Prognostic assessment:

• The Fournier's Gangrene Severity Index (FGSI) should be calculated to predict outcomes, combining physiological parameters including temperature, heart rate, respiration rate, sodium, potassium, creatinine, leukocytes, hematocrit, and bicarbonate 2, 4

Management Principles

The American College of Surgeons recommends prompt recognition and immediate intervention with surgical debridement and broad-spectrum antibiotics to reduce the high associated mortality 1.

Key management steps include:

• Immediate broad-spectrum antibiotic therapy covering aerobic and anaerobic organisms 6, 4
• Emergency aggressive surgical debridement 3, 6
• Cultures of infected fluid and tissues obtained during initial surgical debridement to guide specific antibiotic management 2
• Repeat debridement after 24 hours is recommended 4
• Foley catheterization for urinary diversion in most cases 6
• Diverting colostomy should be considered when simple catheterization is not sufficient or with severe fecal contamination 6
• Negative pressure wound therapy (NPWT) after debridement 3, 4
• Intensive care unit admission when indicated for septic shock and organ dysfunction 6, 5

A common pitfall is delayed recognition—early diagnosis with aggressive surgical treatment is the key to reducing mortality, as the disease progresses rapidly and can be fatal if untreated 6, 7.