Not Just Rectal Bleeding: A Case of Fournier’s Gangrene EMRA

A 59-year-old man with a history of recently diagnosed anal squamous cell carcinoma and alcohol use disorder presented to the ED with rectal bleeding and pain that had worsened over a week.

On arrival, the patient had low-normal blood pressure but otherwise normal vitals, and was uncomfortable appearing and rigoring. An exam revealed perianal erythema, fluctuance, induration, and tenderness, with necrotic bullae in the perineum. General surgery was urgently consulted, and the patient received fluid resuscitation and broad-spectrum antibiotics.

Labs were significant for WBC 31.2 bil/L, Hgb 12.3 g/dL, Na 135, Cr 2.3, CO2 14 mmol/L, anion gap 26, glucose 149 mg/dL, INR 1.3, CRP 529 mg/L, and lactate 12.6 mmol/L. A CT abdomen/pelvis with contrast revealed stranding and gas tracking from the right buttock and perineum through the retroperitoneum to the aortic bifurcation in the abdomen, concerning for an ascending necrotizing infection such as Fournier’s gangrene.

Epidemiology and Pathophysiology
Fournier’s gangrene is a rapidly progressive necrotizing soft tissue infection of the perineal, genital, or perianal regions. An eponymous disease named after French dermatologist and venereologist Jean Alfred Fournier (1832–1914 CE), Fournier’s gangrene has been described even in earlier historical records by Persian physician Abu Ali al-Husayn ibn Sina (980–1037 CE).¹

While rare (<0.02% of hospital admissions), Fournier’s is highly morbid with a mortality rate approaching 40% even with optimal treatment; delays in diagnosis and care can increase the mortality rate to 88%.¹ Key risk factors include diabetes mellitus, alcohol use disorder, immunosuppressive states, colorectal malignancy, recent trauma or surgery to the area, and the use of SGLT2 inhibitors, although a significant portion (up to 30%) of patients do not have any comorbidities.^1,2 Male sex is associated with a higher incidence of Fournier’s, but female patients are more acutely ill upon presentation, experience longer hospitalizations, and have higher rates of multiorgan failure and case fatality.²

Necrotizing soft tissue infections are typically categorized by the involvement of any or multiple soft tissue layers, including cellulitis (epidermis, dermis, subcutaneous tissue), fasciitis (fascia), and myositis (muscle). In Fournier’s, infections are typically polymicrobial involving genitourinary, gastrointestinal, and cutaneous organisms which produce endotoxins and tissue-destructive enzymes that facilitate rapid extension along fascial planes into surrounding pelvic organs and deeper structures.^1,2 This results in fulminant tissue destruction, ischemic gangrene, and often systemic toxicity.

Presentation and Diagnosis
Fournier’s gangrene, as with other necrotizing soft tissue infections, is a clinical diagnosis. Early clinical manifestations include localized erythema without sharp margins, edema and induration, itchiness, and tenderness. As these findings can be present in much more common infections and dermatologic conditions, early cases can be very difficult to identify — up to 75% of early cases are misdiagnosed.¹ Later manifestations include bullae formation, crepitus, skin necrosis, and purulent drainage.¹

Clinicians should thoroughly inspect the genitourinary and perianal regions for these malignant and sometimes indolent findings, especially in patients who appear systemically ill with fever, malaise, or hemodynamic instability. Severe pain out of proportion to exam should also raise clinical suspicion for a necrotizing infection.¹

Laboratory testing is nonspecific and should not be used in isolation to diagnose Fournier’s, but it can assist with triage and prognostication. Patients may have a leukocytosis with left shift, elevated inflammatory markers, electrolyte abnormalities such as hyponatremia, metabolic and lactic acidosis, and signs of renal failure. Blood cultures may be positive in a subset of patients but more so in monomicrobial necrotizing infections.³

While the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score is a clinical decision tool used in the diagnosis of necrotizing infections, its sensitivity for Fournier’s gangrene among ED patients is unacceptably low (68-80%).² However, one study suggests that a LRINEC score ≥9 may be a useful predictor of mortality in Fournier’s.⁴ Other risk calculators including the Fournier’s Gangrene Severity Index (FGSI) have been developed to predict disease severity but are not routinely used in the ED setting.²

Imaging can help diagnose, but cannot rule out, Fournier’s. CT is the most sensitive (88.5%) and specific (93.3%) in diagnosing a necrotizing infection.¹ The presence of gas on X-ray is highly specific (94%), but poorly sensitive (49%).² Point-of-care ultrasound can be utilized to identify “dirty shadows” as a sign of subcutaneous gas.² MRIs are cost- and time-intensive and are not recommended as an initial imaging modality. Critically ill patients may need immediate surgical intervention if there is high clinical suspicion, and their disposition to the OR should not be delayed to obtain imaging. Ultimately, definitive diagnosis only occurs during surgical exploration.²

Management
Fournier’s gangrene is a surgical emergency. Time to surgical intervention is the most significant modifiable risk factor for mortality in these necrotizing infections, and early intervention can halve the mortality rate.²

Surgery involves radical exploration and aggressive, wide debridement of necrotic and gangrenous tissue, often done in stages.¹ Depending on the anatomy involved, the surgical team may comprise any combination of urology, general surgery, colorectal surgery, OB/GYN, and plastic surgery.

Broad-spectrum antibiotic therapy is a cornerstone of medical management. Empiric therapy should cover gram-positive, gram-negative, and anaerobic organisms. Acceptable regimens include a carbapenem (e.g., ertapenem) or beta-lactamase inhibitor (e.g., piperacillin-tazobactam), plus an agent with MRSA activity (e.g., vancomycin or linezolid), plus clindamycin for its antitoxin and mortality benefits.³ Doxycycline should be added for those with wounds exposed to freshwater (Aeromonas) or sea water (V. vulnificus).³ Antifungal coverage can be considered for those with significant risk factors.

Because electrolyte derangements often co-occur, fluid resuscitation is warranted, especially in cases of sepsis or septic shock. Preferred treatment is with balanced crystalloids such as PlasmaLyte or Lactated Ringer’s.¹ Patients with hypotension and organ hypoperfusion refractory to appropriate fluid resuscitation should be started on vasopressors, particularly norepinephrine.² With surgery being the only definitive treatment for Fournier’s, medical interventions should not delay prompt surgical consultation and intervention.

After debridement, patients may require reconstructive surgeries and/or vacuum-assisted wound closure devices, and those with significant perineal or anorectal involvement may need fecal diversion such as a temporary colostomy to promote wound healing.¹ If available, hyperbaric oxygen therapy can be used as a post-operative adjunct, as it has been shown in some studies to facilitate wound healing and decrease mortality.⁵

Case Conclusion
The patient was taken emergently to the OR with general surgery, colorectal surgery, and urology for wide debridement. Post-operatively, he was admitted to the surgical ICU with septic shock and multiorgan system failure and required multiple OR takebacks, including loop colostomy creation. The patient was continued on broad-spectrum antibiotics. He had a prolonged hospital course and was discharged after a 2-month stay.

References

Not Just Rectal Bleeding: A Case of Fournier’s Gangrene

A 59-year-old man with a history of recently diagnosed anal squamous cell carcinoma and alcohol use disorder presented to the ED with rectal bleeding and pain that had worsened over a week.

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