Overview

Fournier gangrene is a condition characterised by necrotising fasciitis, which is a severe infection that involves genital, anal, or perianal area. It is a rapidly progressive cognition that requires immediate surgical intervention in the form of surgical debridement to remove dead tissue. Surgical debridement should be performed as early as possible, in addition to administering antibiotics and fluid resuscitation. This protocol minimises the mortality rate associated with Fournier gangrene.¹

Aetiology and risk factors

Fournier gangrene is a rare life-threatening infection that is usually encountered in patients with low immunity and pre-existing chronic illness. Risk factors include: 

• Sex: Fournier gangrene is more common in persons assigned male at birth (AMAB) compared to persons assigned female at birth (AFAB), with around 90% of cases encountered in AMAB patients 
• Alcohol abuse is associated with 25-50% of cases
• Diabetes: Present in around 20-70% of patients
• Obesity¹

Initiating factors of Fournier gangrene include local trauma to the affected area or infection spread from other sources like the urogenital tract, lower gastrointestinal tract, or surrounding skin. Additional sources of infection in women include female genital organs or obstetric operations. Fournier gangrene in children may be associated with circumcision, insect bites or burns.² 

Importance of early intervention

Fournier gangrene is a rapidly progressive infection with a high mortality rate (generally 40%). Delay in the diagnosis and delay in initiating surgical debridement contribute significantly to a higher mortality rate (that may reach up to 88%). Therefore, early detection of Fournier gangrene and timely surgical debridement are crucial for survival.¹

Pathophysiology of Fournier gangrene

Mechanism of infection

Infection in Fournier gangrene results from multiple microorganisms acting synergistically together, producing tissue-destructive enzymes, ultimately causing tissue death and gangrene, and spreading the infection to the surrounding tissues. 

Spread and progression

The source of the infection can be either from the urogenital tract, the bowel, or the surrounding skin. However, there could be no identifiable source of infection in 25% of cases. The spread of infection to the genitalia and perineal area can cause life-threatening Fournier gangrene in patients with low immunity, especially diabetic patients. The spread of the infection follows the facial planes and extends up to the anterior abdominal wall.¹ 

Clinical presentation

The initial symptom of Fournier gangrene is pain, and the pain may be so severe, even with small apparent lesions. Pain out of proportion to the apparent lesion should alert the clinician as it is a classic finding in Fournier gangrene.¹ Early lesions may look simple but can progress rapidly and cause complications. Patients also often present with:

• Fever, chills, and malaise
• Nausea and vomiting
• Urinary retention
• Swelling and redness of the genital and perineal regions

High-risk patients include those with diabetes, hypertension, malignancies, or chronic alcohol use.

Diagnostic workup 

Diagnosis of Fournier gangrene is primarily clinical, but can be assisted with blood tests and imaging. 

Blood test 

• Complete blood count shows an elevated white blood cell count
• Complete metabolic panels may show electrolyte abnormalities and kidney function abnormalities. This is important, as a pre-existing kidney impairment is considered a risk for Fournier gangrene development and is also associated with higher morbidity and mortality³
• Blood and wound cultures are essential to guide antibiotic therapy

Imaging 

Imaging can aid in the confirmation of Fournier gangrene extent and progression; however, imaging alone can not make up or exclude the diagnosis. Another essential point is that surgical intervention should never be delayed to obtain imaging in unstable patients, as surgical debridement is always the priority in cases of Fournier gangrene. 

• Ultrasound: May reveal gas in the scrotum (a specific sign) 
• X-ray: Detects subcutaneous gas, which is present in 90% of cases¹
• Computed tomography (CT): It is considered to be the most sensitive and the most specific imaging for Fournier gangrene, showing signs of fat around affected structures, subcutaneous gas, and abnormal fluid collections
• Magnetic resonance imaging (MRI): This is also an excellent imaging technique; however, it is not recommended as an initial investigation due to the prolonged time needed for MRI imaging

Surgical techniques and approaches

Initial management of Fournier gangrene 

There are three main principles in the initial management of Fournier gangrene: 

1. Immediate and aggressive surgical debridement
2. Rapid haemodynamic resuscitation with fluids
3. Broad-spectrum parenteral antibiotics

Surgical debridement

Initial debridement of infected tissue should be performed within 6-12 hours of presentation to remove all dead, nonviable tissue. This is vital for survival, and even hospitals without a minimum capacity for definitive care should consider performing this initial debridement before transfer. These patients also need close monitoring in the intensive care unit (ICU) due to the associated high mortality. Studies have shown a reduction in mortality rate from 40% to 10-20% in early surgical debridement and an intensive care unit (ICU) access.³

En bloc debridement is the most common approach used for Fournier gangrene debridement, and it includes the removal of all infected subcutaneous, fascial, muscle tissue, and overlying skin. However, this leaves wide defects that may then require skin grafts.³ 

Infection control

Early initiation of antibiotics along with the debridement process is essential. The choice of antibiotics is based on the most likely microorganism according to the suspected route of infection (urogenital, anorectal, or cutaneous). However, prolonged use of antibiotics is not recommended, and antibiotic de-escalation is indicated as soon as possible according to the clinical picture.³

Fluid resuscitation and pain management 

Patients with Fournier gangrene need aggressive fluid resuscitation, metabolic support, and monitoring.³ 

Repeat debridement 

Repeat debridement is usually indicated for Fournier gangrene, a “second look” debridement is usually performed after 24-48 hours of the initial one for the aim of more wound inspection and care.³

Adjuvant treatments in fournier gangrene 

• Negative-pressure wound therapy (NPWT): Applies continuous suction via foam dressings to promote healing and reduce bacterial burden
• Hyperbaric oxygen therapy (HBOT): Delivers 100% oxygen in a pressurised chamber to enhance oxygen delivery to hypoxic tissue, accelerating healing and reducing infection severity

Monitoring for disease progression 

Most patients warrant monitoring in an intensive care unit (ICU) after the initial debridement, this is essential to detect patients who require additional debridement and supportive treatments. 

Post-debridement closure of the wound 

Closure of the wound created by the aggressive surgical debridement can be done with a variety of methods:

• Primary closure of the wound by suturing 
• Healing by secondary intention, by leaving the wound open to heal by itself
• Local tissue rearrangement by recruiting healthy adjacent tissue to the wound to close the defect 
• Skin graft 
• Flap reconstruction from the perineum or the thigh

Summary

Fournier gangrene is a rare, life-threatening infection of the genital or perianal area that is most commonly encountered in patients assigned male at birth with diabetes or chronic alcohol abuse. Fournier gangrene is rapidly progressive and requires an immediate surgical debridement and antibiotics to limit the degree of tissue destruction and to improve the survival rate, patients also need rapid fluid resuscitation and monitoring in an intensive care unit. Repeat debridement, adjuvant therapies, and reconstructive procedures often form part of the treatment pathway. Early, multidisciplinary intervention is vital for optimal outcomes.