Fournier’s gangrene, sometimes called Fournier’s disease, is a bacterial infection of the skin that affects the genitals and perineum (i.e., area between the scrotum and anus in men and between the vulva and anus in women). The disease develops after a wound or abrasion becomes infected.
A combination of anaerobic (living without oxygen) microorganisms (e.g., staphylococcal) and fungi (e.g., yeast) causes an infection that spreads quickly and causes destruction (necrosis) of skin, tissue under the skin (subcutaneous tissue), and muscle.
Staphylococcal bacteria clot the blood, depriving surrounding tissue of oxygen. The anaerobic bacteria thrive in this oxygen-depleted environment and produce molecules that instigate chemical reactions (enzymes) that further the spread of the infection.
Fournier’s gangrene can be fatal if the infection enters the bloodstream.
Incidence and Prevalence of Fournier’s Gangrene
Men are ten times more likely than women to develop Fournier’s gangrene. Men aged 60-80 with a predisposing condition are most susceptible.
Women who have had a pus-producing bacterial infection (abscess) in the vaginal area, a surgical incision in the vagina and perineum to prevent tearing of skin during delivery of a child (episiotomy), an abortion resulting in fever and an infection of the lining of the uterus (septic abortion), or surgical removal of the uterus (hysterectomy) are susceptible.
Rarely, children may develop Fournier’s gangrene as a complication from a burn, circumcision, or an insect bite.
Risk Factors for Fournier’s Gangrene
Men with alcoholism, diabetes mellitus, leukemia, morbid obesity, and immune system disorders (e.g., HIV, Crohn’s disease), and intravenous drug users are at increased risk for developing Fournier’s gangrene.
The condition also can develop as a complication of surgery.
Causes of Fournier’s Gangrene
Fournier’s gangrene develops when bacteria infect the body through a wound, usually in the perineum, the tube that carries urine outside the body from the bladder (urethra), or the colorectal area.
Existing immune system deficiencies help infection to spread quickly, producing a disease that destroys the skin and superficial and deep fascia (membranes that separate muscles and protect nerves and vessels) of the genital area.
The chambers in the penis that fill with blood to create an erection (corpora cavernosa), testicles, and urethra are not usually affected.
Signs and Symptoms of Fournier’s Gangrene
Early physical symptoms of Fournier’s gangrene may not indicate the severity of the condition. Pain sometimes diminishes as the disease progresses. Symptoms are progressive and include the following:
- Crepitant (“spongy” to the touch) skin
- Dead and discolored (gray-black) tissue; pus weeping from injury
- Fever and drowsiness (lethargy)
- Increasing genital pain and redness (erythema)
- Severe genital pain accompanied by tenderness and swelling of the penis and scrotum
Fournier’s Gangrene Diagnosis
Physical examination and blood tests are used to diagnose Fournier’s gangrene and the diagnosis is made when examination reveals gangrenous (i.e., spongy, weeping, discolored) skin.
Microscopic examination of a tissue specimen (biopsy) may be taken if visible symptoms are insufficient to distinguish between Fournier’s and other bacterial infections.
Fournier gangrene is typically seen in diabetic men aged 50-70, but is rarely seen in women. Other than age, predisposing factors include:
- perineal/scrotal pain, swelling, redness
- crepitus from soft tissue gas (up to 65%)
- systemically unwell
- fever and leukocytosis
The source of infection can usually be identified, most commonly anorectal (such as from a fistula or perianal abscess) and less commonly genitourinary or perineal trauma. Sometimes the cause is not found.
The infection is usually polymicrobial. The commonest organisms cultured are E.coli, Klebsiella, Proteus, Staph, Strep.
It begins as a cellulitis that causes an endarteritis and then necrotising infection that spreads through the fascial planes. The organisms often produce gas, thus causing a gas gangrene.
The diagnosis is usually clinical. The role of imaging includes:
- diagnosis not established
- determine extent of disease
- detect underlying cause
- thickened scrotal wall
- echogenic gas foci in scrotum pathognomonic – seen as dirty shadowing
- testes and epididymi spared (due to their separate blood supply)
- soft tissue stranding, fascial thickening
- soft tissue gas
- extent of disease can be assessed prior to surgery
- cause of infection may be apparent (e.g. perianal abscess, fistula)
Treatment for Fournier’s Gangrene
Antibiotics (often double or triple drug therapy) along with aggressive surgical removal of the diseased tissue is required immediately for an optimal outcome.
Without early treatment, bacterial infection enters the bloodstream and can cause delirium, heart attack, respiratory failure, and death.
Complications of Fournier’s Gangrene
Incomplete debridement (surgical removal of dead tissue) allows wound infection to continue to spread. In this event, follow-up surgery is performed.
It was first described by French venereologist Jean Alfred Fournier in 1883 who noted a fulminating gangrenous infection of male genitalia in young healthy males without an obvious cause.
The differential in the setting of acute scrotal pain includes:
- testicular torsion
- testicular trauma
- scrotal cellulitis/abscess