Fournier Gangrene

What happens in Fournier gangrene

Bacteria enter the deep tissues of the perineum, usually from a nearby infection or small wound. A mix of bacteria, often including E. coli, Streptococcus, Staphylococcus, Bacteroides and other anaerobes, work together to produce toxins and cause clotting in small blood vessels. Tissues lose their blood supply and die (gangrene). The infection spreads quickly along the fascia, the connective tissue layers, sometimes as fast as an inch (2 to 3 cm) an hour, and can extend to the abdomen and thighs. Because the deeper tissues are affected first, the skin can look less severe than the damage underneath.

Causes and sources of infection

• Anorectal infections: perianal abscesses, fistulas and diverticulitis. See perianal abscess.
• Urinary tract sources: urethral stricture, catheter injury, epididymitis, kidney stones.
• Skin infections of the genitals or perineum, including infected hair follicles.
• Trauma or surgery in the area, including hemorrhoid procedures, circumcision and vasectomy, and genital piercings.
• Insect bites or minor injuries.

Risk factors

• Diabetes: the most common risk factor, especially when poorly controlled
• SGLT2 inhibitor diabetes medicines: the FDA has warned about rare cases of Fournier gangrene in people taking them
• Obesity
• Alcohol misuse
• Weakened immune system: HIV, cancer, chemotherapy, long-term steroids
• Kidney or liver failure
• Older age and peripheral vascular disease

Symptoms

Early

• Pain, tenderness and swelling in the genitals, perineum or around the anus
• Pain that is out of proportion to the visible signs
• Redness and warmth of the skin
• Fever, chills and feeling generally unwell
• Itching or discomfort that rapidly becomes severe

Advanced

• Skin that becomes dusky, purple, gray or black
• Blisters filled with dark fluid
• Crackling under the skin (crepitus) from gas produced by bacteria
• A foul-smelling discharge
• Numbness as nerves are destroyed
• Signs of sepsis and septic shock: fast heart rate, low blood pressure, confusion, reduced urine

Diagnosis

Fournier gangrene is a clinical diagnosis. Surgery should not be delayed for tests when it is suspected.

• Physical examination of the genitals, perineum and surrounding areas.
• Blood tests: blood count, glucose, kidney function, lactate, inflammation markers and blood cultures. Scoring systems use these to estimate risk.
• Imaging: CT scan can show gas in tissues and the extent of spread, and look for an abdominal or pelvic source. Ultrasound may show gas in the scrotal wall.
• Surgical exploration confirms the diagnosis: tissues that separate easily, gray dead fascia, and "dishwater" fluid.

Treatment

• Emergency surgery (debridement): all dead and infected tissue is removed. Most people need repeat operations every 24 to 48 hours until all infection is cleared. The testicles are often spared because they have a separate blood supply.
• Broad-spectrum IV antibiotics: started immediately, covering many types of bacteria, then adjusted to culture results.
• Intensive care support: fluids, medicines to support blood pressure, blood sugar control.
• Diversion procedures: a temporary colostomy to keep stool away from wounds, or a suprapubic catheter to divert urine, in some cases.
• Wound care: dressings or vacuum-assisted closure (negative pressure wound therapy).
• Reconstruction: skin grafts or flaps once the infection is controlled.
• Hyperbaric oxygen therapy is used in some centers, but evidence is mixed.

Outlook

Fournier gangrene is a serious condition with a significant risk of death, often reported at around 20 to 40 percent, higher in older adults, those with diabetes or other illnesses, and when treatment is delayed. Survivors usually need long hospital stays and reconstruction, and may have lasting effects on sexual and urinary function and body image. Early recognition and surgery are the most important factors for survival.

Prevention

• Control blood sugar well if you have diabetes.
• Keep the genital and perianal area clean and dry.
• Seek prompt treatment for abscesses, urinary problems and perianal infections.
• If you take an SGLT2 inhibitor, know the warning signs and seek care quickly for genital or perineal pain and swelling.

Frequently asked questions

What are the first signs of Fournier gangrene?

Early signs are pain, swelling and redness in the genitals, perineum or around the anus, often with fever and feeling generally unwell. The pain is often much more severe than the skin appearance suggests. Seek emergency care immediately if you notice these, especially if you have diabetes.

What causes Fournier gangrene?

It is caused by a mix of bacteria that enter the deep tissues, usually from an infection of the anus or rectum, urinary tract or skin of the genitals, or after trauma or surgery. Diabetes, obesity, alcohol misuse and a weakened immune system greatly increase the risk.

Can women get Fournier gangrene?

Yes. Although it is much more common in men, women can develop Fournier gangrene of the vulva and perineum, often from abscesses, childbirth injuries, surgery or episiotomy. The warning signs and treatment are the same.

Is Fournier gangrene linked to diabetes medicines?

The FDA has warned that rare cases of Fournier gangrene have been reported in people taking SGLT2 inhibitors such as canagliflozin, dapagliflozin and empagliflozin. The risk is very low, but anyone taking these medicines should seek urgent care for pain, redness or swelling in the genital or perineal area.