Risk Factors of Fournier's Gangrene - A Complete Guide

Introduction:

Fournier’s gangrene is a highly infectious, debilitating soft tissue lesion usually affecting males and immunocompromised or co-morbid patients. The infection progresses deep into the soft tissues and involves the underlying subcutaneous fat and muscle, causing necrotic degeneration of the tissues leading to multi-organ failure. This necrotizing soft tissue lesion usually affects the male genital organs like the penis, scrotum, and perineum. Women and children are less commonly affected. This highly infectious benign tissue lesion is of bacterial origin and is caused by polymicrobial agents, which include group A - beta-hemolytic Streptococcus (Streptococcus pyogenes), Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Proteus, and anaerobes like Bacteroides and Clostridium perfringens. This is a urological emergency that demands aggressive surgical debridement and antibiotic therapy.

How Does One Get Fournier's Gangrene (FG)?

Fournier’s gangrene usually develops from perianal or genital skin infections. Trauma to the pelvic or perineal region, anorectal or urogenital trauma, and pelvic interventions can also predispose to FG. Some of the most common causes include,

1. Urogenital:

• Urethral stricture.

• Indwelling catheters.

• Traumatic catheterization procedures.

• Calculi involving urethra.

• Biopsy of the prostate gland.

• Vasectomy.

• Penile prosthesis insertion.

• Tension-free vaginal tape procedure (TVT).

• Aspiration of hydrocele.

• Rupture of the ileal neobladder.

• Intracavernosal cocaine injection.

• Genital piercing.

2. Anorectal:

• Perianal abscess.

• Rectal biopsy.

• Anal dilatation.

• Haemorrhoidectomy.

• Rectosigmoid malignancy.

• Appendicitis.

• Diverticulitis.

3. Gynecological:

• Infected Bartholin’s gland.

• Septic abortion.

• Wound caused by episiotomy.

• Coital injury.

• Genital mutilation.

4. Comorbid conditions like diabetes mellitus and chronic alcohol use pose a high risk for developing FG.

5. Patients with HIV (human immuno-virus) infection are at high risk.

What Happens When One Gets the Fournier’s Gangrene (FG)?

• Most of the polymicrobial aerobic and anaerobic organisms like Coliforms, Klebsiella, Streptococci, Staphylococci, Clostridia, Bacteroides, and Corynebacteria and E.coli are the normal commensals in the perineum and genital region in the human body. When the host immunity becomes impaired, these commensals become virulent, invading the host tissues and causing tissue damage.

• The impaired immunity of the host enables the infection to spread rapidly along the fascial planes of the skin and go undetected.

• Various exotoxins and enzymes like collagenase, heparinase, hyaluronidase, streptokinase, and streptodornase are released by the synergistic activity of aerobes and anaerobes. These enzymes cause tissue destruction and result in the spread of infection.

• Heparinase and collagenase released by the aerobes cause microvascular thrombosis and dermal necrosis due to their induced complement fixation and platelet aggregation.

• During the course of the suppurative infection, micro thrombosis results, causing obstruction of blood flow in small subcutaneous vessels supplying the overlying skin.

• Necrotic tissues further enable the spread of the infection, as phagocytic activity is impaired in such tissues.

What Are the Clinical Features of Fournier’s Gangrene (FG)?

FG is known for its vast heterogenetic clinical findings where some patients present with slow onset and gradual progression, whereas some report the acute onset and fulminant course of the infection. And the affinity is more toward elderly men. The signs and symptoms include,

• Fever and chills.

• Nausea and vomiting.

• Dehydration.

• Malaise.

• Severe pain and swelling involving the genital area.

• Fetid suppuration (smell from the involved tissues).

• Crepitus (crackling sound heard on palpation).

• Anemia.

• Disseminated intravascular coagulation.

• Tachycardia.

• Hypotension.

• Urethral obstruction.

• Urinary extravasation (filling of urine in cavities other than the urinary bladder).

• Sepsis.

• Multi-organ failure.

What Are the Risk Factors of FG?

• Diabetes mellitus.

• Chronic alcohol use.

• Weak immune system.

• Chemotherapy.

• Chronic use of corticosteroids.

• HIV (human immuno-virus)/AIDS (acquired immunodeficiency syndrome).

• Leukemia.

• Liver disease.

• Comorbid condition.

How Is FG Diagnosed?

• The classic clinical findings give the main diagnostic clues.

• Ultrasound can be used to differentiate FG and acute inflammatory processes, like epididymitis or orchitis.

• Computed tomography (CT) scan helps in determining the portal of entry and progression of the disease process and is preferred over ultrasonography as patients cannot bear the pain caused by the pressure on the tissues to obtain diagnostic images in ultrasound studies.

• X-ray radiological studies help in confirming the location and extent of gas distribution in the affected tissues. Computerized tomographic (CT) images are preferred because they resolve smaller amounts of soft tissue gasses and fluids.

• A scoring system is devised called Fournier's gangrene severity index to evaluate the prognosis of infection, using clinical vital signs and laboratory investigations such as,

1. Temperature.

2. Heart rate.

3. Respiration rate.

4. Serum sodium.

5. Serum potassium.

6. Serum creatinine.

7. Packed cell volume percent.

8. Whole blood cell count.

9. Serum bicarbonate.

What Are the Differential Diagnoses for FG?

• Cellulitis.

• Strangulated hernia.

• Scrotal abscess.

• Streptococcal necrotizing fasciitis.

• Vascular occlusion syndromes.

• Herpes simplex.

• Gonococcal balanitis and edema.

• Pyoderma gangrenosum.

• Allergic vasculitis.

• Polyarteritis nodosa.

• Necrolytic migratory erythema.

• Warfarin necrosis.

• Ecthyma gangrenosum.

How Is Fournier’s Gangrene (FG) Treated?

• FG demands an aggressive multimodal treatment approach that includes hemodynamic stabilization, broad-spectrum antibiotics therapy, and meticulous surgical debridement.

• Surgical debridement should always be carried out as soon as possible, which highly determines the prognosis of the disease.

• A split-thickness skin graft is the treatment of choice for perineal and scrotal skin defects.

• Broad-spectrum antibiotic therapy is instituted to fight against the poly-microbes involved. Penicillin is most commonly given to the streptococcal species, gram-negative organisms are treated with third-generation cephalosporins, with or without an aminoglycoside, and anaerobes are treated similarly to gram-negative organisms except for the addition of Metronidazole.

• Hyperbaric oxygen is used as an adjunctive therapy for treating FG, as it causes the neutralization of anaerobic organisms, improves the neutrophil function, and helps in increased fibroblastic proliferation and angiogenesis.

• Dakin's solution (sodium hypochlorite) and hydrogen peroxide are used to separate the slough and aid in the formation of granulation tissue.

Conclusion:

Although the course and management of FG are widely understood, at times, FG proves to be a fatal complication. Timely diagnosis becomes the need of the hour, and so does the meticulous surgical debridement, along with aggressive antibiotic therapy and supportive care. The further management of FG demands an inter-professional collaborative approach as reconstructive procedures need to be planned to replace the surgically excised tissues. Effective management of diabetic and immunocompromised patients with perianal or genital infections can prevent them from developing into full-blown FG infections, which majorly affects the prognosis.