Fournier's Gangrene

Definition

An acute, rapidly progressive and potentially fatal, infective necrotizing fasciitis affecting the external genitalia, perineal or perianal regions

History

• First described in 1764 by Baurienne
• Named after Professor Jean-Alfred Fournier (1832-1914), a Parisian venereologist, who presented in 1883 a case of perineal gangrene in an otherwise healthy young man

Relevant anatomy

• See Figure
• Superior to inguinal ligament
  • Layers (superficial to deep)
    • Skin
    • Camper’s fascia
      • Layer of fat-containing tissue of varying thickness and the superficial vessels to the skin that run through it.
    • Scarpa’s fascia
      • Continuous with
        • Colles’ fascia (superficial perineal fascia) in the perineum
        • Dartos fascia in the penis
        • Dartos fascia in the scrotum
• Pelvis
  • Colle’s fascia (see Figure)
    • Attached to the pubic arch and the base of the perineal membrane
      • Perineal membrane is also known as the inferior fascia of the urogenital diaphragm and, together with Colles’ fascia, defines the superficial perineal space
        • Superficial perineal space contains the membranous urethra, bulbar urethra, and bulbourethral glands. In addition, this space is adjacent to the anterior anal wall and ischiorectal fossae.
          • Infectious disease of the male urethra, bulbourethral glands, perineal structures, or rectum can drain into the superficial perineal space and can extend into the scrotum or into the anterior abdominal wall up to the level of the clavicles.
• Fournier's gangrene involves superficial and deep fascia (Camper's, Scarpa's/Dartos/Colle's) and skin
  • Often spares the deep muscular structures and, to variable degrees, the overlying skin.
    • Corpora, urethera, testes, and cord structures are usually not involved
      • The contents of the scrotum, namely the testes, epididymides and cord structures, are invested by several fascial layers distinct from the Dartos fascia of the scrotal wall.
        • The most superficial layer of the testis and cord is the external spermatic fascia, which is continuous with the external oblique aponeurosis of the superficial inguinal ring.
        • The next deeper layer is the internal spermatic fascia, which is continuous with the transversalis fascia.
        • The Buck fascia covers the erectile bodies of the penis, the corpora cavernosa, and the anterior urethra. The Buck fascia fuses to the dense tunica albuginea of the corpora cavernosa, deep in the pelvis.
        • These fascial layers do not become involved with an infection of the superficial perineal space and can limit the depth of tissue destruction in a necrotizing infection of the genitalia.
  • Infection travels along the facial planes
    • Can extend posteriorly the Dartos fascia to involve the Colles' fascia, but are limited from the anal margin by the attachment of the Colles' fascia to the perineal body.
      • Clinical implication: infection limited posteriorly by Colles' fascia
    • Can extend along the anterior abdominal wall through a potential space between the Scarpa’s fascia and the deep fascia of the anterior wall (external abdominal oblique).
      • Superiorly, Scarpa’s and Camper’s fasciae coalesce and attach to the clavicles
      • Clinical implication: infection limited superiorly by clavicles

Pathogenesis

• Infection most commonly arises from the skin, urethra, or rectal regions.
  • The infection commonly starts as cellulitis adjacent to the portal of entry.
• Risk factors (8):
  1. Diabetes mellitus
  2. Local trauma
  3. Paraphimosis
  4. Urethral stricture associated with sexually transmitted disease resulting in peri-urethral extravasation or urine
  5. Urethral cutaneous fistula
  6. Peri-rectal or peri-anal infections
  7. Instrumentation
  8. Surgery such as circumcision or herniorrhaphy

Diagnosis and Evaluation

• History and Physical Exam
  • Early on, the involved area is swollen, erythematous, and tender as the infection begins to involve the deep fascia. Discharge is not present in the early stage.
  • Pain is prominent, and fever and systemic toxicity are marked.
  • Clinical differentiation of necrotizing fasciitis from cellulitis may be difficult because the initial signs including pain, edema, and erythema are not distinctive. However, marked systemic toxicity and pain out of proportion to the physical exam should alert the clinician.
• Labs
  • Wound cultures
    • Generally yield multiple organisms, implicating anaerobic-aerobic synergy
• Imaging
  • CT pelvis
    • Sign's of necrotizing fascitis
      • Subcutaneous gas

Management

• Urological emergency; requires urgent management
  • Essential interventions in stopping the rapidly progressing infectious process of Fournier's gangrene
    1. Early recognition of the diagnosis
    2. Aggressive surgical debridement
    3. Use of broad-spectrum antibiotics
       • Anti-microbial regimens include broad-spectrum antibiotics (β-lactam plus β-lactamase inhibitor) such as piperacillin-tazobactam
  • IV hydration is indicated in preparation for surgical debridement
  • Immediate debridement of skin and involved dartos/scarpa/colle fasica is essential.
    • Extensive incision should be made through the skin and subcutaneous tissues, going beyond the areas of involvement until normal fascia is found.
      • Clinical implication: prepare with antiseptic solution widely at the time of surgery (i.e. up to clavicles, down thighs)
    • Necrotic fat and fascia should be excised, and the wound should be left open.
      • External, cremasteric, and internal spermatic fasciae are spared
        • These layers are embryologically distinct from the skin and dartos layers and have their own blood and nerve supplies.
    • Orchiectomy is almost never required
      • Testes have their own blood supply independent of the compromised fascial and cutaneous circulation to the scrotum.
    • A second procedure 24 to 48 hours later is indicated if there is any question about the adequacy of initial debridement.
• Adjunctive procedures (should be included in pre-surgical consent)
  • Suprapubic diversion should be performed in cases in which urethral trauma or extravasation is suspected.
  • Colostomy should be performed if there is colonic or rectal perforation.
• Insert figure

References

• Kim, Ik Yong. "Gangrene: the prognostic factors and validation of severity index in Fournier’s gangrene." Gangrene-current concepts and management options. IntechOpen, 2011.
• Wein AJ, Kavoussi LR, Partin AW, Peters CA (eds): CAMPBELL-WALSH UROLOGY, ed 11. Philadelphia, Elsevier, 2015, vol 2, chap 12