Fournier gangrene

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Steven C. Campbell, M.D., Ph.D.; Associate Editor(s)-in-Chief: Yamuna Kondapally, M.B.B.S[1]; Jesus Rosario Hernandez, M.D. [2]

Synonyms and keywords: Idiopathic gangrene of scrotum; Periurethral phlegmon; Streptococcal scrotal gangrene; Genito-perineal gangrene

Fournier gangrene
ICD-10	N49.8 (ILDS N49.81), N76.8
ICD-9	608.83
DiseasesDB	31119
MeSH	D018934

Overview

Fournier gangrene is a type of necrotizing infection (gangrene) of the perineal, genital or perianal regions usually affecting the male genitals but can also occur in female and children. It is a fulminant form of necrotizing fasciitis. It was first described by Baurienne in 1764 and is named after a French venereologist, Jean-Alfred Fournier following five cases he presented in clinical lectures in 1883.

Historical Perspective

• Fournier's gangrene was first described by in 1764 by Baurienne.
• The detailed description of fournier's gangrene was given by Jean Alfred Fournier, who is a French venereologist in 1883.

Classification

There is no classification system established for Fournier's gangrene.

Pathophysiology

• The transmission of pathogens occurs through the following routes:

• External trauma (e.g., laceration, abrasion, burn, insect bite)
• Direct spread from a perforated viscus (particularly colon, rectum, or anus) or another surgical procedure (e.g., vasectomy, hemorrhoidectomy)
• Urogenital organ
• Perirectal abscess
• Decubitus ulcer

• Following transmission, the bacteria uses the entry site to invade the fascial planes which causes the wide spread necrosis of superficial fascia, deep fascia,

subcutaneous fat, nerves, arteries, and veins.

• Superficial skin and deeper muscles are typically spared.
• In late stages, lesions develop liquefactive necrosis at all tissue levels.

Pathogenesis

• The pathogenesis of fournier's gangrene is the result of an imbalance between bacterial and host factors.

• Host factors: Decrease in host immunity provides favourable environment to initiate the infection
• Bacterial factors: Virulence and synergism between multiple bacteria promotes rapid spread of infection

• The aerobic and anaerobic bacteria produce exotoxins and enzymes like collagenase, heparinase, hyaluronidase etc which promote spread of infection.
• The aerobic bacteria cause acceleration of coagulation by promoting platelet aggregation and complement fixation and the anaerobic bacteria produce collagenase and heparinase that promote the formation of clots leading to obliterative endarteritis.
• The cutaneous and subcutaneous vascular necrosis develops leading to local ischemia and further bacterial proliferation.
• The infection spreads from superficial (colles fascia) and deep fascial planes of genetalia to the overlying skin sparing the muscles. The infection then spreads from colles fascia to the penis and scrotum via Buck's and Dartos fascia or to the anterior abdominal wall via Scarpa's fascia or vice versa.
• The inferior epigastric and deep circumflex iliac arteries (supply anterior abdominal wall), and external and internal pudendal artery supply the scrotal wall. Except internal pudendal artery, each of these vessels travels with in Camper's fascia and can therefore become thrombosed in the progression of fournier's gangrene.
• The progression of infection to the perineal body, urogenital diaphragm and pubic rami is limited due to perineal fascia.
• Because of direct supply of blood from aorta, testicular involvement is limited in Fournier's gangrene. However involvement of testis suggests retroperitoneal origin or spread of infection.
• Fournier's gangrene of the male genetalia spares testes, urethra and deep penile tissues while the skin sloughs off.
• Sepsis and multiorgan failure is the most common cause of death in Fournier's gangrene.

Microscopic histopathological analysis

On microscopic histopathological analysis, the characteristic findings of Fournier's gangrene are:

• Early stages

• Obliterative vasculitis with microangiopathic thrombosis
• Acute inflammation of subcutaneous tissue
• Superficial hyaline necrosis along with edema and inflammation of the dermis and subcutaneous fat
• Dense neutrophil-predominant inflammatory infiltrate

• Late stages

• Noninflammatory intravascular coagulation and hemorrhage
• Myonecrosis

• File:==Causes==
• File:===Bacteria===
• File:'''Aerobic organisms'''
• File:*Group A streptococcus
• File:'''Anaerobic organisms'''
• File:Most common anaerobic organisms are:
• File:===Other organisms===
• File:*Streptococcus
• File:*Enterococcus
• File:*Clostridium
• File:*Pseudomonas
• File:*Proteus species
• File:===Idiopathic===
• File:*Scrotal abscess
• File:*Herpes simplex
• File:*Cellulitis
• File:*Strangulated hernia
• File:*Streptococcal necrotizing fasciitis
• File:*Gonococcal balanitis and edema
• File:*Vascular occlusion syndromes
• File:*Allergic vasculitis
• File:*Pyoderma gangrenosum
• File:*Necrolytic migratory erythema
• File:*Ecthyma gangrenosum
• File:*Warfarin necrosis
• File:*Polyarteritis nodosa
• File:==Epidemiology and Demographics==
• File:===Incidence===
• File:===Age===
• File:===Gender===
• File:===Mortality===
• File:*Mortality rate decreases with early aggressive treatment.
• File:==Risk Factors==
• File:*Comorbid systemic disorders
• *Male Gender
• *Diabetes mellitus
• *Alcohol misuse
• *Immunosupression
• *Chemotherapy
• *Chronic corticosteroid use
• *HIV
• *Leukemia
• *Liver disease
• *Debilitating illness
• *Malignancy
• *Cytotoxic drugs
• Anorectal
  Anorectal
• Genitourinary
  Genitourinary
• Dermatology
  Dermatology
• Gynaecological
  Gynaecological
• File:*Steroid enemas for radiation proctitis
• File:*Urethral strictures with urinary extravasation
• File:*Coital injury
• File:'''Neonates and Children'''
• File:*Burns
• File:*Insect bites
• File:*Circumcision
• File:==Screening==
• File:According to the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for Fournier's gangrene.
• File:==Natural History, Complications, and Prognosis==
• File:===Natural history===
• File:*If the patient has survived, a line of demarcation between viable and necrotic tissue would become sharply defined from days 7 to 10.
• File:===Complications===
• File:Common complications of Fournier's gangrene include:
• File:*Auto-amputation of the penis
• File:*Sepsis
• File:*Disseminated intravascular coagulation
• File:*Tetanus
• File:*Marjolin's ulcer
• File:*infertility (rare complication)
• File:===Prognosis===
• File:Depending on the underlying comorbidities, the prognosis of Fournier's gangrene varies. Few of the prognostic factors include:
• File:*Severe sepsis
• File:*Extent of necrosis
• *≥5% of body surface area have worse prognosis
• File:==Diagnosis==
• File:The diagnosis is primarily based on clinical findings.
• File:===Diagnostic Criteria===
• File:'''The Uludag Fournier's gangrene severity index'''
• Physiologic Variables
  Physiologic Variables
• High Abnormal Values
  High Abnormal Values
• Normal
  Normal
• Low Abnormal Values
  Low Abnormal Values
• + 4
  + 4
• Temperature
  Temperature
• Heart Rate
  Heart Rate
• Respiratory Rate
  Respiratory Rate
• Serum Sodium (mmol/L)
  Serum Sodium (mmol/L)
• Serum Potassium (mmol/L)
  Serum Potassium (mmol/L)
• Serum Creatinine (mg/100/ml*2 for acute renal failure)
  Serum Creatinine
  (mg/100/ml*2 for acute renal failure)
• Hematocrit
  Hematocrit
• WBC (Total/mm*1000)
  WBC (Total/mm*1000)
• Serum Bicarbonate (Venous,mmol/l)
  Serum Bicarbonate (Venous,mmol/l)
• File:*Score ≤10.5 indicates 96% probability of survival
• File:According to Loar and colleagues, the severity of Fournier's gangrene is:
• File:*Score ≥9 indicates 46% probability of death
• File:'''Laboratory risk indicator for necrotizing fasciitis (LRINEC) scoring system'''
• File:*It was first established by Wong et al in 2004.
• File:*Risk assessment of necrotizing faciitis using LRINEC score:
• *Low risk: ≤5
• *Intermediate risk: 6-7
• *High risk: ≥8
• File:! Variable
• File:! Score
• File:4
• File:2
• File:2
• File:2
• File:1
• File:===History===
• File:===Symptoms===
• File:*Pain and selling in the scrotum
• File:*Erythema
• File:*Discoloration of involved skin
• File:*Purulence or wound discharge
• File:*Pallor
• File:*Crepitation
• File:*Prostration
• File:*Fluctuance
• File:*Fetid odour
• File:===Physical examination===
• File:====Gallery====
• File:=====Genitourinary system=====
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Laboratory Findings

Laboratory findings consistent with the diagnosis of Fournier's gangrene include:

• CBC with differential count
• Culture of open wound or abscess
• Disseminated intravascular coagulation panel

• Coagulation studies(PT, aPTT, thrombin time etc)
• Fibrinogen/fibrin degradation product levels

• Blood culture
• Urine culture
• Arterial blood gas analysis
• Electrolyte panel
• Blood urea nitrogen (BUN)
• Creatinine
• Blood glucose levels

Imaging Findings

The diagnosis of Fournier's gangrene is based on clinical findings.The role of imaging includes:

• Diagnosis not established
• Determine the extent of disease
• Detect underlying cause

Radiography

• On X-ray, Fournier's gangrene is characterized by:

• Subcutaneous gas or soft tissue swelling (specific x-ray finding) seen extending from scrotum and perineum to the inguinal regions, anterior abdominal wall, and thighs.
• Increase in the soft tissue thickness and opacity.

• Plain x-ray is a poor screening study for Fournier's gangrene because:

• Subcutaneous emphysema is an insensitive finding and is present in a minority of patients
• In the early stages the findings are similar to cellulitis

Ultrasound

On ultrasound, Fournier's gangrene is characterized by:

• Thickened scrotal wall
• Echogenic gas foci in scrotum pathognomonic-Seen as dirty shadowing
• Testes and epididymi spared (due to their separate blood supply)
• Reactive unilateral or bilateral hydroceles are present
• Differentiate Fournier gangrene from inguinoscrotal incarcerated hernia (In inguinoscrotal incarcerated hernia gas is observed in the obstructed bowel lumen, away from the scrotal wall)

Computed tomography

The CT of Fournier's gangrene is characterized by:

• Soft tissue stranding and fascial thickening
• Soft tissue gas
• The extent of disease can be assessed prior to surgery
• A cause of infection may be apparent(e.g.perineal abscess, fistula)

Gallery of Imaging Findings

• 
  X ray of Fournier's gangrene
• 
  Ultrasound of Fournier's gangrene
• 
  CT of Fournier's gangrene
• 
  CT of Fournier's gangrene with spontaneous perforation of rectal cancer

Treatment

Medical Therapy

Fournier gangrene is a urological emergency requiring intravenous antibiotics and debridement (surgical removal) of necrotic (dead) tissue. Despite such measures, the mortality rate overall is 40%, but 78% if sepsis is already present at the time of initial hospital admission.

Antimicrobial Therapy

• Fournier gangrene

• If caused by streptococcus species or clostridia

• Preferred regimen: Penicillin G

• Polymicrobial

• Preferred regimen: Doripenem OR imipenem OR meropenem

• MRSA (methicillin resistant staphylococcus aureus) suspected

• Preferred regimen: vancomycin OR daptomycin

External links

• Template:WhoNamedIt2 and Template:WhoNamedIt