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: Fournier's gangrene; Idiopathic gangrene of scrotum; Periurethral phlegmon; Streptococcal scrotal gangrene; Genito-perineal gangrene; Phagedena

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 synergistic polymicrobial necrotizing infection (gangrene) of the perineal, genital or perianal regions usually affecting the male genitals but can also occur in females 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 gangrene was first described in 1764 by Baurienne.
• The detailed description of Fournier gangrene was given by Jean Alfred Fournier, a French venereologist, in 1883.

Classification

The ICD 10 classification of Fournier gangrene include:

• ICD-10: N49.3
• Code Classification

• Diseases of the genitourinary system

• Diseases of male genital organs (N40-N53)

• Inflammatory disorders of male genital organs, NEC (N49)

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 gangrene is the result of an imbalance between host and bacterial factors. A decrease in host immunity provides a favorable environment to initiate the infection, while virulence and synergism between multiple bacteria promotes rapid spread of infection.

The aerobic and anaerobic bacteria produce exotoxins and enzymes, such as collagenase, heparinase, and hyaluronidase, which promote the spread of infection. The aerobic bacteria accelerate coagulation by promoting platelet aggregation and complement fixation. The anaerobic bacteria produce collagenase and heparinase that promote the formation of clots leading to Obliterating endarteritis. The development of cutaneous and subcutaneous vascular necrosis leads to local ischemia and further bacterial proliferation.

The infection spreads from superficial (colles fascia) and deep fascial planes of genitalia 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 the anterior abdominal wall, and the deep external pudendal and internal pudendal arteries supply the scrotal wall. Except for the internal pudendal artery, each of these vessels travels within Camper's fascia and can therefore become thrombosed in the progression of Fournier gangrene.

The progression of infection to the perineal body, urogenital diaphragm and pubic rami is limited due to perineal fascia. Because of the direct supply of blood from the aorta, testicular involvement is limited in Fournier gangrene. However involvement of testis suggests retroperitoneal origin or spread of infection. Fournier 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 gangrene.

Common locations

The common locations of Fournier gangrene are:

• Perineum
• Scrotum
• Penis

Gross pathology

On gross pathology, the characteristic findings of Fournier gangrene include:

• Subcutaneous emphysema
• Swollen scrotal wall
• Edema
• Erythema
• Bullae
• Skin sloughing

Microscopic histopathological analysis

On microscopic histopathological analysis, the characteristic findings of Fournier 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

• 
  Histology of excised skin shows full thickness, featureless, coagulative necrosis with no viable tissue remaining
• 
  Histology of excised scrotal skin shows zones of neutrophil polymorph infiltration, with embedded foreign material possibly representing hair shafts
• 
  Histology of excised skin shows bacterial colonies (cocci and bacilli) in the superficial zone

Causes

Fournier gangrene is caused by mixed aerobic and anaerobic organisms which normally exist below the pelvic diaphragm in the perineum and genitalia. Fournier gangrene may be caused by the following organisms:

Bacteria

Aerobic organisms

Most common aerobic organisms are:

• Group A streptococcus
• Escherichia coli
• Klebsiella pneumoniae
• Staphylococcus aureus

Anaerobic organisms

Most common anaerobic organisms are:

• Bacteroides fragilis

Other organisms

• Streptococcus
• Enterococcus
• Corynebacterium
• Clostridium
• Pseudomonas
• proteus species
• Candida species
• Lactobacillus gasseri

Idiopathic

Less than quarter of cases of Fournier gangrene are idiopathic.

Differentiating Fournier gangrene from Other Diseases

Fournier gangrene must be differentiated from other diseases that cause pain, swelling, erythema, discharge and raised temperature (fever) such as:

• Scrotal abscess
• Herpes simplex
• Cellulitis
• Strangulated hernia
• Streptococcal necrotizing fasciitis
• Gonococcal balanitis and edema
• Vascular occlusion syndromes
• Allergic vasculitis
• Pyoderma gangrenosum
• Necrolytic migratory erythema
• Ecthyma gangrenosum
• Warfarin necrosis
• Polyarteritis nodosa

Epidemiology and Demographics

Incidence

Incidence of Fournier gangrene in the United states:

• The overall incidence of Fournier gangrene annually is 1.6 cases per 100,000 males. The incidence peaked and remained steady after age 50 at 3.3 cases per 100,000 males.
• The incidence of Fournier gangrene increased 0.2 per 100,000 males for each 1% increase in the regional prevalence of diabetes.
• The incidence rate was highest in the southern U.S. and lowest in the western and mid-western U.S.

• 
  Distribution of annual cases per hospital.

Age

Fournier gangrene affects individuals of all ages but more commonly affects individuals older than 50 years of age.

Gender

Men are more commonly affected with Fournier gangrene than women, with a male:female ratio of 10:1.

Mortality

• Mortality rate decreases with early aggressive treatment.
• The mortality rate of Fournier gangrene is between 20% to 80%. Higher mortality rates are found in daibetics, alcoholics and those with colorectal sources of infection.

Risk Factors

Common risk factors in the development of Fournier gangrene are:

• Comorbid systemic disorders

• Age >50 yrs
• Male Gender
• Diabetes mellitus
• Alcohol misuse
• Immunosupression
• Chemotherapy
• Chronic corticosteroid use
• HIV
• Leukemia
• Liver disease
• Debilitating illness
• Malignancy
• Cytotoxic drugs

The most common foci of Fournier gangrene include:

Anorectal	Genitourinary	Dermatology	Gynaecological
Trauma Steroid enemas for radiation proctitis Hemorrhoidectomy Anal fissures excision Diverticulitis Colonic perforations Ischiorectal, perirectal, or perianal abscesses Appendicitis Steroid enemas for radiation proctitis	Trauma Cancer invasion to external genitalia Hemipelvectomy Epididymitis or orchitis Penile artificial implant or a foreign body Hydrocele aspiration Genital piercing Intracavernosal cocaine Urethral catheterization or instrumentation Penile implants insertion Prostatic biopsy Vasectomy Urethral strictures with urinary extravasation	Blunt perineal trauma Intramuscular injections Genital piercings Scrotal furuncle Perineal or pelvic surgery/inguinal herniorrhaphy	Episiotomy wound Infected bartholin's gland Septic abortion Genital mutilation Coital injury

Neonates and Children

• Trauma
• Burns
• Insect bites
• Circumcision

Screening

According to the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for Fournier gangrene.

Natural History, Complications, and Prognosis

Natural history

If left untreated, the acute inflammatory changes spread quickly, accompanied by high fever and extreme weakness. The overlying skin becomes smooth, tense and shiny and diffuse erythema without distinct borders are seen.

During the first 1 or 2 days, the lesions develop with progressive color changes from red to purple to blue and then become gangrenous, first turning black, then greenish yellow. If the patient has survived, a line of demarcation between viable and necrotic tissue would become sharply defined from days 7 to 10.

Sloughing of necrotic skin would reveal the underlying pus and extensive liquefactive necrosis of subcutaneous tissues, which will be significantly more extensive than would be suspected with the overlying area of necrotic skin. Metastatic abscesses and pulmonary distress may develop as well.

Complications

Common complications of Fournier gangrene include:

Systemic complications

• Renal failure
• Acute respiratory distress syndrome
• Heart failure
• Cardiac arrhythmias
• Septic metastasis
• Urinary tract infection
• Stroke
• Acute thromboembolic disease of lower extremities

Surgical complications

• Wound infection
• Stoma-related complications
• Prolonged ileus (7 days)
• Eventration or evisceration

Long term complications

• Pain (50% of patients)
• Impaired sexual function (due to penile deviation/torsion, loss of sensitivity of the penile skin or pain during erection)
• Stool incontinence
• Extensive scarring

Prognosis

Depending on the underlying comorbidities, the prognosis of Fournier gangrene varies. Some of the prognostic factors include:

• Severe sepsis
• If the affected area calculation/extension of the necrosis is:

• <3% of the body surface area, death is rare
• ≥5% of the body surface area, the prognosis is worse

Diagnosis

The diagnosis of Fournier gangrene is primarily based on clinical findings. The diagnosis is based on following criteria:

• Soft tissue infections with involvement of the scrotum, perineum and perianal areas
• Presence of air infiltrating the subcutaneous tissue (demonstrated by physical examination or radiological findings)
• Surgical findings of gangrenous and necrotic tissue
• Histologically proven necrotizing fasciitis.

Diagnostic Criteria

The Uludag Fournier gangrene severity index

Physiologic Variables	High Abnormal Values				Normal	Low Abnormal Values
	+4	+3	+2	+1	0	+1	+2	+3	+ 4
Temperature	>41	39-40.0		38.5-39	36-38.4	34-35.9	32-33.9	30-31.9	<29.9
Heart Rate	>180	140-179	110-139		70-109		55-69	40-54	<39
Respiratory Rate	>50	35-49		25-34	12-24	10-11	6-9		<5
Serum Sodium (mmol/L)	>180	160-179	155-159	150-154	130-149		120-129	111-119	<110
Serum Potassium (mmol/L)	>7	6-6.9		5.5-5.9	3.5-5.4	3-3.4	2.5-2.9		<2.5
Serum Creatinine (mg/100/ml*2 for acute renal failure)	>3.5	2-3.4	1.5-1.9		0.6-1.4		<0.6
Hematocrit	>60		50-59.9	46-49.9	30-45.9		20-29.9		<20
WBC (Total/mm*1000)	>40		20-39.9	15-19.9	3-14.9		1-2.9		<1
Serum Bicarbonate (Venous,mmol/l)	>52	41-51.9		32-40.9	22-31.9		18-21.9	15-17.9	<15

• Score >10.5 indicates 96% probability of death
• Score ≤10.5 indicates 96% probability of survival

According to Loar and colleagues, the severity of Fournier gangrene is:

• Score ≥9 indicates 46% probability of death
• Score <9 indicates 96% probability of survival

Laboratory risk indicator for necrotizing fasciitis (LRINEC) scoring system LRINEC is a diagnostic scoring system used to distinguish necrotizing fasciitis from other soft tissue infections. It was first established by Wong et al in 2004.

Variable	Score
	0	+1	+2	+3	+4
C-reactive protein (mg/dL)	<150				>150
Total White Blood Cell Count (/mm3)	<15	15-25	>25
Hemoglobin (g/dL)	<13.5	11-13.5	<11
Sodium (mmol/L)	≥135		<135
Creatinine (μmol/L)	<141		>141
Glucose (mmol/L)	<10	>10

• Score of ≤5 indicates low risk
• Score of 6-7 indicates intermediate risk
• Score of ≥8 indicates high risk

History

A detailed and thorough history from the patient is necessary. Specific areas of focus when obtaining a history from the patient include:

• Trauma
• Alcohol misuse
• Immunosupression
• Chemotherapy
• Chronic corticosteroid use
• HIV
• Leukemia
• Liver disease
• Debilitating illness
• Malignancy
• Cytotoxic drugs
• Abdominal disease
• Surgery
• Epididymitis or orchitis

Symptoms

The symptoms of Fournier gangrene include:

• Pain and swelling in the scrotum
• Erythema
• Discoloration of involved skin
• Purulence or wound discharge
• Pallor
• Fever >38°C
• Crepitation
• Prostration
• Fluctuance
• Fetid odour

Physical examination

The physical examination of Fournier gangrene include:

Appearance of the Patient

The patients with Fournier gangrene usually appear to be ill.

Vitals

• Fever (is often absent)
• Tachycardia
• Hypotension
• Tachypnea

Skin

• Jaundice
• Evidence of trauma, surgery, insect or human bites, or injection sites

Local examination

Local examination of patient under local anesthesia includes palpation of genitalia and perineum, and digital rectal examination.

• Induration
• Warmth
• Tenderness beyond margins of erythema
• Swelling
• Erythema with ill defined margins
• Blistering/bullae
• Skin discoloration
• Foul discharge (greyish or brown discharge)
• Fluctuance
• Crepitus
• Skin sloughing or necrosis
• Absence of lymphangitis or lymphadenopathy (lymphangitis is rarely seen in Fournier gangrene)
• Sensory and motor deficits (e.g. localized anesthesia)

Images

Genitourinary system

• 
  Brownish-black discolouration of the penis with erythema of the scrotum.
• 
  Discolouration of the penis with vesicles filled with hemorrhagic fluid.
• 
  Fournier gangrene.
• 
  Fournier gangrene.
• 
  Fournier gangrene.
• 
  Fournier gangrene.
• 
  Fournier gangrene.

Laboratory Findings

Laboratory findings consistent with the diagnosis of Fournier 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 gangrene is based on clinical findings.Imaging is used when diagnosis has not been established, to determine the extend of the disease or to detect the underlying cause.

Radiography

• On X-ray, Fournier 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 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 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 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)

MRI

On MRI, Fournier gangrene is characterized by:

• Edema and inflammation of skin and subcutaneous planes of the scrotum and perineal planes
• Subcutaneous emphysema

Gallery of Imaging Findings

• 
  X ray of Fournier gangrene
• 
  Ultrasound of Fournier gangrene
• 
  CT of Fournier gangrene
• 
  CT of Fournier 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. The spread of gangrene is rapid at the rate of 2–3 cm/h, hence early diagnosis and emergency surgical treatment is of very importance.

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

Nutritional Support

• The metabolic demands of Fournier gangrene patients are similar to those of other major trauma or burns.
• Nutritional support to replace lost proteins and fluids from large wounds and/or the result of shock is required from the first day of patients hospital admission.

Hyperbaric oxygen

• Delivery of 100% oxygen (hyperbaric) at two or three times the atmospheric pressure for 30 to 90 minutes with three to four treatments daily.
• Hyperbaric oxygen inhibits infection and exotoxin release.
• It enhances efficacy of antibiotics by increasing local oxygen tension in tissue and augment oxidative burst and killing ability of leukocytes.
• These effects results in reduced need for surgical debridement and improved morbidity and mortality in patients with necrotizing fasciitis.

Contraindications to hyperbaric oxygen are:

• Pneumothorax
• Cisplatin ((which decreases the production of superoxide dismutase which is protective against damaging effects of high partial O2 pressure)
• Doxorubicin therapy

Side effects of hyperbaric oxygen are:

• Barotrauma of the middle ear
• Seizures
• Loss of respiratory drive in hypercapnic patients (therefore, frequent periods of breathing in room air are interposed when patients are on HBOT)
• Vasoconstriction

IV γ-globulin

• Use of intravenous immune globulin is not FDA approved.
• If used, this treatment is restricted to critically ill patients with either staphylococcal or streptococcal infections.

Surgery

Radical surgical debridement

Surgery is the mainstay of treatment for Fournier gangrene.

• Indications include:

• Patients displaying intense pain and skin color change such as edema and/or ecchymoses
• Signs of skin ischemia with blisters and bullae
• Altered mental status, hypotension, elevated band forms in the differential WBC count and metabolic acidosis.

• Immediate surgical referral remains the only method of reducing mortality and morbidity in Fournier gangrene patients.
• As the patient's are cardiovascularly unstable, immediate resuscitation with intravenous fluids, colloids and inotropic agents are usually necessary.
• Effects of analgesia can be measured by documenting pain score regularly.
• Stop the NSAID's on admission of patients.

Procedure

• Radical debridement of areas of overt subcutaneous necrosis should be done in operation theater in the lithotomy position (allows access to all perineal structures).
• Deep fascia and muscle are rarely involved. Hence debridement is usually not required.
• Separation of the skin and subcutaneous tissue with a hemostat has been recommended to define the limits of excision. Debridement is stopped where these tissues do not separate easily.

Fecal and urinary diversion

• Urinary or fecal diversion are required to treat an underlying condition or prevent wound contamination.
• When there is gross urinary extravasation or periurethral inflammation, suprapubic cystostomy is required (urinary catheter is used in milder cases).
• Colostomy is required when there is gross sphincter infection or colonic or rectal perforation.
• Testes are temporarily implanted into subcutaneous tissue pouch (medial thigh or lower abdomen) until healing or reconstruction is complete.
• Orchidectomy is performed if there is any pre-existing epididymo-orchitis or scrotal abscess.

Plastic reconstruction

• The split thickness skin graft is commonly used technique for reconstructive surgery. For large defects, rotational or free myocutaneous flaps and omental flaps are used to cover larger defects.

Wound management

• The wound is monitored closely after surgery.
• Multiple surgical debridement are required with an average of 3.5 procedures per patient.
• Sodium hypochlorite or hydrogen peroxide are used post-operatively for topical application.
• Lyophilized collagenase (an enzyme that digests and debrides necrotic tissues) is used for enzymatic debridement twice daily until definite reconstruction can be performed.

Vacuum-assisted closure device

• Vacuum assisted closure device is used for faster and effective wound closure.
• Helps wound healing by absorbing excess exudates, reducing localized edema, and finally drawing wound edges together.

Prevention

Primary prevention

Effective measures for the primary prevention of Fournier gangrene include:

• Prevention of trauma/breaks in skin integrity that act as portal of entry
• Treatment of cellulitis to prevent extension into the subcutaneous tissue
• Wounds should be cleaned and monitored for signs of infection
• Do not delay first aid of wounds like blisters, scrapes, or any break in the skin
• Patients with underlying co-morbidities should watch carefully for any signs of infection

Secondary prevention

Secondary prevention strategies following Fournier gangrene include:

• Early diagnosis and prompt treatment with either antibiotics or surgery.
• This strategy prevents or slows the progression and complications of the disease.

External links

• Template:WhoNamedIt2 and Template:WhoNamedIt