Necrotizing Fasciitis

• • Usually caused by multiple bacterial pathogens

  • Infection usually mixed flora, including streptococci, staphylococci, anaerobes, gram-negative aerobes

  • Typically begins in localized area (puncture wound, incision)

  • Spreads along fascial planes

  • Results in thrombosis of penetrating vessels and tissue necrosis

  • Area of fascial necrosis usually more extensive than skin appearance indicates

Epidemiology

• • More common in patients who are immunosuppressed or debilitated and in those who have diabetes or cancer

  • 1000 cases reported in United States per year

  • May also develop more frequently in obese patients, following penetrating trauma, postpartum women, injection drug abusers

Symptoms and Signs

• • Hemorrhagic bullae

  • Crepitus may be present

  • Skin may be anesthetic, edematous

  • Fever, pain

  • Tachycardia

  • Undermining and dissection of the subcutaneous tissue, liquefaction of fat, preservation of overlying skin

  • "Dishwater" exudate from wound

  • Skin necrosis/gangrene seen in advanced disease

Laboratory Findings

• • Elevated WBC count

  • Positive wound culture, Gram stain

  • Biopsy of infected tissue reveals:

  • -Necrosis

    -Polymorphonuclear leukocyte (PMN) infiltration

    -Thrombi of arteries and veins passing through fascia

    -Angiitis

Imaging Findings

• • Plain x-ray may reveal subcutaneous air

• • Superficial cellulitis

  • Abscess

  • Fistula

  • Have high index of suspicion; delay in treatment augments morbidity and mortality significantly

• • High index of suspicion required for diagnosis

  • Obtain tissue biopsy/wound aspirate and culture may help direct antimicrobial therapy

When to Admit

• • Patients require aggressive resuscitation and surgical treatment

• • Wide surgical debridement is mainstay of therapy

  • Aggressive resuscitation

  • Broad-spectrum IV antibiotics

  • Multiple debridements may be required

Surgery

Indications

• • Surgical emergency

  • High index of suspicion required

  • Aggressive debridement of devitalized soft tissue

  • Fascial compartments should be decompressed

  • Amputation may be required if evidence of diffuse myositis, complete loss of blood supply, and if debridement would clearly leave a useless limb

Contraindications

• • Patients should be as aggressively resuscitated as possible prior to operation

Medications

• • IV broad-spectrum antibiotics: penicillin+aminoglycoside+clindamycin or imipenem-cilastatin

  • Intravenous immunoglobulin (IVIG) may be useful for streptococcal toxic shock syndrome

  • Aggressive resuscitation required for potential large volume deficits

Treatment Monitoring

• • Wounds may require further debridement either at bedside or in operating room

  • Wound cultures likely to be polymicrobial

  • May need to change antibiotic regimen based on wound cultures and sensitivities

Complications

• • Sepsis

  • Devitalization of entire limb/limb loss

Prognosis

• • Potentially lethal

  • -20% with necrotizing fasciitis die

    -> 50% mortality with ...