Necrotizing Fasciitis

Necrotizing Fasciitis
Morning report—July 18 2005
Zach Shook, M.D.
1. Epidemiolgy:
• Increased incidence in diabetics, alcoholics, immunosuppressed pts, IV
drug users, pts with PVD.
• Can also occur in YOUNG, HEALTHY ADULTS
2. Etiology:
• Most common in abdominal wall, extremities and perineum
• Entry of pathogen via skin breakdown>>hematogenous (pharyngitis)
• Male (female) genitalia (perineum): Fournier’s Gangrene
3. Clinical presentation and pathophysiology:
• Early Nec Fasc: extremely painful: “PAIN OUT OF PROPORTION TO
EXAM”
• Skin changes: celluliticsmooth, shiny, tensely swollendarkening,
dusky with bullaenecrosis of superficial fascia/fat with “dishwater pus”
• Untreated, disease almost universally fatal
4. Microbiology:
• Type 1: polymicrobial, non-group A strep aerobe + anaerobe or
facultative anaerobe, often enterobacteriaceae.
• Type 2: (classic) group A, beta-hemolytic streptococcus +/- staph.
• “Type 3:” Vibrio: wound caused by fish or exposed to sea water…
• Never anaerobes alone, remember anaerobes often present, not cultured.
• No difference in morbidity and mortality between species.
• Soft-tissue gas formation: anaerobic/mixed infections
• Tissue damage from bacterial toxins and endogenous cytokines
• new strains of more virulent group A strep…maybe not.
Gram + aerobes:
Group A, beta-hemolytic strep, Group B strep, Enterococci, Coag neg staph, Staph aureus, Bacillus
Gram – aerobes:
E. coli, Pseudomonas, Enterobacter, Klebsiella, Proteus, Serratia, Acinetobacter, Citrobacter, Pasturella
Anaerobes:
Bacteroides, Clostridium, Peptostreptococcus
Marine sps:
Vibrio (vulnificus, parahemolyticus, damsela, alginolyticus)
Fungi:
Candida, Aspergillus, Rhizopus
5. Diagnosis:
• “Owing to the paucity of skin findings early in the disease, diagnosis is
often extremely difficult and relies on a high clinical index of suspicion.
• Signs: severe local pain, fever, signs of systemic disease
• Dx by lack of resistance of normally adherent fascia to blunt dissection or
full thickness skin biopsy
• Radiology: gas on plain film (more sensitive than physical exam), CT,
MRI as gold standard--cost, time, clinical availability

6. Treatment
• SURGICAL!!!—early surgical intervention is critical, proven to lower
mortality
• Surgical goal: perform definitive surgery the first resection—wide, wide
margins. (survival documented with up to 45% skin surface area resected)
• Need frequent exams of surgical site post-op as many pts require multiple
debridements
• MEDICALl—broad spectrum coverage of aerobes (gram + and -) and
anaerobes.
• If Group A strep: high dose pcn and clinda.
• SUPPORTIVE CARE
• Hyperbaric Oxygen—retrospective studies with mortality benefit
7. Mortality:
• From 29%--76%, largely dependent on time-course, when treatment
begun…
Reference:
Green, RJ. Necrotizing Fasciitis. Chest, 1996; 110; 219-229
www. chestjournal.org.