II. Definitions

  1. Necrotizing Fasciitis
    1. Rapidly progressive, deep subcutaneous infection resulting in tissue necrosis and systemic toxicity
  2. Fournier's Gangrene
    1. Massive infection and swelling of Scrotum and penis
    2. Extends into perineum or abdominal wall, and legs
    3. Seen in Alcoholic Liver Disease or Cirrhosis, Diabetes Mellitus, IV Drug Abuse

III. Precautions

  1. Necrotizing Fasciitis is a life threatening infection with an insidious, occult presentation
  2. Do not ignore pain out of proportion, Sinus Tachycardia or unexplained fever
  3. Do not delay surgical exploration when Necrotizing Fasciitis is suspected
  4. Physical exam, labs and imaging are unreliable alone at excluding Necrotizing Fasciitis

IV. Pathophysiology

  1. Typically starts with break in skin (e.g. Trauma or recent surgery)
  2. Infection spreads between fascia and subcutaneous tissue
  3. Fibrous bands prevent infectious spread
    1. Present in head and distal extremities
    2. Lacking in trunk and proximal extremities

V. Risk factors

  1. Age over 50 years
  2. Malnutrition
    1. Hypoalbuminemia
    2. Alcoholism
    3. Cirrhosis (esp. Vibrio vulnificans from seafood)
      1. Liver disease is associated with higher mortality
  3. Immunocompromised state (esp. Neutropenia)
    1. Cancer
    2. Corticosteroid use
    3. HIV Infection
  4. Poor vascular supply
    1. Cardiovascular disease
    2. Peripheral Vascular Disease
    3. Diabetes Mellitus
      1. Most common comorbidity (present in 45% of cases)
      2. Higher amputation risk
      3. Diabetic Neuropathy may result in less recognition of pain
  5. Skin Trauma within last 90 days
    1. Burn Injury
    2. Trauma
    3. Intravenous Drug Abuse
    4. Recent surgery
    5. Alcohol Abuse
  6. Miscellaneous risk factors
    1. Obesity
  7. Break in Gastrointestinal or Genitourinary mucosa
    1. Colon Cancer
    2. Diverticula
    3. Hemorrhoids or Anal Fissure
    4. Urethral tear
    5. Cirrhosis

VI. Findings: Symptoms and Signs progression (in order of occurrence)

  1. Pain out of proportion to physical findings (79%)
  2. Unexplained fever (40%)
  3. Tachycardia (60%)
  4. Swelling (80% of cases)
  5. Foul odor
  6. Subcutaneous air with crepitation (pathognomonic, but late finding)
  7. Rapid progression
  8. Brawny Edema and tenderness
  9. Erythema with indistinct margins
  10. Dark red induration
  11. "Dish water" wound drainage
  12. Involved area may parodoxically be without Sensation
  13. Bullae filled with blue or purple fluid
  14. Skin friable, bluish, maroon, or black
  15. Extensive thrombosis of dermal blood vessels
  16. Extension to deep fascia leads to brown-gray appearance
  17. Rapid spread along fascial planes, veins and lymph
  18. Toxicity, shock, and multi-organ failure

VII. Signs: Distribution

  1. Extremities (53%)
  2. Perineum or buttocks (20%, especially in Diabetes Mellitus, Alcoholism)
  3. Trunk (18%)
  4. Head and neck (9%)
  5. References
    1. Bosshardt (1996) Arch Surg 131:846-52 [PubMed]

VIII. Exam

  1. Mark the erythematous border of infection
    1. Mark the time of each consecutive margin re-evaluation

IX. Types

  1. See Clostridial Myonecrosis (Gas Gangrene)
  2. Polymicrobial (Type 1) - Mixed aerobic and Anaerobic Bacteria
    1. Break in Gastrointestinal or Genitourinary mucosa or on trunk and extremities
    2. Includes Fournier's Gangrene
    3. Comorbid conditions associated with mixed infection
      1. Elderly patients
      2. Diabetes Mellitus
      3. Peripheral Vascular Disease
      4. Immunocompromised state
    4. Typically a combination of anaerobic and aerobic Bacteria
      1. Anaerobic Bacteria include Bacteroides, Clostridium, peptostreptococcus
      2. Aerobic Bacteria include E. coli, Klebsiella, Enterobacter and Proteus
    5. Findings
      1. Gas in tissue (also seen in clostridal myonecrosis)
  3. Monomicrobial (Type 2)
    1. Causes
      1. Group A Streptococcus (Streptococcus Pyogenes)
      2. Staphylococcus aureus
      3. Vibrio vulnificus (see Vibrio Cellulitis, saltwater Gram Negative Rod)
      4. Aeromonas (fresh water Gram Negative Rod)
    2. Begins deep at non-penetrating minor Trauma in typically healthy patients
      1. Risk Factors include IV Drug Abuse and skin popping
      2. May also be associated with Toxic Shock Syndrome
      3. Soft tissue Contusion seeded by transient bacteremia (often from nasopharyngeal source)
    3. Findings
      1. Gas production only if mixed infection (gas is typically absent)
      2. Soft tissue swelling is prominent
      3. Severe toxicity, renal Impairment may precede shock
      4. Associated Diarrhea, Anorexia, fever with Group A Streptococcus
      5. Myositis in 20-40% cases
      6. Creatine Phosphokinase (CPK) is markedly elevated
      7. Mortality: 20-50% despite Penicillin

X. Causes: Bacteria

  1. Group A Streptococcus (Streptococcus Pyogenes)
  2. Staphylococcus aureus
  3. Clostridium perfringens
    1. See Clostridial Myonecrosis (Gas Gangrene)
    2. Hyperbaric Oxygen treatment may help in Gas Gangrene
  4. Vibrio haemlyticus or Vibrio vulnificus (sea water exposure, seafood ingestion esp. in Cirrhosis)
  5. Aeromonas (fresh water exposure)
  6. Plesiomonas (fresh water exposure)
  7. Superinfection of varicella in children
  8. Omphalitis (Umbilical Cord stump infection) in newborns

XI. Diagnosis: Findings Suggestive of Necrotizing Fasciitis

  1. Altered Mental Status
  2. Soft tissue edema (70-80% of cases)
  3. Soft tissue erythema (72%)
  4. Severe Pain out of proportion to the exam (72%)
    1. Tenderness outside the erythematous borders
  5. Vessicles or Bullae (25%)
    1. Bullae become violaceous after 4-5 days
    2. Skin then becomes necrotic
    3. Hemorrhagic bullae are nearly pathognomonic for Necrotizing Fasciitis (esp. Vibrio vulnificus)
  6. Fever (40-60%)
    1. Temperature over 99.5 F (37.5 C)
  7. Tachycardia
    1. Unresponsive to Intravenous FluidResuscitation and antipyretics
  8. Hypotension (21%)
    1. Systolic Blood Pressure <90 mmHg
  9. Tissue Crepitation (20%)
    1. In Fournier's Gangrene, may not be readily evident (e.g. inguinal region or buttocks)

XII. Diagnosis

  1. Definitive diagnosis
    1. Deep tissue biopsy with culture and Gram Stain (performed during surgical source control as below)
  2. Finger Test
    1. Indicated in remote medical care in resource limited regions (lacking imaging, surgical Consultation, delayed transfer)
    2. Local Anesthetic injected within suspected infection region (inject into deep space)
    3. Make 2 cm incision
    4. Expose tissue down to deep fascia
    5. Findings consistent with Necrotizing Fasciitis
      1. Dishwater-like fluid appears from wound site, but no significant bleeding
      2. Gloved finger inserted into deep fascia offers little resistance

XIII. Labs

  1. LRINEC Score
    1. See Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC Score)
    2. High False Positive and False Negative Rate (misses up to 50% of cases)
  2. Complete Blood Count
    1. White Blood Cell Count over 15,000/mm3 (esp. if >25,000/mm3)
    2. Hemoglobin less than 11 g/dl
    3. Platelet Count <150,000 per mm3
  3. Serum Electrolytes
    1. Serum Sodium under 135 meq/L (SIADH related)
    2. Blood Urea Nitrogen 15 mg/dl
    3. Serum Calcium under 8.4 mg/dl
    4. Serum Creatinine >1.6 mg/dl
  4. Coagulation Studies
    1. Prothrombin Time (PT) prolonged
    2. Partial Thromboplastin Time (aPTT) prolonged
  5. Other markers
    1. C-Reactive Protein >150 mg/L
    2. Arterial or venous pH < 7.35

XIV. Imaging

  1. Background
    1. Liquefaction necrosis and gas formation lead to many of the findings on imaging
  2. XRay
    1. Test Sensitivity: 25-50% for subcutaneous gas
    2. Test Specificity: 94%
    3. Gas along fascial planes is pathognomonic for Necrotizing Fasciitis (but a late finding)
    4. Negative xray does NOT exclude Necrotizing Fasciitis
  3. Ultrasound
    1. Consider in children, or in Ultrasound-guided fluid aspiration
    2. Fascial planes are thickened and distorted with fluid and subcutaneous edema
      1. Fluid at fascial layer 1 mm with Test Sensitivity 87%, Test Specificity 50%
      2. Fluid at fascial layer 5 mm with Test Specificity 98%
    3. Limited visualization if soft-tissue gas is present
      1. Gas-related shadowing appears as scattered clouds within tissue
  4. CT
    1. Soft tissue gas formation in subcutaneous and deep tissues
    2. Deep fascia contains fluid tracking around its planes (inconsistent)
    3. Superficial and deep fascial layers (as well as subcutaneous fat) with thickening and contrast enhancement
    4. Abscess may variably be present
    5. Reactive Lymphadenopathy
    6. Identitifies other complications (e.g. vascular rupture) as well as conditions in differential diagnosis
    7. CT is a first-line study in fourniers gangrene
      1. Contrast is not required for fourniers diagnosis, but contrast allows for differential diagnosis evaluation
  5. MRI
    1. Preferred imaging if no delay, and patient stable enough to withstand the lengthy study in the radiology department
    2. Efficacy
      1. Test Sensitivity: 100%
      2. Test Specificity: 86%
    3. Findings
      1. Fascial fluid (abnormally increased signal on T2-weighted images)
      2. Gas bubbles (variably present, signal voids on T1 and T2-weighted images)
      3. Reticular increased signal at subcutaneous tissues (similar to Cellulitis) as well as deep fascia involvement
        1. Deep intermuscular fascia involvement
        2. Fascial thickening (>3mm)
        3. Thickened fascia completely lacks signal enhancement post-Gadolinium
      4. Necrotic tissue is over-estimated as normal tissue may have a similar appearace on MRI
      5. Gadolinium is optional for diagnosis but assists in identifying abscesses, joint effusions
  6. References
    1. Malghem (2013) Joint Bone Spine 80(2): 146-54 [PubMed]
    2. Fugitt (2004) Radiographics 24(5): 1472-6 +PMID:15371620 [PubMed]
      1. https://pubs.rsna.org/doi/pdf/10.1148/rg.245035169

XV. Differential Diagnosis

  1. Superficial Skin Infections (no significant systemic signs or Necrotizing Fasciitis critieria)
    1. See Skin Infection (Pyoderma)
    2. Cellulitis
    3. Erysipelas
    4. Skin Abscess
  2. Clostridial Myonecrosis (Gas Gangrene)
    1. Clostridium perfringens (Traumatic source)
    2. Clositridium septicum (spontaneous source without skin break)
    3. Clostridium sordellii (gynecologic source)
  3. Pyomyositis (skeletal Muscle abscess)
  4. Toxic Shock Syndrome
  5. Necrotizing Insect Bite (e.g. Brown Recluse Spider)
  6. Septic Superficial Thrombophlebitis
  7. Anaphylaxis

XVI. Management: Surgical exploration to fascia and Muscle

  1. Early exploration and surgical Debridement within 12 hours is critical (delay risks higher mortality)
  2. Observe for
    1. Necrotizing Fasciitis
    2. Myositis
    3. Gangrene
  3. Technique
    1. Visualize deep structures
    2. Remove necrotic materials
    3. Reduce compartment pressure
    4. Send material for Gram Stain and Culture

XVII. Management: Empiric

  1. Expect Cellulitis to improve with antibiotics
    1. Necrotizing Fasciitis will worsen with antibiotic management alone
    2. Monitor closely for signs of deep space infection in unclear cases
  2. Combination Regimen (3 drugs plus MRSA coverage)
    1. Anaerobe and Gram Positive coverage (and inhibits ribosomal production of toxins)
      1. Clindamycin 600 to 900 mg IV every 8 hours (40 mg/kg/day divided every 8 hours in children)
    2. Gram Positive coverage
      1. Ampicillin-sulbactam (Unasyn) 1.5 to 3 g IV every 6-8 hours OR
      2. Piperacillin-tazobactam 3.375 IV q6-8 hours
    3. Gram Negative coverage
      1. Ciprofloxacin 400 mg IV every 12 hours
  3. Combination Regimen (2 drugs plus MRSA coverage)
    1. Cefotaxime 2 grams IV every 6 hours AND
    2. Anaerobic coverage
      1. Metronidazole 50 mg IV every 6 hours OR
      2. Clindamycin 600 mg IV every 8 hours (typically preferred)
  4. Single agent regimens (choose one plus MRSA coverage and often Clindamycin is added)
    1. Imipenem-Cilastin 1 g IV every 6-8 hours
    2. Meropenem 1 g IV every 8 hours
    3. Ertapenem 1 g IV every 24 hours
  5. MRSA Coverage (use with above regimens)
    1. Vancomycin 15 mg/kg IV every 12 hours
    2. Linezolid 600 mg IV every 12 hours
  6. Other antibiotics
    1. Add Doxycycline if hemorrhagic bullae are seen (cover for Vibrio vulnificus)
  7. Other measures
    1. Maximize nutritional status

XVIII. Management: Post-exposure Prophylaxis

  1. Indications
    1. Household contact exposure from onset to 48 hours from antibiotic start
  2. Treatment options (choose one)
    1. Penicillin G Benzathine
      1. Weight <60 pounds (<27 kg): 600,000 units IM for 1 dose or
      2. Weight >60 pounds (<>7 kg): 1,200,000 units IM for 1 dose
    2. Rifampin 5 mg/kg/day (up to 300 mg maximum) orally twice daily for 4 days
    3. Clindamycin 20 mg/kg (up to 300 mg maximum) orally three times daily for 10 days
    4. Azithromycin (Zithromax) 12 mg/kg (up to 500 mg) orally daily for 5 days
  3. References
    1. Sablier (2010) Lancet 375(9719): 1052 [PubMed]

XIX. Complications

  1. Very high mortality (see below)
  2. Complex wounds, Chronic Pain and debility from extensive Debridement
  3. Intensive Care related complications (e.g. Ventilator Associated Pneumonia, catheter associated infections)
  4. Toxic Shock Syndrome
  5. Acute Kidney Injury
  6. Cardiomyopathy (associated with Toxic Shock Syndrome)
  7. Severe Anemia (Bacterial hemolysin related)

XX. Prognosis

  1. Mortality: 25-35% (up to 70% in those who develop Sepsis, 100% with delayed diagnosis, management)
  2. Truncal involvement mortality approaches 100%
  3. Hypotension is a strong predictor of multiorgan failure and death

XXI. References

  1. Binder (2019) Crit Dec Emerg Med 33(9): 28-9
  2. Goldberg (2015) Crit Dec Emerg Med 29(3): 9-19
  3. Mason, Herbert and Swadron in Herbert (2019) EM:Rap C3 3(10): 1-12
  4. Jhun and Raam in Herbert (2016) EM:Rap 16(8): 9-10
  5. Inaba, Swadron, Long and Gottlieb in Herbert (2020) EM:Rap 20(10):10-11
  6. Inaba, Swadron, Long and Gottlieb in Herbert (2020) EM:Rap 20(11):11-2
  7. Khidir and Eyre (2021) Crit Dec Emerg Med 34(10): 12-3
  8. Elliott (2000) Am J Surg 179:361-6 [PubMed]
  9. Headley (2003) Am Fam Physician 68(2):323-8 [PubMed]
  10. Ramakrishnan (2015) Am Fam Physician 92(6): 474-83 [PubMed]
  11. Stevens (2014) Clin INfect Dis 59(2): 147-59 +PMID:24947530 [PubMed]
  12. Stevens (2017) N Engl J Med 377(23):2253-65 +PMID:29211672 [PubMed]
  13. Usatine (2010) Am Fam Physician 82(7): 773-80 [PubMed]
  14. Wall (2000) J Am Coll Surg 191:227-31 [PubMed]

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Related Studies

Ontology: Necrotizing fasciitis (C0238124)

Definition (NCI) Infection of the deep skin and subcutaneous tissues and necrosis of the fascia. It is caused by bacteria including group A streptococcus, Staphylococcus aureus and Clostridium perfringens. It may develop following trauma and invasive procedures.
Definition (MSH) A fulminating bacterial infection of the deep layers of the skin and FASCIA. It can be caused by many different organisms, with STREPTOCOCCUS PYOGENES being the most common.
Concepts Disease or Syndrome (T047)
MSH D019115
ICD9 728.86
ICD10 M72.6
SnomedCT 52486002, 186428007, 320701000009109
English Fasciitides, Necrotizing, Fasciitis, Necrotizing, Fascitides, Necrotizing, Fascitis, Necrotizing, Necrotizing Fasciitides, Necrotizing Fascitides, Necrotizing Fascitis, Streptococcal gangrene, Necrotizing fasciitis NOS, FASCIITIS NECROTISING, FASCIITIS NECROTIZING, necrotizing fasciitis, necrotizing fasciitis (diagnosis), Fasciitis necrotising, Necrotising fasciitis NOS, Fasciitis necrotizing, Necrotizing Fasciitis, Fasciitis, Necrotizing [Disease/Finding], necrotizing cellulitis, fasciitis necrotize, fascitis necrotizing, necrotizing myositis, streptococcal gangrene, necrotising fasciitis, fasciitis necrotising, fasciitis necrotizing, necrotizing fascitis, Necrotizing erysipelas, Necrotising erysipelas, Necrotising fasciitis (disorder), Necrotizing myositis, Necrotising cellulitis, Necrotising fasciitis, Necrotizing cellulitis, Necrotising myositis, Necrotizing fasciitis (disorder), Necrotizing fasciitis
Dutch necrotiserende fasciïtis NAO, necrotiserende cellulitis, fasciïtis necrotiserend, necrotiserende fasciïtis, Fasciitis necroticans, Necrotiserende fasciitis
French Cellulite nécrosante, Fasciite nécrosante SAI, FASCIITE NECROSANTE, Fasciite nécrosante, Cellulite gangréneuse, Fasciite gangréneuse, Gangrène sous-cutanée à streptocoques bêta-hémolytiques, Syndrome de Meleney
German Fasziitis nekrotisierend, nekrotisierende Zellulitis, nekrotisierende Entzuendung der Faszien NNB, nekrotisierende Fasziitis, Fasziitis, nekrotisierende
Italian Fascite necrotizzante NAS, Cellulite necrotizzante, Fascite necrotizzante
Portuguese Celulite necrosante, Fasceíte necrosante, Fasceíte necrosante NE, FASCEITE NECROSANTE, Fasciite necrotizante, Fasciite Necrosante
Spanish Fascitis necrotizante, Celulitis necrotizante, Fasciitis necrosante, Fasciitis necrotizante NEOM, Fascitis necrosante, miosistis necrotizante, erisipela necrotizante, erisipela necrosante, fascitis necrosante (trastorno), fascitis necrosante, fascitis necrotizante, miositis necrosante, Fasciitis necrotizante, Fascitis Necrotizante
Japanese 壊死性筋膜炎NOS, 壊死性蜂巣炎, エシセイキンマクエン, エシセイホウソウエン, エシセイキンマクエンNOS, 筋膜炎-壊死性, 壊死性筋膜炎
Swedish Fascit, nekrotiserande
Czech fasciitida nekrotizující, Nekrotizující celulitida, Nekrotizující fasciitida, Nekrotizující fasciitida NOS
Finnish Nekrotisoiva faskiitti
Korean 괴사 근막염
Polish Zapalenie powięzi martwicze
Hungarian necrotizáló fasciitis, cellulitis necrotisans, Necrotizáló fasciitis k.m.n., Fasciitis necrotisans, Necrotizáló cellulitis, Nekrotizáló fasciitis
Norwegian Nekrotiserende fasciitt, Fasciitt, nekrotiserende

Ontology: Fournier Gangrene (C0238419)

Definition (MSHCZE) Infekce skrota a hráze pokračující do gangrény, vyvolaná smíšenou bakteriální flórou a kandidou. Zejm. u diabetiků. (cit. Velký lékařský slovník online, 2013 http://lekarske.slovniky.cz/ )
Definition (MSH) An acute necrotic infection of the SCROTUM; PENIS; or PERINEUM. It is characterized by scrotum pain and redness with rapid progression to gangrene and sloughing of tissue. Fournier gangrene is usually secondary to perirectal or periurethral infections associated with local trauma, operative procedures, or urinary tract disease.
Concepts Disease or Syndrome (T047)
MSH D018934
ICD10 N49.3
SnomedCT 398318005, 236742003
English Fournier Disease, Fournier Gangrene, Fournier's Disease, Fournier's Gangrene, Fourniers Disease, Fourniers Gangrene, Gangrene, Fournier's, FOURNIERS DIS, FOURNIER DIS, Gangrene, Fournier, Fournier gangrene, Fournier Gangrene [Disease/Finding], fournier disease, fournier gangrene, fournier's gangrene, fourniers gangrene, fourniers disease, gangrene fournier's, fournier's disease, fournier gangrene (diagnosis), Fournier's gangrene, Fournier's gangrene (disorder), Fournier; gangrene, gangrene; Fournier
German Fournier-Gangraen, Fournier-Krankheit, Fournier-Gangrän, Skrotalgangrän
Japanese フルニエー壊疽, フルニエーエソ, Fournier壊疽, Fournier病, フルニエ壊疽, フルニエ病
Swedish Fourniers gangrän
Czech Fournierova nemoc, Fournierova gangréna
Finnish Fournierin gangreeni
Italian Malattia di Fournier, Gangrena di Fournier
Polish Choroba Fourniera, Zgorzel Fourniera, Zgorzel moszny
Hungarian Fournier-gangraena
Norwegian Fourniers sykdom, Fourniers gangren
Dutch Fournier; gangreen, gangreen; Fournier, Fournier-gangreen, Fournier-ziekte, Gangreen, Fournier-
Spanish gangrena de Fournier (trastorno), gangrena de Fournier, Gangrena de Fournier, Enfermedad de Fournier
French Gangrène de Fournier, Gangrène génitale, Gangrène périnéo-scrotale, Gangrène périnéoscrotale, Maladie de Fournier
Portuguese Doença de Fournier, Gangrena de Fournier

Ontology: Streptococcal necrotizing fasciitis (C0854084)

Concepts Disease or Syndrome (T047)
SnomedCT 449900006
Italian Fascite necrotizzante streptococcica
French Fasciite nécrosante à streptocoques, Fasciite nécrosante streptococcique
Spanish Fascitis necrosante por estreptococos, fascitis necrosante debida a Streptococcus pyogenes, fascitis necrosante debida a Streptococcus pyogenes (trastorno), gangrena estreptocócica, Fasciitis necrosante estreptocócica
Japanese レンサ球菌性壊死性筋膜炎, レンサキュウキンセイエシセイキンマクエン
Czech Streptokoková nekrotizující fasciitida
English Necrotising fasciitis streptococcal, Necrotizing fasciitis streptococcal, Necrotizing fasciitis due to Streptococcus pyogenes, Type II necrotising fasciitis, Streptococcal gangrene, Streptococcal necrotising fasciitis, Necrotizing fasciitis due to Streptococcus pyogenes (disorder), Type II necrotizing fasciitis, Necrotising fasciitis due to Streptococcus pyogenes, Streptococcal necrotizing fasciitis, necrotizing fasciitis due to streptococcus pyogenes (diagnosis)
Hungarian streptococcalis necrotizáló fasciitis, Necrotizáló streptococcalis fasciitis
Portuguese Fasceíte necrosante estreptocócica
Dutch necrotiserende streptokokkenfasciïtis
German nekrotisierende Fasziitis durch Streptokokken