ENT (Otorhinolaryngology) · MU Sofia

38. Specific inflammatory diseases in otorhinolaryngology. Necrotizing fasciitis of the neck.

Covers necrotizing fasciitis of the neck as a rapidly progressive, life-threatening infection, starting with its definition and typical origins in dental, pharyngeal or traumatic sites and its risk factors. It then sets out the polymicrobial microbiology and the stepwise pathogenesis, and includes the Melandri classification into four types. The clinical picture moves from early signs to late signs such as crepitus and skin changes, followed by laboratory and imaging tests including the LRINEC score and CT. Treatment, possible complications and differential diagnosis, including Ludwig's angina and gas gangrene, close the note.

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Topic 38 of 52 in the MU Sofia syllabus for ENT (Otorhinolaryngology) (Medicine, Year 4). The free AceMed note covers it in 3 sections, about 559 words (4 min of reading), with 15 flashcards.

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  1. Specific inflammatory diseases in otorhinolaryngology. Necrotizing fasciitis of the neck.
  2. Possible Complications
  3. Differential Diagnosis

Specific inflammatory diseases in otorhinolaryngology. Necrotizing fasciitis of the neck.

1. Definition: Necrotizing fasciitis of the neck is a rapidly progressive, life-threatening bacterial infection characterized by extensive necrosis of the superficial fascia and subcutaneous tissues, with secondary involvement of skin and muscles, commonly originating from odontogenic or oropharyngeal infections. Leads to systemic toxicity.

2. Etiopathogenesis

The infection is rarely primary and usually stems from a pre-existing site of infection:

  • Odontogenic (Commonest): Dental abscesses (especially the lower second and third molars) or periodontal disease.
  • Pharyngeal: Peritonsillar abscess or pharyngitis.
  • Trauma: Lacerations, surgical wounds, or even insect bites.
  • Risk Factors: Immunocompromised states (Diabetes Mellitus is the most common), chronic renal failure, malnutrition.

Microbiology: It is typically polymicrobial (type 1), involving a synergy between:

  1. 1. Aerobes: Streptococcus pyogenes (Group A Strep), Staphylococcus aureus.
  2. 2. Anaerobes: Bacteroides, Peptostreptococcus, Fusobacterium.

Pathogenesis

  1. 1. Entry of bacteria through mucosa or skin
  2. 2. Rapid spread along fascial planes
  3. 3. Microvascular thrombosis → ischemia
  4. 4. Tissue necrosis → toxin release
  5. 5. Systemic inflammatory response → sepsis

3. Classification - Melandri Classification

  • Type I: Polymicrobial (aerobes + anaerobes). Most common in the neck.
  • Type II: Monomicrobial (usually Group A Streptococcus).
  • Type III: Gas gangrene (Clostridium species) or marine-related (Vibrio).
  • Type IV – Fungal (immunocompromised)

4. Clinical Picture

The clinical hallmark is that the physical signs often seem disproportionate to the severity of pain (initial extreme pain followed by anesthesia as nerves are destroyed).

  • Early signs: Erythema, warm skin, and "woody" hardness of the neck, rapidly progressive neck swelling.
  • Late signs:
  • Crepitus: A "crackling" sensation under the skin due to gas-forming bacteria.
  • Skin Discoloration: Progression from dusky red to purple/blue, and finally black (frank gangrene).
  • Skin Vesicles/Bullae: Formation of fluid-filled blisters.
  • Loss of skin sensation (nerve destruction)
  • Systemic Toxicity: High fever, tachycardia, hypotension (septic shock), and altered mental status.

5. Paraclinical and Radiological Examinations- Clinical suspicion (very important)-

  • LRINEC Score: (Laboratory Risk Indicator for Necrotizing Fasciitis). Uses CRP, WBC count, Hemoglobin, Sodium, Creatinine, and Glucose to help distinguish NF from simple cellulitis.
  • Elevated serum lactate
  • CBC: marked leukocytosis with CRP / ESR: very high
  • Blood Cultures & Wound Culture: Essential for targeted antibiotic therapy.
  • ABG: To monitor for metabolic acidosis (signs of sepsis).
  • CT Neck with Contrast (Gold Standard): Shows asymmetrical fascial thickening, fluid collections, and—most characteristically— gas bubbles (emphysema) in the soft tissue spaces.
  • X-ray: May show "gas streaks" in the soft tissues, but is less sensitive than CT.

6. Treatment Options

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