Msk Dermatology · Year 2 · from Msk Dermatology

Case 1: Necrotizing Fasciitis

Patient Presentation

Demographics: 54-year-old male with diabetes

Chief Complaint: Rapidly spreading leg pain, swelling, and fever

History of Present Illness: The patient developed a small abrasion on his right lower leg 3 days ago. Yesterday he noticed increasing redness and swelling. Over the past 12 hours, the pain has become severe and out of proportion to the visible findings. He developed fever, chills, and the affected area now has dusky discoloration with hemorrhagic bullae.

Past Medical History:

  • Type 2 diabetes mellitus (poorly controlled, HbA1c 9.8%)
  • Peripheral vascular disease
  • Obesity

Physical Examination:

  • Temperature: 39.4C
  • Blood pressure: 88/54 mmHg
  • Heart rate: 128 bpm
  • Right lower leg:
  • Dusky, mottled skin with central necrosis
  • Hemorrhagic bullae
  • Crepitus on palpation
  • Severe tenderness extending beyond visible margins
  • Pain out of proportion to examination findings
  • Skin anesthesia over necrotic areas
  • No dorsalis pedis pulse palpable on right

Workup and Results

Laboratory Studies:

  • WBC: 24,500/mcL with 15% bands
  • Hemoglobin: 11.2 g/dL
  • Platelets: 85,000/mcL
  • Creatinine: 2.4 mg/dL
  • Glucose: 385 mg/dL
  • Sodium: 128 mEq/L
  • Lactate: 6.2 mmol/L
  • CRP: 32 mg/dL

LRINEC Score: 9 (high risk for necrotizing fasciitis)

CT Scan:

  • Gas tracking along fascial planes
  • Soft tissue thickening with fat stranding

Wound Culture (intraoperative):

  • Polymicrobial: E. coli, Bacteroides fragilis, Peptostreptococcus

Clinical Image

Clinical photograph demonstrating necrotizing fasciitis with characteristic dusky discoloration, hemorrhagic bullae, and tissue necrosis. The presence of crepitus and pain out of proportion are critical diagnostic clues.

Diagnosis

Necrotizing Fasciitis Type I (Polymicrobial)

Classification:

  • Type I: Polymicrobial (mixed aerobic and anaerobic) - as in this case
  • Type II: Monomicrobial (usually Group A Streptococcus)

Discussion

This case illustrates necrotizing soft tissue infection:

  • Pain Out of Proportion: The lecture emphasizes that pain out of proportion to examination findings is the clinical hallmark that should raise immediate concern for necrotizing fasciitis.
  • Type I vs Type II: The lecture distinguishes Type I necrotizing fasciitis (polymicrobial) from Type II (monomicrobial, usually Group A Streptococcus). This patient has Type I with mixed aerobic and anaerobic organisms.
  • Surgical Emergency: The lecture states that urgent surgical debridement is the most critical intervention. Antibiotics alone are insufficient and delays in surgery dramatically increase mortality.
  • Clindamycin Rationale: The lecture notes that clindamycin is added to the antibiotic regimen because it inhibits toxin production, not just for anaerobic coverage.

Treatment Plan

  1. Immediate Surgical Debridement:
  • Emergent wide debridement of all necrotic tissue
  • Return to OR every 24-48 hours for re-exploration
  • Consider amputation if limb not salvageable
  1. Broad-Spectrum Antibiotics:
  • Vancomycin (MRSA coverage)
  • Piperacillin-tazobactam (broad gram-negative and anaerobic)
  • Clindamycin (toxin production inhibition)
  1. Resuscitation:
  • Aggressive IV fluid resuscitation
  • Vasopressor support if needed
  • ICU admission
  1. Supportive Care:
  • Tight glucose control
  • Wound VAC after debridement
  • Consider hyperbaric oxygen (adjunctive)
  1. Monitoring:
  • Serial lactate levels
  • Renal function
  • Signs of septic shock/organ failure

Teaching Points

  1. Pain out of proportion to exam is the hallmark of necrotizing fasciitis
  2. Type I = polymicrobial; Type II = monomicrobial (usually GAS)
  3. Urgent surgical debridement is the most critical intervention
  4. Clindamycin inhibits toxin production
  5. Crepitus and gas on imaging indicate gas-forming organisms

All cases for this lecture as Markdown