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עברית
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Table of Contents
0:00 – Introduction
0:41 – Overview
1:10 – Types of Necrotizing Fasciitis
2:21 – Pathophysiology & Risk Factors
3:16 – Clinical Presentation
4:06 – Diagnosis
5:37 – Treatment
7:09 – Prognosis and Recovery
7:37 – Take Home points
Introduction
- Necrotizing soft tissue infections can be easily missed in routine cases of soft tissue infection.
- High mortality and morbidity underscore the need for vigilance.
Definition
- A rapidly progressive, life-threatening infection of the deep soft tissues.
- Involves fascia and subcutaneous fat, causing fulminant tissue destruction.
- High mortality often due to delayed recognition and treatment.
Types of Necrotizing Fasciitis
- Type I (Polymicrobial)
- Involves aerobic and anaerobic organisms (e.g., Bacteroides, Clostridium, Peptostreptococcus).
- Common in immunocompromised patients or those with comorbidities (e.g., diabetes, peripheral vascular disease).
- Type II (Monomicrobial)
- Often caused by Group A Streptococcus (Strep pyogenes) or Staphylococcus aureus.
- Can occur in otherwise healthy individuals.
- Vibrio vulnificus (associated with water exposure) is another example.
- Fournier’s Gangrene (Subset)
- Specific to perineal, genital, and perianal regions.
- Common in diabetic patients.
- Higher mortality, especially in females.
Pathophysiology
- Spread Along Fascia
- Poor blood supply in fascial planes allows infection to advance rapidly.
- Tissue ischemia worsened by vascular thrombosis → rapid necrosis.
- High-Risk Patients
- Diabetes with vascular compromise.
- Recent surgeries or trauma (introducing bacteria into deep tissue).
- Immunosuppression (e.g., cirrhosis, malignancy, or immunosuppressive meds).
- NSAID use may mask symptoms, delaying diagnosis.
Clinical Presentation
Early Signs & Symptoms
- Severe Pain out of proportion to exam findings.
- Erythema (often with indistinct borders).
- Fever, Malaise (systemic signs of infection).
- Rapid progression with possible color changes (red → purple).
- Bullae Formation (fluid-filled blisters) and skin necrosis/gangrene.
- Crepitus in polymicrobial cases (gas production in tissue).
Late-Stage Signs
- Systemic toxicity: hypotension, multi-organ failure if untreated.
Diagnosis
- Clinical Suspicion Is Key
- Pain out of proportion, rapid progression, systemic signs.
- The “finger test” (small incision to explore fascial planes).
- Surgical Consultation
- Early surgical exploration is often the definitive diagnostic step.
- Lab Tests
- LRINEC Score (CRP, WBC, Hemoglobin, Sodium, Creatinine, Glucose) to stratify risk.
- Not definitive but can guide suspicion.
- Imaging
- CT scan may reveal gas in tissues, fascial edema, or muscle involvement.
- Must not delay surgical intervention if clinical suspicion is high.
Treatment Principles
- Immediate & Aggressive Surgical Debridement
- Often multiple surgical procedures are required as necrosis progresses.
- Debridement back to healthy tissue margins.
- Empiric Broad-Spectrum Antibiotics
- Cover gram-positive (including MRSA), gram-negative, and anaerobes.
- Examples include:
- Vancomycin or Linezolid (for MRSA).
- Piperacillin-tazobactam or Carbapenems (for gram-negative & anaerobes).
- Clindamycin (to inhibit bacterial toxin production).
- Adjust based on culture results later.
- Adjunct Therapies
- Hyperbaric Oxygen Therapy (if available) for resistant cases.
- Evidence is mixed; not universally accessible.
- Supportive Care
- Intensive monitoring, often in an ICU setting.
- Fluid resuscitation & vasopressors for septic shock.
Prognosis & Disposition
- High Mortality Rate
- Influenced by infection site, patient’s baseline health, and speed of intervention.
- Importance of Rapid Intervention
- Early recognition, aggressive surgery, and antibiotics improve survival.
- Long-Term Considerations
- Patients may require extensive rehabilitation.
- Reconstructive surgery often needed for tissue deficits.
- Disposition
- Operative management is mandatory; patients do not go home.
- Critical care admission is typical for hemodynamic monitoring and support.
Five Key Take-Home Points
- High Suspicion Saves Lives: Recognize severe pain out of proportion as a critical red flag.
- Know Your NF Types & Risk Factors: Type I polymicrobial vs. Type II monomicrobial, plus subsets (Fournier’s).
- Clinical Diagnosis Above All: LRINEC and imaging help, but timely surgical exploration is paramount.
- Combined Surgical & Medical Therapy: Early debridement + broad-spectrum antibiotics (including toxin inhibition) is lifesaving.
- Extended Recovery & Mortality Risks: High mortality if missed or delayed. Expect prolonged rehab and possible multiple surgeries.
