How to Diagnosis a Soft Tissue Infection

Join our Emergency General Surgery team as they discuss Necrotizing Soft-Tissue Infections. Hosted by Drs. Jordan Nantais, Ashlie Nadler, Stephanie Mason and Graham Skelhorne-Gross.

Necrotizing Soft-Tissue Infections:
- Also known as “flesh eating disease”, gas gangrene, necrotizing fasciitis/myositis, Fournier’s gangrene.
- Early findings are non-specific
- Rapidly fatal - diagnostic delay can lead to tremendous additional morbidity and mortality

Classification:
- Type 1 - polymicrobial category (most common) found in immunosuppressed or elderly
- Type 2 - monomicrobial infection [Group A Streptococcus > Methicillin-resistant Staphylococcus aureus (MRSA)]
- Type 3 - monomicrobial infection (Vibrio or Clostridium)
- Type 4 - fungal (rare) in immunocompromised or after penetration or trauma from candida or Zygomycetes.

Initial Workup
- History: (comorbidities, immunosuppression, recent infections or trauma)
- Exam: swelling, open lesions, drainage, erythema, crepitus, and pain out of proportion
     - Most common: swelling, pain, erythema
     - Bullae, skin necrosis, crepitus are less common
- Labs: Hb, wbc, Na, Creat, glucose, and CRP
- Imaging: CT, MRI *sensitive and specific but may not change management
- Cut-down: bedside vs in OR
- Gm stain 

Management
- Initially: two large bore IVs, foley catheter, aggressive fluid resuscitation, broad spectrum antibiotics, vasopressors PRN
- Abx choices: carbopenem or piperacllin-tazobactam or cefotaxime plus metronidazole. Clindamycin (antitoxin effect) and vancomycin (MRSA) should be considered.
- OR: must debride all dead/infected tissue, involve other surgical specialties as needed
     - Mark edge of cellulitis and use as initial debridement
     - Healthy dermis – pearly and white
     - Healthy fat – pale, yellow, glistening
     - Healthy fascia – should bleed, doesn’t easily separate from muscle
     - Healthy muscle – contract with cautery
     - Dressing: betadine-soaked gauze on the wound
     - Most patients will need at least 3 ORs (second OR generally 8-12 hours after the first)
     - No VAC or stoma at first OR

References: 
1.    Pelletier J, Gottlieb M, Long B, Perkins JC Jr. Necrotizing Soft Tissue Infections (NSTI): Pearls and Pitfalls for the Emergency Clinician. J Emerg Med. 2022 Apr;62(4):480-491. doi: 10.1016/j.jemermed.2021.12.012. Epub 2022 Jan 31. 
2.    Sarani B, Strong M, Pascual J, Schwab CW. Necrotizing fasciitis: current concepts and review of the literature. J Am Coll Surg. 2009 Feb;208(2):279-88. 
3.    Edlich RF, Cross CL, Dahlstrom JJ, Long WB 3rd. Modern concepts of the diagnosis and treatment of necrotizing fasciitis. J Emerg Med. 2010 Aug;39(2):261-5
4.    Hoesl V, Kempa S, Prantl L, Ochsenbauer K, Hoesl J, Kehrer A, Bosselmann T. The LRINEC Score-An Indicator for the Course and Prognosis of Necrotizing Fasciitis? J Clin Med. 2022 Jun 22;11(13):3583
5.    Bulger EM, May A, Bernard A, Cohn S, Evans DC, Henry S, Quick J, Kobayashi L, Foster K, Duane TM, Sawyer RG, Kellum JA, Maung A, Maislin G, Smith DD, Segalovich I, Dankner W, Shirvan A. Impact and Progression of Organ Dysfunction in Patients with Necrotizing Soft Tissue Infections: A Multicenter Study. Surg Infect (Larchmt). 2015 Dec;16(6):694-701.
6.    LRINEC Score from: https://www.mdcalc.com/calc/1734/lrinec-score-necrotizing-soft-tissue-infection#:~:text=Patients%20were%20classified%20into%20three,%25%20and%20NPV%20of%2096%25. Retrieved July 2022.

If you liked this episode, check out our recent episode titled, "Journal Review in Colorectal Surgery: Timing of Biologics and Surgery in the Setting of Crohn’s Disease" - https://behindtheknife.org/podcast/journal-review-in-colorectal-surgery-timing-of-biologics-and-surgery-in-the-setting-of-crohns-disease/

Please visit behindtheknife.org to access other high-yield surgical education podcasts, videos and more.