Current Insights On The Multidisciplinary Treatment 
Of Necrotizing Fasciitis


Author(s): 
David M. Davidson, DPM

This author presents a multidisciplinary approach to diagnosing and treating a 54-year-old patient with diabetes who presented with intense pain and a toe that was turning black.

Necrotizing soft tissue infections are rare but potentially fatal. They are generally divided into three categories based upon anatomical involvement: crepitant cellulitis, necrotizing fasciitis and myonecrosis.

   Crepitant cellulitis is characterized by infection limited to the skin. Typically, this infection involves ample soft tissue crepitus, limited pain and minimal systemic symptoms. Necrotizing fasciitis extends beyond the skin into the subcutaneous tissue and fascia. Usually, there is less air present in the soft tissue but pain is more pronounced and systemic symptoms are prominent. Myonecrosis includes muscle involvement, pronounced pain, systemic symptoms and further risk for loss of limb.

   Despite these distinctions, one should note there is often significant overlap between these entities, depending upon the amount of tissue involved and the pathogens present.

   Necrotizing soft tissue infections are characterized by rapidly developing tissue destruction due to the presence of bacterial enzymes and toxins. Vascular ischemia and tissue necrosis result from the combination of virulent factors present in the tissue. Typically, these infections are polymicrobial. There is usually the presence of an anaerobic organism (Bacteroides fragilis, Clostridium species, Peptostreptococcus species) with one or several members of the Enterobacteriaceae family (E. coli, Proteus species, Klebsiella species). Beta hemolytic streptococci such as Streptococcus pyogenes (Group A strep) may be present with either an anaerobe or an Enterobacteriaceae. Clostridium species can act alone to create a rapidly progressive illness, especially in cases of myonecrosis.

   Necrotizing soft tissue infection is typically more severe in patients with an underlying immunodeficiency. Examples include poorly controlled diabetes mellitus, organ transplant recipients, chronic steroid use and the use of immune modulators, alcohol abuse with liver disease, and patients undergoing chemotherapy for malignancies.

   In most cases, the anaerobic bacteria proliferate in an environment of local tissue hypoxia. Due to lower oxidation reduction potential, these bacteria produce gases such as hydrogen, nitrogen, hydrogen sulfide and methane, which accumulate in the soft tissue spaces because of reduced solubility in water.

Comments

Dear Dr. Davidson,

Congratulations on this important study! It confirms our earlier results (Crew JR, Varilla A, Rocas III TA, Abdul Rani S, Debabov D. 2013. Treatment of acute necrotizing fasciitis using negative pressure wound therapy (NPWT) and adjunctive NeutroPhase® irrigation under the foam. Wounds. 25: 272-277). We feel that these results represent a new paradigm for therapy of necrotizing fasciitis (NF). The new important element is NPWT with HOCl irrigation after incisions are made and surgical suctioning of the necrotic toxic material is removed. Below are some specific comments.

Your comment: Necrotizing soft tissue infections are rare but potentially fatal. They are generally divided into three categories based upon anatomical involvement: crepitant cellulitis, necrotizing fasciitis and myonecrosis

My answer: It is important to realize that NF or flesh eating bacteria are just reflections of a disease process which should be labeled Toxic Inflammatory Cellulitis. The accurate description of pathogenesis is “Frozen in phase II of wound healing” or “cytokine storm”, even though bacteria and bacterial toxins start the process. Finally, I think the three phases you describe, cellulitis, NF and myonecrosis, are just that, phases of Toxic Inflammatory Cellulitis.

Your comment: Typically, these infections are polymicrobial.
My answer: Type I NF is classified as a polymicrobial infection whereas type II is classified as a monomicrobial infection. Historically, Group A Streptococcus (GAS) made up most cases of type II infections. However, since as early as 2001, another serious form of monomicrobial NF has been observed with increasing frequency (Lee TC,Carrick MM, Scott BG, Hodges JC, Pham HQ. Incidence and clinical characteristics of methicillin-resistant Staphylococcus aureus necrotizing fasciitis in a large urban hospital. Am J Surg. 2007;194(6):809-813.)

Your comment: Two days after surgery, I removed the packing and we started negative pressure wound therapy (NPWT) with instillation using Dakin’s solution. Instillation therapy delivers and removes topical solutions to an infected wound at controlled times and also provides standard negative pressure

My answer: As pure 0.01% hypochlorous acid in saline pH 4 (NeutroPhase®) has been shown to both rapidly kill bacteria and neutralize bacterial toxins in vitro, clinical administration of NeutroPhase® with NPWT was recently explored in a case of NF (Crew et al.,2013). This patient was dying with a totally sterile arm. This is how we discovered that NeutroPhase inactivates toxins. Dakin’s solution contains sodium hypochlorite along with hypochlorous acid (HOCl) which is the active species. Starting the instill VAC immediately rather than waiting for 2 days later would be probably more beneficial.

John Crew, MD, FACS
Medical Director of AWCW Seton Hospital Daly City Ca.
jcrewmd@att.net

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