Necrotizing Soft Tissue Infections

- Discussion:
    - necrotizing fascitits is any necrotizing soft tissue infection spreading along fascial planes, with or without overlying cellulitis; 
    - rapidly progressive inflammation and necrosis of subQ tissues and deep layer of superficial fascia with sparing of deep fascia and muscle;
    - also called Meleney ulcer, NF is severe manifestation of lymphangitis that progresses in a frightening manner within a few hours;
    - tissue necrosis develops rapidly behind advancing wall of inflammation that limits penetration by antibiotics;
    - desquamation followed by gangrene may be relentless; 
    - clinical findings:
           - clinical signs of pain out of proportion to exam coupled with areas of anesthesia (from microvascular and nerve damage)
           - hyperyrexia, and chills are severe;
           - skin lesions are incised and drained or aspirated to obtain fluid for culture;
           - initial findings are localized pain and minimal swelling, often w/ no visible trauma or discoloration of the skin;
           - dermal induration and erythema eventually become evident; 
           - firm, tense, "woody" induration of the subcutaneous tissues;
           - eventually the patient has limited range of motion, chills, fever; 
           - probe open wounds:
                    - dx is confirmed when a probed can be passed laterally along fascial cleft in a open wound; 
                    - probing edges with a blunt instrument permits ready dissection of the superficial fascia well beyond the wound margins;
           - blistering of the epidermis is a late finding; 
           - hyponatremia and hyperkalemia are ominous findings;
                    - ref: Necrotizing fasciitis of the extremities: a prospective study
    - historical note:
           - necrotising fasciitis was originally named by Wilson in 1952: Wilson B. Necrotizing fasciitis. Am Surg 1952; 18:416.
           - other previous descriptions include: haemolytic gangrene, acute streptococcal gangrene, gangrenous erysipelas, necrotising
                     erysipelas, suppurative fasciitis, and hospital gangrene
                     - ref: Paediatric Surgery: A Comprehensive Text For Africa [Chapter 21]

    - gram stain:
            - Gram Negative Bacilli: / Gram Negative Cocci: / Gram Positive Bacilli: Gram Positive Bacilli
            - bacterial Menu: 
    - may be caused by single organism - streptococci pyogenes or vibrio, or may be caused by a combination of organisms;
    - anaerobic or microaerophilic streptococci are believed to be the usual cause, but these microorganisms are difficult to culture;
    - clostridium perfringes :
            - ref: Gas Gangrene of a Prosthetic Hip
    - staph aureus / MRSA
            - ref: Necrotizing fasciitis caused by methicillin-resistant Staphylococcus aureus resulting in death. A report of three cases.
    - vibrio (vulnificus):
            - typically the patient is exposed to sea water
            - course is measured in hours esp in alcoholics and diabetics;
            - despite in vitro sensitivity to tetracycline, response to ATB is poor;
            - immediate wide excision and amputation may be necessary; 
            - references:
                    - Necrotizing Soft-tissue Infections and Sepsis Caused by Vibrio vulnificus Compared with Those Caused by Aeromonas Species.
                    - Infections caused by halophilic marine Vibrio bacteria
    - streptococci pyogenes infections: 
           - isolation of group A Streptococcus from a normally sterile body site or 4-fold rise against: streptolysin O, DNase B
           - most superficial form is impetigo which affects stratum corneum;
           - ecthyma contagiosum describes shallow superficial dermal ulcers caused by a slightly deeper infectios;
           - erysipelas is the term for streptococcal dermal cellulitis, often associated with lymphangitis as it spreads along dermal lymphatics;
                   - cellulitis can spread to the dermal lymphatics as classical lymphangitis, commonly causeced by strep pyogenes;
           - necrotizing streptococal infections:
                   - acute gangrene: at level of fascia, streptococci pyogenes, produces acute gangrene, a form of necrotizing fascitis;
                   - initially there is rapid onset of marked tissue edema and redness w/ little pain, progressing to local cyanosis & skin blistering; 
                   - lymphangitis and lymphadenopathy are absent;
                   - soft tissue gas may be uncommon; 
                   - serious systemic disease
                          - shock (systolic blood pressure <90 mm of Hg)
                          - DIC
                          - respiratory failure, liver failure, renal failure
                   - treatment is parental penicillin, debridement, and measures to prevent edema;
                   - before antibiotics were available this was a surgical emergency mandating immediate amputation to
                          prevent streptococcal septicemia and death; 
                   - w/ a high suspicion that a group-A streptococcus was the pathogen, intravenous immune globulin therapy should be initiated;
                   - ref: Necrotizing fasciitis with toxic shock syndrome in a child: a case report and review of literature

- Treatment:
     - Antibiotic Menu
             - IV infusion of aqueous penicillin must be instituted immediately;
             - typically ATB is given without response, unless concomitant radical debridement is also performed;
     - Radical Surgical Debridement:
             - fascial planes are extensively opened and debrided;
             - every anecdotal story about necrotizing fascitis seems to involve the retrospective wish on the part of the surgeon that a
                      much more radical debridement
                     had be performed;
             - fasciotomy / fasciectomy
                     - single or multiple linear incisions over the affected areas;
             - muscle debridement:
                     - muscle necrosis occurs in patients with strep infections (gangrenous streptococcal myositis) which is similar to
                                 clostridial myonecrosis (gas gangrene) but there is no gas in the tissues;
             - ref: Aggressive surgical management of necrotizing fasciitis serves to decrease mortality: a retrospective study.

Necrotizing fasciitis in contused areas.

[Gas gangrene: A discussion of 3 cases and review of the literature.]

Early diagnosis, nutritional support, and immediate extensive debridement improve survival in necrotizing fasciitis.

Necrotizing Fasciitis of the Extremities.

Necrotizing fasciitis: review of the literature and case report.

All That Is Gas Is Not Gas Gangrene: Mechanical Spread of Gas in the Soft Tissues. A Case Report.

Necrotizing Fasciitis of the Shoulder Following Routine Rotator Cuff Repair. A Case Report 

Letter to the Editor. Necrotizing Fasciitis: Clinical Presentation, Microbiology, and Determinants of Mortality

Necrotizing Fasciitis: Clinical Presentation, Microbiology, and Determinants of Mortality 

Necrotizing fasciitis of the extremities: 34 cases at a single centre over the past 5 years 

Comparison of Necrotizing Fasciitis and Sepsis Caused by Vibrio vulnificus and Staphylococcus aureus

Management of Necrotizing Fasciitis Infections

Clinical Presentations of Soft-Tissue Infections and Surgical Site Infections

Extensive Subcutaneous Emphysema Resembling Necrotizing Fasciitis

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Wednesday, September 27, 2017 5:11 am