A 57 y.o. woman comes in with neck pain and fever.
she has a hx of a “bad tooth’
you notice some air in the soft tissues
and you can follow the air all the way to the mediastinum and heart. What happened here?
Our patient had necrotizing fasciitis from a dental source. The infection had spread to the mediastinum requiring a thoracic surgery drainage procedure. Necrotizing fasciitis is a surgical diagnosis characterized by dishwater-gray exudate and an absence of pus.
Necrotizing fasciitis is distinguished by whether the cause is polymicrobial ( type I) l or monomicrobial(type II).
Type I- Polymicrobial infections are usually seen in the elderly or patients with underlying illness. Diabetes is a major risk factor. Type I infections often contain gas as in our patient. This makes them difficult to distinguish from gas gangrene, a clostridial infection.
These polymicrobial infections penetrate fascial compartments causing Ludwig’s angina in the floor of the mouth, Lemierre’s syndrome(thrombophlebitis of the jugular vein) , and fournier’s gangrene in the perineum.
Type II- monomicrobial infections are often gram positive with group A strep (flesh eating bacteria) and MRSA being most common. They can occur at any age and often in healthy individuals. Two other pathogens: vibrio vulnificus and clostridia can also cause necrotizing fasciitis.
this pt went on to an arm amputation. he had been eating raw seafood and developed a vibrio vulnificus infection.
Vibrio vulnificus is found in seawater. Often this is transmitted through a minor wound at the sea shore. It is also transmitted by eating raw or poorly cooked seafood.
where to find vibrio vulnificus
Clostridial infection is the result of a deeply penetrating wound compromising blood supply and creating an anaerobic environment for spore germination. The spores are commonly found in soil and once infection occurs progressive myonecrosis occurs. (this is the original “gas gangrene”accounting for 12% of the deaths in WWI. ) Non traumatic gas gangrene does occur presumably through a bowel entry site in those with adenocarcinoma or the bowel or neutropenia.
gas gangrene
Group A invasive strep infections present in one of two ways; either there is a defined portal of entry like a rash or needle injection or there is not. When there is a defined lesion(50%), only mild inflammation occurs at first, then in 72 hours bullae develop and bacteremia with sepsis. In the other 50% of those presenting with strep infections there is no obvious source. The only clue to the presence of necrotizing fasciitis is severe pain out of proportion to exam. The mortality in this group is 70% because the diagnosis is delayed. By the time skin manifestations are present exotoxins are released causing venous and arterial occlusion with deep tissue necrosis. 15% of cases are resistant to clindamycin.
Our patient had a classic type I polymicrobial infection growing out mixed anaerobes: Prevotella buccae, Dialister pneumosintes, and Solobacterium moorei. Dishwater fluid was seen on surgical exploration and she required a reoperation five days later for increasing WBCs. She also had a trop of 11,000 and DKA on arrival both of which have improved. Tooth 17 was removed.
Park J, Lee C. Vibrio Vulnificus Infection NEJM: 2018 ;379:375
Stevens D, Bryant A. Necrotizing soft tissue infections. NEJM 2017;3772253-65.
Stevens D, Musher D, Watson D et al. spontaneous nontraumatic gangrene due to clostridium septicm Fev Infect Dis 1990:12;286-96.
Bechar J, Sepehripour S, Hardwiche J, et al. Laboratory Risk Indicator for necrotizing fasciitis score for the assessment of early necrotizing fasciitis: a systematic review of the literature. Ann R coll Surg Engl 2017:99:341-6