Infectious Disease Compendium

Necrotizing fasciitis

Diagnosis

An acute, usually rapidly progressive, necrotizing soft tissue infection. Often anesthetic over the infection. It can involve the skin (cellulitis), the muscle (myositis) and/or fascia (fasciitis). From a practical point of view, it is the surgeon who decides the extent of infection when she debrides it.

In the groin,ß it is called Fourniers and in the cecum typhlitis.

Gas, which by the way is made by all organisms, shows up towards the end of the disease, around the time they are going to code. So do NOT send the patient for x-rays looking for gas. You are just wasting precious time as the infection progresses.

Epidemiologic Risks

Diabetes, liver disease, immunocompromise of all kinds, trauma, surgery, bad luck.

I tend to favor NSAIDs as a risk for Streptococci although the data is variable (PubMed).

Skin popping/black tar heroin a risk for C. perfringens and other Clostridium.

Monomicrobial gram-negative disease is particularly severe, with 3x the mortality (Pubmed).

Microbiology

- Mixed synergistic necrotizing fasciitis: Streptococci plus anaerobes plus coliforms.

- Meleney's: an indolent infection in abdominal wounds, often of diabetics, due to a combination of Group A Streptococcus and Staphylococcus aureus.

- Aeromonas hydrophilia: after freshwater trauma or use of leeches. Really. The plastic surgeons use leeches and the leech requires Aeromonas to exist in its gut to live. Once you treat the Aeromonas, the leech will die.

- Klebsiella pneumoniae. In Taiwan (and elsewhere) it is a cause on mono-microbial necrotizing fasciitis (Pubmed).

- Vibrio vulnificus saltwater exposure in patients with hepatic disease, diabetes mellitus, chronic renal insufficiency, and adrenal insufficiency (PubMed).

- Gas Gangrene: C. perfringens and other Clostridia.

- Group A Streptococcus: especially with prior NSAID use or trauma.

- Staphylococcus aureus: especially MRSA that makes the Panton-Valentine leukocidin. In some series, it is the most common cause of necrotizing fasciitis (PubMed).

- Cirrhotic patients (in Taiwan) had monomicrobial infections mainly by gram-negative rods (GNBs) (76%), including Vibrio (36%), Klebsiella (21%), and Aeromonas spp. (14%) (PubMed).

- Apophysomyces after trauma like tornado injury or penetrating injuries from wood/dirt in normal hosts (PubMed).

- Saksenaea and Apophysomyces (molds) after environmental trauma (PubMed).

Empiric Therapy

They all require debridement. ASAP. Don't Richard around. Call the surgeon. No I&D, no cure. Know I&D, know cure.

Then

- Mixed synergistic necrotizing fasciitis: (third-generation cephalosporins PLUS metronidazole) OR carbapenems OR (quinolone PLUS metronidazole) OR penicillin/beta-lactamase inhibitors.

- Meleney's: Nafcillin/oxacillin OR cefazolin OR vancomycin OR linezolid.

- Gas Gangrene: Penicillin PLUS clindamycin.

- Group A Streptococcus: Penicillin PLUS clindamycin PLUS 1g/kg IVIG day one, 0.5 g/kg day 2 and 3 if toxic shock syndrome. Why? The Eagle effect, where high inoculum of Group A Streptococci are resistant to penicillin and patients do better on clindamycin (PubMed). Plus I do have an affinity for screwing with bacterial virulence factors aka proteins.

- S. aureus: Vancomycin (it is usually MRSA) PLUS clindamycin.

Pearls

While IVIG is (relatively) proven for streptococcal toxic shock syndrome, it's used for Streptococcal and staphylococcal necrotizing soft tissue infection is not proven. I am a believer in IVIG in these circumstances.

Rants

Hyperbaric you ask? I remain skeptical. If you are going to use it, use AFTER debridement and AFTER antibiotics. I remember once I was asked by a doctor what I thought about hyperbaric. I said it was great for the bends but primarily served to make hyperbaric doctors richer. Why do you ask? Turns out he was the medical director of the hyperbaric chamber. Oops. Open mouth, insert foot. The rule: when someone asks out of the blue your opinion on some medical issue, ask them why BEFORE you answer.

I also hate the term 'flesh-eating', especially when it precedes 'virus' (Stupid). All infecting organisms are feasting on us one way or the other.

Old terms, per the Wikipedia, are "phagedaenic (gnaw - biting or chewing which gradually make a hole or destroying it) ulcer, phagedena gangrenous, gangrenous ulcer, malignant ulcer, putrid ulcer, or hospital gangrene." We really should use the word putrid more.

Curious Cases

Relevant links to my Medscape blog

Cringe Worthy

Common, Critical, or Cool

What makes me guilty

It bugs me not to have an answer

Variations on a Theme

0 for 2

Bugs don't care.

Last update: 07/02/19