Infectious Disease Compendium

Gangrene

Diagnosis

It is due to dead tissue, often from a lack of blood. In ID it is nn acute, usually rapidly progressive, necrotizing soft tissue infection.

Diabetics get a fetid foot: dead meat and bacteria where the foot once was, often called wet gangrene.

There is also dry gangrene, where a toe dies and withers, kind of like dry aging beef.

Epidemiologic Risks

Diabetes, trauma, surgery, bad luck.

Microbiology

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

- Aeromonas hydrophilia: after fresh water exposure often after trauma or use of leeches. Really. Leeches need Aeromonas in their gut to survive and when the plastic surgeon puts the leeches on the wound and forgets the quinolone, the patient gets infected.

- Gas Gangrene: C. perfringens.

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

- Meleney's Mixed Synergistic: often diabetic, often surgical wounds, tends to progress slooooowly. Due to streptococci and Staphylococcus aureus.

- Staphylococcus aureus: especially MRSA that makes the Panton-Valentine leukociden.

Empiric Therapy

They all require debridement first. Then

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

- Meleneys: nafcillin / oxacillin or cefazolin or vancomycin or linezolid.

- Gas Gangrene: penicillin PLUS clindamycin (and metronidazole as well?) all at maximum dose.

- Group A Strep: penicillin PLUS clindamycin PLUS 1g/kg IVIG day one, 0.5 g/kg day 2 and 3.

- Staphylococcus aureus: vancomycin (change to nafcillin / oxacillin if susceptible) PLUS clindamycin PLUS 1g/kg IVIG day one, 0.5 g/kg day 2 and 3. The data for S. aureus and IVIG is not as good as for streptococcal, which, in turn, is barely adequate.

Pearls

While IVIG is proven for streptococcal toxic shock, it's use for Streptococcal and staphylococcal necrotizing infections are not proven. I am a believer in IVIG in these circumstances.

Per the Wikipedia: "The etymology of gangrene derives from the Latin word gangraena and from the Greek gangraina (γάγγραινα), which means "putrefaction of tissues". It has no etymological connection with the word green..."

Rants

Hyperbaric oxygen 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 oxygen. 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.

Last Update: 07/26/18.