Infectious Disease Compendium

Gangrene

Diagnosis

An acute, usually rapidly progressive, necrotizing soft tissue infection.

Diabetics get a fetid foot: dead meat and bacteria where the foot once was.

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 Strep: 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.

- Staph aureus: esp 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 ALL SELECTIONS +/- aminoglycosides if septic.

- 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.

- Staph 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.

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.

ICD9 Codes (Soon to be supplanted by ICD10)

Gangrene 785.4; abdomen (wall) 785.4; adenitis 683; alveolar 526.5; anus 569.49; bladder 595.89; Clostridium perfringens 040.0; decubital 707.0; diabetes 250.7 ; diphtheritic 032.0; erysipelas 035; extremity (lower) (upper) 785.4; gallbladder or duct 575.0; gas 040.0; glossitis 529.0; gum 523.8; intestine, intestinal 557.0; laryngitis 464.00; liver 573.8; lung 513.0; lymphangitis 457.2; Meleney's (cutaneous) 686.09; mesentery 557.0; mouth 528.1; orchitis 604.90; ovary 614.2; Pott's 440.24; pancreas 577.0; penis 607.2; perineum 785.4; pharynx 462; pneumonia 513.0; pulmonary 513.0; quinsy 475; Raynaud's (symmetric gangrene) 443.0 ; rectum 569.49; retropharyngeal 478.24; scrotum 608.4; sore throat 462; spermatic cord 608.4; spine 785.4; spirochetal 104.8; spreading cutaneous 785.4; stomach 537.89; stomatitis 528.1; testis 604.99; throat 462; tonsillitis (acute) 463; tuberculous NEC 011.9; umbilicus 785.4; uterus 615.9; uvulitis 528.3; vas deferens 608.4; vulva 616.10.