Introduction Definition also called clostridial myonecrosis Epidemiology Demographics male:female ratio no sexual predilection Anatomic location buttocks, thigh, perineum Risk factors posttraumatic (associated with C perfringens) car accidents (most common) crush injuries gunshot wounds with foreign bodies burns and frostbite IV drug abuse postoperative bowel resection or perforation biliary surgery premature wound closure spontaneous colon cancer (associated with C. septicum) neutropenia Etiology Pathophysiology Clostridial species Clostridium perfringens (most common), Clostridium novyi, Clostridium septicum found in soil and gut flora gram-positive obligate anaerobic spore-forming rods that produce exotoxins (e.g. C. perfringens alpha toxin) login to view 2 more bullets incubation period <24h gas produced by fermentation of glucose login to view 1 more bullet other bacteria include E. coli, Pseudomonas aeruginosa, Proteus species, Klebsiella pneumoniae Presentation History recent surgery to GI or biliary tract Symptoms triad sudden progressive pain out of proportion to injury login to view 1 more bullet tachycardia not explained by fever feeling of impending doom Physical exam sweet smelling odor swelling, edema, discoloration and ecchymosis blebs and hemorrhagic bullae "dishwater pus" discharge crepitus altered mental status Imaging Radiographs findings linear streaks of gas in soft tissues Studies Labs Elevated LDH Elevated WBC Metabolic acidosis and renal failure Histology Gram stain reveals Gram-positive bacilli absence of neutrophils lack of acute inflammatory response is hallmark of gas gangrene Culture blood culture rarely grows Clostridial species Differential Necrotizing fasciitis Treatment Nonoperative high dose IV antibiotics 1st line is penicillin G and clindamycin alternative treatment is erythromycin, tetracycline or ceftriaxone login to view 1 more bullet hyperbaric O2 indications login to view 1 more bullet outcomes login to view 1 more bullet Operative radical surgical debridement with fasciotomies indications login to view 1 more bullet Complications Shock Renal failure both mediated by TNF alpha, IL-1, IL-6 Prognosis Overall 25% mortality 50% mortality if bacteremic 100% mortality if treatment is delayed Poorer prognosis for older patients with comorbidities