412: C Septicum Fasciitis and Refractory Shock: A Deadly Presentation of Occult Colonic Dysplasia

Introduction: Clostridium septicum (C. septicum) is a virulent, spore-forming, gram-positive anaerobe that causes spontaneous gas gangrene and necrotizing fasciitis, even in the absence of trauma. In a review of 94 cases of gas gangrene due to C. septicum, an associated malignancy was identified in 71% of patients, 61.5% of which were gastrointestinal. Given its aggressive nature and poor prognosis, timely recognition and source control are essential. Description: A 60-year-old woman with type 2 diabetes (status post right below-knee amputation), chronic kidney disease, heart failure with preserved ejection fraction, peripheral vascular disease and prior pulmonary embolism presented with fever, nausea, vomiting, and confusion after a fall owing to hypotension, resulting in gluteal bruising. She was hypotensive (BP 74/45), tachycardic (HR 120), febrile (102.2°F) and tachypneic. Labs showed leukocytosis, anemia, elevated creatinine, hyperglycemia, lactic acidosis and an anion gap metabolic acidosis. Physical exam showed left gluteal tenderness and bruising. CT abdomen/pelvis revealed subcutaneous emphysema in the gluteus maximus and pancolitis. She received broad-spectrum antibiotics and underwent debridement revealing necrotic fascia and purulence. Blood cultures confirmed C. septicum bacteremia. Given the known malignancy association, further evaluation was pursued. Total abdominal colectomy revealed polypoid ileocecal mass, identified as tubulovillous adenoma with high-grade dysplasia. The patient was on vasopressors in the ICU for septic shock, subsequently stabilized and transferred to the floor on day 20. Discussion: C. septicum infections may present as cellulitis, fasciitis, visceral abscesses or spontaneous gas gangrene. Vague early symptoms often mimic other intra-abdominal conditions. Pathogenesis involves tumor-related mucosal disruption, bacterial translocation and a hypoxic, acidic environment favoring spore germination and toxin release. In our patient, rapid decline despite antibiotics and debridement prompted surgical evaluation, revealing underlying colonic neoplasia, highlighting the importance of considering gastrointestinal malignancy in patients with C. septicum bacteremia and emphasizing the need for early diagnosis, surgical intervention and appropriate antimicrobial therapy.