Student Case Presentation
Clostridial Myonecrosis: When Gas Gangrene Goes Full Bovine
| Date/Time: |
9/11/2025 2:00
|
| Presenter: |
Madison Smith |
| Veterinary School: |
COR |
Abstract:
Gas gangrene is a condition caused by Clostridium spp., which are gram-positive obligate anaerobes. Although gas gangrene has low morbidity, mortality is high. Understanding the etiology of clostridial myonecrosis– endogenous or exogenous– is important for mitigating potential risk factors.
A third lactation Holstein freshened unassisted with live male twins on November 12th, 2024. She presented 3 DIM for difficulty ambulating. A physical exam performed by Cornell Ambulatory revealed she was quiet and responsive, recumbent, febrile, had a hypomotile rumen, an involuting uterus with minimal retained fetal membranes, and crepitus along the right shoulder with severe antebrachial swelling. The rest of her physical exam was unremarkable, leading to the top differential diagnosis of clostridial myonecrosis. No history of recent injections or puncture wounds were noted, favoring endogenous myonecrosis (black leg, Clostridium chauvoei) over exogenous myonecrosis (gas gangrene, Clostridium chauvoei, C. septicum, C. novyi type A, C. perfringens type A, C. sordellii). She was treated with 500 mL 23% calcium gluconate IV, 30 mL flunixin meglumine (2.2 mg/kg) IV q24hr, 72 mL procaine penicillin G (30,000 U/kg) IM q12hr, and surgical fenestrations around areas of crepitus were made.
Despite continued antimicrobial and anti-inflammatory administration, a 48-hour decline in 1768’s condition prompted euthanasia via captive bolt and pithing, followed by necropsy and diagnostic work-up at the Animal Health Diagnostic Center (Cornell University). Histologic examination confirmed muscular necrosis with emphysema, fascial edema, and gram-positive bacilli containing a terminal spore were noted within the lesions. Clostridium septicum was isolated from the muscle, acknowledging a diagnosis of exogenous myonecrosis.
This case suggests that exogenous clostridial myonecrosis from environmental contamination can mimic black leg. This highlights the importance of considering gas gangrene even when clinical signs suggest typical postpartum black leg.
