Myonecrosis, Clostridial
Basic Information 
Clinical Presentation
History, Chief Complaint
• Onset of signs within 48 hours of injection of a pharmacologic or biologic agent in the affected area of the body.
• Incriminated medications include nonsteroidal antiinflammatory drugs, antihistamines, multivitamins, antipyretics, dewormers, vaccines, diuretics, and synthetic prostaglandins.
• Depression, lethargy, and inappetence are chief signs.
Physical Exam Findings
Etiology and Pathophysiology
• Most commonly, the etiologic agent is Clostridium perfringens.
• Clostridium septicum, Clostridium chauvoei, Clostridium novyi, and others are occasionally incriminated.
• Infection may originate from introduction of surface bacteria into soft tissue at the time of injection.
• Alternatively, dormant spores may be present in the muscle and convert to vegetative form when anaerobic conditions develop secondary to injection-site inflammation.
• α-Toxins from C. perfringens are dermonecrotic and considered critical in development of the disease.
• Toxins lead to systemic toxemia, cardiovascular collapse, and multiorgan dysfunction.
