Intramedullary Gas on CT: Recognizing Emphysematous Osteomyelitis in Dogs Before It’s Too Late

Emphysematous Osteomyelitis: A Rare Manifestation of Osteomyelitis in Dogs. Multimodality Diagnostic Imaging and Evaluation of Clinical Progression

Anastasia M. McHaney; Katherine A. Weber; Erica Chávez-Peón Berle; Michelle Riehm; William H. Whitehouse; Seng Wai Yap; Nicolette Cassel

Background

Osteomyelitis is a relatively common condition in veterinary patients; however, emphysematous osteomyelitis, defined by the presence of intramedullary gas, is exceedingly rare in both veterinary and human medicine. In human patients, this entity is associated with significant mortality and is often linked to systemic comorbidities. Prior to this report, emphysematous osteomyelitis had been documented only once in dogs. The study aimed to describe the imaging characteristics, clinical progression, and outcomes of two canine cases and to contextualize these findings within the existing veterinary and human literature.

Methods

This retrospective descriptive case series evaluated two young dogs presenting to tertiary veterinary centers with acute inflammatory and infectious clinical signs. Inclusion criteria required complete medical records, CT-confirmed intramedullary gas, and positive bacterial cultures from adjacent soft tissues. Diagnostic evaluation included radiography, ultrasonography, and computed tomography, with imaging interpreted by diagnostic imaging residents and board-certified radiologists. Clinical data, imaging findings, culture results, treatment, and follow-up outcomes were reviewed.

Results

Both dogs demonstrated multiple small, irregularly marginated intramedullary gas foci within the femur on CT, producing a “pumice stone” appearance characteristic of emphysematous osteomyelitis. Peri-femoral abscessation was present in both cases, and bacterial cultures were positive (Clostridium haemolyticum in one case and beta-hemolytic Streptococcus spp. in the other). One dog responded favorably to prolonged antimicrobial therapy, with progressive imaging changes consistent with chronic osteomyelitis followed by near-complete osseous remodeling and resolution of intramedullary gas. The second dog experienced rapid systemic deterioration with suspected septic thromboembolic disease and was euthanized despite aggressive medical and surgical intervention.

Limitations

The study was limited by its retrospective design and the extremely small sample size inherent to the rarity of the condition. Lack of standardized treatment protocols and limited long-term outcome data restrict broader prognostic conclusions. Additionally, definitive routes of infection could not be established in either case.

Conclusions

Emphysematous osteomyelitis represents a rare but severe form of osteomyelitis in dogs, associated with a guarded prognosis and potential for rapid clinical decline. CT is the imaging modality of choice for diagnosis, as the presence of multiple small intramedullary gas foci without a history of trauma or surgery is considered pathognomonic. Early recognition and aggressive, prolonged antimicrobial therapy may improve outcomes. Increased awareness and early CT utilization may lead to earlier diagnosis and better characterization of this underrecognized condition in veterinary medicine.

Disclaimer: The summary generated in this email was created by an AI large language model. Therefore errors may occur. Reading the article is the best way to understand the scholarly work. The figure presented here remains the property of the publisher or author and subject to the applicable copyright agreement. It is reproduced here as an educational work. If you have any questions or concerns about the work presented here, reply to this email.