Any infection of a synovial-fluid-filled structure requires prompt and aggressive management. In a study conducted by University of California, Davis, veterinarians, septic bicipital bursitis occurred very rarely. Upon reviewing those medical records, the research team determined affected horses had a fair outcome, which was better than hypothesized.
The Bicipital Bursa
The shoulder is an infrequent cause of lameness in horses. Its anatomy is complex and includes the bicipital bursa—a synovial-fluid-filled structure located between the head of the humerus and the tendon of the origin of the biceps brachii muscle. The bicipital bursa allows the tendon to glide smoothly between the bones of the shoulder joint. Because little soft tissue covers the bicipital bursa, trauma to the shoulder can result in septic bicipital bursitis.
Study Population
In their retrospective study, Spiesshofer et al. (2023) reviewed medical records of nine horses diagnosed with septic bicipital bursitis between 2000 and 2021. Six horses had a history of trauma, and the remaining three had swelling of the shoulder region. All horses were diagnosed based on the result of synovial fluid cytologic analysis, and all horses underwent radiography and ultrasonography.
Treating Septic Bicipital Bursitis
Two of the nine horses were treated medically at the owner’s request. This included non-steroidal anti-inflammatory drugs and systemic antimicrobials. If a wound was present, it was thoroughly cleaned, debrided, and lavaged. Four horses underwent bursoscopy, which involved debriding the synovial lining and lavaging the bursa thoroughly. Amikacin was instilled into the bursa at the end of surgery. One horse underwent a combination bursoscopy and bursotomy. Through-and-through needle lavage was performed in three horses. Four horses required a second procedure (bursoscopy, bursotomy, or needle lavage).
A Fair Prognosis
The researchers hypothesized that horses with septic bicipital bursitis would have poor prognoses, especially in long-standing cases. In this study, four horses were treated by the primary veterinarian prior to referral. Median duration of treatment of those horses was 9.5 days. Once referred, length of hospital stay ranged from 0 to 47 days, with a median of 9 days.
Five of the nine horses survived to hospital discharge, including one of the two horses managed medically and four of the seven horses treated surgically. Three horses were available for long-term follow-up. One of the horses treated medically required three months of antibiotic therapy but was ultimately used for trail riding. An additional surviving horse was treated with through-and-through lavage followed by bursoscopy and was in training at the time of follow-up.
Conclusion
The shoulder has little soft-tissue coverage, making it vulnerable to trauma and infection. Septic bicipital bursitis occurs rarely but should be considered in all cases where shoulder lameness is accompanied by swelling or trauma. Medical management might be successful, but other techniques such as bursoscopy, bursotomy, and through-and-through lavage might also be beneficial. The prognosis for septic bicipital bursitis is fair, not poor as previously suspected, even with nonsurgical treatment.
Reference
Spiesshofer P, Kilcoyne I, Spriet M, et al. Septic inflammation of the bicipital bursa: clinical, imaging, and surgical findings in nine horses. J Am Vet Med Assoc 2023;261(9):1380-87.
Related Reading
- Fetlock Radiographs: No Association Between Lameness, Pathology
- Flumetasone’s Effects on Inflammation in Horses
- Causes of Immune-Mediated Myopathies in Horses
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