Ultrasound Helpful For Diagnosing Infected Joints in Horses (AAEP 2010)

When a veterinarian suspects a horse's joint is infected, but it is not practical or feasible to obtain a joint fluid sample, he or she should consider using ultrasound to image the joint. Alex Young, BVSc, of the University of California, Davis' William R. Pritchard Veterinary Medical Teaching Hospital made this recommendation during a presentation at the 2010 American Association of Equine Practitioners convention, held Dec. 4-8 in Baltimore, Md.

Synovial sepsis, or infection of a synovial structure such as a joint in a horse's limb, is common in equine practice.

"Properly diagnosing the condition can be challenging, particularly if the horse has a laceration or cellulitis (a diffuse bacterial infection of the skin and associated tissues) because synoviocentesis, or a 'joint tap' (and subsequent examination of the joint fluid), can be difficult or even contraindicated in these situations," said Young.

In these cases, an ultrasound examination is a worthwhile endeavor.

Young said, "Ultrasonography is widely available, yet not often used to help diagnose synovial sepsis largely because the features of infected joints are not well-described."

To help veterinarians recognize synovial sepsis on ultrasound, Young and colleagues reviewed the ultrasound exams of 62 horses diagnosed with synovial sepsis via synoviocentesis .

Key features the veterinarians noted on the ultrasound examinations that supported a synovial sepsis diagnosis included:

  • Severely thickened synovium (joint lining);
  • A mild to moderate effusion (an increased amount of synovial fluid) in most cases; and
  • The appearance of an anechoic (black) or echogenic (gray) effusion on the ultrasound images.

"In addition to identifying features that would support a diagnosis of synovial sepsis, ultrasound examinations can also help practitioners locate pockets of effusion that can be used to collect synovial samples to confirm the diagnosis," concluded Young.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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