Equine Health Update Issue 2 Volume 19 - Page 21

EQUINE | Equine Disease Update At left, a PET scanner captures images of a lower limb. Above, an overlay of CT and PET scans (middle row) of this mare’s front feet shows a severe lesion on her left navicular bone and reveals an early one on her right that’s indiscernible on CT scan but evident on PET. an old lesion and what’s a more recent active lesion ac- tually causing a problem.” Spriet and his team deduced that PET images of horses’ lower limbs are easily obtained and might be particu- larly useful for tendinopathy and laminitis research. Elevated SAA Can Help Vets Diagnose Septic Arthrits Septic arthritis—inflammation of a joint caused by an infectious agent—can cause significant pain and lame- ness in horses. Early and accurate diagnosis is key to suc- cessful treatment. Signs of joint infection can be difficult to distinguish from synovitis, or noninfectious joint inflammation, said Elsa Ludwig, DVM, MS, CVA, now an associate veterinar- ian at the Vermont Large Animal Clinic, in Milton. While she was completing her residency at the Virginia- Maryland College of Veterinary Medicine, Ludwig and colleagues sought to determine whether a biomarker— serum amyloid A, or SAA— might help them diagnose septic arthritis. Serum amyloid A is a protein produced in the liver in response to inflammation or infection. It increases and decreases quickly, which means it can give veterinarians nearly real-time information about what’s going on in the horse’s body. Additionally, SAA levels can be mea- sured rapidly and easily using stall-side assays. In their study, Ludwig and colleagues induced septic arthritis and synovitis in nine healthy horses. They col- lected blood and synovial fluid samples at several time points after. They performed synovial fluid cytology and measured the SAA levels in both types of samples. (Traditionally, these tests have been run on blood, but the researchers wondered if synovial fluid could yield a helpful result.) They found that: • In synovial fluid, the total nucleated cell count and • Volume 19 no 2 • June 2017 • 21