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