Diagnosing Equine Bone Fragility Syndrome (AAEP 2011)

When owners think of potentially or ultimately fatal horse health conditions, colic, laminitis, or rabies are some common ailments that might come to mind. A less common eventually fatal condition is bone fragility syndrome (BFS). There's no known cause or cure, and researchers are just working to understand the debilitating disorder. Recently, a research team studied which diagnostic options are most effective in detecting the condition. The results were presented at the 2011 American Association of Equine Practitioners convention, held Nov. 18-22 in San Antonio, Texas.

According to a 2008 article from the University of California, Davis (UC Davis), Center for Equine Health publication, The Horse Report, BFS is a progressive disorder that mainly affects the ribs, spine, and upper portion of the limbs. Horses with advanced stages of BFS usually have a marked swayback that is characteristic of the disease.

"Horses that are mildly affected with BFS appear to have an intermittent lameness without an identifiable cause," the authors wrote in the UC Davis report. "The lameness may affect one leg, several legs, or different legs at different times. When multiple legs and/or the spine are affected, horses can appear to have a generalized stiffness and reluctance to move. As the disease progresses, bones of the spine and upper portions of the front and hind legs become weak. Over the course of months to years, the bones deform and sustain incomplete bone fractures that attempt to heal. "

Noted lead author Amanda Arens, DVM, MPVM, a graduate student at UC Davis,, "Prevention of bone resorption using anti-osteoclastic therapies (those designed to prevent bone breakdown, such as bisphosphonate drugs) may improve lives of affected horses with early diagnosis. However there is a need to assess the accuracy of diagnostic tests for BFS."

The research team compared the effectiveness of nuclear scintigraphy (bone scans), scapular ultrasound, physical examination, and serum biomarkers of bone turnover (formation and resorption) in a prospective case-control study. Key findings included:

  • Nuclear scintigraphy was most accurate method for diagnosing BFS in general, allowing veterinarians to diagnose the disease in the early stages, and providing disease severity and distribution information;
  • Scapular ultrasound and physical examination were both effective methods for diagnosing moderate to severe BFS; and
  • Serum markers were ineffective for diagnosis.

The team also created severity indices for nuclear scintigraphy and physical examination findings "to capture the broad spectrum of disease," Arens noted.

She concluded that these clearly defined criteria for interpreting diagnostic tests could help veterinarians detect BFS earlier and more accurately and, as mentioned, earlier diagnosis and treatment could lead to a better quality of life for mildly affected horses.

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.