Strategies to identify specific problems of a horse with indistinct or unusual gait deficits, particularly if it's unclear whether they're related to the musculoskeletal system, neurologic deficits, or behavior, were discussed at the 2009 Association of Equine Practitioner's convention, held Dec. 5-9 in Las Vegas, Nev. Bradford Bentz, VMD, discussed a systematic diagnostic approach that relies on an algorithm involving information on the horse's history, breed, age, gender, and athletic use, along with rider input about changes in behavior and performance.
The equine practitioner then begins a thorough physical examination that includes palpation of the skeleton and musculature, assessment of flexibility and range-of-motion, palpation and manipulation of the neck, spine, and pelvis, as well as exam of airway and heart function.
Dr. Bred Bentz discusses some of the ways a vet discerns the root of lameness.
The veterinarian evaluates the gait, noting if the gait deficit is easily detected. Bentz admonished the examiner to "be honest as to what you are and are not seeing in lameness."
Conduct the exam on changing terrain (hard vs. soft, flat vs. hilly) and observe athletic maneuvers; these might amplify the gait abnormality. The horse should also be ridden under saddle, especially in skills related to the intended athletic pursuit. Bentz encouraged veterinarians to perform further exam of the neurologic system, eyes, and axial skeleton; thoracic and abdominal auscultation (listening with a stethoscope) and percussion; diagnostic imaging; laboratory blood work; and cytology. He noted that behavior assessment also might be necessary to define the problem.
He recommended that veterinarians not base a diagnosis on equivocal exam findings, and exam findings should corroborate the rider complaint and horse's performance history. An exercise test is appropriate if no neurologic deficit is present.
In Bentz' practice population, approximately 65% of gait deficits were related to a primary skeletal, musculoskeletal, or connective tissue cause, while 35% were associated with neurologic dysfunction. Less than 3% were associated with primary muscle disorders. He summed up by reminding everyone that "common things are common," and to remember that a leading cause of treatment failure is misdiagnosis.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.