Differentiation between musculoskeletal and neurologic causes of lameness in horses: 22 cases (1993–1995)

Abstract

Summary Medical records of 78 horses tested for EPM via Western Blot and/or PCR tests on cerebrospinal fluid between January 1993 and September 1995 were examined. Twenty-two (Group 2) of the 78 horses in which the origin of gait abnormality (musculoskeletal vs neurologic system) could not be clearly determined on initial examination were compared to the remaining 56 horses (Group 1). Horses in Group 2 were compared with respect to signalment, presenting problem, history, physical examination findings, results of diagnostic tests, and final diagnosis. Horses in Group 2 were more likely to be of warmblood breed and to be presented for lameness or for gait abnormality of uncertain origin (musculoskeletal vs neurologic). All horses presented for lameness or for gait abnormality of uncertain origin whose CSF samples subsequently tested positive for EPM were in Group 2. Horses in Group 2 tended to have multiple problems involving mild hind limb lameness and/or mild neurologic deficits. Some similarities of unusual movement were observed among cases where movement description was recorded. There was a marked increase in positive test results for EPM among Group 2 horses after introduction of the Polymerase Chain Reaction (PCR) test.