THYROXINE-RESPONSIVE UNILATERAL FORELIMB LAMENESS AND GENERALIZED NEUROMUSCULAR DISEASE IN 4 HYPOTHYROID DOGS

Four dogs were examined because of unilateral forelimb lameness. For a ll dogs, results of physical examination, including complete neurologi c examination, were unremarkable except for vague, intermittent signs of pain upon deep palpation of the affected limb. During electromyogra phy, insertional activity, fibrillation potentials, and positive sharp waves were recorded symmetrically from all major muscle groups. Gener alized neuromyopathy was diagnosed. All dogs were determined to be thy roid deficient, and L-thyroxine supplementation was initiated. The lam eness resolved within 2 months in all dogs. During follow-up electromy ography, abnormalities were not recorded from 3 of the dogs and were l ess severe in the fourth. Thyroxine supplementation was discontinued i n 2 dogs, and tameness redeveloped. Lameness again resolved when suppl ementation was reinstituted.