Patient: Zoe, 6-year-old female Hound Mix
Presenting complaint: Progressive stiffness, difficulty walking, and exercise intolerance
Referring DVM: Randolph Regional Veterinary Hospital (Dr. Taylor Hull)
Exam/Diagnosis: Zoe's general exam was unremarkable. On neurologic exam, she was ambulatory with a stilted, short-stride choppy gait affecting all four limbs. No ataxia was noted, but weakness culminating in collapse was observed after only short periods of ambulation. Generalized and marked non-painful muscle hypertrophy was observed. She was nonpainful on palpation of her spine and the orthopedic exam was unremarkable. Her exam neuro-localized to a generalized myopathy.
Initial diagnostics included a complete blood count, chemistry profile, TT4, and CK level. Zoe's CK and AST were found to be significantly elevated, most consistent with an inflammatory myopathy (myositis). An infectious disease panel and muscle biopsies were submitted. The muscle biopsy confirmed an inflammatory and necrotizing myopathy with no infectious agents identified. Zoe's exam and diagnostic findings were consistent with suspected immune-mediated polymyositis.