What Is Your Neurologic Diagnosis?

An 8-year-old 48.2-kg neutered male German Shepherd Dog was presented for examination because of a sudden onset of apparent spinal discomfort (noted as a reluctance to jump, vocalization, and signs of discomfort elicited by palpation of the vertebral column), which progressed to ambulatory paraparesis and an inability to void its urinary bladder. The dog had a preexisting comorbidity of exocrine pancreatic insufficiency, for which it was receiving treatment (a pancreatic enzyme supplement and oxytetracycline); the condition was considered controlled. Prior to referral, routine hematologic and serum biochemical profiles were performed and results were considered unremarkable. Physical examination revealed reduced muscle mass in both pelvic limbs and a large, flaccid urinary bladder upon abdominal palpation. The dog was normothermic (rectal temperature, 37.9 °C).