Abstract

A four-year-old male toy poodle presented with signs of cervical pain over a period of two years, with subsequent progression to tetraparesis. Neurological examination suggested a transverse myelopathy in the cervical spinal cord. Radiographs of the cervical spine showed fractured endplates of the third through the sixth cervical vertebrae and delayed growth plate closure of all skeletal structures. Total serum thyroid-stimulating hormone and T4 concentrations were very low, indicating hypothyroidism. MRI revealed a pituitary gland cyst and spinal cord compression by fractured metaphysis which were displaced dorsally into the spinal canal. Surgical treatment resulted in marked improvement in clinical signs. Open physes were nearly closed 16 months after continuous administration of levothyroxine sodium hydrate. Based on these findings, a presumed diagnosis of Salter–Harris type III fractures of the vertebral endplates associated with delayed ossification of the growth plates due to hypothyroidism was made.