Cervical Stenotic Myelopathy in a Thoroughbred Colt

A 14-month-old Thoroughbred colt with hind limbs lameness was referred to Equine Hospital of Jeju National University. During physical examination, the patient could not walk in a straight line but wobbled especially with hind limbs. He hesitated when backing and crossed hind limbs while circling tightly by protracting the outer hind limb keeping the inner hind limb stationed. Stenosis was observed between the 2nd (C2) and 3rd (C3), and the C3 and 4th (C4) cervical vertebrae on radiographs. The colt diagnosed as cervical stenotic myelopathy (CSM) based on the clinical signs and radiological findings. To confirm the diagnosis, postmortem computed tomography (CT) and histopathologic examination were performed after the euthanasia. The CT images revealed severe compression of the spinal cavity and cord between C3 and C4 cervical vertebrae. Grossly, there was compression of the spinal cord between the C3 and C4 cervical vertebrae. Histopathologically, severe axonal swelling and demyelination characterized by vacuolation and cavity formation were observed in the white matter of the spinal cord, especially in C3 and C4. CSM is problematic in the horse racing industry because of abnormal walking. This case report of CSM may offer information for diagnosis of the disease in the equine veterinary fields in the Republic of Korea.