Wobbler Syndrome in Older Horses
The neurologic condition cervical vertebral stenotic myopathy (CVSM, commonly known as wobbler syndrome) is much less common in older horses than it is in young, growing animals. But according to one clinician, this condition should be on all veterinarians' differential diagnoses list when evaluating an aged horse presenting with neurologic signs and/or neck pain.
At the 2013 Western Veterinary Conference, held Feb. 17-21 in Las Vegas, Nev., Laurie Beard, DVM, MS, Dipl. ACVIM, associate clinical professor at Kansas State University's College of Veterinary Medicine, presented a review of CVSM in aged horses.
Horses affected by CVSM essentially have a damaged spinal cord. The major causes of spinal cord damage include cervical (neck) vertebrae malformation or trauma.
"The exact pathogenesis of CVSM in older horses is unknown and likely different than younger horses," Beard said. She said older horses are more likely to have lesions located in the caudal cervical vertebral column (near the base of the neck), between the vertebrae C5 and C6 or C6 and C7. She noted that some studies suggest biomechanical loading related to "wear and tear" could contribute to lesions. Additionally, she said, articular process osteophytosis (bony remodeling) is a common finding in older horses with CVSM.
Beard said common clinical signs associated with CVSM in older horses include:
Beard said veterinarian frequently use standing cervical radiographs to diagnose CVSM in mature horses. However, if cervical radiograph results are inconclusive, a myelogram, considered the gold standard CVSM test, might be required. This procedure involves injecting dye into the spinal canal before taking a set of radiographs to evaluate the spinal column's width and to identify possible sites of compression.
Treatment options for mature horses diagnosed with CVSM include:
The prognosis for for return to work in mature horses with CVSM is variable and depends on the degree of ataxia present, Beard said.
"A horse with mild clinical disease that is a trail riding horse (or low-level performance horse) probably does have a reasonable chance of still performing," she said. "However, higher level performance horses probably will not be able to perform at the level they were."
Additionally, horses used for pleasure riding are more likely to have a good prognosis for full return to athletic function than higher performance athletes, she said.
Although it's commonly thought of as a young horse disorder, Beard stressed that veterinarians should consider CVSM as a differential diagnosis in any horse with spinal ataxia. Prognosis for return to work depends on the degree of ataxia present, but many horses show improvement with medical management, she said.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.
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