Wobblers Syndrome a Disappointing Diagnosis
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Aug 10, 2011
I was called out to look at a yearling gelding that developed ataxia. The horse was ataxic enough that he had trouble getting out of his stall and almost fell down coming out of the barn. This horse was easy to diagnose as Cervical Stenotic Myelopathy from the neurologic tests and medical history. This disease is one of the most common causes of spinal ataxia in young horses.
I could not help but recall when one of my own yearling thoroughbreds was led out for the farrier. I saw a strange or odd step. After a thorough neurologic exam he was diagnosed as a "Wobbler". This was a disappointing outcome, with no hope of a race career for this young colt.
In this condition, neurologic gait deficits result from compression of the spinal cord by malformed cervical vertebrae. Developmental orthopedic diseases such as physitis, joint effusion, OCD, and flexoral limb deformities occur more frequently in horses with CSM (Wobblers).
The cause of CSM is likely multifactoral; consisting of genetic and environmental influences. A high plane of nutrition, rapid growth, or trauma often affects the largest best looking individuals. To date, no single cause of the condition has been identified.
Most horses with CSM develop clinical signs at 6 months to 3 years of age. Late yearlings are most common. Males are affected three times as often as fillies. Most light and draft breeds can be affected, while thoroughbreds are particularly predisposed. Affected horses grow rapidly and are large for their age. Onset of the clinical signs can be gradual or come on all at once.
Hind limb deficits are typically one grade worse than fore limbs. Circling, raising the head, and walking over obstacles or inclines make the condition worse. Toe dragging and knuckling are common findings. These horses have difficulty backing and may stand base wide and drag hind limbs. The musculature of the neck may be thin. Cervical pain may be elicited during movement of head position.
Radiographic and myelographic examination are helpful in making a diagnosis.
Treatments for CSM include dietary management or surgery. Management of diet involves avoiding excess weight gain and monitoring the balance of minerals ingested. Limiting exercise is also recommended. Dietary changes are most helpful in mild cases with horses under 1 year of age. Surgical treatments include ventral stabilization or dorsal laminectomy. These surgeries will generally improve the neurologic grading score by 1.
Most horses diagnosed with CSM are euthanized due to the cost of surgery with often less than desirable results. Very few ever become athletic enough to perform.