Wobblers Syndrome in Horses Marissa Kazeck

What is Wobblers Syndrome? Wobblers Syndrome is a neurological condition in younger horses that results in abnormal neurological control of the limbs. The most common is termed cervical vertebral malformation (CVM) and is characterized by malformation or compression of the spinal cord, which leads to spasticity, ataxia, and incoordination. There are two distinct types of CVM: Cervical vertebral instability (CVI): causes dynamic spinal cord compression, typically affects horses from 4-12 months of age. Malformation occurs mostly at C3-4 and C4-5 Cervical static stenosis (CSS): characterized by a closing of the cervical canal causing compression on the spinal cord, typically affects horses between 12 to 36 months of age. Malformation occurs mostly at C5-6 and C6-7

What causes this? The exact cause of wobbler syndrome in horses is unknown. There are several factors that it is believed to be caused by: Genetic predisposition Nutritional imbalances Rapid growth Physical trauma Work or excessive exercise on immature bones The cervical vertebrae are supposed to protect the spinal cord while allowing for normal movement of the neck. With wobbler syndrome, these bones have grown in such a way as to compress the spinal cord and cause both degeneration of the cord and signs of neurological impairment in the function of the limbs. The spinal cord seems to grow out of the small space left inside the deformed vertebrae.

What horses are affected? Breeds most commonly affected: Thoroughbred Quarter Horse Morgan Males out number females three to one Horses that gain weight rapidly during their first two years of life.

Clinical Signs Noticeable incoordination (ataxia): occurs because of the malformed or compressed vertebrae on the spinal cord, interferes with messages being sent by the brain = interference with normal nerve transmission from brain to legs. Usually seen in the hind quarters. Weight loss Weakness “Wobbler’s heel”: occurs when the horse is in the advanced stages of the syndrome and incoordination is evident. Characterized by the horse reaching forward with the back foot and lacerating the bulbs of the hell on the front foot. Falling down Clinical signs may appear suddenly or gradually, horse may show periods of slight improvement but will never recover if treatment is not performed.

Diagnosis Diagnosis of spinal cord damage requires quality radiographs of the cervical region. Radiographs will reveal signs of lipping, flaring, evidence of lesion or stenosis of the vertebrae to indicate whether the horse is suffering from CVM. Sometimes it is necessary to resort to a myelographic (dye) study in order to isolate the exact location or locations of spinal cord compression. Other ways to diagnosis include: Turning the horse in a small circle: horse will swing his rear legs out as he turns Backing the horse: instead of using their back up, the horse will back up with their front legs until they get into an awkward position and they will hop backwards with their rear legs. Sway test: one person walks the horse away while another person grabs the tail and pulls the horse to one side. A normal horse will allow you to do that and then correct itself, however a horse with wobblers cannot tell where his limbs are and its easy to pull him over to one side.

Pictures and Video Backing the horse to test for wobblers Appearance of cervical vertebra from a horse affected with cervical stenotic myelopathy Backing the horse to test for wobblers Radiographic appearance of severe cervical vertebral malformation Appearance of a cervical vertebra from a horse affected with cervical stenotic myelopathy. Note the asymmetrical appearance of the articulation http://www.youtube.com/watch?v=0aTJFfUnaeA&feature=related

More pictures…. Tight Circles Placement Test Tail sway “A”- will show the Atlas occipital joint to C2/C3 “B”- will show C2 to C4 “C”- will show C4 to C7 Using a software program with the radiographs, the cord ratio measurements are taken. These ratios help objective assessment of narrow spinal canal. Cassette Placement

Treatment Horses with this syndrome can be treated in different ways Drug therapy Drugs directed at the spinal cord inflammation to decrease the nerve tissue swelling and intracranial pressure Mannitol (0.5-1.0 g/kg, iv) Dimethylsulfoxide (0.5 g/kg of a 40-50% solution, iv, diluted with isotonic fluids given by gravity flow) Furosemide Surgery Fuses the vertebrae Involves drilling a hole between the affected vertebral bodies from underneath the neck and inserting a stainless steel prosthesis called a “bagby basket” which fuses and immobilized the vertebrae. Aggressive management Nutritional imbalances

Prognosis Aggressive nutritional management and controlled exercise, coupled with early diagnosis, have recently proven to produce excellent results in the treatment of wobblers The more ataxic the patients are the more likely there can be recovery problems Patience is the key in long term prognosis Physical therapy and exercise is very important in the rehabilitation period The earlier noticed and treated = best results

Quiz What is Wobblers Syndrome? List 2 causes of this. T/F : Females out number males 4 to 1 List two signs of Wobblers What are 3 test performed to diagnosis? What are the 3 treatment options? What is the most important part of the rehabilitation period?

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