Wobbler Syndrome Signs and Diagnosis

A veterinarian can say several things that will chill every horse owner's heart, including colic, laminitis, navicular disease, and wobbler syndrome. These cause fear because of the unknown--and often unfavorable--outcome for your horse. But as veterinary medicine progresses, these terms cause less anxiety because some of the unknowns are being solved. A case in point is a horse affected with wobbler syndrome.

Clinical Signs

A wobbler is a horse with a damaged spinal cord. The major causes of spinal cord  damage include malformation of the cervical (neck) vertebrae, trauma to the vertebrae, proliferation (excessive growth) of surrounding soft tissue, or damage by viruses, protozoa (as with equine protozoal myeloencephalitis, or EPM) or parasites. The most obvious clinical sign is a horse which presents with an abnormal gait characterized by wobbling (he looks like he has had a fair amount of tranquilizers). Mild cases might only demonstrate an inability to change leads or stop smoothly, or a negative change in behavior that results in poor performance. The mild cases are often confused with subtle problems of the hind legs, especially of the hock and stifle.

The hind limbs are affected because the nerves that supply the area are located on the outside of the spinal cord in the cervical area and therefore are more easily damaged than nerves leading to the front limbs, which are protected deep within the spinal cord.


Since other conditions can mimic wobbler syndrome, it's important to obtain a complete diagnosis to facilitate treatment and improve the long-term prognosis. Clinical diagnosis usually requires a complete neurological exam, radiographs of the skull and cervical area, a myelogram, and cerebrospinal fluid testing.

A veterinarian experienced in observing neurological deficits should perform the neurological exam. The exam might include procedures to assess back withdrawal, tail and anal tone, panniculus (skin sensation), mobility of the neck, limb placement, tail sway, position of the body and limbs when walked in tight circles and up and down hills, and observation of natural gaits during free exercise.

If the neurological exam suggests that the cervical area might be the source of the problem, a series of radiographs (X rays) are taken with the horse lightly sedated. The radiographs are then examined for fractures, collapsed intervertebral disc space, misalignments, narrowed spinal canal measurements, and arthritic articular (joint surface) facets.

Depending on the examination findings, a myelogram will be used for a more complete diagnosis. The horse is placed under general anesthesia, cerebrospinal fluid is withdrawn for analysis, and an iodine-based fluid is placed in the spinal canal to outline the spinal cord on radiographs. The spinal fluid is examined for increases in white cells that might indicate an infection, for unusual cells that might be seen with a neoplastic (cancer) condition, and for the presence of antibodies for herpesvirus or protozoa (Sarcocystis neurona, the organism that causes EPM).

In summary, if your horse presents with neurological signs of lameness, it will be important to enlist the help of your veterinarian for diagnosis. Recognizing early signs of any disease and seeking veterinary expertise will help increase your horse's chances of successful treatment and recovery.


AAEP member Barrie Grant, DVM, Dipl. ACVS, is a partner at San Luis Rey Equine Hospital in Bonsall, Calif. Grant and his team of veterinary surgeons with George Bagby, MD, a human orthopedic surgeon, are credited with developing and performing the surgical procedure that saved the life of the famous Thoroughbred racehorse Seattle Slew (article Quick Find #3381 at www.TheHorse.com). Lori Roberts is a former Director of Education for the AAEP.

About the Author

American Association of Equine Practitioners

AAEP Mission: To improve the health and welfare of the horse, to further the professional development of its members, and to provide resources and leadership for the benefit of the equine industry. More information: www.aaep.org.

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