New
Treatment Available for Wobblers
By
Dr. Antonio M. Cruz, Veterinary Teaching Hospital
Wobbler
syndrome encompasses a group of diseases characterized
by gait instability. One of these diseases comes
under the name of cervical vertebral stenotic
myelopathy, producing spinal cord compression
at the neck level. This is a disease characterized
by an abnormal gait in the front and/or hind legs,
usually worse in the hind. It is referred to as
“wobbler” syndrome as the horse may seem wobbly
when walking or exercising. The severity of the
observed signs varies among horses. Some horses
may seem to have a stiff neck, appear weak or “lazy”,
stumble more than normal, or give missteps. Others
may be reluctant to rise or fall easily. These horses
suffer from “ataxia” -- a loss of the sense of where
their feet are placed -- and may appear “drunk”
as the horse lacks perception of where its limbs
are.
The
etiology of this condition has been linked to osteochondrosis
and to nutritional factors including mineral imbalances.The
potential inherited nature of this disease has been
widely debated. To date, no single cause of the
condition has been identified but in growing animals
it is believed that a strong dietary component is
involved in this disease.
Diagnosis
It is important to recognize the signs of wobbler
syndrome and identify an affected horse early to
give your horse the best chance to heal. Since the
clinical condition known as “wobbler” encompasses
spinal cord compression as well as other conditions
causing ataxia, the collection and examination of
the cerebrospinal fluid (CSF) is essential. Other
differentials include Equine Protozoal Myeloencephalitis
(EPM), a neurological form of rhinopneumonitis and
traumatic injuries. The perception that the problem
is increasing in the horse population may actually
be due to an increased awareness, as well as improved
expertise in applying more sophisticated diagnostic
methods.
To
correctly diagnose your horse a veterinarian will
perform a neurologic examination and identify the
location of the lesion (i.e. brain, spinal cord).
Further diagnostic tests will be required, including
the radiography (x-ray) of the cervical spine and
performing a contrast study of the spinal canal
(myelogram) under general anesthesia. This is currently
only available in Ontario at the Ontario Veterinary
College (OVC). A myelogram involves the injection
of a special contrast media around the spinal cord
immediately followed by radiographs. The contrast
media will highlight the roof and floor of the spinal
canal allowing a view of any significant narrowing.
The development of low-toxicity contrast media has
diminished the side effects and the rate of complication
associated with this procedure. A cerebrospinal
fluid (CSF) sample will be collected prior to the
myelogram. The CSF will be submitted to the university
laboratory for routine examination as well as to
a Kentucky laboratory for EPM testing.
Treatment
A wobbler left untreated may deteriorate to the
point of injuring itself or others, especially when
struggling to rise. In the short term, medical treatment
for subtly affected animals, along with stall rest,
may provide relief. In the long term, often the
animal will relapse when allowed unrestricted exercise
or when placed in training. Until now, most wobblers
were euthanized. However, horse owners have demanded
a better approach to treating these animals. This
has resulted in a more widespread acceptance of
surgical treatment. These techniques are now being
demonstrated successfully at the Ontario Veterinary
College (OVC), Large Animal Clinic.
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