Ischemic myelopathy
Ischemic myelopathy is a vascular disease of the spinal cord (myelopathy) caused by a lack of its
blood supply (ischemia).
What is an ischemic myelopathy?
Like any other organ, the spinal cord critically relies on a permanent blood supply to bring nutrients necessary for its proper
function and remove waste products. Arteries supply defined segments on each side and all along of the spinal cord. Blockage
of one of these arteries results in a sudden switch off of the portion of the spinal cord fed by this precise artery.
Although many unusual causes of blockage have been recognised (fragment of tumour, fat), the most common nature of this
blockage is a fibrocartilaginous fragment of the intervertebral disc (hence the term fibrocartilaginous embolism often used
instead of ischemic myelopathy). Despite many suggested theories, how and why this fragment of intervertebral disc suddenly
gets into the spinal cord artery remains unknown.
What are the signs of ischemic myelopathy?
Ischemic myelopathy is a common cause of acute paralysis in dogs (particularly large and giant breed of dogs). It is occasionally
seen in cats. Depending which portion of spinal cord is affected and whether or not only one side or both sides are concerned
by the lack of blood supply, this condition can cause paralysis of one back limb, both back limbs, all four limbs or only
one side of the body. Typically, this paralysis has a sudden onset, is not causing any pain and do not worsen with time (at
least after the first 24 hours).
Diseases that could mimic ischemic myelopathy and cause acute paralysis include intervertebral disc herniation ("slipped
disc" - see specific fact sheet), spinal fracture or dislocation ("broken neck" or "broken back"),
spinal cord contusion ("spinal cord bruising") caused by a road traffic accident or a bad fall.
How is ischemic myelopathy diagnosed?
Ischemic myelopathy is often a diagnosis made by exclusion of other causes of acute paralysis (see above). For this purpose,
diagnostic tests such as spinal radiographs, myelography and/or MRI scan (see specific fact sheet) are indicated to rule-out
conditions causing pressure on the spinal cord (intervertebral disc herniation or spinal fracture/dislocation) that might
necessitate surgical treatment. In the majority of animal, these tests of the spinal cord will typically come back as normal
in case of ischemic myelopathy.
It is therefore fundamental that the correct portion of the spinal cord is checked before any conclusions are drawn on the
absence of abnormality on myelography or MRI scanner. In occasion, swelling of the spinal cord can be detected on myelography
or MRI scan (picture MRI scan ischemic nyelopathy).
Definitive diagnosis of ischemic myelopathy and identification of its exact cause can only be made by post-mortem examination
of the spinal cord.
Can you treat ischemic myelopathy?
There is no specific treatment for ischemic myelopathy. Nursing cares (physiotherapy, assisted walking, hydrotherapy, adequate
bedding to prevent bed sores) are essential for the recovery of the animal.
What is the prognosis of ischemic myelopathy?
Although there is no specific treatment for ischemic myelopathy, most dogs tend to recover within a few weeks pending on the
fact that they have retained the ability to feel pain in their feet. In case of complete paralysis, improvement may not be
seen until a couple of weeks and some animal may not fully recover.
If you are concerned about the health of your pet you should contact your veterinary surgeon. |
