Scourge of syringomyelia
by Steve Dean
07 May 2009 08:00
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It was February 2004 when I first wrote about syringomyelia following a question from a reader. Now this disease hits headlines regularly and there is little doubt it is a serious condition of the brain, spinal cord and nervous system.
Much of what follows was written in 2004 and frankly our knowledge of the disease has advanced very little in that time.
The normal spinal cord consists of discreet bundles of nerve fibres and running through the centre is a fluid-filled spinal canal that links up with the fluid within the brain cavities. The nerve bundles carry electric pulses up and down the spinal cord to and from the brain and nerves emerging from the spinal cord at all levels of the spine link the brain to all regions of the body.
Syringomyelia is typically characterised by abnormal cavity formation in the nervous tissue of the cord, whereas the related condition of hydromyelia is a dilation of the central canal. The two conditions may appear together or individually.
Not surprisingly, the cavitation results in damage to the nerve bundles nearby and the pressure involved may damage a wider area of spinal cord. The inevitable interference with nerve transmissions will give either sensory or motor deficits and in many cases associated pain can be quite severe. In other words muscles and limbs may not work correctly and the dog may be in considerable discomfort.
The extent of the effects depends upon the level of the damage, the higher up the spinal cord the greater the extent of the symptoms.
In some breeds it is a congenital defect but it can also occur because of an injury to the spinal column. Alternatively tumours may cause a cavity to develop, especially if the growth interferes with the fluid flow in the central canal or the blood supply to the cord. More recently an increasing number of cases involving the spinal cord and lower reaches of the brain have been seen in some breeds causing disruption to balance and co-ordination but the classic sign in the Cavalier is intense irritation at the back of the neck often associated with scratching and pain.
Surgical treatment in the dog is somewhat pioneering and on occasions heroic with highly variable and often disappointing results. The congenital and inherited cases are thought to be related to defective fluid flow in the brain and spinal cord and more recently postualted to be related to the cranial cavity being too small.
The condition may not manifest itself until the dog is several years old, by which time it may have been bred from and more importantly for the owner, has become a highly valued companion. Thankfully while said to be increasing in some breeds, in most dog populations it is quite uncommon. Back in 2004 some real experiences were provided by readers.
The main points are summarised again for readers who missed out: “I just wanted a dog to love and share my life with and she was a very happy and confident little dog. Everybody fell in love with her. One or two people commented on her ‘funny walk,’ a sort of rolling gait, which looked slightly comical. She was often quite restless in the evenings and she did not like to be too warm and seemed to scratch quite a lot.
“In September 1999 she suddenly screamed with pain and for the next few days did so intermittently. An x-ray showed nothing and the consultant prescribed corticosteroid for pain relief. The pain episodes became less frequent and less severe until January 2000 when a very severe bout of pain occurred again. The pain was so severe that she would try to hide in a corner trembling with shock. I was distressed and so many times those eyes seemed to say, ‘Do something.’
“She showed signs of increasing tiredness. On walks, she started sitting down and refusing to follow me and she had some difficulty getting up and down from steps and furniture. A lack of co-ordination of her back legs developed and in May 2001 she was very lethargic and off colour.
“Following two more periods of intermittent pain, in October syringomyelia was considered as the cause and confirmed by MRI scan. The final strange symptom was seen walking on the lead when her hind left leg would attempt a scratching movement without making contact with the skin. She was also scratching her neck and ears even more.
“I felt devastated, angry, guilty and powerless to do anything to help my beloved companion. After some surgery a better period followed and in spite of everything, she remained a happy, lively and sociable dog but she tired easily and whimpered when driven to distraction by the irritation in her neck and ears. When she deteriorated and failed to respond to further treatment I asked the vet to visit and put her to sleep.”
Now from a different breed of dog: “I have an 11-year-old bitch who was being treated for rheumatism etc, but after an MRI scan the problem was revealed as not only disc problems, but considerable signs of chiari type malformation with syringomyelia. She had been getting very unsteady on her back legs, with lack of sensation and poor co-ordination. The bitch had no signs of such a problem till aged about nine or ten. However, she has always been a little ‘odd’ and I have always called her a dog of very little brain! Having viewed the extent of the fluid in her brain cavity, it has proved to be literally true.”
Finally a short personal account of a human sufferer: “Our daughter had symptoms at eight years old, but although she was severely affected mainly by pain and weakness to lower limbs, it took another 13 years to find a diagnosis. She has hydromyelia, with the syrinx stretching from T3 to T12, with the largest part at T8/9.
Life is dreadful and you are right about there being no treatment let alone a cure. My daughter goes through pain 24/7 and an affected dog would not be able to tell anyone how awful it is. Even on high doses of morphine and other pain relief drugs my daughter is still in considerable pain and virtually bed bound.”
Perhaps these accounts once again provide understanding for readers who do not know this disease and perhaps they justify why syringomyelia deserves some scrutiny and action.