It had been five months since Mr. Smith had noticed that Shep, his trusty German Shepherd sidekick for the past 10 years, was starting to struggle to use his hind end when getting up from resting and going up the stairs. He had gotten some anti-inflammatory medication from his veterinarian , but in spite of faithfully taking his medication every day Shep seemed to be having more and more difficulty getting around. Now he had a bit of a drunken sway to his hindquarters when he walked and he was dragging his feet enough that the tops of his toenails were wearing down. Occasionally he would stand with his hind feet crossed, and when he stood still for any period of time his rear end would start sagging toward the ground. In spite of his impaired mobility Shep still seemed to have the same happy attitude and would stagger to the kitchen as rapidly and enthusiastically as he could when he heard the familiar crinkle of the dog treat bag. There was nothing was slow about his front end when treats came his direction.
When Mr. Smith went back to his veterinarian to see if there was anything else he could do to help Shep get around better he got a bit of a surprise. It turned out that Shep’s problems in the hind end weren’t due to arthritis after all. Something in his spinal cord was scrambling the messages his brain was sending to and receiving from his hind legs. Shep was unable to tell exactly where his feet were and couldn’t get them to do what he wanted, and that communication issue was causing his weakness and stumbling.
There are three things that most commonly cause symptoms like Shep’s in older large breed dogs: A long standing bulging disc in the spine compressing the spinal cord, a tumor in the spinal canal growing slowly and compressing the spinal cord, and a condition called degenerative myelopathy (DM), where the nerves in the spinal cord start to conk out for no reason that anyone can explain. Bulging discs and tumors have some potential for a surgical fix, but DM progresses inexorably toward paralysis of the hind end, sometimes quickly and sometimes very slowly, and no medication or surgery can stop it. Most of the time these conditions do not cause much pain, but the early signs are very commonly mistaken for arthritis. Anti inflammatory medications have no effect on the neurological problems, and as they become more advanced it becomes more clear that the problem is with the nerves, not with the joints.
Figuring out the specific cause for the symptoms can be difficult. X-rays do not show the discs in the spine or tumors in the spinal canal. Ultrasound cannot penetrate the bone around the spinal cord to be able to see inside. MRI studies usually give the answer clearly and quickly, but those require multi-million dollar pieces of equipment that no general purpose veterinarian will have available. We can, however, refer patients to veterinary neurology specialists or very large teaching hospitals which usually have access to such wonderful machines. The point of pursuing advanced diagnostics would be that if something that could be fixed surgically were to be discovered then the plan would be to proceed to surgery. The tests and surgery will run in the multiple thousands of dollars and could result in a complete cure, or sometimes a difficult recovery or possibly even complications that could be worse than the original problem. If the cost, age of the patient, or ability of the patient to recover well make the option of surgery impractical then there is probably not a strong reason to spend a few thousand dollars on an MRI just to satisfy our curiosity.
A big dog that is unable to walk starts presenting a serious problem. They are hard to keep clean and tend to develop pressure sores that can get infected and cause pain and illness. There are wheelchair carts that have been developed to help dogs with hind end paralysis. The idea is great, but maintenance of a dog in a wheel cart is demanding and often more difficult than it first appears, especially for big dogs. Make sure you are properly prepared for what you will have to do before committing to using such a device. Often euthanasia is a heartbreaking but necessary choice.
Shep was diagnosed with DM, but he was somewhat fortunate that his problem wasn’t painful and the progression of his paralysis was slow enough that he had another year before he couldn’t use his hind legs at all. Having him euthanized was one of the hardest choices Mr. Smith had ever made, because Shep’s front half was still the same smiling, happy dog he had always been, but his useless back end had made his quality of life unacceptable and Mr. Smith knew that he couldn’t let him go on like that any more.