The Stages of Degenerative Myelopathy


People have often written and telephoned asking me to explain what they might expect throughout the various stages of Degenerative Myelopathy. As there has been such interest in a description of the various stages of this disease, I thought writing an article would be helpful to educate people about what they might expect throughout the different stages of the disease.

The early stages of Degenerative Myelopathy start with an almost imperceptible weakness in the hindquarters. DM is an insidious disease and it is all too easy to overlook, in it's earlier stages, unless you are specifically looking . Even then, DM is elusive and hard to detect.

(I always check the rear nails on a dog once a month for uneven wear, especially on the innermost nails of the rear feet, as this is an early tip-off to DM.)

In early and up to the mid-mid stage DM, occasionally you will hear the sound of the dog’s nails scraping on the pavement during a walk. This scraping will not be constant; rather, will present periodically. The dog will begin to show some difficulty getting up. If the dog is standing, it may have difficulty balancing, but it can recover on its own. If you turn the dog’s toes under in this stage, the dog may still be able to right its foot, although response time could be lengthened.

As the disease further progresses to late mid-stage, difficulty getting up increases. The nails begin to scrape more often on the pavement, until it becomes constant. As the disease progresses, the rear legs will cross under the dog’s body as the dog, losing sensation in its hindquarters, will not know where it has actually placed its feet. Faulty perception of foot placement leads to tripping and stumbling.

When the dog is in a standing position, if you move the dog from side to side, using your hands, the dog will lose its balance and topple over. Often, you will notice exaggerated movements, such a high stepping when going up a curb. This is due to prioceptive functions being affected by DM.

The tail will rarely become active and wag. If the tail is longer, the dog’s legs will easily become tangled in it. If the dog’s foot is placed on the ground, toes down, the dog will not right its foot, or they may be a delayed response time. The reason for this delay is due to the fact that the dog cannot feel its foot; hence, the dog knuckles. A dog with feeling in its hind paws will have a quick/quicker response in placing its foot in the proper position. A dog with little or no feeling will have a slow or non-existent reflex action placing its foot in the proper, pad-down position.

As DM becomes more advanced, in early late-stage DM, uncontrolled jerkiness of the rear legs and tail signals that the nerve impulses are going haywire and short- circuiting. Kicking out with the rear legs, without reason, will be observed, along with the tail seeming to raise and lower, as if the dog is preparing to defecate.

Sometimes, if you pinch the pad of one foot, the other foot will respond. This is called Cross Extensor Response. Maintaining balance during defecation becomes almost impossible. When the dog squats, it will lose its balance and fall.

As the disease process reaches late stage, the dog will not be able to bear any weight, on its own, in the hindquarters. The affected dog will not be able to get up or, once lifted, will not be able to remain in a standing position, without some form of support for its hindquarters.

In late stage DM, this can happen overnight or within the space of a few days. I always counsel people with DM dogs not to wait until the dog goes down to have the appropriate equipment on hand for dealing with what is most definitely, at this point in time, inevitable. I am not a *fan* of towel walking, as it can place pressure on the bladder, causing the dog to urinate. Urinary incontinence and bowel incontinence will occur, inevitably.

Our instincts tell us to try to protect the dog’s feet from bleeding, due to knuckling. However, booties on the feet are NOT a good idea, due to the fact that booties interfere with foot placement and the conduction of nerve impulses. If you place booties upon a DM dog's feet, you can actually do more harm. A DM dog with booties is apt to fall more often suffering consequences such as cruciate ligament tears, knee injuries, disk injuries and further spinal damage. You are better walking the dog on grassy surfaces while using a rear end harness, which will allow you to lift the hindquarters into a position for correct foot placement. The Bottoms Up Leash or the Hartman Harness are some of the items people have found to be extremely helpful. Carts can be successfully used, outdoors. There are many new lightweight carts that have been introduced to the marketplace.

Never, and I do mean never, ever, hold or attempt to hold a DM dog up by its tail!!! To do so, can cause great harm to a DM dog!! Holding a DM dog up, supporting it, or lifting it by the tail can break the tail. Please- do not do this to your DM dog. By doing so, you put your dog in grave danger and in harm's way. DM is a terribly destructive disease without complicating it by ignorant and thoughtless actions. Should a vet suggests this as a method of transporting your DM dog or implies and encourages this as a way to deal with a DM dog- run, don’t walk, to another vet, please!

There are good vets and there are bad vets. There are good vets with bad hearts, bad vets with good hearts, and there are, unfortunately, too many vets who are completely ignorant when it comes to DM! Rear end harnesses were created for the purpose of lifting a DM dog safely! They enable one to lift the hindquarters without harming the spine, the disks or the tail. Please do not listen or give credence to anyone who suggest, "tail walking" a dog as a solution to mobility problems!

If your dog is exhibiting pain, it probably isn't DM, unless there is a concurrent condition. DM is not painful. There is zero pain because the nerve cells have died.

Myelograms do not rule in DM - they rule out surgical disease. Before a myelogram is undertaken, an Electromyogram should be given. EMG results can differentiate between peripheral nerve disease, inter-vertebral disc disease and myelitis and polyradiculoneuropathy. It is not wrong to rule out the presence of surgical disease (DM is one of the non-surgical diseases), but it can be better to start testing for DM with the least invasive tests, leaving the more serious tests for last.

The latest in DM testing is the new DM DNA sampling test, which must be shipped via CBC vial, with a cold pack (not frozen), overnight mail to Dr. Clemmons at the following address:

R.M. Clemmons, DVM, PhD
Associate Professor of Neurology & Neurosurgery
SACS, College of Veterinary Medicine
Box 100126, HSC
2015 SW 16th Avenue, V2-107
University of Florida
Gainesville, FL 32610-0126

352.392.4700

With the CBC vial, you must enclose a $50 donation made out to the University of Florida Foundation. On the memo portion of the check, you must write "For Dr Clemmons Research".

Degenerative Myelopathy is believed to be an inflammatory, autoimmune disease where the immune system attacks the dog's central nervous system. This attack leads to a loss of insulation around the nerve fibers (myelin) and of nerve fibers (axons). The animal can no longer walk, once the nerves in the spinal cord are destroyed. Without nerve connections, muscles cannot work. The control pathways that make muscles work are located all throughout the spinal cord.

In another words, to simplify things, DM = inflammatory autoimmune disease= immune system attack's central nervous system = loss of myelin and axons=nerves in spinal cord destroyed = control pathways destroyed =muscles wont work = dog loses ability to walk.

I hope this article has explained the various stages of Degenerative Myelopathy, and has imparted greater knowledge in relation to correctly dealing with the mobility problems associated with DM. I pray that none of you will ever need this information...

~ By Marjorie Zimmerman Founder: The Degenerative Myelopathy Support Group: http://mzjf.com

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