Post by Hat In Ring on Apr 30, 2014 12:49:39 GMT -5
What is Degenerative Myelopathy?
Canine Degenerative Myelopathy (DM) is a progressive disease of the spinal cord and ultimately the brain stem and cranial nerves which, at it’s end stages, results in complete paralysis and death. Myelopathy is the disintegration of the sheathing that protects each and every individual nerve. The gene that creates this disease is present in most dog breeds. The closest human equivalent may be Amyotrophic Lateral Sclerosis, or ALS, also known as Lou Gehrig’s disease. The same gene mutation is implicated in both diseases.
Symptoms/Warning Signs
Degenerative Myelopathy has a slow, insidious onset with a slow progression of weakness. It is not uncommon for the signs to progress slowly, plateau, and then start to progress again. These symptoms often begin in one rear leg and then eventually involve both rear legs as the disease progresses; alternatively, it could affect both rear legs at the same time. This condition is NOT painful. As a result, with appropriate physical therapy and nursing care, patients with DM can still have a good quality of life for a significant length of time but when the back legs start to become unusable the progression is fairly rapid.
Symptoms may come in a different order than what's given in this article depending on where the myelopathy begins in the spinal cord. Some dog owners state they notice the knuckling begins first where the dog is walking on the tops of his/her paws instead of the pads. This knuckling is due to the dog not being able to send signals from the brain to the paw and when the leg moves the paw drags backward. Since there is no pain the dog walks on the top of its paw in a backward position which creates bleeding. Usually in most cases the back legs go first but in some cases the dog gets hoariness in the bark, heavy panting when walking, loss of appetite, stops drinking water, etc..... A lot of these symptoms are the same as other disorders also so the dog owner has to wait until an accumulation of known degenerative myelopathy symptoms start to appear. A veterinarian will run tests to rule out other disorders before they diagnose a dog with degenerative myelopathy. The only physical way to diagnose degenerative myelopathy is through an autopsy.
Once the dogs hind legs are no longer usable the progression is fairly rapid and over a short period of time the other symptoms will start to appear and get worse. You dog may be able to get up on their front legs after the hind legs become unusable but soon after the hind legs become unusable the front legs will start to become unusable.
Early signs (Duration: 3-6 months)
DM initially affects the rear limbs. At first you may notice rear limb weakness and muscle loss, decreased coordination, loss of balance, difficulty transferring from lying down or sitting, to standing, and/or an inability to climb stairs, jump into the car, or onto furniture. These symptoms are also typical of other conditions, such as arthritis, hip dysplasia and other spinal diseases (e.g., disk protrusion/herniation). If you are seeing these signs you should contact your veterinarian and have your dog examined.
Problems In The Early Stages
Loss of balance
Damage to the feet and nails of the hindlimb from knuckling.
Heavy hard panting
Hard time getting up
DM initially affects the rear limbs. At first you may notice rear limb weakness and muscle loss, decreased coordination, loss of balance, difficulty transferring from lying down or sitting, to standing, and/or an inability to climb stairs, jump into the car, or onto furniture. These symptoms are also typical of other conditions, such as arthritis, hip dysplasia and other spinal diseases (e.g., disk protrusion/herniation). If you are seeing these signs you should contact your veterinarian and have your dog examined.
Problems In The Early Stages
Loss of balance
Damage to the feet and nails of the hindlimb from knuckling.
Heavy hard panting
Hard time getting up
Intermediate Phase (Duration: 3-6 months)
The next stage of symptoms are knuckling or walking on the tops of their feet (loss of conscious proprioception), limp tail, crossing of the hindlimbs under the body (scissoring), or a rear leg drag. Check the two middle toes of the feet to see if there is unusual toe nail wear. The middle two toes are the main weight bearing digits of the foot.”
As the symptoms progress you will begin to see worsening signs of weakness and dragging the hindlimbs on the ground or floor. Urinary and/or fecal incontinence occur very late in the course of the disease You may also note a hoarseness or loss of volume to the bark.
Problems in intermediate stage
Increasing difficulty with walking
More extensive damage to the feet from knuckling
Loss of mobility (partially paralyzed) (the back legs usually go first)
Incontinence (depending on if you can get your dog up and out)
Hoarseness in bark or no barking
Gagging and heaving clear fluids or vomiting stomach contents
Heavy hard panting
Irregular breathing pattern
Loss of appetite
Not drinking water
Quality of life issues
The next stage of symptoms are knuckling or walking on the tops of their feet (loss of conscious proprioception), limp tail, crossing of the hindlimbs under the body (scissoring), or a rear leg drag. Check the two middle toes of the feet to see if there is unusual toe nail wear. The middle two toes are the main weight bearing digits of the foot.”
As the symptoms progress you will begin to see worsening signs of weakness and dragging the hindlimbs on the ground or floor. Urinary and/or fecal incontinence occur very late in the course of the disease You may also note a hoarseness or loss of volume to the bark.
Problems in intermediate stage
Increasing difficulty with walking
More extensive damage to the feet from knuckling
Loss of mobility (partially paralyzed) (the back legs usually go first)
Incontinence (depending on if you can get your dog up and out)
Hoarseness in bark or no barking
Gagging and heaving clear fluids or vomiting stomach contents
Heavy hard panting
Irregular breathing pattern
Loss of appetite
Not drinking water
Quality of life issues
End Stage (Duration: 3-6 months)
In the very late stages of the disease progression is more rapid and you will see forelimb involvement with muscle mass loss to the shoulders and forelimbs. As the disease progresses, your dog will develop weakness in all 4 legs. Eventually, your dog will be unable to stand or walk. There may be residual head movement at this stage and they will not be able to remain sternal (on their belly) without assistance. The disease will then progress to the brain stem and eventually to the cranial nerves which may affect breathing.
The nervous system’s spinal cord and brain stem are the only structures affected by DM. However weakness from DM can have secondary effects such as decubitus ulcers (pressure sores), systemic infections, and urinary tract infections due to urine retention. There can be kidney, lung and heart failure. Death from DM results from multisystem failure.
Problems in end stage
Immobility (paralyzed) (can't get up or roll their bodies)
Incontinence
Systemic infections
Decubitus ulcers
Abnormal breathing
Heavy loud cough
Wasting away from not eating or drinking
Quality of life issues
In the very late stages of the disease progression is more rapid and you will see forelimb involvement with muscle mass loss to the shoulders and forelimbs. As the disease progresses, your dog will develop weakness in all 4 legs. Eventually, your dog will be unable to stand or walk. There may be residual head movement at this stage and they will not be able to remain sternal (on their belly) without assistance. The disease will then progress to the brain stem and eventually to the cranial nerves which may affect breathing.
The nervous system’s spinal cord and brain stem are the only structures affected by DM. However weakness from DM can have secondary effects such as decubitus ulcers (pressure sores), systemic infections, and urinary tract infections due to urine retention. There can be kidney, lung and heart failure. Death from DM results from multisystem failure.
Problems in end stage
Immobility (paralyzed) (can't get up or roll their bodies)
Incontinence
Systemic infections
Decubitus ulcers
Abnormal breathing
Heavy loud cough
Wasting away from not eating or drinking
Quality of life issues
The gene that dogs are born with that causes this degenerative myelopathy is slowly but surely being breed out of dogs slowly but surely and it will take several human lifetimes for this to be accomplished. The problem is finding certain dogs in all the breeds that were born without this gene then breeding these dogs without the gene. Degenerative myelopathy usually strikes dogs between the ages of 9 thru 15 years of age and by the time dogs hit these older ages breeding gets tough. Degenerative myelopathy can strike dogs at the age of 5 but this is very rare. Most cases occur in older dogs. At the time this article was written I don't know if breeders can genetically test every animal they want to breed this nasty disease out of or the time and expense of doing this testing. Even if they genetically test puppies for this disease it will take many human life times to get rid of it.
Below is a link to a genetic website for animals. It shows many dog breeds that are genetically prone to degenerative myelopathy and other animal disorders.
