Canine Degenerative Myelopathy
This hereditary disease is also known as German Shepherd myelopathy and Chronic Degenerative Radiculomyelopathy and is a progressive disease that is fatal. In dogs with DM the nerves, fibers in the brain and spinal cord slowly degenerate caused by a genetic mutation. Dogs affected begin with symptoms less severe but it will progress and at the moment there is no cure. Pure breeds and mixed breeds can be diagnosed and both female and male dogs. It is not common in young dogs, the average age of dogs diagnosed is 9 years. Breeds most affected by this disease are German Shepherds but other breeds can develop it including;Advertisement
Pembroke Welsh Corgi
Bernese Mountain Dog
Wirehaired Fox Terrier
Old English Sheepdog
Cardigan Welsh Corgi
Kerry Blue Terrier
Chesapeake Bay Retriever
Soft-Coated Wheaten Terrier
Symptoms of Canine Degenerative Myelopathy
This is not a common disease and sometimes owners assume it is old age causing the initial stiffness and difficulty getting up. Apart from discomfort from the bed sores and urine scalding wounds this disease is not painful for the dog. Early stages will have symptoms such as;
Loss of muscle co-ordination
Dragging their rear paws
Loss of balance in the back legs
Rear paws have sores on top of them
Rear paw toe nails have abnormal wear on them
Difficulty and reluctance to jump, walk, run or just stand
Incomplete hind end paralysis
Muscle wasting in the hind legs
Urinary and or fecal incontinence
Difficulty standing using its hind legs
Symptoms as the disease progresses will worsen into;
Complete paralysis in the rear end
Bed sores and urine scalding which can be painful
Front legs will then be affected by poor co-ordination
Front legs will progress to paralysis
Unable to chew or swallow food
Struggle to even breathe
Cause and Prevention
For a long time experts thought DM was an immune-mediated disorder akin to MS in humans. However fairly recently it was found that it is caused by a mutation in a specific gene called the SOD1 gene. This is the same gene that if mutated in people can lead to amyotrophic lateral sclerosis or Lou Gehrig's disease. It can show up in both pure and mixed breed dogs but is more often found in the former and for that reason experts believe there is a hereditary component to the cause it being an autosomal recessive inheritance disease.
This means the parents of your dog were both carriers of the mutated gene but had one normal and one mutated so probably did not have health issues from it. But puppies from those two dogs would have received two mutated genes, which means they are at risk of developing DM though it should be said that not all dogs with two mutated genes so go on to develop it. For this reason the only way to prevent DM is to make sure dogs are not bred if they are a carrier of the mutated gene. There is a test that can be done to check for this.
Diagnosing Canine DM
This is not always a simple disorder to diagnose as there are symptoms similar to other conditions such as spinal cord cancer, intervertebral disk disease, and hip dysplasia to name a few. Part of the testing will involve ruling out other diseases and a history from the owner will be needed. As well as a full physical exam the vet will also likely carry out a neurological exam too along with blood tests and urine tests.
The neurological exam will help the vet to narrow down where the spinal cord lesions are and they will also check for tumors. A sample of the cerebrospinal fluid can also be analyzed to see if there is inflammation. Other tests may include an MRI, nerve conduction studies, a CT scan, myelography and electromyography. A confirmed diagnosis can only really be made from examining the spinal cord of the dog when he has died. In a living dog the diagnosis is made by ruling out other conditions.
Treatment and Care
There is no cure for this disease and it is progressive and fatal. Most dogs within six months of diagnosis lose their ability to walk normally and smaller dogs last longer than larger dogs. But there are things you can do to delay the progression and make your dog happier for the time it has left. Exercise that is moderate in nature and physical therapy is important to help put off muscle deterioration and help keep some mobility. There are exercise that can be done for range of motion involving stretching and flexing the dog's rear legs. This will help him keep some strength and be able to walk for longer. Other exercises that would benefit him include swimming and other water exercises where there is no stress on the joint.Advertisement
Other things you can do are;
His bedding needs to be something that has a lot of padding like a human mattress, air mattress, waterbed, lots of blankets, fleeces, a lounge chair and so on. Change the outer layers often.
Clean and dry your dog regularly too to prevent urine scalding and bed sores.
Keep the hair around the anus trimmed short.
Manage their diet carefully to keep their weight down.
Dogs who cannot get up need to be turned often to prevent lung collapse and sores.
Dogs who have no use of their hind legs but still have use of their front ones can use a wheel cart to get around.
While supplements may be beneficial it is as yet unproven how much of a role they play in slowing this disease.
There are experimental chemical therapies out there but your vet is the best person to discuss these with.