What is degenerative myelopathy?
Degenerative myelopathy (DM), also known as chronic degenerative radiculomyelopathy (CDRM), is a disease affecting the spinal cord, resulting in slowly progressive hind limb weakness and paralysis. The symptoms result from degeneration of the white matter of the spinal cord. DM is similar to some of the forms of human amyotrophic lateral sclerosis (ALS) more commonly known as Lou Gehrig’s Disease.
The exact cause of DM is unknown. In its early stages, the symptoms of DM resemble those of osteoarthritis (arthritis), which often occurs secondary to hip dysplasia in many large breed dogs, making diagnosis challenging.
In later stages of the disease, the progressive weakness and ataxia (wobbling, stumbling) distinguish it from osteoarthritis of the hip joints. Other considerations for this condition include spinal injuries, spinal tumors, lumbosacral stenosis, fibrocartilaginous embolism, myasthenia gravis, and discospondylitis.
What are the clinical signs? Early clinical signs include:
The hind paws "knuckle" or turn under so that the dog walks on its knuckles, especially when turning.
The dog's hindquarters appear to sway when standing still.
The dog falls over easily when pushed from the side.
The hind feet seem to scrape the ground when walking and sometimes the top surface of the feet become hairless and irritated from repeated trauma.
The dog has difficulty getting up from a lying position.
As the condition progresses and the spinal cord deteriorates, these symptoms worsen, eventually progressing to paralysis of the hind end.
Hyperuricosuria is an inherited disorder characterized by elevated levels of uric acid in the urine that can lead to the formation of bladder/kidney stones.
Juvenile Hereditary Cataract (JHC)
Juvenile hereditary cataracts are an inherited form of cataracts that commonly cause blindness in dogs by clouding the lens of the eye and affecting both eyes symmetrically.
Canine Multifocal Retinopathy 1 (CMR1)
Canine multifocal retinopathy 1 is an inherited eye disease characterized by areas of retinal detachment. The disease does not typically lead to blindness or vision deficits
Chondrodystrophy (CDDY and IVDD Risk) and Chondrodysplasia (CDPA)
Chondrodysplasia is a short-legged phenotype characteristic of many dog breeds. Chondrodystrophy, a separate mutation, also includes a short-legged phenotype as well as susceptibility to intervertebral disc disease.