Degenerative Myelopathy (DM) is a fatal, neurodegenerative disease characterized by a general lack of coordination of muscle movements in the pelvic limbs. Dogs affected slowly lose control and function of their hindlimbs.
DM is a condition that progresses slowly and typically affects dogs 8 years of age or older. DM has been detected in dogs as young as 3 years. If you observe a sudden onset of disease symptoms in your dog, this may indicate that another condition is the cause for muscle or movement problems.Although variable in presentation and course, generally, Dogs with DM typically require mobility assistance within 9 months of the first onset of symptoms. Symptoms can progress to paralysis in 3-6 months when untreated. DM is not a painful disease, so if your dog is exhibiting pain, this may indicate that another condition is the cause or that a concurrent problem exists.
The first symptoms of DM include:
- subtle weakness of one pelvic limb
- the weakness progresses in the hind limb and displays as a tendency for the limb to be dragged
- dragged rear paws will show unevenly worn toenails (inner nails will be more worn than outer nails)
- the other hindlimb becomes affected within weeks to months
- uncoordinated or drunken gait
- loss of balance
- exaggerated movements, such a high stepping when going up a curb
- tendency to fall when cornering
- affected dogs are often keen to exercise despite disability
- no indication of spinal pain
- dogs may be able to run, in a bunny-hopping gait, more easily than they can walk or climb
At this point, dogs affected with DM will have a strong knee jerk reflex (hyperactive patella spinal reflex) when examined by a veterinarian or neurologist. This is consistent with disease of the spinal cord between the third thoracic vertebrae and the third lumbar vertebrae. Defects in proprioceptive functions lead to the unevenly worn toenails, and can be seen in a typical neurological test (in this linked example, the dog does not have DM, but the photo and video show defects in the dog's proprioceptive pathways. This is exactly the same symptom that DM dogs display).
As the disease progresses, the DM dogs present with the following symptoms:
- decreased ability to walk
- difficulty in supporting their own weight
- difficulty rising or laying down
- knuckling under while walking
- limp tail; longer tail will easily get tangled with the dog’s legs
- rear legs crossing under body
- lack of coordination of muscle movements in the spine
- hoarseness of bark
- loss of knee jerk reflex
- faecal incontinence
- sudden profound muscle weakness; immobility and paralysis (flaccid tetraparesis)
The presentation of the disease can vary between different dog breeds with some of them (e.g. Corgi and Rhodesian Ridgeback) having more obvious disease of the (lower) motor neuron rather than the spinal cord.
Please contribute to this article! If you have a dog affected by DM, please send us your photos, videos and feedback so we can include them in our article. Videos and photos are particularly useful for demonstrating symptoms to new owners who may have to face this disease. Send us materials by uploading them to DogHeirs or by sending them directly to us at Team@DogHeirs.com
Copyright 2013 DogHeirs. All Rights Reserved.