Degenerative Myelopathy (DM) is a degenerative disease of the white matter of the spinal cord in dogs, and was first described in 1973. DM is equivalent to some forms of Lou Gehrig’s disease (human amyotrophic lateral sclerosis [ALS]).
Symptoms of DM often appear around four years of age or older and often resemble osteoarthritis. Eventually, disease progression could result in muscle weakness, paralysis, and loss of bowel and urinary control.
Further complicating the matter is accurate diagnosis, which – at this time – can only be definitively concluded upon post-mortem examination. However, we do have a variety of diagnostic tests at our disposal, as well as genomic testing for mutations of the superoxide dismutase (SOD-1) gene.
In fact, it is recommended that breeds that are at the highest risk of developing DM – German Shepherd, Pembroke Welsh Corgi, Siberian Husky, Boxer, Labrador Retriever, Chesapeake Bay Retriever, and Bernese Mountain Dog – should be tested for the mutation. Dogs with two copies of the mutated gene are at higher risk of developing DM. However, there are some reports of dogs with two copies that never develop the disease.
It should go without saying, that all dogs of breeds at higher risk of DM should be tested prior to breeding and should not be bred if they have the mutation. Breeding dogs that have the mutation for this essentially fatal disease is inhumane because of its impact on future generations.
On the bright side, gene therapy studies are on the horizon. But, that does not help dogs afflicted with DM now. So, what can we do to make their lives better?
Besides medications, we found some fascinating studies that took a basic look at exercise. A pivotal study from 2006 divided 22 dogs with DM into three groups: intensive physiotherapy, moderate physiotherapy and no rehabilitation.
Intensive physiotherapy included active exercises 3–5 times per day, massages three times per day, and hydrotherapy (underwater treadmill or swimming pool) once per day. Dogs participating in the a moderate physiotherapy program performed three sessions of active exercises per day and hydrotherapy once per week.
Intensive physiotherapy delayed disease progression significantly and dogs receiving any physiotherapy remained ambulatory longer. Dogs in the intensive program lived an average of 255 days. The dogs that received moderate treatment lived an average of 130 days. Finally, dogs with no therapy sadly only lived 55 days.
In addition to exercise and medications, another study added a new component to the mix: laser therapy, which can suppress pro-inflammatory cytokines (certain proteins that effect the immune system), decrease invading T lymphocytes and macrophages, as well as a host of other benefits.
All 20 dogs received laser therapy. You may be thinking that one group was not used as a control. Well, laser therapy brings with it a cornucopia of variables, such as where to point the laser. But this team targeted the same section of the spine on all of the dogs. Additional variables the team considered were class of laser used, wavelength, grid method or continuous movement, and duration.
A class 3 laser was used on dogs in Protocol A. A class 4 laser was used for Protocol B. The researchers considered this to be the lynchpin and that the class 4 laser worked more effectively because it had a higher intensity to positively interact with the underlying tissues and create a therapeutic effect. Why did it work more effectively?
The times between symptom onset and euthanasia of Protocol B were 38.2 ± 14.67 months compared to Protocol A dogs (11.09 ± 2.68 months). Additionally, times between symptom onset and non-ambulatory muscle weakness or paralysis of dogs of Protocol B were 31.76 ± 12.53 months, compared to dogs enrolled in Protocol A (8.79 ± 1.60 months).
References
Awano, Tomoyuki, et al. “Genome-Wide Association Analysis Reveals SOD1 Mutation in Canine Degenerative Myelopathy That Resembles Amyotrophic Lateral Sclerosis.” Proceedings of the National Academy of Sciences, vol. 106, no. 8, 24 Feb. 2009, pp. 2794–2799, https://doi.org/10.1073/pnas.0812297106.
Kathmann, I., et al. “Daily Controlled Physiotherapy Increases Survival Time in Dogs with Suspected Degenerative Myelopathy.” Journal of Veterinary Internal Medicine, vol. 20, no. 4, 28 June 2006, pp. 927–932, https://doi.org/10.1111/j.1939-1676.2006.tb01807.x.
Miller, Lisa A., et al. “Retrospective Observational Study and Analysis of Two Different Photobiomodulation Therapy Protocols Combined with Rehabilitation Therapy as Therapeutic Interventions for Canine Degenerative Myelopathy.” Photobiomodulation, Photomedicine, and Laser Surgery, vol. 38, no. 4, 16 Apr. 2020, pp. 195–205, https://doi.org/10.1089/photob.2019.4723.
Spinella, Giuseppe, et al. “Overview of the Current Literature on the Most Common Neurological Diseases in Dogs with a Particular Focus on Rehabilitation.” Veterinary Sciences, vol. 9, no. 8, 13 Aug. 2022, p. 429, https://doi.org/10.3390/vetsci9080429.