Unfortunately, there are several nervous system disorders that can occur in dogs. Some of which are incurable and progressive and share many similarities with human nervous system disorders . In dogs, severe nervous system issues can affect the spinal cord and cause weakness in the hind limbs, which progresses into their full paralysis.
Nervous System disorders are usually diagnosed in middle-aged or older dogs, and can often be mistaken for arthritis or other joint issues in the earlier stages. In larger dogs, it usually manifests around 8 years of age, but in smaller breeds it may not show up until into their second decade. On rare occasions, very young dogs have also presented with severe nervous system disorders.
What Causes Nervous System Disorders?
The exact cause of nervous system disorders has not been determined, but scientists have traced some specific occurrences of it to the existence of the genetic mutation in a gene called superoxide dismutase 1 (SOD-1). According to our current understanding, a dog must have two copies of the mutated Gene in order to develop certain types of nervous system disorders. However, there are some dogs with two copies of this gene mutation that do not develop it at all.
Genetic Test for Canine Nervous System Disorders
Genetic testing is available through the Orthopedic Foundation for Animals in order to identify whether a dog has this gene mutation. This DNA testing uses saliva to help identify whether a dog has an elevated risk of nervous system disorders as well as whether or not they are a carrier.
# of SOD-1 Mutation(s)
Dog is clear
Dog is carrier
Dog at high risk for developing
This genetic screening is only recommended for predisposed breeds, but can be performed on any dog using a sample collected from swabbing the inside of the cheek.
Breeds affected by Nervous System Issues
Nervous System issues are significantly more prevalent in certain dog breeds including German Shepherds, German Shepherd mixes, Siberian Huskies, and Collies. Recently, elevated risk status has been expanded to include a number of additional breeds including: Bernese Mountain Dogs, Boxers, Golden Retrievers, Chesapeake Bay Retrievers, Rhodesian Ridgebacks, Kerry Blue Terriers, Pembroke Welsh Corgis and more.
Phase One: Early Nervous System Disorder Signs
Nervous System disorder symptoms in dogs are caused by the deterioration of the white matter of their spinal cord.
Early symptoms you may find in a dog include:
- Lack of balance/coordination or other signals of instability i.e. falling when pushed gently from the side
- Difficulty getting to standing position after lying down
- One or both of hind paws turns inward, giving the appearance of a dog walking on knuckles
- Loss of muscle in rear legs
The presence of one or more of these does not mean that your dog definitely has degenerative myelopathy as there are other spinal cord problems that may have similar presentation.
Phase Two: Intermediate Nervous System DisorderClinical signs of canine nervous system disorders that have progressed to the second, intermediate, stage include:
- Assistive mobility device needed for walking
- Muscle atrophy/ severe in hind limbs
- Rear body has “sagging” appearance from combination of muscle loss and body’s struggle to support weight
- Balance and coordination difficulties
- Knuckling of rear paws when standing or walking
- Limp tail
- Urinary / fecal control issues may start to present
Phase Three: Advanced DM Clinical Signs
Dogs in the final stages of advanced nervous system disorders show many signals of their body’s decline as the disease’s grasp extends to the rest of the body with symptoms including:
- Erratic motions of the tail and rear legs
- Front legs and shoulders also show weakness
- Complete paralysis of rear legs
- Total loss of continence
- Respiratory issues
- Organ failure
- Complete lack of coordination
- Assistance needed for all movement
Bowel and Bladder Problems
While a dog may retain its ability to control urination and defecation during the earlier phases of nervous system shutdown , they will eventually lose these functions as the issue progresses to paralysis. Initially this may present as the occasional accident and over time will develop to full loss of urinary and fecal control.
Diagnosis of Nervous System Issues and What Can Be Done
If a dog is displaying any of the troublesome health problems outlined above, it should be promptly evaluated by a licensed veterinarian to rule out other causes like severe joint issues. In some dogs, both nervous system disorders and these conditions are present, Nervous System disorders are diagnosed using a combination of genetic testing, health history, x rays, and physical evaluation of the dog’s hind end.
Veterinary Treatments for Nervous System Disorders
Currently, there is no veterinary treatment or cure for nervous system shutdown in dogs. However, treating any comorbid conditions can reduce symptoms, provide discomfort relief, help keep your dog as mobile as possible and improve their overall quality of life. Diet and exercise are critical in dogs with nervous system dysfunctions, especially preventing obesity, which adds additional stress on the spine and joints. Physical Therapy can be used to prolong quality of life as well as protect muscle mass in dogs. Research shows that clinical signs of the progression of nervous system issues can be slowed with a combination of vitamins, corticosteroids like prednisone, and exercise therapy.
Quality of life for Dogs with DM
Diagnosis with a degenerative issue or condition does not have to signal the end of your happy relationship with your pet. Great advances have been made in the technology used for assistance devices, which can help a dog retain some mobility after its legs have been weakened/paralyzed. Many dogs are unable to walk within 6 to 9 months of a particularly severe case of nervous system shutdown onset. Maintaining an open dialogue with your vet is crucial to your pets quality of life.