Q: I have a young Labrador named Faith who is acting very strangely lately. After she plays Frisbee, her favorite game, she starts to stagger and has trouble walking for a little time, then she is normal again. It has happened several times and is starting to scare me. I made some videos and sent to my vet to look at. We both think she may have exercise induced collapse. Have you ever heard of this or seen it in any of your patients? What should we do now?
A: I have not seen this condition, that I know of, but will try to give you some information that you can discuss with your veterinarian to try to help Faith. exercise induced collapse is an inherited autosomal recessive neuromuscular disease that does cause collapse in certain breeds of dogs only. It does not occur in cats.
Typically, the ataxia or weakness starts in the back legs and can progress to full on collapse. You can see it in the Labrador and all types of retrievers and in several breeds of Spaniels and corgis to name a few. The episodes are always associated with several minutes of intense exercise that the pets love to do and usually resolves 10 to 15 minutes after rest.
What owners experience with exercise induced collapse is a completely normal dog running and playing one minute only to observe them staggering and stumbling the next. Some dogs will have a swollen tongue and thick saliva drooling out of their mouths as they wander awkwardly around. Often their rectal body temperature will reach 107 degrees.
So this condition can be confused with malignant hyperthermia or heat stroke but there are laboratory differences that your veterinarian can perform on Faith after an episode that will differentiate the different conditions from exercise induced collapse. If and when it happens again try as best as you can to have her seen and evaluated.
The dogs are typically young adult hunting or field trial dogs, but signs can develop younger than 1 year, too. They are not painful and moderate to mild exercise does not affect them, only strenuous exercise. It has been found that affected dogs have a mutation in the DNM1 gene on one of their chromosomes that causes this disease. Dogs that are homozygous for the mutation become clinical. Dogs that are heterozygous are carriers.
To diagnose the condition a blood test can be sent out to one of several veterinary schools or private laboratories. I know University of California at Davis and the University of Minnesota have the ability to test for this condition but I am not sure if they are performing the testing at this point due to a back log of samples and COVID. Calls can be made if you are interested. There may be other private labs to look at too.
Unfortunately there is no treatment for exercise induced collapse. Although I did read that supplements with L-carnitine, Co enzyme Q10 and riboflavin may help. Owners are just directed to exercise their pets with only mild levels of exercise for short amounts of time. Breeders are directed to certainly screen all breeding pairs prior to breeding any of these breeds and to not breed carriers or affected pets.
I hope this helps you and Faith. Dogs with exercise induced collapse can live a long full life if you are able to manage their drive and exercise levels. Good luck to you both.