Exercise induced collapse

by Dr. Mikel Delgado, PhD and Dr. Nate Ritter, DVM

Exercise Induced Collapse

Exercise induced collapse (EIC) is a genetic condition which leads to muscle weakness, a lack of coordination, and eventual collapse after intense exercise. Affected dogs are typically healthy and very physically fit, but EIC can be life-threatening to them. EIC was first identified in Labrador Retrievers, but has also been observed in other breeds.

Signs of Exercise Induced Collapse

Affected dogs typically show signs between 5 months and five years of age (average age of onset is around 14 months of age). Dogs may appear completely fine when at rest, but may be affected after 5 to 15 minutes of intense exercise. Their gait may suddenly change, and weakness in the back legs makes them unable to support their weight. Some dogs will continue to play or exercise despite the leg weakness, even dragging their rear legs behind them. Other dogs will lose their balance and fall over, and may be temporarily unable to move. Dogs may be completely conscious during an episode, or may appear disoriented. EIC is not considered painful. Usually after a short rest, dogs appear normal again. Unfortunately some cases are fatal, dogs may die during exercise or an episode of collapse.

Treatment of Exercise Induced Collapse

Currently, there is no available treatment for EIC. The mainstay approach to management is to avoid activities that trigger EIC by not exercising an affected dog to the point of collapse. When properly managed, affected dogs can live an otherwise healthy life as a pet. 

Some anecdotal reports suggest dogs may improve with age and neutering. Anti-seizure or sedative medications may offer benefits to dogs with EIC, but the reduction in symptoms in all these cases may simply be due to decrease in general excitement.

Breeds at Risk for Exercise Induced Collapse

Labrador Retrievers, especially those from field trial lines, are at risk. EIC tends to affect fit, lean, highly motivated dogs. The mutation of the gene responsible for EIC has also been observed in other dog breeds including Bouvier Des Flanders, Boykin Spaniels, Chesapeake Bay Retrievers, Curly Coated Retrievers, Clumber Spaniels, Old English Sheepdogs, and Pembroke Welsh Corgis. A similar condition in Border Collies (Border Collie Collapse) is not related to the genetic mutation that causes EIC.

Inheritance and DNA Testing for Exercise Induced Collapse

The genetic cause for EIC, a mutation in the dynamin 1 gene, was discovered at the University of Minnesota. A test is readily available through several commercial genetic testing sites, and results can be registered with the OFA.

EIC is an autosomal recessive disorder, and a puppy would need to inherit two copies of the mutation to be affected. Dogs who are carriers (one normal copy, one mutation) will not show signs of EIC. 

Puppies can be tested as young as five or six weeks of age, and affected puppies should not be entered into training programs. Affected dogs with two copies of the mutation should not be bred. If your dog is a carrier, consider consulting with a veterinary geneticist. Carriers should only be bred with dogs who are clear for EIC. Carrier-to-carrier breedings should be avoided. 

Resources

Minor, K. M., Patterson, E. E., Keating, M. K., Gross, S. D., Ekenstedt, K. J., Taylor, S. M., & Mickelson, J. R. (2011). Presence and impact of the exercise-induced collapse associated DNM1 mutation in Labrador retrievers and other breeds. The Veterinary Journal, 189(2), 214-219. https://www.sciencedirect.com/science/article/pii/S109002331100236X 

Patterson, E. E., Minor, K. M., Tchernatynskaia, A. V., Taylor, S. M., Shelton, G. D., Ekenstedt, K. J., & Mickelson, J. R. (2008). A canine DNM1 mutation is highly associated with the syndrome of exercise-induced collapse. Nature genetics, 40(10), 1235-1239. https://www.nature.com/articles/ng.224

Taylor, S. M., Shmon, C. L., Shelton, G. D., Patterson, E. N. E., Minor, K., & Mickelson, J. R. (2008). Exercise-induced collapse of Labrador retrievers: survey results and preliminary investigation of heritability. Journal of the American Animal Hospital Association, 44(6), 295-301. https://pubmed.ncbi.nlm.nih.gov/18981194/

Western College of Veterinary Medicine: Exercise-induced collapse (EIC)