Exercise-Induced Collapse (EIC)
“Exercise-Induced Collapse (EIC) is a genetic neuromuscular disorder characterized by muscle weakness, lack of coordination and life-threatening collapse after intense exercise in otherwise apparent healthy dogs.” [1]
“Affected dogs can tolerate mild to moderate exercise, but 5 to 20 minutes of strenuous exercise with extreme excitement induces weakness and then collapse. Severely affected dogs may collapse whenever they are exercised to this extent - other dogs only exhibit collapse sporadically. The first thing noted is usually a rocking or forced gait. The rear limbs then become weak and unable to support weight. Many affected dogs will continue to run while dragging their back legs. Some of the dogs appear to be incoordinated, especially in the rear limbs, with a wide-based, long, loose stride rather than the short, stiff strides typically associated with muscle weakness. In some dogs the rear limb collapse progresses to forelimb weakness and occasionally to a total inability to move.”… “It is common for the symptoms to worsen for 3 to 5 minutes even after exercise has been terminated.” [3]
“EIC episodes occur when the dog is excited and exercising intensely. Observant owners will notice that the hindquarters begin to wobble until the hind end of the dog collapses. The dog feels no pain and the limbs are not stiff. They may keep trying to play and move forwards, but they need to be made to rest to regain the use of their hindquarters. A few dogs have died but stopping exercise once the dog collapses does lead to recovery without lasting consequences. However, it will all happen again. Affected individuals can have a normal life as pet dogs as long as their exercise is managed to avoid the intensity that triggers a collapse.” [2]
Recovery From Collapse
“Most dogs recover quickly but the recovery is gradual rather than instantaneous. Dogs are normal within 5 to 25 minutes with no residual weakness or stiffness. Dogs are not painful during the collapse or after recovery. Massage of the muscles or palpation of the joints or spine does not cause discomfort. Affected dogs are not stiff or sore or limping upon recovery.” [3]
“There is a similar collapsing syndrome in Border Collies but this does not show up on the DNA test which gives us the diagnosis of EIC. The Border Collie Collapse (BCC) has a slightly different pattern with gradually increasing fatigue followed by loss of mental and optical focus leading to collapse involving forelimbs as well as hindlimbs. Both conditions have an associated transient pyrexia, which is also found in normal dogs in intense activity. This has led to EIC and BCC being mistaken for heat stroke which is a very different condition. Heat stroke follows over-exertion at high ambient temperature.” [2]
“In Labradors, EIC is most common in dogs bred for field trials, which fits with the observation that it shows most frequently in lean, fit, intensely exercising and highly motivated individuals. About 50 percent of the Labrador population carry the gene, but both parents must be carriers to produce affected puppies. It usually shows from five months of age, in both sexes, most often when the young dog starts intensive training. The animal will be normal in all other respects, including full clinical work-up.” [2]
“any Labrador Retriever with exercise intolerance should always have a complete veterinary evaluation to rule-out treatable conditions such as orthopedic disorders, heart failure, anemia, heart rhythm disturbances, respiratory problems, low blood sugar, cauda equina syndrome, myasthenia gravis, hypoadrenocorticism, and muscle disease. Genetic (DNA) testing for EIC can now be performed to confirm a suspected diagnosis of EIC.” [3]
“The Veterinary Genetics Laboratory offers a genetic test for EIC. Test results assist veterinarians with diagnosis of EIC and help breeders identify carriers among breeding stock to avoid producing affected dogs. Matings between carriers are expected to produce 25% of affected puppies.” [1]
“It can be tested for so that dogs as young as five to six weeks old can be identified and not put forward for training.” [2]
Testing recommendation: Australian Cobberdog, Australian Labradoodle, Bouvier des Flandres, Boykin Spaniel, Cardigan Welsh Corgi, Chesapeake Bay Retriever, Cockapoo, Cocker Spaniel, Clumber Spaniels, Curly Coated Retriever, Deutsch-Drahthaar, English Cocker Spaniel, German Wirehaired Pointer, Labrador crosses, Labradoodle, Labrador Retriever, Old English Sheepdog, Pembroke Welsh Corgi [1]