Exercise Induced Collapse (EIC)
This condition causes affected dogs to lose muscle control following periods of strenuous exercise. Symptoms generally occur after 5-20 minutes of strenuous exercise with extreme excitement which induces weakness and then collapse. Severely affected dogs may collapse every time they exercise to this degree whereas others may collapse more sporadically.
Attacks often begin with a rocking motion, then the rear legs become weak and unsupportive. Severity of these attacks may differ as some will continue to attempt to carry on running, dragging their hind legs along, whilst others may be unable to move either through disorientation or because the weakness has progressed to the forelimbs. The muscles remain relatively flaccid during the attack which typically lasts between 5-25 minutes. An affected dog's exercise should ALWAYS be stopped at the first sign of incoordination or wobbliness as in extreme cases an attack may be fatal.
An elevated temperature may play some role in Exercise Induced Collapse (EIC) in relation to collapse and may contribute to the death of some affected dogs, but temperature regulation is not the underlying problem. Affected dogs hyperventilate and experience a dramatic reduction in their blood carbon dioxide concentration and an increase in their blood pH, but these changes are also observed in normal exercising dogs. Interestingly, they do not take longer to cool down following exercise either.
At rest, neurological, cardiovascular and musculoskeletal examinations are unremarkable and routine blood analysis both at rest and during an episode of collapse is normal. Affected dogs do not experience heart rhythm abnormalities, low blood sugar, electrolyte disturbances or respiratory difficulty that could explain their collapse. They are also negative for myasthenia gravis (ACh-R Aby), thyroid gland function (T4, TSH) and adrenal gland cortisol production (ACTH stimulation test).
Following collapse, the dog may appear disorientated and may fall over when they try to stand. Most dogs recover quickly (not spontaneously) and are normal within 5-25 minutes with no residual weakness or stiffness. Episodes are not painful and after recovery they are not stiff, sore or limping.
EIC is a syndrome whereby there is reduced nerve transmission from the brain to muscle. It is a mutated gene that is responsible for making a protein related to the chemical and electrical signals in the nerve.
EIC is a recessive disorder and a dog must have two copies of the mutation (one from either parent) for the disease to manifest. A dog can have one copy of the mutation and not experience any signs or symptoms of EIC and this dog would be known as a carrier. A carrier, if bred, can pass either their normal gene or the mutated gene to their off spring. If two carriers of EIC are bred, the puppies could receive the mutated gene from both parent, which would lead to an affected puppy.
There is no such thing as an EIC unaffected dog. There are dogs that have neither gene mutated and these can not pass down a mutated gene and these dogs are CLEAR. A CARRIER has one mutated gene out of the two and there is a 50% chance they will pass this to their offspring. An AFFECTED dog has two mutated genes and this dog can only pass a mutated gene to their offspring.
From January 2022, the Kennel Club will limit the assignment of ‘hereditary clear’ status of registered dogs to two generations. This change will be put in place to safeguard against the impact that dogs with an incorrect ‘hereditary clear’ status could have on health issues within a breed. This is to reduce the risk of unintentionally breeding affected puppies.
An economical way to test for both EIC and PDP1 is to have your dog DNA tested by Embark. Further information is available on the Embark DNA test Here, including a discount code for Clumber Spaniels ($99.00).
The results from Embark (OFA Submission report, available on your Embark account) can be forwarded to the Kennel Club (Breeder Services - firstname.lastname@example.org). If previously recorded as ’hereditary clear‘ the dogs details wIll be updated to ‘clear’ status for PDP1 (and EIC) and replaced with ‘clear’ and a test date registered as the date the KC received your email.