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A closer look: Exercise Induced Collapse

6/14/2005

Editor's note: This is the second part of a two-part series on Exercise Induced Collapse. For part one, click here.

In my last column, we saw and example of what might happen if your dog were to be affect by an emerging problem called Exercise Induced Collapse. Now let's look a little closer at what this problem is all about.

Named for the symptoms seen with the syndrome, all cases of a true EIC are exercise related. In severe cases, even the anticipation of exercise (i.e. work, retrieving, etc) can stimulate the onset of a collapse. In fact, anticipation is a key component of true EIC cases, and while this does point to a behavioral component, university clinicians and researchers working on the problem have also located a metabolic component as well.

Blood and muscle testing of affected dogs suggests that EIC dogs have a defect in the chemical reactions used to metabolize energy sources and make them available for use in the muscle and brain. When energy is unavailable, muscles loose their ability to function — leading to collapse.

The questions are: What is triggering the energy production systems to quit working? Why does the problem only occur during times of intenseness? And, then, of course, once these questions are answered —how do we deal with the problem?

There are several areas that are NOT part of the problem. Exercise Induced Collapse dogs are not: hypothyroid, hypoglycemic (low blood sugar), undergoing heat stress, nor do they experience electrolyte or cortisol production problems. Their hearts are functioning normally, they do not have a muscle condition known as myasthenia gravis, and although an EIC can look very much like a seizure, they do not exhibit pre- and post-collapse activity indicative of a seizure. Preliminary work at this time seems to indicate a genetic component as EIC cases are found within familial lines, but the type of inheritance has not been determined.

The typical EIC dogs have intense excitable personalities, even under calm conditions. Although EIC among littermates and half-siblings is common, there is indication that littermates of an affected dog that do not posses the excitable temperament may not have a problem with EIC. Along the same vein, sport purists such as agility, frisbee, jogging, swimming, and even routine waterfowl hunting do not seem to produce collapse. In fact, EIC is less common while swimming than during land retrieves.

The most prevalent occurrences of EIC are found in the bloodlines of field trial Labradors. Although EIC has been seen in all the major Labrador color groups (black, chocolate, yellow) there is a higher incidence in male black Labradors. However, this may not be significant since there are a higher number of black male Labradors competing in top-level field trial events.

While "routine" waterfowl hunting was indicated as an area less likely to induce an EIC event, other hunting activities such as upland pursuits (grouse and pheasant), repetitive retrieving drills (especially with high correction levels), and roading exercises using ATV's have all been associated with collapse. Additionally, very intensive and extreme-condition waterfowling, such as hunting in severe cold with lots of ice to deal with, have also produced problems with EIC.

As you have probably guessed, since much is unknown about EIC any treatments used at this time are very speculative. As such, there are several different treatment protocols being tried — with each protocol being aimed at different areas.

The best treatment is avoidance. Simply avoid the conditions that cause collapse. Of course, this is easier said than done and for some is an unacceptable choice that would require retirement of their dog. Current treatment protocols include the use of carnitine, CoEnzyme Q10, Riboflavin,7-KETO, and anticonvulsants such as phenobarbital. It should be noted that while each of these protocols has been successful in some dogs, none of them have been successful in all EIC dogs.

The work to understand EIC is still in its infancy. Researchers at major college universities are performing research to try and find answers to all the questions surrounding EIC and hopefully come up acceptable ways of dealing with the problem. Remember, at this point EIC is a very uncommon finding outside the field trial Labrador circle. Before a diagnosis of EIC is made, all other possibilities should be explored.