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Discussion Starter · #1 ·
How is EIC distinguished from canine narcolepsy? I came across this description on the site that offers DNA tests for narcolepsy in Labradors:


Affected dogs are often described as falling fast asleep right in their tracks—but that’s not quite the case. Indeed, they suddenly lose control of their hind legs, or even collapse in complete, limb-numbing paralysis—yet they are entirely aware of their surroundings and can track things with their eyes. Attacks last a few seconds, or a minute or two, tops; then the dog is up again and moving, with no residual grogginess, no indication that things were ever amiss.
I have yet to witness either.

Amy Dahl
 

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Amy, I've witnesses two episodes of EIC in dogs while pheasant hunting (neither dog mine). Both dogs were later diagnosed as probable EIC after a battery of tests that eliminated other things. Both of these dogs were in the midst of quartering/chasing birds in cool weather. I have never heard of the disease you have described but find it hard to imagine a dog going to sleep while chasing birds.
 

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Discussion Starter · #3 ·
Apparently they don't go to sleep. Something happens that they're excited about, and they lose muscle tone in their hindquarters, then it can progress to the front. They lie there alert for a few minutes, then get up and act normal. Excitement, not exercise, is thought to be the trigger--but in EIC exercise without excitement doesn't seem to cause it. Maybe the excitement is the real issue, and differences in details are caused by the incidental factor of exercise?

I've been reading sites on EIC and they discuss differential diagnosis for CNM, malignant hyperthermia, and a lot of other disorders--but not narcolepsy. The narcolepsy apparently is caused by a shortage of REM sleep, as in humans (which is why it's been studied) but, just like EIC, would not cause abnormalities in blood or muscle chemistry, as I understand it.

The defective gene is called hcrtr2. I'll be really interested to find out if that's in the region being studied by the EIC people.

Amy Dahl
 

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Discussion Starter · #5 ·
To preface, let me mention that before posting this morning I emailed Dr. Sue Taylor at Saskatchewan, whose contact info was listed in connection with the EIC project. When I came in from morning training, I found a response. She describes differences in the onset and recovery from "cataplexy," which appears to be the term describing these attacks that the Stanford group consider narcolepsy, and EIC. Apparently in cataplexy onset and recovery are more sudden, while in EIC onset can be subtle at first and can be stopped by removal of the trigger, and recovery is less dramatic.

But for all of us and our general-practice vets, it might still be difficult to tell the difference, I imagine. Here are a couple of links.

The OptiGen site, which offers the DNA test for narcolepsy, includes an informative article here:

http://www.optigen.com/opt9_test_narc.html

Here's an article about the discovery and the team behind it, at Stanford University School of Medicine, with emphasis much more on applications in human medicine:

http://www.stanford.edu/~dement/ngene.html

The similarities include that both conditions are said to become less pronounced in later life. I was relieved to get the email from Dr. Taylor and learn that narcolepsy had not been overlooked in the EIC research.

Amy Dahl
 

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Discussion Starter · #7 ·
Thanks for the links. I looked at another narcoleptic-dog video, and to me the action of the hindquarters (before he falls asleep) looks just like that in the Lab.

http://www.youtube.com/watch?v=LbmbQkX7czo&NR

But I gather that Dr. Taylor and the others are confident enough of the difference that they haven't tested the EIC dogs for narcolepsy, and it's their job to know.

Being an incurable skeptic, though, if I had a dog with a diagnosis of EIC, I don't think I could resist submitting a sample for a NARC test.

Amy Dahl
 

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Amy,

With you never experiencing a dog with EIC symptoms, I cannot help wonder, how many labradors are actually affected. The mode of inheritence (? autosomal recessive) and the degree of symptoms seem varied. Some dogs show symptoms relatively young, others intermittently, while others used to call this condition a type of heat stroke.

If its not one condition to worry about, its another. SIGH.
 
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