Very interesting thyroid case

Hello vets! **ROXY’S VET SAYS THAT THIS IS AN INTERESTING CASE, ALL VET OPINIONS/IDEAS ARE VERY WELCOME** I’ll try to keep it as short as I can. My dog (husky/gsp mix, female,spayed, 1year old and 10 months) went from weighting 60lbs 10 months ago to weighting 99lbs as of few days ago. She started being slower, lethargic at times, reduced appetite, hair loss with extreme shedding and getting tired after walking 15 minutes. She also started kind of scraping the tip of her front paws while walking. I was very concerned so I took her to her vet that made a wellness panel (blood test, thyroid check, urinalysis and fecal testing.) What they found is the cholesterol at 1000 and thyroid issues - which the vet was already suspecting. Now the “mistery” is the fact that her T4 is high while her T3 is low. The vet can not explain this and he’s going to get in touch with thyroid experts on the matter because he has never seen a case like this. Do any one of you vets ever seen a situation like this? I am very worried for my girl and I want her to be able to feel better again as soon as possible. They did not take X-rays or anything else. They did just what I mentioned above. Her vet said he’ll get in touch before Wednesday, I assume with an answer or something. Thank you in advance for any help. Pic of Roxy from 10 months ago and now.

Hello!   This is interesting.  It sounds as though T4 is being produced within the body, but is not working on the cells.   Perhaps this may result in more T4 being produced, because the chemical is simply not acting on the body, so causing hypothyroid symptoms and triggering further T4 production.  I don't know how likely this loop-effect is, but the lab will usually be happy to advise your vet on the subject and this might be what is causing a small delay in your vets final interpretation of the results. It is, however, definitely possible for a dog to carry extra antibodies that react with T4 antibodies when the tests are run, resulting in artificially high readings (info from Nationwide laboratories website).  These are called T4 cross-reacting antibodies.  So this may be a possibility. There are numerous further tests that can be done with the thyroid hormones and a combination of tests, together with the interpretation from your vet or the laboratory specialist, will be the most useful way of understanding what is going on in this case.  I hope that your girl is okay and trust that your vet will do their research, so hopefully you will understand the underlying cause by now.     Please will you let us know what is found?