Dog Thyroid being Produced but not Utilized

by Olsen
(Nashville TN USA)


Our 6 1/2 year old named Patrick, a Bernese Mountain Dog, is producing normal amounts of thyroid but is not utilizing it per serial labs done at the Univ of MN.

His undercoat is falling out in clumps, he is losing weight despite a 15% increase in feeding, no energy, and just isn't feeling well. A trial of seloxin resulted in a hypermetabolic state that was close to fatal.

Consultations with specialists in internal medicine and cardiology have not resulted in any diagnosis, let alone a treatment plan.

Any information or suggestions on how to proceed would be appreciated.

Thank you,


Suggestion from our Vet regarding Thyroid Levels and Utilization


From your description, it sounds like your dog is suffering from canine sick euthyroid syndrome. When a dog is ill from non-thyroidal illness, his or her total T4 levels may drop, but additional testing can rule out true hypothyroidism.

Sick euthyroid syndrome should not be treated with thyroid hormone supplementation. Also, your dog’s weight loss does not fit with hypothyroidism, weight gain is more typical.

Your veterinarians will need to continue to search for an underlying illness, and as you have unfortunately already found out, this can be easier said than done.

I do not know what types of diagnostic testing your dog has undergone, so it is difficult for me to recommend a next step. It is probably best if you consult with the internal medicine specialists that you have been working with and see what they recommend.

Best of luck,

Jennifer Coates, DVM

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