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Does This Ferret Have A Thyroid Problem?

Could a listless ferret have thyroid trouble?

By Karen Rosenthal, DVM, DABVP
Posted: February 1, 2009, 5 a.m. EST

Q: My ferret recently became very lethargic. He more or less lies in his hammock with a distant look on his face. He was taken to the vet today and given a full blood work evaluation. Everything came back well within norms except for the T4 thyroid test. He had a 1.6 value, which my veterinarian said was a little low but still within normal ranges. My veterinarian has never had a hypo/hyperthyroidism case before, and is still going to investigate.
I would like to know where the 1.6 score puts my ferret. What is the treatment if he does have hypothyroidism? He is eating, drinking and doing all other functions regularly.

A: Both hypothyroidism and hyperthyroidism have not been described in ferrets as a common or even rare disease. Let’s be thankful there is one endocrine gland that remains normal in ferrets!

Hypothyroidism is very difficult to diagnose, even in animals that we know get this disease, such as dogs. It is more common in certain breeds. Because this disease is difficult to diagnose, veterinarians use many blood tests to diagnose hypothyroidism. The resting thyroid level, which is the test your doctor did on your ferret, is a screening test. If this test is abnormal, it indicates that further tests need to be done. Also, a few different methods are used to measure thyroid levels, and some are more likely to be accurate than others.

If this were a dog with a slightly low number, the next step would be to consider a few more specific tests, and possibly a stimulation test. A stimulation test is given to the patient to try to force the thyroid to produce more thyroid hormone. If this stimulation test does not elicit the correct response, than a diagnosis of hypothyroidism can be made.

Because we do not see hypothyroidism in ferrets, the stimulation test is rarely performed. Interestingly enough, though, a protocol exists for performing this test in ferrets.

Based on a 1.6, it is highly unlikely your ferret has hypothyroidism. This number should be much lower if it is hypothyroidism. Because hypothyroidism is a very rare disease, the odds are stacked against your ferret having it. It may be worthwhile to investigate other avenues of disease diagnosis. If you believe, however, that there is a good chance this is hypothyroidism, then the stimulation test may be your next step.

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Does This Ferret Have A Thyroid Problem?

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Reader Comments
My ferret is also "lazy" but he eats, drinks and poops just fine, so I am attributing this to his advanced age. He is on Lupron and Pred for adrenal disease and insulinoma. Your little buddy could also be bored, maybe you want to get him some new toys, let him in a new area of the house ... if this is his new normal, just love him as much as you can!
Dana, Killingly, CT
Posted: 2/13/2009 11:18:36 AM
Anyone interested in hypothyroidism in ferrets may want to contact Dr Cheryl Greenacre:
Associate Professor of Avian & Zoological Medicine
Department of Small Animal Clinical Sciences
College of Veterinary Medicine
The University of Tennessee
2407 River Drive
Knoxville, TN 37996
Phone: (865) 974-8387
FAX: (865) 974-5554

She has been actively working in this area and I think she may soon publish (if I understand correctly).

I was originally referred to Dr Greenacre by my regular veterinarian in December to be evaluated for Adrenal Disease. My ferret, Gizmo; had began loosing hair, lethargic, and determined by Dr Greenacre to be severely obese at 4.5lbs (we thought he was just a big guy). My vet took blood and sent to UT for testing. He WAS determined to have adrenal disease and an ultrasound was performed to se which side the tumor might be located. The ultrasound was indeterminate as the tumor(s) are as yet too small to see. Our current plan is to give him monthly Lupron injections and redo the ultrasound in six months.
First I'll say, the Lupron has made a HUGE difference. He is more active, seems to feel better, and almost all his fur has grown back.
As for the obesity, Dr Greenacre suspected hypothyroidism as a cause. She is (or was) doing a study of hypothyroidism in ferrets and performed all Gizmo's test gratis. Specifically a 6 hour stimulation test. She had from the literature 3 different ranges for thyroid levels in ferrets and Gizmo was below all the ranges. We started him on .025mcg of Levo-Thyroxine (human Synthroid brand) each morning and he is doing great. Lots of energy and he takes it well crushed and mixed with about a tsp of cat milk, yogurt, or laxatone.
I would note that he was originally prescribed Soloxine (same as human Levo-Thyroxine) at the hospital, but it was only available in 0.1mg which meant I had to crush and then divide the powder into 4ths; which i wasn't comfortable with. I contacted MY pharmacist to see if he could somehow compound for me and he suggested going with the Synthroid which came in scored, .05mcg tablets and spliting each in half. I did not know, but at least here in TN, your pharmacist can fill animal Rxs with a prescription from your vet. I informed Dr Greenacre and she happily called in the Rx. They reccomend NOT using generic as the dosage is better controlled with the brand name. It is not expensive for the brand name. $22.00 for 45 tablets so when halved comes out to a 90 day supply.
You can read more about Dr Greenacre at the following:

I hope this might help someone.
Jeff, Maryville, TN
Posted: 2/11/2009 11:43:32 AM
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