Submitted by Veterinary Wellness Partners on Thu, 06/05/2014 - 11:28am

A Common Feline Disorder


Hyperthyroidism - and overproduction of thyroxine by the thyroid gland.  This disease mainly affects our feline patients.

What does a cat with hyperthyroidism look like?

Clinical signs include:

  1. Weight Loss
  2. Increased activity levels
  3. Increased drinking (polydypsia)
  4. Increased Urinating (Polyuria)
  5. Increased appetite (often to the point of "begging for food")
  6. Poor hair coat
  7. Rapid Breathing (Tachypnea)
  8. Aggression
  9. Difficulty breathing (Dyspnea)
  10. Vomiting
  11. Diarrhea

How is this condition detected or diagnosed?

The most common test for hyperthyroidism is the Tyroxine test, often referred to as a T4 screening.  In some cases, a thyroid panel may be necessary.  This tests not only T4, but free T4, T3 and TSH (Thyroid Stimulating Hormone)

Can overactive thyroid in cats be treated?

The simple answer is yes.  The more difficult response is that it requires effort on the part of the cat owner.  Twice a day medication is necessary for life. The medication is least expensive in a pill format, but specialized pharmacies can compound a medication that can be rubbed onto the ear flap (A transdermal gel).  Other options include diet therapy (Hill's y/d diet), removal of the thyroid gland (thyroidectomy) and administration of radioactive iodine (I131).   It is recommended to try the medication for at least a month and then to retest both a biochemical profile (to retest kidney function) and a T4 (to monitor the response to therapy).  

What does the long term look like for my cat?

Long term therapy is generally successful, but each patient is an individual.  Some cats have underlying kidney damage, which is masked by the overactive thyroid hormone.  Once the thyroid gland is regulated, the renal failure becomes more apparent.  Cats that do not have underlying kidney disease seem to do very well with therapy.

For more information, please contact us at (330) 682-2971

Dr. Jeff Fink composed and published the information above on behalf of The Orrville Veterinary Clinic, Inc.