Meds or tumor might cause hyperthyroidism
QOur little westie was just diagnosed with hyperthyroidism. The dog has had various small growths removed before and for the past two years has been taking thyroid medication to replace his low levels of thyroid hormone. A few days ago, he started drinking excessively and urinating nonstop. Our vet suspected either a kidney problem or diabetes. When he called the next morning to report the findings of the blood tests, he indicated that the dog either got into too much medication or that he could have a thyroid tumor. Is this common? The crazy thing is, the dog is otherwise acting normally. Is this an emergency, or do we have a few days to get this worked up?
AHyperthyroidism in dogs is unusual, and, as you were informed, your dog either received too much medication for an extended period of time or there may be a hormonal cause, such as a thyroid tumor. There are many signs associated with hyperthyroidism in dogs, including the thirst and urine production you cited. Other signs include increased appetite, vomiting, aggression, hyperactivity and more.
The pituitary gland in the brain produces something called thyroid stimulating hormone (TSH), which then stimulates the thyroid gland to produce thyroxine (T4) and triiodothyronine (T3). T3 is the hormone that actually stimulates all metabolism in the body.
One can have a high thyroid level due to either a benign pituitary mass or a primary thyroid mass in the thyroid gland that can be benign or malignant. Surgical removal of the thyroid gland can be performed, but it can lead to low thyroid, so it must be done carefully. Surgery is usually reserved for benign masses since malignant ones readily metastasize locally and distally. Alternatively, radioactive iodine can be given to selectively attack the thyroid and reduce its production levels, but this can mean hospitalization and some risk to people around the dog.
While this is not an emergency, I suspect your veterinarian will not want to delay in exploring all avenues to help your dog.