Hyperthyroidism in Dogs

Jun 1, 2022

3 min read

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Hyperthyroidism means that your dog is producing too much of the thyroid hormone thyroxine. As a result, your dog’s metabolic rate can reach dangerously high levels — meaning they’re burning more calories than normal and might not have enough leftover for their body to function. Imagine a metabolism in overdrive and how it would affect your pet. Hyperthyroidism in dogs is thankfully rare, but when it does occur, it is caused by thyroid cancer.

What are the potential symptoms of hyperthyroidism in dogs?

When any mammal has a high metabolism, it helps them stay healthy. But if it’s too high, it can cause problems. Watch out for these symptoms in your dog:

Weight loss
Increased appetite and thirst
Excessive excitability
Swollen thyroid gland (located in your dog’s neck)
Excess stool
Vomiting
Diarrhea
Enlarged heart
Heart murmur
Heart palpitations or heart failure

What tests are used to confirm hyperthyroidism in dogs?

Hyperthyroidism in dogs can be a dangerous problem, but it is one that’s easy to diagnose.

Physical examination. Your vet will check to see if the thyroid gland is swollen.
Blood work. This will not only measure thyroid hormone levels, but will also test for secondary conditions, like cancer, that might be causing the hyperthyroidism.

What is the treatment for hyperthyroidism in dogs?

If your dog has hyperthyroidism, you must treat the underlying cancer. There are four treatment options: surgery, radiation therapy, chemotherapy, and medication. Surgery is complex and can often have complications afterwards. The vet will only be able to remove one of the thyroid glands, so if both are affected, your dog will need further treatment. Radiation therapy is rare for dogs, but is still an option, and chemotherapy can help decrease any cancers inside your pet’s body. Medication can be used to keep your dog comfortable while managing the cancer.

What is the typical cost of treatment for hyperthyroidism in dogs?

Hyperthyroidism in dogs is an expensive problem. Expect to spend up to $1,000 on testing, and then another $1,000 to $3,000 per chemotherapy session if you go that route. You’ll also need to add in the cost of any vet visits, hospital stays, and medication. All told, expect to spend around $8,000 or more.

Hours at the vet: As little as 5 hours for diagnosis, as long as 24 hours or more depending on choice of treatment.

What are the recovery steps for hyperthyroidism in dogs?

Determine which treatment path you’d like to take.
If you choose surgery, you’ll need to go back for regular follow-up visits every three to six months. For radiation or chemotherapy, you’ll be at the vet with your dog every couple weeks until the treatment is complete, and then go back for follow-up visits every three to six months.
After a round of medication, and after all other treatments, you’ll need to be sure your dog has regular vet visits for the remainder of its life.

How do I prevent hyperthyroidism in dogs?

Unfortunately, there’s virtually nothing you can do to prevent hyperthyroidism in dogs, since it is caused by thyroid cancer. We cannot control whether dogs develop thyroid cancer.