Thyroid Disease in Pets

Have you noticed your dog is gaining weight despite all your efforts to maintain a healthy weight? Has your older cat been eating everything in sight, but appears to be losing weight? Your dog or cat may be affected by thyroid disease. Dogs are affected by hypothyroidism, while cats commonly become hyperthyroid.

Thyroid disease affects the thyroid hormone, which affects metabolism and many other processes in the body. Signs of thyroid disease will develop over time, and might not be noticeable on a day-to-day basis. This is one of the reasons why regular veterinary visits are so important, as weight gain/loss is a hallmark sign of thyroid disease. To diagnose thyroid disease your veterinarian will run bloodwork, usually a chemistry panel, CBC, and T4. This can be run in-house or may be sent to a lab.

Happy dog isolated is a cute funny enthusiastic German Shepherd with a great big happy smile on his face.

Hypothyroidism in dogs results from decreased production of thyroid hormone. The most common cause is atrophy of the thyroid gland or immune-mediated destruction of the gland. Dogs that are diagnosed with hypothyroidism are usually middle-aged and medium to large breed. Common signs of hypothyroidism are weight gain, lethargy, and skin infections. Hypothyroidism is treated with daily medication, a thyroid supplement. Your veterinarian will monitor the patient with regular bloodwork, so that the dose can be adjusted if necessary.

Cats on the other hand are commonly diagnosed with hyperthyroidism. A benign nodule forms on the thyroid gland and causes overproduction of thyroid hormone. Cats are usually middle-aged or older. Signs are increased activity and appetite, but at the same time losing weight. There are many other signs that hyperthyroidism can be related to including increased thirst and urination, vomiting, and an unkempt hair coat. Hyperthyroidism can become very serious, because if left untreated it can cause high blood pressure, heart disease, and kidney disease. The most common treatment for cats is a daily medication. There are specialty hospitals that can treat hyperthyroid cats with radiotherapy or surgery. Recently, a prescription diet for hyperthyroid cats has become available that can treat the patient, though the patient must be in a single cat household.

Cat in Deep sleep

Both hypothyroidism and hyperthyroidism can be managed and the pet can have a normal life. Most clinical signs of the disease resolve with treatment. The hypothyroid dogs will start losing weight and be more active. The hyperthyroid cats will gradually start gaining back weight. If thyroid disease is not managed the patient may have poor quality of life and have a shorter lifespan due to the effect of thyroid hormone on the body.

At your pet’s annual exam, your veterinarian will do a physical exam and talk to you about your pet’s history. If your veterinarian suspects thyroid disease, testing will be recommended. You know your pet best, so if you notice your pet acting differently, speak to your veterinarian and together you can work towards keeping your dog or cat happy and healthy!