Hyperthyroidism (an overactive thyroid gland disease) occurs when the thyroid gland overproduces the thyroid hormones T3 and T4, which are then released into the bloodstream. The thyroid gland has two lobes (right and left) that are found on the neck on either side of the windpipe. The hormones produced by the thyroid gland control the metabolism processes.
Thyroid hormones help control the body's metabolic rate and activity level so dogs with hyperthyroidism tend to burn energy quickly and lose weight despite having an increased appetite.
Hyperthyroidism is rare in dogs, but a malignant (cancerous) tumor known as a thyroid adenocarcinoma can cause hyperthyroidism. It is important to understand that not all thyroid tumors cause hyperthyroidism and a dog’s thyroid function can be normal despite thyroid carcinoma. The treatment used for hypothyroidism (under active thyroid gland) can also cause hyperthyroidism.
• weight loss despite increased appetite
• increased thirst and urination
• increased irritability
• rapid heart rate
• unkempt coat
• mild to moderate diarrhea
• heat intolerance (seeking cool place to sit)
• panting when stressed
Visit your vet if you notice any of the symptoms listed above. Your vet will make his or her diagnosis based on your pet’s history, symptoms, and a physical examination confirmed by a blood test to measure hormone levels.