Hyperthyroidism describes the disease of having an overactive thyroid gland. It is seen mostly in middle-aged cats. Symptoms include weight loss in the face of a voracious appetite, nervousness, restlessness. Hyperthyroidism causes the body’s metabolism to race at a rapid rate, causing multiple organ dysfunctions. Rapid heart rate (tachycardia) as high as 220 or 250 beats per minute (normal 90-110) is a key symptom. Sustained elevated heart rate possibly leads to heart failure if untreated. Three common treatment protocols include:
surgery (thyroidectomy)
radiation treatment of the thyroid gland performed at a licenced radiation treatment center such as UGA Veterinary Clinic in Athens
medical (conservative drug) treatment “Tapazole” (methimazole)
The medical approach is least expensive and least risky to the pet’s health. However, even generic methimazole is not inexpensive. A common symptom of methimazole treatment is vomiting, but the side-effect is usually temporary. Methimazole is often dosed once daily, but some cats need twice daily dosing (every 12 hrs). Although hyperthyroidism is a potentially deadly disease, many cats can lead high quality lives for years after diagnosing if treated properly.

Annual thyroid testing is recommended to confirm that the proper dose is being administered.

Hypothyroidism is seen commonly in middle aged dogs, females more often than males. It describes a diseased thyroid gland that has ceased to produced and secrete sufficient thyroxin. The metabolism slows and multiple organ systems are adversely effected.

Symptoms include weight gain, skin problems, ear infections and in long term untreated severe cases lameness and other musculoskeletal disorders.

The disease is diagnosed through a blood test. Treatment consists of oral thyroid gland supplementation. Drug names include Thyroxin, Soloxin, Levothyroxin, and several generic formulations that work very well. Dosing is usually once daily. Annual blood tests are needed to confirm proper blood levels of thyroid hormone. Once regulated many dogs are able to lose the extra weight and return to their normal activity level