Hyperactive Thyroid in Dogs

The canine thyroid is responsible for regulating the body's metabolic rate, or rate at which the dog's body burns calories through use of the hormone thyroxine. Hyperthyroidism occurs when the dog's body produces too little thyroxine, causing the metabolism to slow.

  1. Symptoms

    • Canine hyperthyroidism symptoms include lethargy, increased sleeping, disinterest in play, depression, fatigue, weight gain without apparent increase in appetite, obesity, low body temperature, constipation or diarrhea.

    Causes

    • Hyperthyroidism is usually caused when the dog's immune system attacks his own thyroid gland usually as a result of genetic predisposition to this condition. Hyperthyroidism may also be caused by radiation or iodine therapy for thyroid tumors.

    Diagnosis

    • Veterinarians diagnose canine hyperthyroidism by means of physical examination, medical history and tests including urinalysis, complete blood count, thryroxine level (T4), and occasionally X-rays.

    Treatment

    • Treatment may include surgical removal of the thyroid gland, and hormone therapy (using a pill form of thyroxine) to adjust levels of thyroxine.

    Prevention/Prognosis

    • There are no effective preventative measures regarding hyperthyroidism, but careful treatment once diagnosed usually resolves symptoms of the disease in weeks.