Treatment involves surgical removal of a large majority of the thyroid gland or injection of radioactive iodine. The radioactive iodine travels to the thyroid gland and destroys thyroid cells. Hypothyroidism, on the other hand can be due to an iodine deficiency, which results in failure to produce sufficient amounts of thyroxine. However, more commonly the individual produces sufficient quantities of thyroxine, but fails to secrete it. Symptoms include fatigue, weight gain, constipation, reduced heart rate and lethargic muscles.
Treatment involves ingestion of thyroxine and usually the person returns to normal.
Guyton, A.C. and J.E. Hall. The Thyroid Metabolic Hormones, p. 945-956. In A.C. Guyton and J.E. Hall, Textbook of Medical Physiology. W.B. Saunders Company, Philadelphia. Mindell, E. 1985.