This book is also included as a section in "The Everything Thyroid Disease Book ", so this version is for those who are interested in the subject of hyperthyroidism specifically (also available in eBook). Hyperthyroid conditions account for about 20% of thyroid disease cases. The causes of an overactive thyroid gland can be varied but the most common cause is an autoimmune condition called Graves' disease. Complications can also occur with hyperthyroidism,...