**6.1. Thyroid gland**

Thyroid gland is diffusely enlarged in Graves' disease, but it can be nodular especially in areas of iodine deficiency where nodular goiter preexists before the onset of Graves' disease. Goiter size is variable. It can range from normal size thyroid gland to massively enlarged thyroid. Usually size of goiter is two to three times that of normal. Normal size thyroid gland can the seen in as many as 20% of patients and most of them are elderly. The consistency of the goiter varies from soft to firm but softer than the goiter of Hashimoto's thyroiditis. Thrill and bruit can be present over goiter in severe cases and it is due to increased vascularity of the gland. Thrill and bruit are present usually on upper or lower pole and continuos in nature, but sometimes can present only in systole. Large goiter with intrathoracic extension can be associated with facial swelling and flushing, and neck vein distension upon raising the arm above the head. This is known as Pemberton sign.
