Generalized diffuse overactivity ("toxicity") of the entire thyroid gland which becomes enlarged into a goiter . Graves disease is the most common cause of hyperthyroidism . See the entire definition of Graves disease

Graves disease is a medical disorder that may manifest several different conditions, including goitre and hyperthyroidism (over-activity of thyroid hormone production), infiltrative exophthalmos (protuberance of one or both eyes and associated problems) and infiltrative dermopathy (a skin condition usually of the lower extremities). This disorder is the most common cause of hyperthyroidism. It is known to be related to an antibody mediated type of auto-immunity, but the trigger for the reaction is unknown.