Hyperthyroidism is a pathological condition characterized by the excessive synthesis and release of thyroid hormones by the thyroid gland. It is identified by high or normal thyroid radioactive iodine uptake, known as true hyperthyroidism or thyrotoxicosis with hyperthyroidism. In cases of thyrotoxicosis without hyperthyroidism, the cause can be either an extrathyroidal source of thyroid hormone or the release of preformed thyroid hormones into the circulation. Hyperthyroidism exhibits higher prevalence in white populations compared to dark races and in females compared to males. Additionally, it is more prevalent in the older population than in the young. Graves' disease stands out as the most common cause of thyrotoxicosis with hyperthyroidism in iodine-sufficient areas, accounting for 80% of cases. Being an autoimmune disease, Graves' disease often coexists with another autoimmune disorder affecting a different system or organ in the same patient. Many cases have reported the concurrent occurrence of Rheumatoid arthritis and Graves' disease.
