Toxic Multinodular Goiter

Toxic Multinodular Goiter is a condition affecting the thyroid gland, which is located in the neck and controls how the body uses energy. In this disorder, multiple lumps or nodules form in the thyroid, and some of these nodules produce too much thyroid hormone without regulation. This excess hormone causes symptoms like weight loss, rapid heartbeat, and feeling hot or anxious. The condition mainly affects the body's metabolism and can lead to serious heart problems if untreated. It usually develops slowly over time and is more common in older adults. Diagnosis often involves blood tests and imaging to check thyroid function and structure.

Toxic Multinodular Goiter is characterized by the presence of multiple autonomously functioning thyroid nodules that produce excess thyroid hormones, leading to hyperthyroidism. It typically arises in patients with a long-standing multinodular goiter, often due to iodine deficiency or somatic mutations activating the TSH receptor or G-protein signaling pathways. The condition results in elevated serum free T4 and T3 with suppressed TSH levels. Clinically, it presents with symptoms of thyrotoxicosis such as palpitations, weight loss, and heat intolerance. Unlike Graves disease, it lacks diffuse thyroid enlargement and thyroid-stimulating immunoglobulins. The nodules are usually palpable and may cause compressive symptoms if large. It is a common cause of hyperthyroidism in older adults and iodine-deficient regions.