Toxic multinodular goiter is a condition where the thyroid gland becomes enlarged and develops multiple nodules that produce excess thyroid hormones. This overproduction can lead to symptoms such as weight loss, increased heart rate, and anxiety. The condition is often associated with iodine deficiency and can affect individuals of any age. Diagnosis typically involves blood tests to measure hormone levels and imaging studies like ultrasound to assess the nodules. Treatment options may include medication to manage symptoms, radioactive iodine therapy, or surgery to remove the affected thyroid tissue, depending on the severity of the condition and the patient's overall health.