A 45-year-old man complains of frequent mood swings, palpitations, and increased sweating. He also mentions weight loss despite an increased appetite and frequent bowel movements. On physical examination, his pulse is 110 beats per minute, and his thyroid gland is diffusely enlarged. What could be the cause, and what are the next steps?
The symptoms presented, including mood swings, palpitations, excessive sweating, weight loss despite increased appetite, frequent bowel movements, tachycardia, and an enlarged thyroid gland, suggest hyperthyroidism. Possible causes include Graves' disease, toxic multinodular goiter, or thyroiditis. Initial laboratory evaluation should include serum TSH, free T4, and free T3 levels. If these indicate hyperthyroidism, additional testing like thyroid autoantibodies or a radioactive iodine uptake test can help determine the cause.