A 38-year-old woman presents with nervousness, sweating, and a racing heartbeat. She also complains of weight loss despite eating more and says she feels "too hot" all the time. On physical examination, her thyroid gland is enlarged, and she has a noticeable tremor. What could be the cause, and what are the next steps?
This patient's symptoms, including nervousness, sweating, tachycardia, weight loss despite increased appetite, heat intolerance, an enlarged thyroid gland, and tremors, suggest hyperthyroidism. The most common cause is Graves' disease. Initial evaluation should include a serum TSH, free T4, and free T3. If these suggest hyperthyroidism, further diagnostic tests such as thyroid autoantibodies or a radioactive iodine uptake test may be necessary to confirm the diagnosis and determine the cause.