Thyroid nodules may cause increased levels of free thyroxine. Benign, small nodules usually do not cause an increase in free thyroxine. If a high-functioning adenoma is secondary to a nodule, the nodule will secrete thyroxine and cause an increase in free thyroxine in the blood, or the nodule will increase in size and increase the secretion of thyroxine to a certain degree, which can lead to an increase in free thyroxine levels. The majority of thyroid nodules are benign. If there are no special symptoms and the solid nodules are small in size, they can be checked regularly and no special treatment is needed for the time being. If the nodule is caused by hyperthyroidism, oral methimazole tablets can be used for antithyroid therapy; if the solid thyroid nodule is caused by subacute thyroiditis, oral non-steroidal anti-inflammatory drugs, such as meloxicam, etc. are needed; if secondary high-functioning adenomas or the nodule is too large, surgical resection is needed. In summary, it is recommended that the patient go to the hospital for a thyroid function test and consult a thyroid surgeon for advice.