A diagnosis of recurrent Graves’ disease may be suspected when a patient with a history of treated Graves’ disease presents with symptoms, physical signs, or laboratory test results that suggest the presence of thyrotoxicosis. If thyroid function tests confirm the presence of thyrotoxicosis, further evaluation may vary depending on the form of treatment the patient initially received.
If a patient was initially treated with an antithyroid drug that was held once remission was confirmed, any subsequent thyrotoxicosis that develops is likely to represent hyperthyroidism due to recurrent Graves’ disease. In most cases it may not be necessary to perform any further tests to confirm a suspected diagnosis of recurrent Graves' disease.
If a patient initially underwent treatment with radioactive iodine or thyroid surgery, further evaluation may depend on whether the patient progressed to develop postablative or postsurgical hypothyroidism. If a patient in this situation has been treated with thyroid hormone replacement therapy, the main question that must be considered is whether any thyrotoxicosis that has developed is likely to represent hyperthyroidism due to recurrent Graves’ disease or whether it is more likely to reflect the effects of treatment with excess doses of levothyroxine. In most cases the only way to sort this out is to hold levothyroxine replacement therapy for several weeks so that thyroid function tests can be checked and followed while the patient is off all treatment. If serial thyroid function tests continue to reveal changes consistent with persistent thyrotoxicosis after levothyroxine has been held for several weeks, that thyrotoxicosis is likely to represent hyperthyroidism due to recurrent Graves’ disease.