Are pituitary and thyroid function tests useful for the monitoring of antithyroid drug treatment and the post therapeutic control of Graves' disease?

ABSTRACT

The control of Graves' disease patients treated with antithyroid drugs (ATD) involves monitoring the dose of ATD, the duration of therapy and the prediction of the long-term outcome of the disease. The sequential follow-up of free thyroid hormones and ultrasensitive TSH (USTSH) helps in monitoring of ATD therapy, except in patients complemented with thyroid hormones. The normalization of early thyroid uptake of radioiodine or pertechnetate, which seems to be closely related to circulating thyroid-stimulating immunoglobulins, confirms the remission that leads to stopping ATD therapy. The raise of plasma USTSH in a normal range within the six months following ATD withdrawal is another indicator of remission. However, the post therapeutic course of Graves' patients remains unpredictable late relapses and hypothyroidism may occur despite the normalization of the pituitary-thyroid axis, leading to a yearly clinical control with USTSH evaluation.