Graves disease following radioiodine therapy for toxic adenoma: Clinical case report.

RATIONALE

There is a low risk of developing Graves disease (GD) with elevated thyrotropin receptor antibodies (TRAbs) in patients undergoing radioiodine therapy for toxic adenoma.

PATIENT CONCERNS

An old female patient with a history of Hashimoto thyroiditis was referred to our department due to thyrotoxic symptoms. After the administration of radioiodine, a significant remission was achieved. However, after 4 months, she was referred to our department again due to recurrence of hyperthyroid symptoms.

DIAGNOSES

Based on the results of laboratory test, thyroid scan and ultrasound examination, she was diagnosed as thyrotoxicosis induced by toxic adenoma at the first visit. However, 4 months later, she was diagnosed as Graves' disease at the second visit.

INTERVENTIONS

She received radioiodine therapy two times with different doses of 15 mCi and 12 mCi.

OUTCOMES

After the administration of 15 mCi radioiodine, her thyroid hormones and clinical symptoms showed significant improvement. However, 4 months later, she presented thyrotoxicosis again. After the second radioiodine therapy with a lower dose, her clinical symptoms moved towards normalization during regular follow up.

LESSONS

Toxic adenoma and GD are considered as 2 distinct disease entities; however, radioiodine therapy for toxic adenoma may induce GD. We should learn to differentiate these 2 disorders prior to radioiodine therapy because of different treatment strategies and goals.