From subacute thyroiditis to Graves' disease in a patient with a solitary autonomous thyroid nodule

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 471-496-Thyroid Neoplasia & Case Reports
Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-493
Peter Wiesli*1, Michael Braendle2 and Joel Capraro1
1Kantonsspital Frauenfeld, Frauenfeld, Switzerland, 2Kantonsspital St Gallen, St Gallen, Switzerland
Introduction

Subacute thyroiditis usually resolves within some weeks. Recurrent episodes may occur occasionally and rarely, subacute thyroiditis may induce thyroid autoimmune disease.

Clinical Case

A 49 year old woman complained of a sore throat, malaise and fever since 3 weeks. Clinical examination revealed a tender thyroid gland. Laboratory findings showed an increased erythrocyte sedimentation rate (82mm/h) and thyrotoxicosis (fT4 41.3pmol/l, norm 9-23, TSH <0.005mU/l, norm 0.27-4.2). TSH receptor- and TPO antibodies were negative. Ultrasonography of the thyroid gland showed signs of thyroiditis in the right lobe and a solitary nodule of 2cm in diameter in the left lobe. Thyroid technetium-99m uptake was increased to 1.9% in the left thyroid nodule, whereas no uptake was seen in the right lobe. Fine needle aspiration of the right thyroid lobe was performed and cytology revealed granulomatous thyroiditis with giant cells. We initiated a therapy with nonsteroidal anti-inflammatory drugs and glucocorticoids. Thyroid hormones normalized within 3 months (fT4 14.2 pmol/l, TSH 1.9 mU/l), indicating that thyrotoxicosis was mediated by subacute thyroiditis and not by the autonomous adenoma. 8 months after the initial presentation, the patient presented again with clinical signs of thyrotoxicosis (weight loss, tremor, and tachycardia) and recurrence of hyperthyroidism was biochemically confirmed (fT4 50 pmol/l, TSH <0.0002 mU/l). Thyroid gland was no more painful and no signs of inflammation were found in the laboratory evaluation. Both, TSHR- (3.7 U/l, norm < 1.8) and TPO-antibodies (134 U/ml, norm <60) became positive. Thyroid technetium-99m scan showed an increased uptake now in both lobes (1.5% in the right and 2.9% in the left lobe, respectively), suggesting Graves’ disease as cause of hyperthyroidism. Radioactive iodine therapy resulted in hypothyroidism and lifelong levothyroxine substitution therapy.

Conclusion

In this patient with an incidental autonomous thyroid nodule, subacute thyroiditis induced thyroid autoimmunity and triggered Graves’ disease.

Nothing to Disclose: PW, MB, JC

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