SAT-497 Conversion of Hashimoto’s Thyroiditis to Grave’s Disease: A Case Report

Introduction: Hashimoto’s thyroiditis and Grave’s disease are common causes for autoimmune thyroid disease. Conversion from Grave’s disease to hypothyroidism have been previously reported in literature. But development of Grave’s disease after a long standing hypothyroidism rarely occurs.Case report: a 22 -year-old Saudi pregnant female patient, was diagnosed with subclinical hypothyroidism with positive anti -thyroid peroxidase antibodies (Anti-TPO) in 2009. She was started on thyroxin and eventually became euthyroid with normal TSH levels till 2016. During subsequent follow-ups, patient was increasingly complaining of palpitations, weight loss and fine tremors. Thyroid function revealed increasingly suppressed TSH levels and over-replacement was suspected. Thyroxin dose was then gradually reduced and finally stopped for few months. Yet her symptoms persisted. Repeated thyroid function showed suppressed TSH level and elevated T4, T3 levels in keeping with overt hyperthyroidism. Thyroid scan further confirmed the diagnosis with diffuse thyroid uptake suggestive of Grave’s disease.Patient was started on medical treatment initially, then successfully treated with radioactive ablation.Conclusion: Although it rarely occurs, possibility of conversion from hypothyroidism to hyperthyroidism should always be kept in mind while treating hypothyroid patients with persistent clinical or biochemical evidence of hyperthyroidism despite dose reduction.References:[1] McLachlan SM. Rapoport B. Thyrotropin-blocking autoantibodies and thyroid-stimulating autoantibodies: Potential mechanisms involved in the pendulum swinging from hypothyroidism to hyperthyroidism or vice versa. Thyroid. 2013;23(1):14-24.[2] Ohye H, Nishihara E, Sasaki I, et al. Four cases of Graves’ disease which developed after painful Hashimoto’s thyroiditis. Intern Med. 2006;45(6):385-9.