SAT-518 Progression of Graves Disease to Hashimoto’s Thyroiditis Following Alemtuzumab Therapy for Multiple Sclerosis

Introduction: Alemtuzumab, an anti-CD52 monoclonal antibody used in the treatment of relapsing-remitting multiple sclerosis is most commonly associated with Graves disease, but autoimmune hypothyroidism may also be seen. We present an unusual case where both were present in the same patient and progression from hyperthyroidism to hypothyroidism was seen within only a few months. Clinical Case: A 33-year-old female referred to Endocrinology clinic for evaluation of hyperthyroidism. She was complaining of palpitations, tremors, increased sweating, heat intolerance, and unintentional weight loss for 3 months. She received 2 cycles of alemtuzumab treatments over the last 21 months for her multiple sclerosis. Last treatment was 8 months before she developed hyperthyroid symptoms. Patient had no prior history of thyroid disorder. Thyroid stimulating hormone (TSH) level was within normal range before alemtuzumab was administered. TSH was monitored periodically and was normal till 8 months after receiving alemtuzumab therapy. Physical exam was remarkable for diffuse enlarged thyroid, not tender, without palpated thyroid nodules but with thyroid bruit. No proptosis was present. Thyroid function tests obtained by her primary care physician were consistent with hyperthyroidism. Patient found to have suppressed TSH 24.9 ug/dL [5.5 - 11.0 ug/dL]. Further workup revealed elevated Free T3, 10.90 [2.77 - 5.27 pg/mL] and elevated free T4 > 6.99 ng/dL [0.78 - 2.19 ng/dL]. Thyrotropin receptor antibody (TR Ab) was elevated as well at 3.43 IU/L [