SUN-503 Thyroid Storm Followed by ATD Induced Agranulocytosis in Late Pregnancy: A Management Dilemma

Background: Management of Graves’ disease (GD) in pregnancy presents challenges. Thionamide Antithyroid drugs are the treatment for GD hyperthyroidism with goal of achieving mild but persistent hyperthyroidism and avoiding over-treatment in pregnancy. ATD Induced Agranulocytosis is a rare but serous side effect and presents management dilemmas. Clinical Case: A 37-year-old woman with history of Graves’ disease was admitted to our hospital at gestational age of 34 weeks with fever, palpitations and diarrhea. Burch-Wartofsky Point Scale was 35 concerning for impending thyroid storm. She had been diagnosed with hyperthyroidism 6 weeks into her pregnancy, initially treated with PTU which was then changed to methimazole in 2nd trimester. A work up for infection and PE was negative. Non-compliance was suspected, methimazole was resumed, and hydrocortisone and propranolol were added. After 2 days, her vital signs and free hormone levels normalized. Her methimazole dose was decreased and she was discharged home in a stable condition. Five days after her discharge, she presented with sore throat, fever and chills. She had an absolute neutrophil count (ANC) of 0 and a positive rapid strep test. ATD Induced Agranulocytosis was suspected. Her labs showed elevated fT3 of 4.5(nl 1.7–3.7), normal fT4 and suppressed TSH with <0.01(nl 0.3–4.9). A CT scan of the neck showed no evidence of retropharyngeal or thyroid abscess. Methimazole was stopped and she was started on glucocorticoids (initially betamethasone for fetal lung maturity, then switched to prednisone) and cholestyramine. She was also started on Cefepime and G-CSF for her neutropenia. A thyroid ultrasound showed enlarged and hypervascular gland. TSI was 157%(nl. <122%), and thyroglobulin 155 ng/ml (nl. <33 ng/ml). After 4 days, her ANC started to recover. Simultaneously, she started to show worsening thyrotoxicosis but remined hemodynamically stable. A decision to induce labor was then made and was successfully done on the 6(th) day of her admission. Post-delivery, PTU was started at low dose along with SSKI to prepare her for total thyroidectomy which was done on day 3 post-delivery. Post-thyroidectomy, she had an uncomplicated course and was discharged on levothyroxine. Her child did well with no evidence of thyroid disease. Conclusion: We present a unique case of thyrotoxicosis in late pregnancy complicated by ATD Induced Agranulocytosis. Given the high risk of thyroid surgery during pregnancy, our multi-disciplinary team approach opted for labor induction, followed by preparation for thyroidectomy and subsequent surgery. Individualization of management approach using a multi-disciplinary team with emphasis on maternal and fetal well-being is of paramount importance with such challenging presentations.