SAT-474 Amiodarone-Induced Thyrotoxicosis After Weight Loss Following Sleeve Gastrectomy

AMIODARONE-INDUCED THYROTOXICOSIS AFTER WEIGHT LOSS FOLLOWING SLEEVE GASTRECTOMY INTRODUCTION: Bariatric surgeries have shown major health benefits improvement in co-morbidities such as HTN and DM. We are less familiar with how these surgeries affect the pharmacokinetics of drugs.(1,2) CLINICAL CASE: Our patient is a 65-year-old man with a fib/v tach and no prior thyroid history. He was on amiodarone 200 mg daily since September 2016. He had sleeve gastrectomy in March 2019 at weight 380 lbs. By June 2019, weight was 278 lbs. In June 2019, he had palpitations, diarrhea, and heat intolerance for one month. Labs showed: TSH <0.01 (0.4 – 4.5 MCIU/L), FT4 6.5 (0.8 – 1.8 NG/DL), and TT3 309 (76 – 181 NG/DL). Other labs: TPO antibodies <1 IU/mL (<9 IU/mL) TSI <89 (<140% baseline). Thyroid sonogram was heterogeneous without nodule He started Methimazole (MMI) 20mg BID and Prednisone 40mg daily. In the next seven weeks, symptoms and TFTs improved. FT4 was 3.1 NG/DL, TT3 was 85 NG/DL, but TSH remained <0.01 MCIU/L. Because of the rapid improvement, he was felt to have type 2 AIT (destructive thyroiditis). MMI was quickly tapered. Prednisone was tapered to 30mg daily. At week 8, he was hospitalized for septic shock from diverticulitis and perianal abscess. He also had leukopenia attributed to MMI and sepsis. MMI was stopped. Amiodarone was stopped by cardiology. TFTs during hospitalization improved on only steroids: TSH was 0.01 MCIU/ML, FT4 was 2.34 NG/DL, and TT3 was 0.56 NG/ML. He was discharged on Prednisone 30mg daily with plans to taper off steroids. CONCLUSION: Our patient is the second reported case of AIT after bariatric surgery-induced weight loss. Amiodarone is a highly lipophilic drug that accumulates in adipose tissue. Rapid weight loss may result in the release of large amounts of amiodarone into the circulation with resultant thyrotoxicosis. As clinicians, we should be aware that patients who undergo bariatric surgery are at risk for complications that are not only directly related to the operation but also related to rapid weight loss that affects how the body handles drugs. REFERENCES 1. Bourron O, Ciangura C, Bouillot J-L, Massias L, Poitou C, Oppert J-M. Amiodarone-induced hyperthyroidism during massive weight loss following gastric bypass. Obes Surg. 2007;17(11):1525–1528. http://www.ncbi.nlm.nih.gov/pubmed/18219784. Accessed September 21, 2019. 2. Geraldo M de SP, Fonseca FLA, Gouveia MR de FV, Feder D. The use of drugs in patients who have undergone bariatric surgery. Int J Gen Med. 2014;7:219–224. doi:10.2147/IJGM.S55332