Case Presentation: A 49-year-old female presented to the emergency department with three weeks of lower extremity swelling, new abdominal distension, and weight loss. She had no relevant past medical history, but she recently established care with a functional medicine provider who prescribed her multiple herbal supplements around the time of her symptom onset. On arrival, she was found to be in sinus tachycardia with a heart rate in the 160s. The rest of her vital signs were within normal limits. Physical examination revealed a cachectic appearance, three-plus pitting edema in her lower extremities bilaterally, abdominal distention with dullness to percussion, jugular venous distention, hepatojugular reflux, bilateral rales over the lower lung fields, and some right-sided thyroid gland prominence. Her serum workup revealed normal kidney and liver function tests. Additional serologic workup was significant for thyroid-stimulating hormone (TSH) of 0.01 mcIU/mL (normal 0.27-4.20 mcIU/mL), free thyroxine (FT4) of 4.9 ng/dL (normal 0.7-1.7 ng/dL), and free triiodothyronine (FT3) of 13.0 pg/mL (2.0-4.4 pg/mL), consistent with thyrotoxicosis. A thyroid ultrasound revealed an enlarged, heterogeneous, hypervascular thyroid gland with no nodules. The patient was initially treated with 100 mg of propylthiouracil (PTU) and 1 mg of propranolol intravenously before being transitioned to atenolol 50 mg daily and methimazole 10 mg daily within 24 hours. A review of the patient’s home supplements found that one contained sheep thyroid hormone. She showed rapid improvement in her symptoms and lab values following discontinuation of the supplement, implicating the supplement as the cause of the patient’s severe symptoms. She was discharged home on atenolol and methimazole after nine days. Her FT3 normalized before discharge, but the FT4 remained minimally elevated. The Thyroid Stimulating Immunoglobulin (TSI) index later resulted as 3.6 (normal TSI index
Discussion: Adverse events from over-the-counter supplements contribute to over 23,000 emergency department visits and more than 2,100 hospitalizations annually in the United States. These supplements do not require a prescription, are underregulated, and do not have to undergo safety testing, giving patients access to substances that could potentially cause them harm (1). Supplement-induced thyrotoxicosis is a rare condition previously reported with weight loss supplements (2) and alternative medicine herbs (3). These supplements pose a risk to all patients, especially those with underlying or undiagnosed medical conditions. This case highlights that supplements are not always benign additions to a patient’s medical care, so it is important to take a thorough history, identify if a patient is taking supplements, and consider whether the supplements are contributing to their current condition.
Conclusions: Adverse events from over-the-counter supplements are relatively common, so it is important for physicians to be aware of the side effects patients may experience when taking them. It is important to consider how a patient’s home supplements may be related to their presenting symptoms. This case highlights a unique diagnosis of supplement-induced thyrotoxicosis that revealed a patient’s underlying Graves’ disease.