A 45-year-old female presents with fever (103°F), severe tachycardia (140 bpm), altered mental status, and a history of Graves' disease not adherent to medication. On examination, she has lid lag and tremor. What is the most crucial initial pharmacological step to inhibit new thyroid hormone synthesis?

The correct answer to the question "A 45-year-old female presents with fever (103°F), severe tachycardia (140 bpm), altered mental status, and a history of Graves' disease not adherent to medication. On examination, she has lid lag and tremor. What is the most crucial initial pharmacological step to inhibit new thyroid hormone synthesis?" is Option C: Administer propylthiouracil (PTU).

The other options — A) Administer propranolol, B) Administer iodine solution (e.g., Lugol's), D) Administer hydrocortisone — are incorrect for this USMLE Exam Prep question. As explained above: In thyroid storm, the most crucial initial pharmacological step to inhibit new thyroid hormone synthesis is administering an antithyroid drug like propylthiouracil (PTU). PTU also inhibits peripheral…