A patient on excessive/high-dose levothyroxine may develop signs overlapping with hyperthyroidism. Which finding, though more specifically an autoimmune (Graves') feature than a direct drug effect, is sometimes discussed in this context?

True exophthalmos is an autoimmune (Graves' orbitopathy) phenomenon involving orbital tissue inflammation, not a direct pharmacologic effect of levothyroxine itself — but excess levothyroxine produces a thyrotoxic state (tachycardia, weight loss, heat intolerance, tremor, anxiety) that clinically overlaps with hyperthyroid presentations students are commonly asked to recognize, which is likely why this distractor appears paired with levothyroxine in exam questions.