A patient on levothyroxine for hypothyroidism is found to have excessive thyroxine levels. Which sign would you expect?

Correct answer: B. Tachycardia, heat intolerance, tremor and weight loss

• A. EXOPHTHALMOS is NOT caused by excess thyroid hormone. It is caused by the autoantibody-driven orbital inflammation specific to GRAVES DISEASE, and it does not occur from taking too much levothyroxine.
• B. CORRECT. Over-replacement with levothyroxine produces IATROGENIC THYROTOXICOSIS: tachycardia and palpitations, atrial fibrillation in older patients, heat intolerance, sweating, fine tremor, anxiety, insomnia, weight loss despite good appetite, and accelerated bone loss. These are the hypermetabolic effects of excess circulating thyroid hormone.
• C. Fatigue and cold intolerance likewise indicate insufficient replacement.
• D. Constipation and weight gain are features of UNDER-treatment (persistent hypothyroidism), the opposite problem.

Note: ⚠️ The source keyed exophthalmos. This is a valuable distinction: exophthalmos is a Graves-specific autoimmune orbitopathy, not a manifestation of thyrotoxicosis in general. Please correct in the group file. Dental relevance: avoid or limit epinephrine in an uncontrolled thyrotoxic patient, and defer elective care.