Medical Emergencies · patient case question
A patient taking a high dose of levothyroxine presents with heat intolerance, tremor and tachycardia. Which finding would NOT be attributable to the medication?
Patient case: Emergencies and risk assessment
demo: Assorted patients
chief: Several patients present with findings that alter the safety of planned dental care.
history: One patient with well-controlled asthma using albuterol reports her last attack was ten months ago. Another feels faint on being returned to upright. A third has type 1 diabetes and presents unwell with deep rapid breathing and a fruity breath odour.
meds: Albuterol; insulin; various.
findings: Not applicable.
Show answer and explanation
Correct answer: B. Exophthalmos
- A. Weight loss despite a preserved or increased appetite is characteristic of thyrotoxicosis from any cause.
- B. Correct, and this is the exception. Exophthalmos is not caused by excess thyroid hormone. It results from the autoimmune orbitopathy of Graves disease, in which antibodies drive inflammation and glycosaminoglycan deposition in the retro-orbital tissues. A patient over-replaced on levothyroxine becomes thyrotoxic but does not develop protruding eyes.
- C. Heat intolerance follows the increase in basal metabolic rate.
- D. Tachycardia is a direct effect of excess thyroid hormone, which upregulates beta-adrenergic receptors in the myocardium.
Note: The recall author picked exophthalmos and flagged real uncertainty. As a feature of thyroid hormone excess it is wrong; it belongs specifically to Graves disease. Dental relevance: an over-replaced or thyrotoxic patient is at risk of thyroid storm, and elective care with epinephrine should be deferred until they are euthyroid.
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