Overt hypothyroidism — CCFP MCQ

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EasyChronic disease managementOvert hypothyroidismCCFP

A 46-year-old woman presents with fatigue and weight gain. Laboratory investigations show TSH 12 mIU/L (reference 0.45–4.5 mIU/L) and a low free T4 level. She is not pregnant and takes no medications that interact with thyroid hormones. What is the most appropriate next step in management?

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Correct answer: B — Start levothyroxine and recheck TSH after 6–8 weeks for dose titration

Explanation lettering: D = shown as A · E = shown as B · A = shown as C · B = shown as D · C = shown as E

The correct answer is E. In overt primary hypothyroidism (elevated TSH, low free T4, symptoms), levothyroxine monotherapy is the standard of care per CFPC and CMAJ guidance. The average dose is 1.6 μg/kg, and TSH should be rechecked 6–8 weeks later to guide titration to a target TSH of 0.45–4.5 mIU/L (or age-appropriate range). A is wrong: liothyronine monotherapy is not first-line and is reserved for rare cases of levothyroxine intolerance after adequate trials. B is wrong: thyroid ultrasound is not indicated when the diagnosis is already biochemically confirmed; imaging delays necessary treatment. C is wrong: iodine supplementation is for iodine deficiency goiter, not autoimmune hypothyroidism (the most common cause in iodine-sufficient regions). D is wrong: overt symptomatic hypothyroidism with TSH >10 mIU/L requires treatment initiation, not observation.

Reference: College of Family Physicians of Canada. Central hypothyroidism. Canadian Family Physician. 2011;57(6). https://www.cfp.ca/content/57/6/677; CMAJ. Hypothyroidism. 2015;187(3):205. https://www.cmaj.ca/content/187/3/205