Gestational transient thyrotoxicosis — SCE Endocrinology MCQ

Correct answer: B — Gestational transient thyrotoxicosis driven by high hCG

The best answer is “Gestational transient thyrotoxicosis driven by high hCG”. Early gestation, severe vomiting, mild biochemical thyrotoxicosis and absent Graves features are characteristic of hCG-mediated gestational transient thyrotoxicosis, which usually improves as hCG falls. “New Graves disease despite the absent clinical and antibody features” is less appropriate because Graves disease remains a differential but is less likely without goitre, orbitopathy or TRAb positivity “TSH-secreting pituitary adenoma causing central hyperthyroidism” is less appropriate because a TSH-secreting adenoma produces an inappropriately normal or raised TSH rather than a suppressed value “Toxic multinodular goitre with autonomous thyroid hormone secretion” is less appropriate because multinodular autonomy is not supported by the age, examination or pregnancy-linked presentation “Factitious levothyroxine exposure as the expected cause of hyperemesis” is less appropriate because exogenous hormone use is not the expected explanation for the tightly linked hyperemesis syndrome

Reference: Endotext: Hyperthyroidism in pregnancy. https://www.ncbi.nlm.nih.gov/books/NBK279107/