Paper II — 2025 March (Supplementary) (2010 Scheme) — Q2
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Paper II
2025 March (Supplementary) (2010 Scheme)
Question
A 32years old woman, presented with complaints of weight loss, palpitations,
sweating, irregular menses and occasional tremors of hands since 2-3 months.
Clinical examination revealed a diffusely enlarged thyroid gland and blood tests
showed decreased TSH. She was started on medication for Grave’s disease.
(a) What are the different pharmacological agents used for the treatment of
hyperthyroidism 3 mark(s)
(b) What is the mechanism of action of Thioamides 1 mark(s)
Beta-blockers — Propranolol (symptomatic adjunct for adrenergic symptoms)
b) Mechanism of action of thioamides
Thioamides inhibit thyroid peroxidase, blocking oxidation/organification of iodide and coupling of iodotyrosines, reducing T3/T4 synthesis; propylthiouracil additionally inhibits peripheral T4-to-T3 conversion.
c) Note on radioactive iodine
I-131 is taken up by the thyroid via the sodium-iodide symporter, concentrating specifically in thyroid tissue, where beta-particle emission causes localized cellular damage/destruction over weeks. Used for definitive treatment of Graves’ disease and toxic nodular goitre. The eventual, expected outcome of adequate treatment is hypothyroidism, requiring lifelong levothyroxine replacement. Absolutely contraindicated in pregnancy — crosses the placenta and concentrates in the fetal thyroid once it becomes iodine-avid, causing fetal hypothyroidism/cretinism.
