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Q1: Definition and diagnosis (2 min)
- Distinguish hyperthyroidism (endogenous overproduction by the gland) from thyrotoxicosis (excess circulating hormone from any source). Why does this matter? (Antithyroid drugs work only when there is active synthesis — useless in destructive thyroiditis.)
- What is the biochemical signature? (Suppressed TSH + raised free T4/T3.) Define T3 toxicosis and subclinical hyperthyroidism biochemically.
- How would you confirm the cause in a 34-year-old with a diffuse goitre and proptosis? (TRAb confirms Graves; uptake scan if unclear — diffuse high uptake in Graves, low in thyroiditis.)
- Always measure free T3 when TSH is suppressed but free T4 is normal.
Q2: Causes and classification (2 min)
- Classify by uptake: high = Graves, TMNG, toxic adenoma, TSHoma, hCG; low = thyroiditis (subacute, silent, postpartum), amiodarone type 2, factitious.
- Distinguish toxic adenoma (Plummer disease) from TMNG and Graves (single hot nodule; no eye disease; no TRAb).
- What is Jod-Basedow? (Iodine-induced hyperthyroidism in an autonomous gland — high uptake, thionamide-responsive.) And amiodarone type 1 vs type 2? (Type 1 = iodine-induced, thionamides; type 2 = destructive, steroids.)
Q3: Management (3 min)
- Three definitive treatments for Graves: thionamides, RAI, surgery. First-line for a young woman with Graves? (Carbimazole 20 to 30 mg daily, titration regimen, 12 to 18 months — 40 to 50% remission.)
- Why methimazole/carbimazole over PTU in general? (PTU is hepatotoxic; reserve for first-trimester pregnancy and thyroid storm.)
- Contraindications to RAI? (Pregnancy, lactation, active/moderate-severe Graves orbitopathy.)
- Pre-operative preparation for thyroidectomy? (Render euthyroid with carbimazole + beta-blocker + Lugol's iodine/SSKI 7 to 14 days — Wolff-Chaikoff, reduces vascularity.)
- Post-thyroidectomy complications? (Hypocalcaemia — hypoparathyroidism; recurrent laryngeal nerve — hoarseness; haematoma — airway; storm if under-prepared.)
- The agranulocytosis counselling point: any sore throat/fever on a thionamide — stop the drug, check FBC immediately.
Q4: Thyroid storm (2 min)
- Clinical triad: hyperpyrexia + tachyarrhythmia + altered mental status.
- The management bundle and the critical pharmacological order: thionamide (PTU) FIRST, then iodine ONE HOUR LATER (block synthesis before feeding substrate), beta-blocker, hydrocortisone, paracetamol (NOT aspirin — why?), treat the precipitant, ICU.
- Burch-Wartofsky score: 45 and above = storm; 25 to 44 = impending.
- Refractory options: plasmapheresis, cholestyramine, emergency thyroidectomy.
Q5: Special situations (1 min)
- Pregnancy: PTU first trimester, carbimazole second/third; measure maternal TRAb to predict fetal/neonatal hyperthyroidism; RAI is absolutely contraindicated.
- Apathetic hyperthyroidism in the elderly: AF, weight loss, apathy — check TSH.
- Thyrotoxic periodic paralysis: young Asian males, hypokalaemic, propranolol + cautious potassium.