PART 17 — THYROID

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Study use: High-yield revision of thyroid embryology, anatomy, hormone synthesis, thyroid-function interpretation, goiter, hyperthyroidism, hypothyroidism, thyroiditis, thyroid nodules, thyroid cancer, radioactive iodine, thyroidectomy, and endocrine emergencies. Management should be interpreted according to age, pregnancy/lactation status, cardiac status, ultrasound/cytology risk, tumor stage, airway status, molecular findings, and current endocrine/endocrine-surgery guidance.

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Priority Guide: 🔴 Core / Must Know | 🟠 Important | 🟡 Additional

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🎯 High-Yield Overview

Follicular cells → T3/T4; C cells → calcitonin
TPO performs oxidation, organification and coupling
Primary hypothyroidism → TSH↑, FT4↓; primary hyperthyroidism → TSH↓, FT4/T3↑
Graves disease → TRAb/TSI + diffuse uptake ± thyroid eye disease
Painful postviral thyroid + ESR/CRP↑ + low uptake → subacute (De Quervain) thyroiditis
Thyroid nodule → TSH + high-resolution ultrasound; low TSH → radionuclide scan; suspicious euthyroid/hypothyroid nodule → risk-based US-guided FNA
Papillary → Orphan Annie nuclei/psammoma/lymphatic spread; follicular → capsular/vascular invasion/hematogenous spread
Medullary → C cells + calcitonin + amyloid + RET; anaplastic → rapidly enlarging invasive mass + urgent molecular testing
Post-thyroidectomy neck swelling + dyspnea/stridor → compressive hematoma = airway emergency
Superior pole surgery risks EBSLN → loss of high pitch; posterior/Berry region risks RLN → hoarseness or bilateral stridor

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RED FLAGS: Rapidly enlarging thyroid/neck mass, stridor, hemoptysis, progressive dysphagia, vocal-fold paralysis, severe thyrotoxicosis with CNS/cardiovascular dysfunction, severe hypothyroidism with hypothermia/altered mental status, or post-thyroidectomy neck swelling requires urgent specialist/airway assessment.

PART 17 — THYROID

🎯 High-Yield Overview

1. THYROID EMBRYOLOGY & ANATOMY

2. THYROID HORMONE SYNTHESIS & FUNCTION TESTS

3. GOITER & RETROSTERNAL GOITER

4. HYPERTHYROIDISM, GRAVES & AUTONOMOUS NODULES