Work-up of a thyroid nodule
- TSH
- Low → isotope scan; a "hot" nodule is almost never malignant and needs no FNA
- Normal or high → ultrasound
- Ultrasound with a risk score (ACR TI-RADS or BTA U1–U5) decides whether to aspirate
- FNA cytology under ultrasound, reported by Bethesda (or the UK Thy system)
- Surgery according to cytology and risk
Ultrasound features
| Suggests benign | Suggests malignancy |
|---|---|
| Purely cystic | Solid and hypoechoic |
| Spongiform | Taller than wide on transverse view |
| Hyperechoic with a halo | Irregular or lobulated margins, extrathyroidal extension |
| Eggshell calcification | Microcalcifications |
| Abnormal cervical lymph nodes |
Cytology systems
| Bethesda | UK Thy | Meaning |
|---|---|---|
| I | Thy1 / Thy1c | Non-diagnostic / cystic |
| II | Thy2 / Thy2c | Benign |
| III | Thy3a | Atypia |
| IV | Thy3f | Follicular neoplasm |
| V | Thy4 | Suspicious for malignancy |
| VI | Thy5 | Malignant |
Thyroid cancers
| Type | Frequency | Cell | Spread | Marker | Key treatment |
|---|---|---|---|---|---|
| Papillary | About 80% | Follicular | Lymph nodes | Thyroglobulin | Lobectomy or total thyroidectomy, radioiodine by risk |
| Follicular | 10–15% | Follicular | Blood — lung, bone | Thyroglobulin | Diagnostic lobectomy; completion thyroidectomy and radioiodine if invasive |
| Medullary | About 5% | Parafollicular C cells | Nodes and blood | Calcitonin, CEA | Total thyroidectomy and central neck dissection; screen for RET and phaeochromocytoma first |
| Anaplastic | Under 2% | Dedifferentiated | Local invasion, rapid | — | Often palliative; BRAF-targeted therapy for BRAF V600E tumours |
| Lymphoma | Under 5% | Lymphocytes | Local, nodal | — | Chemotherapy and radiotherapy, not surgery; core biopsy to diagnose |
Operations
| Operation | What is removed | Use |
|---|---|---|
| Lobectomy (hemithyroidectomy) | One lobe and the isthmus | Indeterminate or benign solitary nodule, toxic adenoma, low-risk cancer 1–4 cm |
| Total thyroidectomy | Both lobes and isthmus | Multinodular goitre, Graves' disease, cancer over 4 cm or with nodes |
| Near-total thyroidectomy | All but under 1 g near the nerve on one side | Protects a nerve or parathyroid |
| Subtotal thyroidectomy | Leaves remnants on both sides | Largely abandoned — recurrence and difficult reoperation |
| Completion thyroidectomy | Remaining lobe after lobectomy | Cancer found on histology needing radioiodine |
Preparing a thyrotoxic patient for surgery
- Carbimazole 20–40 mg daily until free T4 is normal (usually 4–8 weeks); propylthiouracil in the first trimester of pregnancy
- Propranolol 40 mg three to four times daily for symptoms; continue for 5–7 days after surgery
- Potassium iodide or Lugol's iodine for 7–10 days before surgery in Graves' disease only — reduces vascularity and hormone release
- Emergency surgery in an uncontrolled patient: propranolol, potassium iodide, dexamethasone and cholestyramine under anaesthetic and endocrine care
After thyroidectomy
Hypocalcaemia
| Feature | Detail |
|---|---|
| Cause | Parathyroid bruising, devascularisation or removal; hungry bone syndrome after long-standing hyperthyroidism |
| Symptoms | Perioral and fingertip tingling, cramps, carpopedal spasm, laryngospasm, seizures, prolonged QT |
| Signs | Chvostek's — tapping the facial nerve in front of the ear twitches the upper lip. Trousseau's — blood pressure cuff above systolic for 3 minutes causes carpal spasm |
| Check | Adjusted calcium and PTH on the morning after surgery; a low PTH predicts hypocalcaemia |
| Mild (calcium over 1.9 mmol/L, few symptoms) | Oral calcium carbonate 1–1.5 g three times daily, with alfacalcidol if PTH is low |
| Severe (below 1.9 mmol/L, tetany, prolonged QT) | 10–20 mL of 10% calcium gluconate in 50–100 mL of 5% glucose IV over 10 minutes with ECG monitoring, then an infusion; check magnesium |
Thyroid storm
- Features: fever above 38.5 °C, tachycardia or atrial fibrillation, heart failure, agitation or delirium, vomiting and diarrhoea, jaundice
- Treatment in ICU: cooling and fluids; propranolol (or esmolol); propylthiouracil 500–1,000 mg loading dose then 250 mg 4-hourly; potassium iodide at least 1 hour after propylthiouracil; hydrocortisone 300 mg then 100 mg 8-hourly; treat the trigger
Post-thyroidectomy haematoma
Examiner questions
References
- O'Connell PR, McCaskie AW, Sayers RD, eds. Bailey & Love's Short Practice of Surgery. 28th ed. Boca Raton: CRC Press; 2023.
- Haugen BR, Alexander EK, Bible KC, et al. 2015 American Thyroid Association management guidelines for adult patients with thyroid nodules and differentiated thyroid cancer. Thyroid. 2016;26:1–133.
- Tessler FN, Middleton WD, Grant EG, et al. ACR Thyroid Imaging, Reporting and Data System (TI-RADS): white paper of the ACR TI-RADS committee. Journal of the American College of Radiology. 2017;14:587–95.
- Ali SZ, Baloch ZW, Cochand-Priollet B, et al. The 2023 Bethesda System for Reporting Thyroid Cytopathology. Thyroid. 2023;33:1039–44.