Multinodular goitre

for medical students

1. MULTINODULAR GOITRE ANAKHA RAJENDRAN 23

2. MNG is a discordant growth with functionally and structurally altered thyroid follicles presenting as multiple nodules in thyroid. It maybe due to fluctuation in TSH level; other causes include iodine deficiency, goitrogens , hereditary, dyshormonogenesis .

3. STAGES OF MNG FORMATION Stage of hyperplasia and hypertrophy Stage of fluctuation in TSH Stage of formation of nodules.inactive

4. PATHOGENESIS Persistent TSH stimulation Diffuse hyperplasia of gland ..all active lobules and uniform iodine intake When there is Fluctuation of TSH level Mixed areas of active and inactive lobules develop due to Increased sensitivity of follicular cells to TSH Active lobules become more vascular and hyperplastic Haemorrhages causes central necrosis leaving a rim of active follicles Necrotic lobules coalesce .Nodule formation filled with colloid Internodular tissue is active Many nodules formed -> MNG

5. C/F More common in middle age females Slowly progressive disease Multiple nodules of different sizes Firm, nodular, non tender, moves with deglutition Recent increase in size signifies malignant transformation or haemorrhage . Positive Kocher’s test is due to compression of trachea ( tracheomalacia /scabbard’s trachea) in long standing MNG. Nodule when calcified becomes harder; necrosis softens the nodule. Carotid infiltration Pembertons Sign

6. COMPLICATIONS Secondary thyrotoxicosis(30%) Follicular carcinoma of thyroid(10%) Haemorrhage in a nodule Tracheal obstruction, calcification Cosmetic problem

7. INVESTIGATIONS T3, T4, TSH, US neck, FNAC. (Dominant) XRAY neck- ring calcification, position and compression of trachea Indirect laryngoscopy- vocal cords; occult RLN palsy Radioisotope iodine scan Routine blood investigations, serum calcium CT scan/ MRI – retrosternal extension

8. TREATMENT Surgery preferred – irreversible, complications, cosmetic Total thyroidectomy is preferred Subtotal thyroidectomy (8g) Partial thyroidectomy/ Hartley Dunhill operation Post operative L- thyroxine (fluctuation; recurrence) Prevention- 0.1-0.2mg L- thyroxine , iodine- rich diet, iodized salts,avoid goitrogenic diet and drugs

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