A Systematic Approach to Goitre

A presentation describing classification of goitres, common thyroid disorders, basis of investigations and treatment options currently available for treatment of goitres, including the novel technique of transoral thyroidectomy.

1. A Systematic Approach to Goitre Chea Chan Hooi MD, MS, FMAS, DMAS, CMIA, AMM Borneo Medical Centre (Miri) 23rd November 2019

2. Content Definition Anatomy Function Classification Clinical features Investigations Treatment options Medicine Surgery Radioiodine Q&A

3. Definition Goitre Enlargement of thyroid gland Thyroxine (T4) Hormone produced by thyroid gland Triiodotyronine (T3) The active form of thyroid hormone Hypothyroidism Inadequate hormone Hyperthyroidism Excessive hormone Thyrotoxicosis Excessive hormone with fullblown symptoms

4. Anatomy Butterfly shaped 30 - 50% of population have pyramidal lobe

5. Function Cardiac Increase heart rate Increase cardiac output Respiratory Increase respiration rate Biochemical Increase basal metabolic rate Increase protein and carbohydrate metabolism Nervous system Potentiates brain development Increase sympathetic activity Reproductive Increase endometrial thickness

6. Classification of thyroid disorders Anatomical Solitary nodule Dominant nodule of MNG Multinodular goitre (MNG) Diffuse goitre Functional Hyperthyroidism ( ↑) Hypothyroidism ( ↓) Etiology Infective Neoplastic Benign Malignant Degenerative Inflamatory Congenital Autoimmune Traumatic Iatrogenic Vascular Endocrinopathy

7. Thyroid cancers By histology Follicular cells Differentiated Follicular Papillary Poorly differentiated Undifferentiated (Anaplastic) Non-follicular cells Parafollicular - Medullary TC Lymphatics - L ymphoma

8. PTC FTC Etiology Sporadic Endemic goitre Incidence Traditionally PTC < FTC but PTC incidence rising Age (y/o) 20 - 40 30 - 50 Diagnosis Goitre with lymph node mets Goitre with hematogenous mets Microscopy FNAC - Orphan Annie eye nuclei, Psammoma bodies HPE - Angioinvasion, capsular invasion Spread Lymphatic Hematogenous Recurrence rate 20% 30% Death from disease 10% 25%

9. Thyroiditis Etiology Infective Suppurative (rare) Inflamatory S ubacute granulomatous , radiation Auto-immune Hashimoto, post-partum, subacute lymphocytic Traumatic Direct trauma Iatrogenic Amiodarone, interferon, lithium, radiotherapy, RAI (1%) Idiopathic Riedel Symptom Painful > P ainless Hyper (3-6/52) --> hypo (3-6/12) --> euthyroid Women > men

10. History Compressive symptoms Malignancy component Risk factors Red flags Metastatic symptoms Thyroid status Hyper or hypothyroidism symptoms Past thyroid or any neck surgery

11. Physical examination Goitre? Morphology STN MNG Dominant nodule of MNG Diffuse Signs of malignancy Thyroid function status Eye signs General thyrotoxicosis Graves disease Metastatic signs

12. Pemberton sign

13. Graves eye signs NO SPECS Class 0 None Class 1 Only signs (lid retraction ± lag) Class 2 Soft tissue (conjunctival & lids edema, injection) Class 3 Proptosis Class 4 Extraocular muscles involvement Class 5 Corneal involvement Class 6 Sight loss (usually CNII)

14. Imaging - Ultrasonography The first investigation of choice Role Screening - exposed to neck radiation, FH of throid ca Diagnostic & guide FNAC Follow-up Therapeutic in guiding RFA TI-RADS score

15. Histopathology FNAC The standard Image-guided to target solid component of lesion Can be therapeutical for cyst fluid aspiration Not applicable for follicular neoplasm Core needle biopsy Anaplastic or poorly differentiated TC Seldom Excision/Incision biopsy Discrete lymph nodes Cutaneous extension

16. Bethesda classification

17. Other tests TFT TSH T4 T3 Iodine deficiency, in the earliest stages or relapse of thyrotoxicosis T3:T4 ratio low in destruction-induced thyrotoxicosis (thyroiditis) vs high in Graves Antibodies Anti-TPO Anti-Tg Thyroglobulin ECG CXR CT scan

18. Treatment options Cancer Surgery Radioiodine Hyperthyroidism Medical Radioiodine Surgery Thyroiditis Medical Less is more

19. Anti-thyroid drugs Carbimazole is usually the first choice, more rapid control, option of OD dose, less tablet burden PTU recommended in 1st trimester of pregnancy, less teratogenic, less secretion in breast milk, more hepatotoxic Adverse effect Altered taste sensation, rash (1:20), agranulocytosis (1: 1000 - 3000, 2PTU:CMZ) Strategy Titration Block & replace Higher risk for relapse Men, <40 y/o, large goitre, eye involvment, high starting TSI level and drug dosage needed, previous relapse Smoking

20. Thyroidectomy By extent Hemithyroidectomy/

21. By access Open Via collarneck incision Endoscopic Remote Facelift incision approach Breast-axillary approach Locoregional Transoral

22. Transoral thyroidectomy

23. Complications post thyroidectomy Early Haemorrhage RLN injury SSI Other adjacent organ injury Surgical hypothyroidism Surgical hypocalcaemia Tracheomalacia Late Chronic hypocalcaemia Conscious about scar

24. Radioiodine therapy I-131 Thyroid cells will take up iodine from blood stream Indications Adjuvant post total thyroidectomy for DTC Graves disease: 1st choice if younger, large goitre, very high T4, high TSI Risk of precipitating thyroid storm: elderly, poorly controlled thyroid function Absolute contraindication: pregnancy

25. Precautions Stop ATDs 2/52 prior or administer rhTSH Only in SGH, Kuching Do not conceive, do not breast feed x 6/12 Minimise contact with others, especially small children and pregnant women Drink plenty of water Clean the toilet thoroughly regularly and flush 3x after use

26. Conclusion Goitre is common Variety of morphologic presentation, etiologies Beware of red flag symptoms that suggest malignancy Anatomical, functional & diagnostic clinical assessment Transoral thyroidectomy is the next frontier in thyroid surgery

27. TQ! Q&A?