A Systematic Approach to Goitre

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 - Lymphoma

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 Subacute granulomatous, radiation • Auto-immune Hashimoto, post-partum, subacute lymphocytic • Traumatic Direct trauma • Iatrogenic Amiodarone, interferon, lithium, radiotherapy, RAI (1%) • Idiopathic Riedel • Symptom • Painful > Painless • 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?