1. THYROID GLAND Begashaw M (MD)

2. Anatomy Anatomy

4. Goiter  Generalized enlargement of the thyroid gland which is normally impalpable

5. Classification 1. Simple-Euthyroid _Diffuse hyper plastic _(Multinodular) 2. Toxic _Diffuse - Grave’s disease _Nodular _Toxic adenoma 3. Neoplastic _ Benign _Malignant 4. Inflammatory _Autoimmune _Infectious _Acute –bacterial/viral _Chronic -tuberculous

6. Thyroid lesions

7. Simple Goiter  Patho - physiology enlargement of the thyroid gland stimulation of the thyroid gland by high levels of circulating TSH common in Females

8. Etiology _Iodine deficiency _Goitrogens  cabagge _Drugs  iodine,lithium _Defective hormone synthesis _peripheral resistance to thyroid hormone

9. Diffuse hyper-plastic goiter Persistent stimulation by TSH causes diffuse hyperplasia of the thyroid gland Soft, diffuse & large Usually occurs at puberty, pregnancy Areas of active lobule & inactive lobules

10. Goiter –simple

11. Nodular goiter  Nodular goiter -solitary -multinodular  Nodule -colloid when filled with colloid -cellular  Secondary changes -cystic degeneration -hemorrhage -calcification

12. Diagnosis  Clinical presentation _Discrete swelling in one lobe -Solitary  isolated -Dominant nodule  abnormality Elsewhere _smooth, firm _painless _moves with swallowing _ euthyroid

13. Investigation  TFT  T3, T4, TSH  CXR/Thoracic inlet x-rays  calcification, tracheal deviation & compression  Thyroid antibody titers  FNA  Cytology

14. Complications Compression  stridor, dysphagia, pain, & hoarseness Secondary thyrotoxicosis Carcinoma  malignant changes of the follicular type

15. Retrosternal goiter

16. Prevention Introduction of iodized salt Thyroxin of 0.1mg daily Nodular stage is irreversible

17. Indication of surgery Cosmetic Tracheal compression When malignancy cannot be excluded  Options of surgery _Near total thyroidectomy _Subtotal thyroidectomy

18. Toxic goiters  Thyrotoxicosis - increased metabolic rate due to high level of circulating thyroid hormone  8X more commonly seen in females than males

19. Clinical features  symptoms _Loss of weight in spite of good appetite _preference of cold _Palpitation _Tiredness _Emotional liability  signs _excitability _presence of goiter _hot & moist palms _exophthalmus in primary type _tachycardia with cardiac arrhythmia

20. Diffuse Toxic Goiter  Graves Disease Is a diffuse vascular goiter appearing at the same time as symptoms of hyperthyroidism Occurs in younger women Frequently associated with eye signs Hypertrophy & hyperplasia are due to abnormal TS antibodies F > M = 7:1

21. Graves disease

22. Toxic nodular goiter A simple nodular goiter is present for a long time before hyperthyroidism  secondary thyrotoxicosis Seen in middle aged/elderly people Less frequently associated with eye signs Nodules are inactive Intermediate thyroid tissue is involved in hyper secretion

23. Toxic nodule Solitary hyperactive nodule which may be part of a generalized nodularity or a true toxic adenoma is autonomous not due to TS antibodies normal thyroid tissue surrounding the nodule is suppressed & inactive

24. Diagnosis  Clinical picture  T3,T4,TSH  Isotope scanning

25. Treatment Antithyroid drugs Surgery Radioiodine

26. Anti thyroid Drugs used to resume the patient to a euthyroid state  maintain this for a prolonged period cannot cure a toxic nodule

27. Surgery Preoperatively, the patient must be prepared with antithyroid drugs so that the patient becomes euthyroid Subtotal thyroidectomy

28. Post-operative complications Hemorrhage Respiratory obstruction Recurrent laryngeal nerve paralysis Thyroid insufficiency Parathyroid insufficiency Thyrotoxic crisis (storm) Wound infection

29. Thyroid Tumour  Benign  Follicular adenoma  Malignant  Primary - Epithelial  Follicular,Papillary,Anaplastic - Para follicular  Medullary - Lymphoid cells  lymphoma  Secondary - Metastatic - Local infiltrations

30. Benign Tumours  Follicular adenomas -solitary nodules -distinction between a follicular carcinoma & adenoma can only be made by histological examination -Treatment  Lobectomy

31. Malignant Tumors  Clinical feature -Thyroid swelling -Enlarged cervical lymph node -papillary carcinoma -Recurrent laryngeal nerve paralysis –locally advanced disease -Anaplastic-hard, irregular, infiltrating

32. Thyroid Cancer

33. Investigations TFT  T3,T4,TSH FNA Antibody assay Radio isotope scanning

34. Treatment/Prognosis _Surgery  total thyroidectomy _Prognosis  Histological type, age, extra thyroid spread, & size of tumor _ Males > 40 yrs of age & Females >50 yrs have worse prognosis _Distant metastatic disease  worse prognosis

35. Anaplastic Carcinoma Mainly in elderly woman Local infiltration Epread by lymphatics & blood stream Extremely lethal tumors with death occurring in most cases within month Present in advanced stages with tracheal obstruction Radiotherapy