Simple goitre and thyroiditis

For MBBS students

1. Simple goitre & Thyroiditis

2. SIMPLE GOITRE Other names:- Diffuse non-toxic Colloid Juvenile (teenagers) Characteristics:- Soft, symmetrical, diffuse NO nodularity, tenderness, bruit, LNE TFT normal NO anti-thyroid Ab

3. SIMPLE GOITRE Age group:- 15-25 years most common Causes:- Pregnancy Puberty Iodine deficiency Goitrogen intake – Cabbage, cauliflower Inherited thyroid hormone dysgenesis :- Iodine transport, thyroglob synthesis, organification , coupling, iodide regeneration

4. SIMPLE GOITRE Clinical features:- Asymptomatic mainly Noticed by others, self Cosmetic concern Localised pain & swelling ( Spont bleed ) Large goitre - Tracheal compression Esophageal compression

5. SIMPLE GOITRE Examination:- Diffuse, symmetrical enlargement Soft, nontender NO nodules, LNE Pemberton’s sign – raise arms, then Facial congestion Faintness Ext jugular vein compression Substernal goitre

6. SIMPLE GOITRE Investigations:- TFT – r/o hypo/hyper Normal Normal T3 & TSH, low T4 ( Iod def , more T4 → T3) Anti-TPO Ab – r/o autoimmune thyroid disease Urinary Iodine - <10 mcg/ dL = Iodine def USG – If nodularity suspected

7. SIMPLE GOITRE Treatment:- Juvenile/ pregnancy – TFT normal, NO Rx. Usually regress spontaneously Iodine deficiency – Iodine Thyroxine Surgery – Tracheal compression Thoracic outlet obstruction Cosmetic Radioiodine – Follow-up for hypothyroidism

8. SIMPLE GOITRE Recurrent episodes – Fibrosis Nodule formation - MNG Autonomous function – toxic nodule

9. THYROIDITIS

10. CAUSES Acute Bacterial infection: Staphylococcus , Streptococcus, and Enterobacter Fungal infection: Aspergillus , Candida, Coccidioides , Histoplasma , and Pneumocystis Radiation thyroiditis after 131I treatment Amiodarone (may also be subacute or chronic) Subacute Viral (or granulomatous) thyroiditis Silent thyroiditis (including postpartum thyroiditis) Mycobacterial infection Chronic Autoimmunity : focal thyroiditis, Hashimoto's thyroiditis, atrophic thyroiditis Riedel's thyroiditis Parasitic thyroiditis: Echinococcosis , strongyloidiasis , cysticercosis Traumatic : after palpation

11. SUPPURATIVE THYROIDITIS Rare Suppuration – Bacterial F ungal Associated – Pyriform sinus (4 th brachial pouch) Long standing goitre Degeneration of malignancy

12. SUPPURATIVE THYROIDITIS Clinical Thyroid pain – ref to throat, ear Fever, dysphagia Erythema over thyroid Small, tender, asymmetric goitre Differentials Thyroiditis – subacute , chronic Haemorrhage into cyst Malignancy Amiodarone induced thyroiditis Amyloidosis

13. SUPPURATIVE THYROIDITIS Investig – TC & ESR ↑ FNAC – polymorph infiltration Specimen gram stain, C&S CT, USG – abscess Treatment – Antibiotics, antifungals Surgery – Abscess Compressive symptoms (trachea, esophagus, jugular veins)

14. SUPPURATIVE THYROIDITIS Complications – Tracheal compression Retropharyngeal abscess Esophageal compression Septicaemia Mediastinitis Jugular vein thrombosis

15. DRUG INDUCED Interferons – IFN- α IL-2 Amiodarone Can result in – Painless thyroiditis Grave’s Hypothyroidism Risk factor – Anti-TPO Ab+ve before Rx

16. AMIODARONE INDUCED Acute, subacute , chronic Class III antiarrhythmic Structure related = thyroid hormone 39% Iodine ( wt ) Stored in adipose (>6 mths for levels ↓ ) Actions – ↓ T4 release Inhibit deiodinase Weak thyroid hormone antagonist

17. AMIODARONE INDUCED Effects – A/c transient ↓ thyroid function Persistent hypothyroid (women, anti-TPO Ab ) Thyrotoxic (incipient Grave’s, MNG, Jod-Basedow ) TFT – Initial T4 ↓ Then T4 ↑, T3 ↓ & thyroid effect ↓ Wolff- Chaikoff escape, deiodinase inhib , thyroxine inhib TSH initial ↑ , then N/↓

18. AMIODARONE INDUCED - Rx Hypothyroid – Levothyroxine Hyperthyroid – complex Stop drug (often impractical) Type I – P reclinical Grave’s, MNG Anti-thyroid high dose Type II – Destructive thyroiditis Iodinated oral contrast ( ↓ formation, conversion, action) Glucocorticoid Lithium Near-total thyroidectomy

19. SUBACUTE THYROIDITIS Synonyms – d e Quervain’s Granulomatous Viral (lots of viruses) Mimic pharyngitis 30-50 years, women:men = 3:1

20. SUBACUTE THYROIDITIS Pathophysiology – Patchy inflammatory infiltrate Multinucleate giant cells Granuloma, fibrosis Disrupt + destroy thyroid follicles Stages – 1 = Destruction (Tg,T3,T4 release. Hyperthyroidism) 2 = Depletion (T3,T4 fall. Hypothyroidism) 3 = Recovery (TFT slowly returns to normal)

21. SUBACUTE THYROIDITIS Clinical – Painful, symmetric goitre (ref to jaw, ear) Fever +/-, malaise Thyrotoxicosis URTI o/e Exquisitely tender goitre Uncommon – Permanent hypothyroidism Rare – Prolonged course with multiple relapses

22. SUBACUTE THYROIDITIS Investigations – TFT – 1 = T3 & T4 ↑↑ , TSH ↓↓ 2 = T3 & T4 ↓↓ , TSH ↑↑ 3 = TFT normal ESR ↑ TC ↑ /N

23. SUBACUTE THYROIDITIS Treatment – Aspirin – 600mg 4-6 hrly NSAIDs Glucocorticoid – Severe local/systemic symptoms Taper 6-8 weeks β- blocker – hyperthyroidism Levothyroxine – hypothyroidism (low dose) TFT 2-4 weekly (hyper, hypo, normo )

24. SUBACUTE THYROIDITIS Silent thyroiditis – Synonyms – painless, postpartum 3 stages – hyper, hypo, normo Recovery norm Assoc – TPO + ve , type 1 DM ESR normal Severe thyrotoxicosis – propranolol Hypothyroidism – levothyroxine TFT annually – monitor for hypothyroidism

25. AUTOIMMUNE THYROIDITIS Focal – Seen on autopsy Asymptomatic Hashimoto’s – Lymphocytic infiltration Large, irregular, painless goitre Atrophic – More fibrosis Less lymphocytic infiltrate Distorted architecture

26. AUTOIMMUNE THYROIDITIS Main mechanism – T-lymphocytic injury Clinical – Goitre – Hashimoto’s Hypothyroidism – atrophic, late Hashimoto’s Children – Rare Slow growth, delayed facial development

27. AUTOIMMUNE THYROIDITIS Investigations – TFT – Clinical/subclinical hypothyroidism Anti-TPO Ab marker FNAC – Lymphocytic infiltrate (Hashimoto’s) More fibrosis (atrophic) USG – Heterogenous enlargement (Hashimoto’s) Atrophied gland (atrophic) No nodules

28. AUTOIMMUNE THYROIDITIS Treatment – Monitor TFT regularly Levothyroxine if hypothyroid

29. REIDEL’S THYROIDITIS Rare Middle-aged women Pathophysiology – Dense fibrosis Normal architecture lost Gland size enlargement Dysfunction uncommon

30. REIDEL’S THYROIDITIS Clinical – Insidious, painless, hard, nontender goitre Compression – Esophagus Trachea Neck veins Recurrent laryngeal nerves Associated idiopathic fibrosis – Retroperitoneal, biliary tree Mediastinal , lung Orbit

31. REIDEL’S THYROIDITIS Diagnosis – Open biopsy Treatment – Surgical decompression Thyroxine if hypothyroid Tamoxifen (no evidence)