Hyperthyroidism

4TH YR MBBS

1. H yperthyroidism

2. Objectives To understand types ,clinical features , investigation and management of hyperthyroidism

3. Overview Definition Types clinical features Investigation Treatment

4. Hyperthyroidism Disease process associated with increased thyroid secretion result in predictable hyper metabolic state

5. Types: Primary thyrotoxicosis 1. Diffuse toxic goitres - graves disease Secondary thyrotoxicosis 2. Toxic nodular goitre 3. Toxic nodule 4. Hyperthyroidism due to rare cause Hyperthyroidism

6. Diffuse toxic goitre (graves) Most common cause of hyperthyroidism Irish physician- Dr Robert Graves in 1835 Common-young females(20 to 40) Whole gland involved 50% family h/o autoimmune endocrine disease Hypertrophy and hyperplasia- abnormal TSH –R Ab bind to TSH receptor disproportionate and prolonged effect Genetic susceptibility

7. Toxic nodular goitre Middle aged/elderly Eye signs –rare Secondary TT Nodules-inactive Internodular tissue - overactive Toxic adenoma-autonomous

8. Toxic nodule Solitary overactive nodule Part of generalised nodularity or two toxic adenoma Autonomous TSH- suppressed by high T3 and T4 Normal surrounding thyroid tissue – suppressed and inactive

9. Histology Normal acini - with flattened cuboidal epithelium and filled with homogenous colloid Hyperthyroid – acini hyperplasia - lined by high columnar epi - empty or vacuolated colloid - characteristic scalloped pattern adjacent to thyrocytes

10. Clinical Features Symptoms Tiredness Emotional liability Heat intolerance Weight loss Excessive appetite Palpitation Diarrhoea Amenorrhoea Blurring of vision or double vision

11. Signs Tachycardia Hot moist palms Exophthalmos Lid lag \ retraction Agitation Thyroid swelling bruit

12. Cardiac rhythm - Increased sleeping heart rate( sinus tachycardia) - Arryhthmias , multiple extra systoles, paroxysmal atrial tachycardia - Paroxysmal atrial fibrillation - Persistent atrial fibrillation, no response to digoxin Myopathy Proximal limb muscle weakness ( thyrotoxic myopathy)

13. Eye Signs Exophthalmos Unilateral or bilateral Infiltration of retrobulbar tissue with fluid and round cells Retraction/spasm of upper eyelid Levator palpabre superiaris supplied partly by sympathetic fibers Graves ophthalmopathy is autoimmune disease

14. Diplopia –weakness of elevator (inferior oblique Papilloedema and corneal ulcer Malignant exophthalmos Graves ophthalmopathy -autoimmune disease- Ab mediated effects on the ocular muscles

15. Von Graefe's sign (lid lag sign) Dalrymple's sign Joffroy sign (absent creases in the forehead on superior gaze) Möbius sign (poor convergence) Stellwag sign (incomplete and infrequent blinking

16. Pretibial myxoedema thickening of skin – mucin like deposit

17. Thyroid acropathy

18. Thyrotoxicosis factitia : thyroxine induced (0.2 -0.3 mg) Jod - basedow thyrotoxicosis jod = iodine ( german ) Neonatal thyrotoxicosis : increased TSH Ab subsides : 3-4 weeks

19. Diagnosis Clinical Thyroid profile Thyroid scan-autonomous nodule –children with growth spurt , behaviour problems or myopathy - tachycardia / arryhthmia in elderly - unexplained diarrhoea - loss of weight

20. Treatment Rest , Sedation Antithyroid drugs Surgery Radioiodine

21. Drugs Antithyriod drugs- <45yr small goitre - carbimazole - propylthiouracil - oxidation and binding of Iodine to tyrosine 2. B Adrenergic blockers - propranolol,nadolol 3. Iodides

22. Advantages : no surgery rapid control of thyrotoxicosis Disadvantages : treatment is prolonged failure rate-50% SE : agranulocytosis / aplastic anemia Dose :10mg 3-4 times/day Replacement – thyroxine 0.1 mg – 0.15 mg

23. Surgery <45 yr large goitre Toxic nodule Toxic nodular goitre Advantage: goitre removed Cure rapid Cure rate-high

24. Disadvantage : recurrence - 5% - risk of surgery - hypothyroidism-20-45% - hypoparathyroidism

25. Radio iodine Indictions : >45 yr rec thyrotoxicosis after surgery Advantages : no surgery ,no drug Disadvantages : isotope facility must be available

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