Non-specific term for any enlargement of thyroid gland. 2 types: diffuse (whole gland enlarged due to over stimulation by TSH or thyroid stimulating immunoglobulins) & nodular (specific area of enlargement normally due to tumour, sometimes a cyst)
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What causes hypothyroidism? What is the effect on TSH? Is there a goitre present?
Primary failure of thyroid gland e.g. Hashimoto's (increase TSH, goitre). Secondary to hypothalamic/ant pituitary failure (decrease TSH, no goitre). Lack of dietary iodine -> simple non-toxic goitre (increase TSH, goitre)
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What are the symptoms of hypothyroidism?
Weight gain, cold intolerance, decreased heart rate/BP, depression, confusion, myxodema (accumulation of fluid -> puffy pale face, hands, feet), cretinism -> dwarfism & retardation
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How is hypothyroidism diagnosed?
Thyroid function test: Primary -> decreased T3/4, increased TSH. Secondary -> decreased T3/4, decreased TSH. If Hashimoto's suspected, test for thyroid antibodies - anti-microsomal (TPO) & anti-thyroglobulin
What causes hyperthyroidism? What is the effect on TSH? Is there a goitre present?
Abnormal levels of TSI e.g. Graves' (decrease TSH, goitre). Secondary to excess hypothalamic/ant pituitary secretion (increase TSH, goitre). Hyper-secreting thyroid tumour, toxi multinodular goitre or adenoma (decrease TSH, goitre)
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What are the symptoms of hyperthyroidism?
Weight loss, sweating, heat intolerance, diarrhoea, palpitations, tremor, anxiety/emotional/irritable (due to up-regulation of B-adrenoceptors), increased cellular/tissue metabolism due to excessive thyroid hormone aion
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How is hyperthyroidism diagnosed?
Thyroid function test: Primary -> increased T3/4, decreased TSH. Secondary -> increased T34, increased TSH. If Graves' disease suspected, test for thyroid-stimulating antibodies. Perform thyroid uptake test for thyroid tumours
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What is the goal & management of hyperthyroidism?
Goal: euthyroid state & symptomatic relief from increased sympathetic activity. Management: anti-thyroid drugs, radioiodine (131-I), surgery
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How do anti-thyroid drugs work?
Thionamides decrease production of thyroid hormones by inhibiting iodination & coupling processes (via TPO). Thyroid hormones have long half life so takes several weeks for clinical response to occur, usually lasts 12-18 months but 50% relapse rate
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How do non-selective beta-blockers work?
Reduce actions of catecholamines -> rapid symptomatic relief of tremor, palpitations, anxiety. Takes around 4 days to work
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How does radioacitve iodine work? (131-iodine)
First-line for older patients with nodular goitres & hyperthyroidism. Used when thyrotoxicosis recurs after anti-thyroid drug therapy. Given as single drink or capsule, maximum effect 2-4 months after. Hypothyroidism may result.
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When is a thyroidectomy performed?
Not frequently used. Used when severe thyrotoxicosis associated with a large goitre or concern about tumour development or when there are obstructive symptoms. Hypothyroidism may result along with damage to parathyroids or calcium uptake changes
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Other cards in this set
Card 2
Front
What is the effect of hypo & hyperthyroidism on T3/4 & BMR?
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