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14 Cards in this Set
- Front
- Back
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Describe the signs, symptoms, and physiological effects of hyperthyroidism
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Palpitations, nervousness, easy fatiguability, hyperkinesias, irritability, tremor, diarrhea, heat intolerance, sweating, weight loss, increased appetite, muscle weakness, eye exopthalmos
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Characterize graves Dx in terms of age, sex, pathogenesis, gross and micro appearance
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Age: 20-40, Females
Pathogenesis: TSH receptor ab's which bind and stimulate the thyroid. Gross: Thyroid gland looks symmetrically enlarged Micro: Dominant feature is too many cells. follicular cells are tall and more crowded. lymphoid infiltrates are present throughout the interstitium |
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Discuss the clinical use, pharmacokinetics, and adverse effects of the drugs levothyroxine and liothyronine
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Both used to tx hypothyroidism. Levothyroxine has a long half life of 7days, liothyronine is short, 24hrs. Adverse effects: nervousness, heart palpitations, tachycardia, intolerance to heat, unexplained weight loss
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Describe the steps in thyroid hormone synthesis and release
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TSH action is mediated by cAMP and leads to stimulation of iodide uptake. Oxidation of iodine by a peroxidase is followed by iodination of tyrosines on thyroglobulin. Condensation of 2 diiodotyrosine residues gives rise to T4 or T3 still bound to protein.
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Discuss the MOA, Pharmacokinetics, and adverse effects of: PTU, Methimazole, Iodide salts, and Radioiodine
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Prophylthiouracil: Inhibits thyroid peroxidase, blocks iodine organification, coupling of iodotyrosines, inhibits peripheral deiodination of T4,T3.
Is rapidly absorbed, reaching peak levels after 1 hr. Renally excreted. Give every 6-8 hrs. Maculopapular pruritic rash as SE. Agranulocytosis. |
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Discuss the MOA, Pharmacokinetics, and adverse effects of: Methimazole
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Same MOA as PTU except deiodination of T3 and T4 is less than that of PTU. Excretion slower than PTU. Single daily dose effective. Same SE as PTU
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Discuss the MOA, Pharmacokinetics, and adverse effects of: Iodide salts
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Inhibits organification, hormone release, decreases size and vascularity of hyperplastic glands. Crosses the placenta and causes fetal goiter. Causes Acneform rash, swollen salivary glands, ulcerations, conjunctivitis, metallic taste, bleeding dx
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Discuss the MOA, Pharmacokinetics, and adverse effects of: Radioiodine
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Only isotope used for tx of thyrotoxicosis. Destroys thyroid parenchyma. rapidly absorbed, concentrated into thyroid, incorporated into storage follicles. Crosses placenta and excreted in breast milk
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Discuss the use of adrenoreceptor antagonists as adjunct therapy in the tx of hyperthyroidism
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Beta blockers, without intrinsic sympathomimetic activity are effective therapeutic adjuncts in the mgmt of thyrotoxicosis since many of these symptoms mimic those associated with sympathetic stimulation.
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Describe the effects of thyroid hormones as it relates to fetal development, oxygen consumption, heat production and free radical production, pulmonary fxn, the CV system, hematopoetic effects, GI, Sympathetic, neuromuscular, and endocrine effects, lipid and carb metabolism
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Fetal: essential for development
Ox Consumption: increases Heat/free radicals: increases Pulmonary FXN: maintains normal hypoxic/hypercapnic drive in the respiratory center CV:increases HR, increases inotropy Hematopoetic effects: increases 2,3DAG in erythrocytes, allowing incresaed dissociation of O2 GI: increases motility Sympa: incresaes Neuromuscular: Increases Endocrine: increases hormone turnover/fertility INcreases lipid/carb metab. |
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List all the possible d/dx of a thyroid nodule and the type of pt most likely to have these
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Benign: Thyroiditis, multinodular goiter, agenesis of a lobe, postsurgical/radioiodine hyperplasia, adenomas
Malignant: Papillary, follicular, medullary, and undifferentiated carcinomas |
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Describe the actions of TSH on thyroid cells:
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Thyroid growth, transcription of Tg, Iodination of tyrosine by TPO stimulated H2O2, Deiodination of T4 to T3, T3/4 secretion, Thyroiodide trapping, Thyroperoxidase enzyme activity, thyroid metabolism
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Describe how T3 is mediated by nuclear thyroid hormone receptors:
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T3 enters and it binds to a nuclear receptor. TRalpha is associated with cardiac fxn, while Beta is associated with feedback regulation and cochlear development. T3 binds the TR, corepressor dissociates, coactivator binds, and a heterodimer is formed.
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Describe the relationship between TSh and FT4 in normal, hypothyroid, hyperthyroid individuals
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In normal people, TSH and FT4 is normal;
In hyperthyroid: TSH is decreased, but FT4 is increased In Hypothyroid: TSH is increased, FT4 is decreased In Levothyroxine suppressed: TSH is decreased, FT4 is Normal. |
