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  • • Myriad of causes, that include both increased secretion of thyroid hormone from the thyroid gland and disorders that increase thyroid hormone levels without increasing thyroid gland secretion

    • -Solitary toxic adenoma

      -Toxic multinodular goiter (Plummer disease)

      -Jodbasedow disease (thyrotoxicosis that occurs after iodine supplementation)

      -Amiodarone-toxicity

      -Thyroid-stimulating hormone (TSH)-secreting pituitary adenoma

      -hCG-secreting tumor (hydatidiform mole, choriocarcinoma)

      -Postpartum hyperthyroidism

      -Struma ovarii (thyroid tissue in ovarian tumor, usually teratoma)

      -Factitious hyperthyroidism

      -Iatrogenic hyperthyroidism

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Epidemiology

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  • • Toxic multinodular goiter found in the elderly, especially women over 60

    • Solitary toxic adenomas are 4 times more likely to occur in women than men

    • 5-15% of ovarian teratomas with thyroid tissue result in clinical hyperthyroidism

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Symptoms and Signs

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  • • Nervousness, weight loss with increased appetite, heart intolerance, increased sweating, muscular weakness and fatigue, increased bowel frequency, polyuria, menstrual irregularity, infertility

    • Goiter, tachycardia, atrial fibrillation, warm moist skin, cardiac flow murmur, gynecomastia

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Laboratory Findings

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  • • Suppressed TSH (except in TSH-secreting pituitary adenoma)

    • Elevated tri-iodothyronine (T3), free thyroxine (T4 ), and radioactive iodine uptake

    • Failure to suppress radioiodine uptake with exogenous T3

    • Radioactive iodine uptake is generally 35-40% in toxic multinodular goiter

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Imaging Findings

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  • Radioiodine scan: Increased pelvic uptake in cases of struma ovarii

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  • • Toxic multinodular goiter often develops from 1 or more nodule of a nontoxic multinodular goiter becoming autonomous with respect to T3 and T4 secretion

    • Solitary toxic adenomas may be true adenomas, or colloid nodules with areas of hyperplasia

    • Solitary toxic adenomas usually have slow, progressive growth but can have hemorrhage and degeneration

    Jodbasedow disease:Iodine deficiency leads to a rise in TSH and thyroid growth; subsequent iodine supplementation can lead to thyrotoxicosis

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Rule Out

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  • • Thyroid cancer

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  • • Complete history (including family) and physical exam

    • Thyroid function tests

    • Fine-needle aspiration biopsy of toxic nodules

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  • • Treatment often multimodal, including antithyroid medication, radioactive iodine, or thyroid surgery

    • Percutaneous ethanol injections in solitary toxic adenoma have been used outside the United States (especially in Italy)

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Surgery

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Indications

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  • • Amiodarone-induced hyperthyroidism

    • Large goiters with compressive symptoms

    • Suspicion of malignancy

    • To remove hCG-secreting tumors

    • Oopherectomy for struma ovarii

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Contraindications

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  • • Patients who will not tolerate general anesthesia

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Medications

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  • • Propylthiouracil

    • Methimazole

    • Radioiodine (131I)

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Treatment Monitoring

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  • • TSH and T4 measurements

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Prognosis

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  • • After treatment of toxic multinodular goiter, 80% are no longer hyperthyroid; 11-16% are hypothyroid

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References

Metso S et al: Increased cancer incidence after radioiodine ...

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