Hyperthyroidism¶
Griffin Bullock
Background¶
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Low TSH and High T4 and/or T3 (primary): Graves’ disease, Toxic goiter, TSH-producing adenoma, hyperemesis gravidarum, subacute granulomatous thyroiditis, amiodarone, radiation, excessive replacement, struma ovarii
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Low TSH/Normal T4 and T3: Subclinical hyperthyroidism, central hypothyroidism, non-thyroidal illness, recovery from hyperthyroidism, pregnancy (physiologic)
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Subclinical Hyperthyroidism: repeat testing to verify abnormality is not transient
Presentation¶
- Anxiety, emotional lability, heat intolerance, tremor, palpitations, increased appetite, unexplained weight loss, new onset atrial fibrillation, myopathy, menstrual disorder, exophthalmos, tachycardia, pretibial myxedema, hyperreflexia, lid lag, changes to hair or skin
Evaluation¶
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TSH, free T4, free T3 (only T3 or T4 may be elevated, though both often are)
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Biotin affects assay, causes falsely ↓ TSH and falsely ↑ FT4/FT3
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CBC: May have a normocytic anemia due to increased plasma volume
Management¶
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Thyrotropin antibodies (Graves-specific test, not sensitive)
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Radioiodine uptake scan if thyrotropin antibodies negative
- Note: if pt has had a contrasted study wtih radioactive iodine in the past 6 weeks, the RAI update scan will not be helpful
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Treatment: methimazole, PTU, beta blockers, radioiodine ablation, surgery
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Pts should be referred to endocrinology for treatment plan based on work up