The next most appropriate step in this patients management is obtaining a RAIU and scan to differentiate between the causes of hyperthyroidism. The thyrotoxic phase of subacute thyroiditis is associated with decreased uptake throughout the thyroid, whereas patients with Graves disease have increased uptake throughout the thyroid. This patient with a toxic adenoma was found to have decreased or absent uptake throughout the
thyroid except for 1 area of increased uptake that corresponded to the location of the left lobe nodule that was palpated on physical examination. Due to increased morbidity in certain populations, including increased risk of cardiac complications (eg, atrial fibrillation) in older patients4,5 and increased skeletal resorption in postmenopausal women (leading to low bone density and fractures),6 treatment of SCH may be required. Treatment should be considered when serum TSH is less than 0.1 µIU/mL.7.
- Order a RAIU and scan.
4. Sawin CT, Geller A, Wolf PA, et al. Low serum thyrotropin concentrations as a risk factor for atrial fibrillation in older persons. N Engl J Med 1994;331:1249-52.
5. Auer J, Scheibner P, Mische T, et al. Subclinical hyperthyroidism as a risk factor for atrial fibrillation. Am Heart J 2001;142:838-42.
6. Ross DS. Hyperthyroidism, thyroid hormone therapy, and bone. Thyroid 1994;4:319-26.
7. Gharib H, Tuttle RM, Baskin HJ, et al. Subclinical thyroid dysfunction: a joint statement on management from the American Association of Clinical Endocrinologists, the American Thyroid Association, and The Endocrine Society. J Clin Endocrinol Metab 2005;90:581-5.
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