A 27-year-old woman comes to the physician because of poor sleep, hand tremors, and heat intolerance for the last 2-3 weeks. She denies fever or neck pain and she has no previous medical problems. She does not use tobacco or alcohol. She takes a multivitamin in addition to dietary supplements and she exercises daily. Her mother had Graves' disease and was treated with radioiodine. Her sister has hypothyroidism.
Her blood pressure is 150/80 mm Hg, pulse is 120/min, and respirations are 20/min. Her BMI is 23 kg/m². Neck examination shows mild, diffuse thyroid enlargement without any palpable nodule, tenderness, or bruit. She has lid lag without exophthalmos. Her hands are warm and sweaty with fine tremors. The remainder of the examination is unremarkable.
Laboratory results are as follows:

Electrocardiogram shows sinus tachycardia with a heart rate of 120/min with non-specific ST-T changes. Radioactive iodine uptake at 24 hours is 2% (normal 10-30%) . Urine pregnancy test is negative.
Which of the following is the best next step in management?

Question

A 27-year-old woman comes to the physician because of poor sleep, hand tremors, and heat intolerance for the last 2-3 weeks. She denies fever or neck pain and she has no previous medical problems. She does not use tobacco or alcohol. She takes a multivitamin in addition to dietary supplements and she exercises daily. Her mother had Graves' disease and was treated with radioiodine. Her sister has hypothyroidism.
Her blood pressure is 150/80 mm Hg, pulse is 120/min, and respirations are 20/min. Her BMI is 23 kg/m². Neck examination shows mild, diffuse thyroid enlargement without any palpable nodule, tenderness, or bruit. She has lid lag without exophthalmos. Her hands are warm and sweaty with fine tremors. The remainder of the examination is unremarkable.
Laboratory results are as follows:

Electrocardiogram shows sinus tachycardia with a heart rate of 120/min with non-specific ST-T changes. Radioactive iodine uptake at 24 hours is 2% (normal 10-30%) . Urine pregnancy test is negative.
Which of the following is the best next step in management?

Quizplus · Accepted Answer

11ec193a_97af_536f_853d_b553f701873e_MD0002_00 This patient's presentation is consistent with painless thyroiditis, which is defined as transient hyperthyroidism followed by possible hypothyroidism and then recovery. Painless thyroiditis generally occurs > 1 year after pregnancy, but it can also occur in non-postpartum women and men. Certain medications (e.g., lithium, interferon alpha, interleukin-2, and amiodarone) are also known to cause painless thyroiditis. It is important to perform a radioactive iodine uptake (RAIU) scan in order to distinguish painless thyroiditis from Graves' disease in any hyperthyroid patient without exophthalmos, since both can present similarly and have different treatments. Graves' disease and toxic nodular goiter are usually due to excessive thyroid hormone production from hyperactive thyroid tissue and demonstrate high uptake on RAIU. Painless thyroiditis is likely a variant of Hashimoto's thyroiditis with autoimmune thyroid inflammation. The ensuing thyrotoxicosis state is due to preformed thyroid hormone release. As a result, painless thyroiditis has elevated serum anti-TPO antibodies and thyroglobulin. In addition, the RAIU scan shows markedly decreased uptake (sometimes < 1%). Patients may present initially with mild thyrotoxic symptoms lasting for 1-3 months (usually no exophthalmos) followed by hypothyroid symptoms that last 3-6 months. Most patients eventually recover, but up to 20% of patients can develop permanent hypothyroidism (usually with higher anti-TPO antibody titers) and 10% can develop recurrent thyroiditis. Patients with mild symptoms generally require no treatment and are monitored with thyroid function studies in 6-8 weeks. However, patients (such as this one) with significant symptoms (e.g., tachycardia) usually require beta-blockers for symptom relief (Choice D). (Choice B) High-dose glucocorticoids are generally used in amiodarone-induced destructive thyroiditis (type II), subacute (de Quervain's) thyroiditis unresponsive to NSAIDs, and severe cases of painless thyroiditis. (Choice C) Methimazole is effective for Graves' disease and decreases excess thyroid hormone formation. However, it is less effective for painless thyroiditis, since the hyperthyroid state is due to preformed thyroid hormone release from the thyroid gland. (Choice E) Radioactive iodine ablation is effective if there is increased iodine uptake by the thyroid due to excess thyroid hormone formation (e.g., Graves' disease, toxic nodular goiter). However, it is not effective for painless thyroiditis in the hyperthyroid phase, since it is due to preformed thyroid hormone release. Patients with recurrent silent thyroiditis may choose radioactive iodine ablation as an option when euthyroid. Educational objective: Painless thyroiditis usually occurs in women > 1 year post pregnancy, but it can occur in non-postpartum women and men. Patients typically present with 1-2 months of mild hyperthyroid symptoms followed by hypothyroid symptoms and recovery. Patients with mild symptoms usually require no therapy except for thyroid function test monitoring. Beta-blockers are preferred for symptomatic thyrotoxic patients. __________ References: Hyperthyroidism and other causes of thyrotoxicosis: management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists (http://www.ncbi.nlm.nih.gov/pubmed/21510801)

A 27-Year-Old Woman Comes to the Physician Because of Poor