Endocrinology Thyroiditis: Review Questions Jennifer Pedersen-White, DO Dr. Pedersen-White is an assistant professor, Section of Endocrinology, Department of Medicine, Medical College of Georgia, Augusta, GA. Choose the single best answer for each question.
	Questions 1 to 5 refer to the following case. A 32-year-old woman presents to her primary care physician with a 1-month history of heat intolerance, fatigue, and palpitations. She delivered a healthy baby girl by uncomplicated vaginal delivery 12 weeks prior to this visit. She is no longer breastfeeding. The patient’s past medical history is significant for type 1 diabetes diagnosed at age 7 years, which has been well controlled. She has no personal or family history of thyroid disorder. She denies the use of over-the-counter herbal supplements or exogenous thyroid hormone replacement or having received iodinated contrast in the past year. On physical examination, the patient is afebrile with a heart rate of 100 bpm and a blood pressure of 146/88 mm Hg. The patient appears clinically euthyroid. There is no proptosis or lid lag. The thyroid is normal in size, nontender to palpation, and without appreciable masses. Cardiac examination reveals tachycardia and a regular rhythm. The skin is diffusely warm to touch and is nondiaphoretic. Deep tendon reflexes are 3+/4 with assessment of biceps and patellar tendon reflexes. Laboratory testing reveals a suppressed thyroid-stimulating hormone (TSH) level of 0.19 µIU/mL (normal, 0.35–5.5 µIU/mL) and an elevated free thyroxine (FT4) level of 1.98 ng/dL (normal, 0.61–1.76 ng/dL). Medical records show that the patient’s TSH has been within normal limits with routine laboratory evaluation over the past 3 years.   1. Which of the following tests would be most useful in determining a diagnosis in this patient? Repeat TSH and FT4 Thyroid scan and radioactive iodine uptake (RAIU) Thyroid ultrasound TSH receptor antibody assay Click here to compare your answer. 2. An 123I thyroid scan and uptake reveals a grossly normal thyroid contour without evidence of hot or cold nodules. RAIU at 4 hours is less than 1% (normal, 4%–15%). TSH receptor antibody assay is negative, but thyroid peroxidase (TPO) antibody assay returns markedly elevated. What is the patient’s most likely diagnosis? Graves’ disease Postpartum thyroiditis Toxic multinodular goiter (TMG) Transient gestational hyperthyroidism Click here to compare your answer. 3. What is the next step in the management of this patient? 131I thyroid ablation Initiate ß-blocker therapy Initiate levothyroxine therapy Initiate thionamide therapy Click here to compare your answer.		4. What is the relationship of type 1 diabetes to the patient’s current thyroid dysfunction? There is no relationship between type 1 diabetes and thyroid dysfunction Type 1 diabetes has a protective effect against thyroid dysfunction Type 1 diabetics have an increased prevalence of thyroid dysfunction Uncontrolled type 1 diabetes contributes to abnormal thyroid function tests Click here to compare your answer. 5. Which of the following is most likely to occur in this patient in the future? No recurrence of thyroid dysfunction Low likelihood of recurrence after each subsequent pregnancy Permanent hyperthyroidism is likely to develop Permanent hypothyroidism is likely to develop Click here to compare your answer. 6. A 74-year-old man with a past medical history of recurrent atrial fibrillation presents to his primary care physician with a 3-month history of fatigue, weakness, occasional palpitations, hand tremors, and a 10-lb weight loss. Atrial fibrillation has been managed with daily amiodarone therapy for 3 years. He has no personal or family history of thyroid disorder. On physical examination, the patient is afebrile with a heart rate of 104 bpm and blood pressure of 132/78 mm Hg. On examination, the thyroid is normal in size and nontender to palpation, with no thyroid nodules. The heart rate is tachycardic with a regular rhythm. An electrocardiogram reveals sinus tachycardia. Deep tendon reflexes are within normal limits. Laboratory tests reveal a TSH level less than 0.01 µIU/mL and an FT4 level of 3.21 ng/dL, and assays for TSH receptor and TPO antibodies are negative. Thyroid scan and RAIU reveal patchy tracer uptake within the thyroid and an uptake of less than 1% at 6 hours. Thyroid ultrasound reveals normal thyroid size with normal tissue echogenicity and blood flow without nodules or masses. What is this patient’s most likely diagnosis? Acute suppurative thyroiditis Amiodarone-induced thyrotoxicosis (AIT) Graves’ disease TMG Click here to compare your answer.
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