A 26-year-old woman comes to the physician because of increasing fatigue. She was diagnosed with Graves' disease 3 months ago and did not have any extrathyroidal manifestations at that time. Radioactive iodine was administered to treat her thyrotoxicosis approximately 8 weeks ago. Her palpitations and tremors have improved. She has gained 4 lbs (1.8 kg) in the last 4 weeks and she is now experiencing cold intolerance.
Her blood pressure is 130/80 mm Hg and pulse is 80/min. Examination reveals mild diffuse thyromegaly without nodules or bruits. There is no tremor, proptosis, or pretibial myxedema. Deep tendon reflexes do not show delayed relaxation time.
Her serum thyroid stimulating hormone (TSH) level is 0.05 µU/mL.
Which of the following is the most appropriate next step in management?

Question

A 26-year-old woman comes to the physician because of increasing fatigue.  She was diagnosed with Graves' disease 3 months ago and did not have any extrathyroidal manifestations at that time.  Radioactive iodine was administered to treat her thyrotoxicosis approximately 8 weeks ago.  Her palpitations and tremors have improved.  She has gained 4 lbs (1.8 kg) in the last 4 weeks and she is now experiencing cold intolerance.
Her blood pressure is 130/80 mm Hg and pulse is 80/min.  Examination reveals mild diffuse thyromegaly without nodules or bruits.  There is no tremor, proptosis, or pretibial myxedema.  Deep tendon reflexes do not show delayed relaxation time.
Her serum thyroid stimulating hormone (TSH) level is 0.05 µU/mL.
Which of the following is the most appropriate next step in management?

Quizplus · Accepted Answer

The majority of patients receiving radioactive iodine therapy show improvement in 4-8 weeks, and up to 80% of patients develop hypothyroidism between 2-6 months following treatment. However, post-treatment hypothyroidism can sometimes be transient and self-limited. TSH may remain suppressed for months after the resolution of hyperthyroidism and does not always indicate ongoing hyperthyroidism. The most appropriate next steps are to obtain T3 and T4 levels, evaluate patient symptoms, and monitor the patient with occasional clinical examinations. This patient has symptoms of hypothyroidism with a suppressed TSH level. If the T3 and T4 levels indicate chemical hypothyroidism, she should be started on levothyroxine (Choice C). If the levels are normal, she should be reassessed again in 4-8 weeks (Choice B). (Choice A) Radioactive iodine uptake and scan are helpful in the diagnosis and treatment of Graves' disease, but they are not helpful for monitoring in the post radioactive iodine period. (Choice E) Thyrotropin receptor antibody (TRAb) levels will remain elevated following radioactive ablative treatment, even after patients develop hypothyroidism. TRAb is usually measured in the third trimester of pregnancy in hyperthyroid patients with Graves' disease to predict fetal hyperthyroidism. Pregnancy should be avoided for at least 6 months following radioactive iodine ablation. Educational objective: TSH remains suppressed for months after radioactive iodine ablative treatment. Further treatment decisions are based on total T3 and free T4 levels, patient symptoms, and clinical examination. __________ 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) The significance of TSH values measured in a sensitive assay in the follow-up of hyperthyroid patients treated with radioiodine. (http://www.ncbi.nlm.nih.gov/pubmed/1569166)

A 26-Year-Old Woman Comes to the Physician Because of Increasing