MKSAP Quiz: weight loss, heat intolerance and tremor
Flexible anxiety treatment delivers better than usual care
EDITOR’S NOTE: ACP InternistWeekly now features questions from MKSAP 15. See the Answer and Critique for this question for important information about MKSAP 15.
A 55-year-old man is evaluated for a 4-month history of weight loss, heat intolerance, tremor and hyperdefecation and a 1-week history of dry eyes that are sensitive to light and frequently injected. He reports no blurred or double vision but does relate having been previously diagnosed with a “thyroid condition” and having a severe allergic reaction to methimazole therapy. The patient currently takes no medications.
On physical examination, blood pressure is 140/88 mm Hg, pulse rate is 120/min, respiration rate is 18/min, and BMI is 22. Pupils are equal, round, and reactive to light and accommodation; extraocular movements are intact. Mild bilateral conjunctival injection and periorbital edema are noted. There is no chemosis, but some slight lid lag and proptosis are present. Examination of the neck reveals a smooth thyroid gland that is three times its normal size. Cardiac examination shows tachycardia and a regular rhythm. There is a 3+ upper extremity tremor bilaterally.
Laboratory studies show a serum thyroid-stimulating hormone level of 0.01 µU/mL (0.01 mU/L) and a serum free thyroxine (T4) level of 3.8 ng/dL (49.0 pmol/L).
Which of the following is the most appropriate treatment for this patient?
A. Immediate thyroidectomy
B. Orbital decompression surgery
C. Prednisone and radioactive iodine ablation
D. Radioactive iodine ablation alone
MKSAP Answer and Critique
The correct answer is C) Prednisone and radioactive iodine ablation. This item is available online to MKSAP 15 subscribers in the Endocrinology and Metabolism section, Item 46.
This patient should receive prednisone and radioactive iodine ablation concomitantly. He has active Graves disease and mild Graves ophthalmopathy. Because he also has a history of a severe allergic reaction to methimazole, a retrial of antithyroidal drugs is not recommended. Although thyroidectomy is a viable treatment for hyperthyroidism resulting from Graves disease, patients are typically first made euthyroid with antithyroidal drugs preoperatively, which is not an option with this patient.
Graves disease is complicated by Graves ophthalmopathy in approximately 5% to 10% of patients. Graves ophthalmopathy is an autoimmune disease of the retro-orbital tissues that may present with proptosis and periorbital edema. Patients may report irritation in the eyes, tearing, ocular pain, and changes in vision. Vision loss may occur. A persistent thyrotoxic or hypothyroid state appears to exacerbate eye disease activity, so patients should be made euthyroid as soon as possible. However, the use of radioactive iodine to treat hyperthyroidism can exacerbate thyroid-associated eye disease, especially in patients with significant preexisting ophthalmopathy at the time of ablation. Prednisone can mitigate this negative effect. A periablative course of prednisone is thus appropriate in patients with mild ophthalmopathy who are being considered for ablation therapy.
Orbital decompression surgery is reserved for patients with severe ophthalmopathy that has not responded to medical treatment. Furthermore, the patient would first need to be made euthyroid before any such surgery. Decompression surgery is thus inappropriate in this patient.