Figure 7. Hashitoxicosis in a 52-year-old woman who had presented 1 month earlier with symptoms of hyperthyroidism. At that time, laboratory values were as follows: T4 = 13.2 µg/dL, T3 = 192 ng/dL, and TSH = 0.01 µIU/mL. Over the next few weeks, the patient’s symptoms spontaneously resolved. A close-up anterior image was obtained 6 hours following oral administration of 300 µci (
11.1 MBq) of I-123. At the time of the scan, T3 and total T4 values had normalized, and TSH was 0.2 µIU/mL. The 6-hour RAIU was 19%. A TPO antibody titer was elevated at 1:160. The image reveals nonuniformly increased activity throughout the thyroid.