A 73-year-old male with end-stage renal failure on home peritoneal dialysis (PD) (povidone-iodine solution was used) and a recent diagnosis of atrial fibrillation presented to the hospital with fatigue and dyspnea. Examination: On examination, profound muscle weakness was observed. He was found to be thyrotoxic with TSH < 0.01 mIU/L (reference range 0.20–4.0 mIU/L) and free T4 (FT4) >100 pmol/L (reference range 10.0–25.0 pmol/L). There had been no exposures to CT contrast, amiodarone, or iodine.
Thyroid peroxidase antibodies were within normal limits at presentation (17.4 kIU/L, reference range 0.0–34.0 kIU/L). C-reactive protein was elevated at 30.6 mg/L (0.0–8.0 mg/L), and white blood cell count was within normal limits. Thyroid ultrasound revealed a mildly bulky thyroid gland with the right lobe measuring 6.6 × cm and the left lobe measuring cm, with no evidence of increased thyroid…
