Endocrine Abstracts

We present 2 patients who developed severe thyrotoxic exacerbation following radioiodine. The first treated by conventional antithyroid therapy, the second was plasma exchanged.

Patient A aged 39 male with FT3=28.2 pmol/l (2.5–5.3) FT4=49.0 pmol/l (9.1–23.8) TSH=<0.01 mU/l (0.32–5.0),a large diffuse goitre, thyroid eye disease and asthmatic on inhaled ventolin. He received 3.5 years of carbimazole 40 mg and thyroxine 100 mcg. Thyroxine was stopped 15 months before radioiodine. Prednisolone 20 mg was started and Carbimazole 60 mg was stopped 4 days prior to 531 MBq Iodine -131. Within 7 days he developed severe thyrotoxic symptoms. Day 12 FT3=40.8, FT4=67.5, and TSH=<0.05. He was started on Propylthiouracil 200 mg tds, cholestyramine 4gm qds and prednisolone continued. He remained thyrotoxic for 57 days.

Patient B aged 52 male with FT3=42.4 pmol/l, FT4=61.3 pmol/l, TSH=0.01 mu/l, a large diffuse goitre and pretibial myxoedema. He received carbimazole 60 mg and Thyroxine 125 mcg daily for 9 months. Thyroxine was stopped after 4 months and carbimazole 2 days before Iodine-131 527 MBq. Toxic symptoms started day 4. On day 7 FT3=>50 pmol/l, FT4=54.6 pmol/l, TSH=0.01. On day 9 Propylthiouracil 200 mg qds, cholestyramine 1 Gm qds and propranolol 40 mg tds were started and because of previous experience with patient A he was referred for plasma exchange receiving 2 exchanges of 4 L with 4.5% albumin on days 10 and 12. He became biochemically euthyroid on day 10 FT3=6.4 pmol/l, FT4 8.5 pmol/l, TSH 0.01, and clinically euthyroid and asymptomatic day 13. Propylthiouracil continues in decreasing doses.

We have shown avoidance of a serious post radiation thyrotoxic exacerbation by the frequently used renal technique of plasma exchange, and advocate its use in potential as well as actual thyroid storm.