Endocrine Abstracts

Background

Rapid induction of eu/hypothyroidism in patients with immune hyperthyroidism has been known to precipitate Thyroid eye disease (TED). Our aim was to investigate the incidence of TED in patients treated with radio-iodine therapy (RIT) at our hospital.

Methods

We examined case notes of 45 patients who underwent radio-iodine therapy for Graves’ disease with 544.7 (95% CI- 522.3 – 567.1) MBq between June 1999 and June 2002. None of these patients had received steroids prior to RIT.

Results

45 patients with Graves’ disease (age – 48.02, 95% CI-44.02–52.03 years, 84.4% female) were studied. They had a follow-up period of 8.1 (6.1–10.1) months following RIT. 17.8% of patients had TED prior to and 8.9% had TED after having RIT. 2.2% of these patients had pre-existing TED which worsened after RIT. On adjusting for age at RIT administration, first follow up since RIT and duration of follow-up, the initial duration of medical therapy was found to influence both prevalence of TED (Beta −0.006, 95% CI- 0.001–0.011, P=0.03) as well as post RIT incidence of TED (Beta −0.004, 95% CI- 0.001–0.007, P=0.02) while first detection of eu/hypothyroidism since RIT influenced incidence of TED as well (Beta −0.03, 95% CI- 0.00–0.06, P=0.05).

Conclusion

TED is common both prior to and after RIT in patients with Graves’ disease. Rapid development of eu/hypothyroidism is associated with incidence of post-RIT TED. Earlier institution of and use of steroids prior to RIT may decrease the incidence and prevalence of TED in these patients.