Purpose: Thyrotoxic periodic paralysis (TPP) is a complication of thyrotoxicosis mainly observed in male Asian patients. It was proposed that patients with TPP tend to have lower thyroid hormone levels. We aimed to prove this observation and to assess whether a lower 131I dose is feasible for prompt control of TPP.
Methods: A total of 123 male TPP patients were enrolled in this study in a 7-year period. Baseline characteristics were compared with 70 thyrotoxic patients without periodic paralysis (nTPP). Different 131I doses were given to 90 TPP patients with a median follow-up of 11 months, and the outcome was evaluated.
Results: The serum thyroid hormone levels, including total T3 and T4, and free T3 and T4, in TPP patients were slightly less elevated compared with those in nTPP patients. Patients who received lower radioactivity of 131I had an unsatisfactory overall remission rate of 28.6%. Longer time to remission (P = 0.004; hazard ratio, 1.846; 95% confidence interval, 1.216–2.798) was also observed in patients with lower dose.
Conclusions: The serum thyroid hormone levels of TPP patients are lower than those of nTPP patients. Median/high dose of 131I is necessary to achieve rapid control of thyrotoxicosis.