A study on bronchial responsiveness to methacholine in subjects with untreated autoimmune hyperthyroidism.

Because hyperthyroidism can mimic respiratory disorders with dyspnoea, this study was carried out in order to determine whether bronchial hyperresponsiveness is more frequent in hyperthyroid patients versus controls. Eighteen nonatopic subjects with newly-diagnosed untreated Graves' disease and 18 control subjects entered the study. All subjects underwent an aspecific bronchial provocation test with methacholine. Bronchial hyperresponsiveness was diagnosed in seven patients with hyperthyroidism and in two controls, with no statistically significant difference between the groups (Fisher's exact test; p = 0.1212). In conclusion, these results suggest that hyperthyroidism is not associated with a higher frequency of bronchial hyper-responsiveness to methacholine with respect to euthyroid subjects.