ABSTRACT
BACKGROUND: The role of abnormal thyroid function in the aetiology of idiopathic oedema is unclear. Previous studies of small samples of patients have suggested a high prevalence of latent hypothyroidism and a possible deiodination defect in the conversion of T4 to T3 in this condition. There is a need to clarify the possible significance of abnormal thyroid function in a larger sample of idiopathic oedema patients. OBJECTIVE: The study was undertaken to compare basal thyroid function in idiopathic oedema patients and in an age and sex-matched control group. PATIENTS AND DESIGN: After excluding one idiopathic oedema patient and three control subjects with abnormal thyroid function, basal thyroid function was compared in 44 idiopathic oedema patients and in 44 age and sex-matched controls. MEASUREMENTS: Basal thyroid function was assessed in patient and control groups by measuring serum T4, fT4, T3, fT3 and TSH by standard methods. RESULTS: There were no significant differences in basal thyroid function between patient and control groups except for an elevated mean fT4 concentration in the idiopathic oedema group (P = 0.03). Exclusion of patients and controls taking oestrogen abolished this difference. T4:T3 ratios were similar in patient and control groups. CONCLUSION: Abnormalities of basal thyroid function are uncommon in patients with idiopathic oedema and appear unrelated to the pathogenesis of this disorder. Similar T4:T3 ratios between patient and control groups exclude a deiodination defect in idiopathic oedema.
