Abnormal thyroid function test results in patients with Fisher-Evans syndrome

Thyroid function was evaluated in patients affected by Fisher-Evans syndrome (FES) and compared to that of patients affected only by autoimmune hemolytic anemia (AIHA) and to that of patients affected only by idiopathic thrombocytopenic purpura (ITP). The study population consisted of 20 patients with FES, 44 with AIHA and 20 with ITP. All patients were examined for thyroid function abnormalities and thyroid autoantibodies. Abnormal thyroid function test results were observed in 40, 25 and 10% of the patients, respectively. The prevalence of antithyroid antibodies (ATA) in FES was 25%; this is higher than the sum of the prevalences of ATA in patients affected only by AIHA (11.4%) or only by ITP (none). Subclinical primary hypothyroidism and hyperthyroxinemia with or without hypertriiodothyroninemia, with TSH serum levels below normal, were present in 20% and 10% of patients affected by FES, respectively. Of the former, 75% were positive for ATA. These results: i) confirm the high prevalence of abnormal thyroid test results in patients affected by AIHA, ITP and FES; ii) demonstrate the higher prevalence of autoimmune hypothyroidism in FES; iii) lead to the possibility of including FES as one of the multiple autoimmune syndromes.