Evans Syndrome in a Patient with Auto Immune Thyroiditis – A Rare Association

Abstract

A 46-year-old woman, diagnosed with hypothyroidism, was on treatment with synthetic thyroxine 100 micrograms per day for one year. She complained of recent-onset exertional dyspnoea, and had malaise, lethargy, and pica. Investigations revealed significant anaemia and severe thrombocytopenia, necessitating blood transfusion. She had Coombs-positive autoimmune haemolytic anaemia and immune thrombocytopenic purpura, confirming a diagnosis of Evans syndrome. She also had a positive antinuclear antibody test but had no other notable findings of autoimmune disease, suggesting a diagnosis of primary Evans syndrome. The patient was treated with intravenous dexamethasone for four days, followed by oral prednisolone at 1mg/kg/ day, with supplemental calcium and vitamin D. Thyroperoxidase antibody was positive and there was reduced uptake in thyroid scintigraphy, confirming a diagnosis of autoimmune thyroiditis.

Hashimoto’s thyroiditis frequently coexists with non-endocrine autoimmune disorders. Presence of antithyroid antibodies is sometimes observed in Evans syndrome, a condition where there is simultaneous occurrence of autoimmune Haemolytic Anaemia, Cytopoenia and immune thrombocytopenic purpura. However, the development of Evans syndrome in patients with overt hypothyroidism and Hashimoto’s thyroiditis is rare. This case implies the potential existence of a shared immunogenetic pathway among three distinct autoimmune diseases, namely autoimmune haemolytic anemia, immune thrombocytopenic purpura, and Hashimoto’s thyroiditis, in the pathogenesis.