Two Cases of Hyperthyroidism Associated with Idiopathic Thrombocytopenic Purpura

Case 1 : A 27-year-old female was referred to our hospital because of hyperthyroidism and idiopathic thrombocytopenic purpura (ITP). Laboratory examination revealed marked thrombocytopenia (1,000/mm^3) and slightly increase of megakaryocytes in the bone marrow. Serum levels of T_3, T_4 and PBI were 265 ng/dl, 11μg/dl and 8.2μg/dl, respectively. She was treated with prednisolone and methimazole, and her good improvement was observed after correction of the thyroid function. Case 2 : A27-year-old female was referred to our hospital because of hyperthyroidism and ITP. She was treated with propylthiouracil for 2 years before admission. Laboratory examination revealed marked thrombocytopenia (7,000/mm^3), iron deficiency anemia (Hb 7.3g/dl) and increase of megakaryocytes in the bone marrow. Thyroid function was in euthyroid state on admission. (T_3 91ng/dl, T_4 9.7 μg/dl, PBI 6.5 μg/dl) Her platelets were effectively increased soon after prednisolone administration. She took only 50 mg of propylthiouracil after splenectomy, which induced remission of ITP. The incidence of hyperthyroidism with ITP (5.9%), or ITP with hyperthyroidism (0.7%) in our ward is very high compared with general incidence of each disease. The platelet counts returned to normal range after hyperthyroidism was well treated. The observation of these cases suggests that hyperthyroidism probably influences thrombocytopenia, and close relation between ITP and hyperthyroidism.