Isoniazid-induced Immune Thrombocytopenia
Gaku Kuwabara, Kumiyo Tazoe, Waki Imoto, Kazushi Yamairi, Wataru Shibata, Kazuhiro Oshima, Koichi Yamada, Yasuhiro Takagi, Satoshi Shiraishi, Masayuki Hino, Tomoya Kawaguchi, Hiroshi Kakeya
Abstract
Drug-induced thrombocytopenia occurs through immune-mediated platelet destruction, and its management is challenging during tuberculosis treatment. Although rifampicin is the most common drug causing thrombocytopenia, isoniazid can also cause thrombocytopenia. We herein report a 75-year-old man who developed thrombocytopenia during tuberculosis treatment. Platelet-associated immunoglobulin G and a drug-induced lymphocyte stimulation test for isoniazid were positive; no other causes of thrombocytopenia were identified. The patient was diagnosed with isoniazid-induced immune thrombocytopenia, and the platelet count normalized after isoniazid discontinuation. We describe the immunological mechanism of thrombocytosis due to isoniazid, an uncommon cause of thrombocytopenia that physicians should be aware exists.