Abstract
The patient was a 4-year-11-month-old boy with epilepsy with myoclonic astatic seizures. At the age of 3 years and 4 months, he began to have epilepsy, for which valproic acid, clonazepam, and carbamazepine were ineffective, and ethosuximide (ESM) and zonisamide were effective. He was admitted to a local hospital because of protein-losing gastroenteropathy at age 4 years and 2 months. Although he improved with methylprednisolone pulse therapy and intravenous immunoglobulin, he was transferred to our hospital for control of his epileptic seizures, for which ethyl loflazepate was effective. Subsequently, at the age of 4 years and 7 months, he developed thrombocytopenia, followed by aplastic anemia. Although ESM was withdrawn, his bone marrow did not recover. After methylprednisolone pulse therapy and the immunosuppressant cyclosporine, he recovered completely 4 months later. The causative drug was confirmed to be ESM because it was found to inhibit the growth of granulocyte macrophage progenitor cells on an in vitro colony assay, and no drug other than ESM was changed in the acute and recovery phases. Since antinuclear antibody and anti-histone antibody were positive, an immune-mediated, drug adverse reaction was considered to have induced the aplastic anemia. A similar drug adverse reaction was also suspected to be the mechanism of the protein-losing gastroenteropathy.
