Abstract

Central nervous system (CNS) prophylaxis is an essential component of the treatment in childhood acute lymphoblastic leukemia (ALL). Methotrexate (MTX) is an dispensable antimetabolite for treatment of ALL. High-dose (HD) MTX and intrathecal (IT) MTX have improved the prognosis and reduced the rate of CNS relapse. However, the drug also has a significant toxic effect on the CNS and can potentially lead to severe neurologic morbidity. The overall incidence of acute MTX induced neurotoxicity has been estimated to be 0.8∼10% of treated children, depending on the amounts of MTX and leucovorin in the treatment protocol. Acute neurotoxicity generally develops within 5∼14 days after IT MTX or HD MTX and may include headache, nausea, emesis, lethargy, altered mental status, blurred vision, aphasia, hemiparesis, and seizure. Diffusion weighted MRI shows restricted diffusion of water in brains of patients with ALL who experienced stroke-like event after IT MTX. We report the cinical and imaging findings of acute neurotoxicity in two patients after intrathecal administration of MTX for CNS prophylaxes of ALL.

• Keywords: Methotrexate, Neurotoxicity, Acute lymphoblastic leukemia;