Acute ascending myelitis and encephalopathy after intrathecal cytosine arabinoside and methotrexate in an adolescent boy with acute lymphoblastic leukemia.

A 14-year-old boy with acute lymphoblastic leukemia developed acute ascending myelitis followed by encephalopathy after intrathecal administration of methotrexate 15 mg and cytosine arabinoside 50 mg. The patient had none of the risk factors noted previously in other patients with intrathecal therapy (IT) induced neurotoxicity. The doses administered were within the standard scales, and toxicity developed in the second boost of IT 20 days after the first one. There may not be any parameters to predict the occurrence of such severe and rare form of CNS neurotoxicity attributed to IT.