Abstract
Abstract
Purpose In
trathecal (IT) methotrexate (MTX) overdose is a rare but potentially catastrophic emergency with limited management evidence. We report a 10-fold IT MTX overdose in a pediatric acute lymphoblastic leukemia (ALL) patient managed with a concentration-guided multi-modal strategy, with serial cerebrospinal fluid (CSF) pharmacokinetic data.
Case presentation
An 11-year-old boy with BCR-ABL1-positive ALL inadvertently received 120 mg IT MTX (intended: 12 mg) due to a pharmacy error. Rescue comprised early CSF exchange (40 mL), continuous lumbar drainage (~ 690 mL total), alkalinization, and dynamically titrated leucovorin (~ 500 mg total). CSF MTX fell from 416 µmol/L at 9.5 h to 0.94 µmol/L at 73 h (99.8% reduction). The patient recovered completely without neurological sequelae; chemotherapy resumed on Day 7, and he remained in remission with normal neurocognitive function at 3 months.
Conclusion
A staged strategy combining early CSF exchange, sustained drainage, and concentration-guided leucovorin can ensure complete neurological recovery after a 10-fold IT MTX overdose. The serial pharmacokinetic data provide a practical rescue framework when IT carboxypeptidase-G2 is unavailable.