Intrathecal methotrexate, central nervous system toxicity, and response to N-methyl-D-aspartate antagonism: An adult case series.

BACKGROUND

Methotrexate (MTX) is administered for the treatment of central nervous system (CNS) hematologic cancers, prophylaxis of CNS dissemination of certain hematological cancers, and in solid tumor leptomeningeal disease. MTX treatment can be limited by CNS toxicity. Dextromethorphan is used to treat MTX neurotoxicity, with most data derived from pediatric case series. In this report, we profile 4 adult patients who developed intrathecal (IT) MTX neurotoxicity to better characterize their response to dextromethorphan treatment.

METHODS

A case series of 4 patients who developed neurologic symptoms attributed to IT MTX neurotoxicity subsequently treated with dextromethorphan was devised. Demographic data, clinical characteristics, electroencephalography results, magnetic resonance imaging, cerebrospinal fluid (CSF) characteristics, and dextromethorphan treatment outcomes were described.

RESULTS

Of the 4 patients developing MTX neurotoxicity, neurologic symptoms developed over a timeframe of 2 to 14 days from the precedent MTX exposure. Radiologic phenotypes included subcortical white matter diffusion-restricting lesions, bi-hemispheric subcortical white matter T2-FLAIR hyperintensities, as well as other findings described in the report. Time elapsed from initiation of dextromethorphan to neurologic symptom resolution ranged from 1 to 2 days.

CONCLUSIONS

The profiles of 4 adult patients developing suspected IT MTX neurotoxicity syndromes with subsequent response to Dextromethorphan add further data to guide the management of such patients.