Potential neurotoxicity associated with methotrexate

This study aimed to elucidate the incidence and characteristics of neurotoxicity in patients receiving methotrexate (MTX) treatment. A retrospective analysis was performed using data from the electronic cohort database spanning from January 1990 to December 2021. This review focused on patients who manifested neurotoxic symptoms post-MTX therapy, excluding patients with peripheral neuropathy. Of the 498 individuals who received MTX, 26 (5.22%) exhibited neurotoxicity. Pediatric patients (< 18 years) accounted for 18 cases (7.44%), whereas adults (> 18 years) comprised eight cases (3.13%). The median onset age was 11 years (range 4-15) in the pediatric cohort and 39.5 years (range 19-67) in the adult cohort. A predominant male predisposition was noted (21 patients, 80.77%). The majority of patients (21, 80.77%) experienced neurotoxic effects following multiple MTX administrations. Modes of MTX delivery included intrathecal (37.0%), intravenous (22.2%), and combined routes (40.7%). Clinical presentations were predominantly encephalopathy (69.2%), followed by encephalomyelopathy (15.4%), myelopathy (11.5%), and polyradiculopathy (3.8%). Fourteen patients recovered (53.85%). Risk factors were male sex, pediatric age (particularly above 10 years), and administration route (intrathecal in adults and intravenous in pediatrics). Although infrequent, MTX-related neurotoxicity has a substantial impact on patient prognosis, with potential development following even a single dose. Its radiological resemblance to diverse neuropathologies, such as cerebral infarction and subacute combined degeneration, necessitates vigilant diagnostic scrutiny.