Subacute neurological deficits and respiratory insufficiency due to intrathecal methotrexate

BACKGROUND AND AIM: We present a case of a 22-year-old male diagnosed with B-cell acute lymphoblastic leukemia who received intrathecal (IT) methotrexate (MTX) in addition to his systemic chemotherapy regime. During induction treatment, he presented with a rapidly progressive bilateral paresis, anarthria, and respiratory insufficiency requiring intubation. The brain magnetic resonance imaging showed bilateral lesions with diffusion restriction of the corona radiata/centrum semi-ovale without other abnormalities. He recovered spontaneously without neurological sequelae. The clinical course combined with the radiological findings is suspect for an IT-MTX-induced leukoencephalopathy. RELEVANCE FOR PATIENTS: Although neurological deficits after IT-MTX are rare and in most cases self-limiting, it should be recognized as a cause for rapid neurological decline after excluding other causes.