A rare complication of intrathecal methotrexate in a child with acute lymphoblastic leukemia.

Methotrexate (MTX) is an essential component of chemotherapy for childhood acute lymphoblastic leukemia (ALL). Both intravenous and most commonly intrathecal routes of MTX have been implicated in acute, subacute, and chronic neurotoxicity syndromes. Subacute MTX neurotoxicity occurs within days to weeks after the intravenous or intrathecal therapy and characterized by a distinct presentation with remarkable clinical resemblance to stroke, including hemiparesis, hemisensory deficits, aphasia, dysarthria, dysphagia, and diplopia. Herein the authors describe the clinical and typical neuroimaging features of a female patient with ALL who presented with subacute MTX neurotoxicity that rapidly progressed to a severe clinical condition in a few hours but eventually resolved completely with dexamethasone and folinic acid. Subacute MTX neurotoxicity is a transient neurological dysfunction that should be considered in patients presenting with stroke-like and various neurological symptoms 10 to 14 days after intrathecal therapy and diffusion-weighted magnetic resonance imaging should be undertaken for the correct diagnosis and exclusion of possible ischemic infarct. Discontinuation of subsequent intrathecal MTX therapies should be considered in severe cases and treatment with dexamethasone and folinic acid may help to resolve the symptoms.