Methotrexate-Induced Stroke-Like Syndrome: A Typical Presentation of a Rare Complication

Methotrexate (MTX) is one of the mainstay drugs used in acute lymphoblastic leukemia (ALL) management; however, it can cause damage to the central nervous system (CNS), typically to the subcortical white matter. Stroke-like syndrome is one particular form of MTX-related neurotoxicity that occurs within 21 days of methotrexate administration (intrathecal or high-dose intravenous treatment). The clinical picture comprehends fluctuating neurological symptoms evoking acute cerebral ischemia or hemorrhage (paresis or paralysis, speech disorders - aphasia and/or dysarthria, altered mental status, and occasionally seizures), with spontaneous resolution in the majority of cases, without other identifiable cause. The typical neuroimage includes areas of restricted diffusion on diffusion-weighted imaging and non-enhancing T2 hyper-intense lesions in the white matter, on brain MRI. We report a 12-year-old boy with low-risk B-ALL without CNS involvement, who presented to the emergency department with complaints of sudden paresis of the four limbs (more severe on the right side), aphasia, and confusion. He had received one dose of intrathecal MTX 11 days prior to this episode. An angio-MRI of the brain revealed bilateral restricted diffusion areas in the centrum semiovale, and symptoms fluctuated until complete neurological recovery without any medical intervention, which is very suggestive of MTX-related neurotoxicity. This case illustrates a rare complication of MTX administration that presented with typical clinical and radiological characteristics, in an adolescent with hematological malignancy who experienced swift and full neurological recovery.

Cytotoxic Lesion in the Splenium of Corpus Callosum Secondary to Subacute Methotrexate Neurotoxicity

Methotrexate neurotoxicity can present with a wide spectrum of neurologic symptoms and brain magnetic resonance imaging (MRI) typically demonstrates cerebral edema, demyelination, multifocal white matter necrosis, and atrophy relatively selective for the deep cerebral white matter. Here, we report a case of subacute methotrexate neurotoxicity in a 40-year-old man with B cell acute lymphoblastic leukemia. Brain MRI showed cytotoxic lesion in the splenium of corpus callosum and left middle cerebellar peduncle. Patient significantly improved 24 hours after receiving oral dextromethorphan. Methotrexate neurotoxicity should be suspected in any symptomatic patient receiving high dose of methotrexate or intrathecal methotrexate therapy. Dextromethorphan should be considered in these patients as it can modulate the excitatory responses to homocysteine and its metabolite which are usually elevated in such patients.