Neurotoxicité aiguë secondaire au méthotrexate et « pseudo-stroke » syndrome

Treatment of acute lymphoblastic leukemia requires high-dose systemic and/or intrathecal methotrexate to prevent and/or treat central nervous system disorders. Acute neurotoxicity of methotrexate, of unknown etiopathogenesis, is characterized by the polymorphism of clinical manifestations, responsible for a potentially harmful diagnostic delay in these immunosuppressed patients. We describe five episodes of transient acute leukoencephalopathy mimicking a stroke, reported in the literature as “pseudo-stroke syndrome”. Neurologic symptoms occurred 3-10 days after IV or IT methotrexate and manifested as aphasia and alternating sensorimotor deficit. The fluctuating symptomatology regressed completely within a few days. Brain MRI, which is essential for diagnosis, demonstrated early white matter diffusion restriction in the affected cerebral area. These anomalies disappeared in one week, while hyperintense T2 FLAIR signals developed in the corresponding brain areas. The long-term progression of these pseudo-stroke patients was favorable, without any therapeutic modification. Nevertheless, the involvement of transient acute leukoencephalopathy episodes in the progressive onset of neuro-cognitive disorders is discussed.