Methotrexate-induced posterior reversible encephalopathy syndrome

What is known and Objective: Posterior reversible encephalopathy syndrome (PRES) is described clinically as an acute neurologic deterioration characterized by headache, change in mental status and seizures. Although the mechanism(s) for this syndrome is not fully understood, PRES results from vasogenic edema in areas of the brain supplied by the posterior circulation. Methotrexate (MTX)-induced neurotoxicity is a well-known complication of therapy in the paediatric population but is uncommon in adults. Details of the Case: We describe a 55-year-old woman with an acute presentation of PRES caused by intrathecal MTX given as part of a treatment regimen for diffuse large B-cell type lymphoma. Both clinical symptoms and radiographic abnormalities resolved 5 days after cessation of treatment. What is new and Conclusion: We describe what we believe to be the first report of intrathecal MTX-induced PRES in an adult. Clinicians should include MTX-induced PRES in the differential diagnosis of acute neurologic changes in patients receiving this medication. The incidence of MTX-induced neurotoxicity may be under recognized in adults.