Guillain-Barré syndrome mimicking acute methotrexate-associated encephalopathy in an adolescent patient with lymphoblastic lymphoma.

We describe an adolescent case of Guillain-Barré syndrome (GBS) mimicking acute methotrexate-associated encephalopathy during chemotherapy for lymphoblastic lymphoma. Although initial presentations of hemiparesis and irritability were suggestive of acute encephalopathy, the diminished deep tendon reflexes and subsequent rapid progression to flaccid triparesis with bulbar palsy were consistent with GBS. After the initiation of intravenous immunoglobulin therapy her symptoms improved rapidly, and the diagnosis of GBS was confirmed by nerve conduction studies and cerebrospinal fluid examination in recovery phase. GBS should be considered in the differential diagnosis of acute methotrexate-associated encephalopathy, although GBS is a rare neurologic complication.