A case of eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis with unique brain MRI findings

: A 17-year-old Japanese girl was admitted to our hospital because of meningeal irritation, hyperesthesia of extremities, and disturbance of consciousness after having traveled to Okinawa in February, 1996. Examination on admission revealed pleocytosis of CSF with many eosinophils (65%) and increased eosinophils (25%) in the peripheral blood. The history and clinical symptoms were suggestive of a parasitic infection. We diagnosed the patient as having eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis, which was confirmed by immunological tests of double diffusion, counterimmuno-electrophoresis, and ELISA. Magnetic resonance imaging (MRI) of the brain demonstrated multiple small high intensity areas on Gd-DTPA-enhanced T1-weighted images. MRI findings suggested tissue reactions to dead or dying worms, and local vasodilatation associated with minimal thrombus formation.