Eosinophilic meningitis without peripheral eosinophilia.

PEo was within normal limits (100/ l, 0.7%). CSF analysis showed a value of 26 white blood cells (WBCs) per microliter with predominant Eo (91%) ( table 1 ) and the CSF/serum albumin ratio [CSF albumin (mg/dl)/serum albumin (g/dl)] was normal (4.91). Extensive workups for infectious diseases including viral, bacterial and fungal agents were unremarkable. No malignant cells were detected in the CSF. Parasite studies such as stool examination and enzyme-linked immunosorbent assay (ELISA) for parasite infestations including neurocysticercosis, paragonimiasis, and sparganosis were negative. Brain magnetic resonance imaging (MRI) with gadolinium enhancement was normal. Clinical symptoms improved with methylprednisolone (48 mg/day p.o. for 5 days). No Eo was detected in the follow-up CSF study after 13 days. No additional neurologic illness appeared for over 3 years.