Obstructive hydrocephalus due to CNS toxocariasis.

A 46-year-old man developed intermittent headache, diplopia, and visual obscuration for two months. Funduscopic examination showed optic disk swelling in both eyes. Brain MRI exhibited hydrocephalus and leptomeningeal enhancement at the prepontine cistern, left cerebellopontine angle cistern and bilateral cerebral hemisphere, and hemosiderin deposition along the cerebellar folia. CSF analysis revealed an elevated opening pressure with xanthochromic appearance and small amount of red blood cells. Antibody titer against Toxocariasis using ELISA was elevated both in blood and CSF. Obstructive hydrocephalus and hemosiderin deposition in this case may result from the active inflammatory process due to CNS toxocariasis within the subarachnoid space.