Helminth parasitic infections of the central nervous system: a diagnostic approach.

Helminth parasitic infections of the central nervous system (CNS) occur worldwide with high prevalence in tropical and subtropical countries. Clinical evaluation of patients is mandatory, and it is convenient to group the clinical manifestations into syndromes: for example space-occupying lesions, meningitis, and encephalitis. The history should focus on residence or travel to endemic areas, diet, activities, intercurrent medical conditions, and associated clinical clues. Direct parasitological diagnosis can be reached by cerebrospinal fluid and cerebral tissue examination either by microscopy, culture, or immunological techniques. Immunodiagnosis by detection of parasite antibodies or antigens in serum could provide indirect evidence of parasitic infections. In addition, various imaging and radiological techniques e.g., computed tomography (CT) scan and magnetic resonance imaging (MRI) complement the diagnostic work-up of CNS diseases. Finally, the helminthic CNS infections of global impact, such as schistosomiasis, neurotoxocariasis, Strongyloides infection, neurotrichinosis, neurocysticercosis, and echinococcosis will be briefly discussed as regards the principal clinical and diagnostic features.