Cerebral and spinal schistosomiasis.

Cerebral schistosomiasis and spinal schistosomiasis are severe underrecognized complications of Schistosoma sp. infection, and can occur at any time during the parasitic infection. Neuroschistosomiasis has been increasingly reported not only in endemic areas but also in Western countries owing to immigration and international travel. Immunogenic interaction between schistosome egg deposition and the delayed hypersensitivity reaction of the host are the main neuropathogenic mechanisms involved. Eggs induce a periovular granulomatous reaction in the tissues. In some cases, schistosome adult worms may aberrantly migrate to the central nervous system via the vertebral venous plexus and place the ova at an ectopic site. Headache and seizures are common in cerebral schistosomiasis, and intracranial hypertension and hydrocephalus may occur in tumour-like and cerebellar schistosomiasis. Spinal schistosomiasis may manifest itself as acute myelitis and/or myeloradiculopathy. Recognition of neuroschistosomiasis is important so that early treatment with praziquantel and steroids can be started in an attempt to prevent severe disability.