Neurocysticercosis

Neurocysticercosis is an infection of the central nervous system caused by the larval cysticerci of Taenia solium. It is the most common helminthic CNS infection worldwide and a leading cause of acquired epilepsy in endemic areas. Humans acquire it by ingesting eggs from a tapeworm carrier, after which larvae can migrate to the brain, ventricles, or subarachnoid space.

Epidemiology and transmission: Endemic in Latin America, sub-Saharan Africa, and parts of Asia. Transmission occurs via fecal-oral ingestion of eggs from a person with taeniasis; autoinfection can occur. Disease may present as parenchymal brain lesions or extraparenchymal cysts, with lesions passing through vesicular, colloidal, granular-nodular, and calcified stages.

Clinical features and imaging: Seizures are the most common presentation, followed by headaches, focal deficits, and signs of raised intracranial pressure when cysts obstruct CSF flow. Parenchymal disease typically shows multiple cysts; extraparenchymal disease can cause hydrocephalus. CT or MRI may show cysts with or without a visible scolex, inflammatory rings, and calcifications; serology supports diagnosis.

Diagnosis and treatment: Diagnosis combines neuroimaging with serology and clinical criteria. Antiparasitic therapy, usually albendazole or praziquantel, is given with corticosteroids to limit inflammation. Seizures require antiepileptic drugs; management of hydrocephalus or raised intracranial pressure may require neurosurgery. Calcified lesions are inactive and do not require antiparasitics.

Prognosis and prevention: Prognosis is variable; seizures may persist, particularly with calcified lesions. Prevention focuses on sanitation, hygiene, proper cooking of pork, and treatment of tapeworm carriers to reduce transmission.