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Neurocysticercosis is responsible for increased rates of seizures and epilepsy in endemic regions. The most common form of the disease, chronic calcific neurocysticercosis, is the end result of the host's inflammatory response to the larval cysticercus of Taenia solium. There is increasing evidence indicating that calcific cysticercosis is not clinically inactive but a cause of seizures or focal symptoms in this population. Perilesional edema is at times also present around implicated calcified foci. A better understanding of the natural history, frequency, epidemiology, and pathophysiology of calcific cysticercosis and associated disease manifestations is needed to define its importance, treatment, and prevention.Neurocysticercosis is a major cause of seizures and other neurologic problems in many less developed countries 1 and a significant health concern in developed countries as well, mostly due to migration of infected persons. 2 Over the last two decades the development of MRI and CT imaging, effective and safe cysticidal drugs, and specific and relatively sensitive serologic tests have given rise to a renaissance in our understanding of the disease and efficacy of treatments. Much of our increased understanding has focused on disease associated with viable or degenerating cysts, broadly referred to as "active" cysticercosis, Copyright © 2004 Life cycleHumans harbor the tapeworm that is acquired by eating poorly cooked pork containing cysticerci of Taenia solium. Ova or proglottids containing ova are excreted in the feces and when ingested by free roaming pigs develop into cysts primarily in the muscles and brain. The usual life cycle is fulfilled after humans ingest undercooked pork. Ova, accidentally ingested by humans, also develop into cysts, mostly in the brain, muscle, and subcutaneous tissues, and this condition is referred to as cysticercosis. 5 Course of infectionAlthough incompletely documented, a reasonable view of the natural history can be ascertained from pathologic, radiologic, and parasitologic studies. Cysticercosis and epilepsyWhile many patients present with single or groups of seizures at various stages of this disease, not all patients develop recurrent seizures, or epilepsy. There are three possibly different scenarios concerning the relationship between cysticercosis and epilepsy: 1) causal relationship, namely, cysticercosis as the cause of focal epilepsies; 2) non causal relationship or simple overlap of two independent and unrelated diseases; and 3) dual pathology. At present there is overwhelming evidence supporting neurocysticercosis as a cause of seizures and epilepsy. Because neurocysticercosis, particularly calcific cysticercosis, is so common in endemic regions (see below), it is likely that two pathologies known to incite seizure activity will be present in some individuals 12 and whether there are interactions or dual pathology between two conditions is speculative. 12 Multiple causes of seizures in cysticercosisThere are multiple ways that cysticercosis can ca...

Background Cysticercosis due to Taenia solium is a leading cause of adult acquired seizures and epilepsy that frequently occurs in patients with only calcified larval cysts. Transient episodes of perilesional brain edema occur around calcified foci but its importance, association with seizures, incidence, and pathophysiology are unknown. Methods One hundred and ten persons with only calcified lesions and a history of seizures or severe headaches were followed prospectively in a cohort design to assess the incidence of seizure relapses. In a nested case-control sub study, perilesional edema was assessed by MRI at the time a seizure occurred in the symptomatic patient and in a matched asymptomatic control, amongst the 110 followed. Results Median follow up was 32.33 months (SD 19.99). Twenty-nine people had an incident seizure with an estimated 5 year seizure incidence of 36%. Twenty-four patients of the 29 with seizure relapse had an MRI evaluation within five days of the event. Perilesional edema was found in 12 (50.0%) compared to 2 of 23 asymptomatic matched controls (8.7%). Conclusions Perilesional edema occurs frequently and is associated with episodic seizure activity in calcified neurocysticercosis. Our findings are likely representative of symptomatic patients in endemic regions and suggest a unique and possibly preventable cause of seizures in this population.

Here we put forward a roadmap that summarizes important questions that need to be answered to determine more effective and safer treatments. A key concept in management of neurocysticercosis is the understanding that infection and disease due to neurocysticercosis are variable and thus different clinical approaches and treatments are required. Despite recent advances, treatments remain either suboptimal or based on poorly controlled or anecdotal experience. A better understanding of basic pathophysiologic mechanisms including parasite survival and evolution, nature of the inflammatory response, and the genesis of seizures, epilepsy, and mechanisms of anthelmintic action should lead to improved therapies.