this study was a prospective case series of patients who visited any of a network of 11 geographically diverse , university - affiliated , urban emergency departments ( emergency i d net ) from july 1996 to september 1998 . a more detailed description of emergency i d net , including its administration and the processes of data transfer and compilation , has been published ( 14 ) . emergency department patients > 5 years of age were enrolled in the study if they had a known or suspected seizure and had undergone neuroimaging , either computed tomography scanning ( ct ) or magnetic resonance imaging ( mri ) . patients < 5 years of age were excluded to avoid enrolling a potentially large number of patients with febrile seizures . the treating physician recorded demographic and clinical data including age , sex , race , immigrant status , foreign travel , prior seizure history , seizure type , ct and mri findings , presumptive diagnosis , and disposition . when blood was drawn from a patient as part of the evaluation , serum specimens from 890 of the 1,801 patients enrolled were sent to the centers for disease control and prevention so that serologic testing for cysticercosis could be performed . serum samples were tested by enzyme - linked immunoelectrotransfer blot for taenia solium  specific antibodies , as described ( 15,16 ) . briefly , this assay uses seven purified glycoprotein antigens from larval cysts of t. solium , namely , gp50 , gp42 - 39 , gp24 , gp21 , gp18 , gp14 , and gp13 , where the prefix gp stands for glycoprotein and the number indicates the molecular mass in kilodaltons . reactions to at least one antigen band are considered positive ( 15,16 ) . on the basis of a classification scheme proposed by del brutto ( 17 ) , our case definition for neurocysticercosis required either 1 ) ct scan finding(s ) characteristic of neurocysticercosis ( i.e. , multiple calcifications or multiple cystic lesions ) with or without a positive serologic test , or 2 ) ct scan finding(s ) consistent with neurocysticercosis ( i.e. , a single cystic , calcified , or hypodense lesion ) and a positive serologic test . radiologists at each site read ct scans without regard for or knowledge of the study . study coordinators at each site then abstracted the absence or presence of findings relevant to the study from the radiology reports . simple descriptive statistics were used to summarize the clinical features of patients with and without neurocysticercosis . relative risk ratios ( rrs ) and their corresponding 95% confidence intervals ( cis ) were determined by fisher s exact test . a total of 1,801 eligible patients with 1,833 emergency department visits were enrolled during the 2-year study period . twenty - eight patients had multiple visits ; four patients underwent evaluation on three separate occasions ( table 1 ) . a diverse group of seizure patients were enrolled in the study ( table 2 ) . the median age ( interquartile range ) in yrs for these patients was 40 ( range 3051 yrs ) . other category includes six patients with recent neurosurgery , three with toxic levels of anticonvulsant medications , three with reactions to non - anticonvulsant medication , three with systemic lupus erythematosus , and several other less frequently occurring causes . from the entire study population , 2.1% ( 38 ) patients met the case definition for neurocysticercosis ( table 3 ) . of patients who underwent both ct scanning and serologic testing , 2.9% met the case definition . thirty - four patients satisfied the case definition based on classic ct scan findings , and four satisfied the case definition based on a positive serologic test coupled with ct scan findings consistent with neurocysticercosis . neurocysticercosis was identified at 9 of the 11 study sites ; 6 sites enrolled more than one patient ( table 3 ) . patients with this disease tended to be younger than patients who did not meet the case definition ( table 4 ) . patients were also more likely to be hispanic , have been born outside the united states , have visited or lived in an endemic region , be uninsured , and have a reported history of neurocysticercosis . overall , approximately 9% of patients with hispanic ethnicity who came to an emergency room with a seizure met the case definition for neurocysticercosis . the prevalence of the disease in the hispanic patients with seizures ranged from 9% to 13.5% in the highest risk sites . a patient was a person who met the case definition for neurocysticercosis . the median age for neurocysticercosis patients was 32 yrs , with a range of 2544 yrs ; the median age of non - neurocysticercosis patients was 40 yrs ( range 3052 yrs ) . n = 1,343 ; immigrant status was not collected from the first 490 patients enrolled . na , not applicable . comparison was not done since serology was part of the case definition for neurocysticercosis . patients meeting the case definition for neurocysticercosis were not more likely to have a new - onset seizure ( versus having an established history of seizures ; rr 1.1 ; ci 0.56 to 2.01 ) . neurocysticercosis patients were , however , more likely to have focal motor or partial complex seizures than those without neurocysticercosis ( rr 2.6 ; ci 1.3 to 5.5 ) ( table 4 ) . serologic testing was performed on 49.4% ( 890 ) of the 1,801 patients enrolled , and results were positive in 2% ( 18 ) cases . no significant differences were detected in age , seizure history , seizure type , prior history of neurocysticercosis , immigrant status , or exposure to an endemic region between the patients who underwent serologic testing and those who did not . nine of the seropositive patients had ct scan findings consistent with neurocysticercosis ; nine did not . compared with the seronegative patients , seropositive patients were more likely to be hispanic ( rr 8.7 ; ci 3.1 to 24.1 ) , have visited or lived in a neurocysticercosis - endemic region ( rr 6.8 ; ci 2.2 to 20.5 ) , and have an abnormal ct scan ( rr 1.7 ; ci 1.2 to 2.3 ) . seropositivity was not significantly associated with either new - onset seizures or prior seizure history . serology was positive in 27% of the patients who had neuroimaging findings characteristic of neurocysticercosis , 5.3% of those with consistent neuroimaging findings , and 1.1% of those with neuroimaging findings inconsistent with neurocysticercosis . four ( 57% ) of these patients had neuroimaging findings typical of or consistent with neurocysticercosis . serologic testing was performed on two of the seven patients with one negative and one positive result . the use of our case definition identified two patients who were not diagnosed with neurocysticercosis by the emergency department physician but who were later clinically diagnosed with neurocysticercosis . one was a child born in the united states to laotian parents whose travel history was unknown ; the other was a man of hispanic ethnicity whose travel history and immigration status were not available . on the other hand , half of the patients diagnosed with neurocysticercosis by their treating physician did not satisfy our case definition . immigrants continue to make up an increasing proportion of the u.s . population . by some reports , they will constitute up to 60% of the new immigrants and new births over the next few decades ( 18,19 ) . by the year 2037 , latinos will outnumber whites as the dominant ethnic group in california , mirroring a population surge that is sweeping across the southwest ( 20 ) . because neurocysticercosis is endemic in many of the countries from which these persons are emigrating , its presence in the united states reflects these immigration trends . previous etiologic surveys of seizures in the united states and other industrialized countries have focused on brain tumors , strokes , and birth defects ( 2123 ) . infections such as toxoplasmosis and meningitis or meningoencephalitis constitute a small minority of causes in seizure patients . more recently , hiv and its attendant complications have become prominent causes of adult - onset seizures ( 23 ) . neurocysticercosis , while a prominent cause of seizures in less developed nations , has not appeared in these studies . an increasing number of neurocysticercosis cases ( 510 ) have been reported throughout the united states , which suggests that the prevalence of this disease may be on the rise . because these previous case series were conducted retrospectively , primarily through chart reviews over periods as long as a decade , understanding the epidemiology and impact of neurocysticercosis is difficult . to our knowledge , this prospective study is the first to address the prevalence of neurocysticercosis in seizure patients in the united states . neurocysticercosis was identified at 9 of 11 sites and was responsible for 2.1% of seizures overall . in some sites , e.g. , los angeles , california , and albuquerque , new mexico , studies on the epidemiology of seizures and now appears in our study as the cause of up to 10% of seizures in some areas suggests a substantial increase in frequency of this disease . area hospital corroborates this finding : 12% of the seizures seen in the authors emergency department were attributable to neurocysticercosis ( 24 ) . previous reports on neurocysticercosis in the united states , mostly retrospective case series , have focused on the clinical and epidemiologic aspects of the disease ( 510 ) those studies are somewhat limited by the inadequacies and incompleteness inherent in retrospective data collection . it also seems problematic when epidemiologic information ( e.g. , exposure to a disease - endemic area ) constitutes part of the case definition / inclusion criteria ( e.g. , exposure to cysticercosis - endemic area ) but then epidemiologic information is subsequently reported as a result ( e.g. , percentage of patients who had visited an area where cysticercosis is endemic ) . in contrast , our data were collected at the time of evaluation , and our case definition was based solely on clinical criteria . as such , our study provides additional corroboration to the findings of previous studies reporting strong associations between neurocysticercosis and hispanic ethnicity , immigrant status , and prior exposure to disease - endemic regions . neurocysticercosis patients were also more likely to be uninsured ; however , lack of insurance was also associated with being hispanic and an immigrant . consistent with previous studies , most neurocysticercosis patients did come to the emergency department with a generalized tonic clonic seizure , but such patients were more likely to have focal motor or partial complex seizures than were the seizure patients without neurocysticercosis . on the basis of our results , neurocysticercosis must be strongly considered in emergency department seizure patients of hispanic descent since nearly 1 in 10 were affected , a figure that was even higher in certain areas . from 1988 through 1990 , 7.2% of neurocysticercosis cases reported to the los angeles department of health services were locally acquired ( 25 ) . the rate of domestic acquisition has been even higher ( 17% to 26% ) in some studies of pediatric neurocysticercosis ( 6,8 ) . these rates of domestic acquisition appear to have increased from earlier studies in the late 1970s and early 1980s , when the rates were in the range of 2% to 3% . because years can pass before symptoms develop the average cost of hospitalization for seizures in one study was $ 1,615 per patient , not including physician charges ( 26 ) . compared with the general population , seizure patients are seen in the emergency departments 2 times more frequently , admitted to the hospital 3 times more frequently , and treated by specialists 3 times more frequently ; they also receive psychological counseling 7 times more frequently ( 27 ) these figures still underestimate the true economic impact of neurocysticercosis because up to 30% of patients who visit an emergency room do not have seizures but rather a variety of other neurologic symptoms such as headache , visual changes , ataxia , and confusion . the only true measure for the diagnosis of neurocysticercosis is brain biopsy , which is clearly impractical . this study therefore implemented a case definition that incorporates the classification scheme proposed by del brutto ( 17 ) but is therefore limited by the predictive value of ct scan and serology . serology has previously been demonstrated to be sensitive in cases with multiple cysts ( 94% ) but less sensitive with single cysts or calcified lesions ( 28% ) ( 28 ) . we found a considerable discrepancy between patients who were diagnosed with neurocysticercosis by their physicians and patients who met our case definition . because we did not specifically ask the treating physicians how they arrived at their diagnosis , the exact reasons for this discrepancy are unclear . however , emergency room physicians appear to rely considerably on epidemiologic information when diagnosing neurocysticercosis . of patients diagnosed by their physicians , 98% were hispanic ( compared with our 76% ) and 80% were immigrants ( compared with our 50% ) . additional limitations to the study include the fact that the participating network sites are university - affiliated emergency departments . this fact may limit the generalizability of our results to other patient populations . ideally , serologic testing would have been performed on all patients , but laboratory testing is not routinely performed for all seizure patients seen in emergency departments . patients who did undergo serologic testing were , however , not statistically different from those who did not , on the basis of the demographic information collected . in summary , while neurocysticercosis accounts for a small proportion ( 2.1% ) of all seizures in university - affiliated , u.s . emergency department patients , its geographic distribution appears diverse ; the highest concentration is in the southwest and in hispanics . our observations are consistent with current immigration trends that suggest the growing importance of neurocysticercosis in the united states . continued surveillance and further studies of screening and treatment strategies
neurocysticercosis appears to be on the rise in the united states , based on immigration patterns and published cases series , including reports of domestic acquisition . 
 we used a collaborative network of u.s . 
 emergency departments to characterize the epidemiology of neurocysticercosis in seizure patients . 
 data were collected prospectively at 11 university - affiliated , geographically diverse , urban u.s . 
 emergency departments from july 1996 to september 1998 . 
 patients with a seizure who underwent neuroimaging were included . 
 of the 1,801 patients enrolled in the study , 38 ( 2.1% ) had seizures attributable to neurocysticercosis . 
 the disease was detected in 9 of the 11 sites and was associated with hispanic ethnicity , immigrant status , and exposure to areas where neurocysticercosis is endemic . 
 this disease appears to be widely distributed and highly prevalent in certain populations ( e.g. , hispanic patients ) and areas ( e.g. , southwest ) .