Neurocysticercosis : Clinical Manifestations and Assessments

Abstract

Background : In patients who have symptoms of epilepsy and other neurological deficits, one of the most common parasitic infections is neurocysticercosis (NCC) caused by Cysticercus cellulosae, the larval form of Taenia solium. In order to evaluate the characteristics of this illness which define the diagnosis, we assessed clinical manifestations, a positive ELISA for cysticercosis and neurological imaging in patients suspected of having NCC at a teaching hospital.
Methods : This retrospective cohort study assessed 44 patients, who had laboratory results and clinical manifestations compatible with a diagnosis of NCC, between November 1998 and November 2001. The criteria for diagnosing this illness modified from these of Del Brutto and colleagues' criteria. All patients were investigated with serum ELISA, 18 with CSF ELISA, if there was no contraindication. T. solium vesicular cyst soluble antigen was used for the detection of cysticercosis  (T. solium) antibodies by solid-phase enzyme immunoassay. 35 patients were further investigated by a computerized tomography (CT) scan of central nervous system (CNS), if the results of other investigations were inconclusive. Using these criteria, we stratified all patients into three groups: possible NCC (19), probable NCC (10), and definite NCC (15). All definite patients were further examined with ELISA for Angiostrongylus cantonensis and Western blot for Gnathostoma spinigerum in order to look for cross-reactivity of the ELISA for cysticercosis.
Results : In this study, a prevalence of NCC (34.1%) in the group of patients in whom there was clinical suspicion of NCC makes us concerned that Thailand is still an endemic area for this disease. The three most common clinical presentations were seizures, neurological deficit, and signs of increased intracranial pressure. Serum ELISA showed a sensitivity of 33.3% and a specificity of 93.1%. CSF ELISA showed a sensitivity of 40.0% and a specificity of 100%. CT scan brain showed a high sensitivity (92.9%) with a modest specificity (52.4%). Cross-reaction with other parasitic proteins was found with A. cantonensis (6.7%), but not with G. spinigerum.
Conclusion : NCC is still endemic in Thailand. In the approach to this illness, we conclud that the diagnosis of NCC should be based on the patient's history and physical signs in conbination with radiological and serological investigations. Moreover, in areas where A. cantonensis and G. spinigerum were also prevalent, case should be taken in the interpretation of a positive ELISA for cystercercosis because of cross-reactivity with antibodies to A. cantonensis which should be checked individually.