Epigraph Vol. 26 Issue 2, Spring 2024

Neurocysticercosis as the main cause of epilepsy: A misdiagnosis that should be avoided

Leer en español

Read a response to this letter from Dr. Hector H. Garcia

Cite this article: Carpio A, Giagante B. Neurocysticercosis as the main cause of epilepsy: A misdiagnosis that should be avoided. Epigraph 2024; 26(2):74-75.

Dear Editors,

We have reviewed the publication/podcast titled Neurocysticercosis and epileptogenesis (Epigraph Spring 2023; 25(2): 67-72) with great interest, albeit accompanied by concern and surprise. The statement asserting that "Neurocysticercosis (NCC) is one of the most common causes of epilepsy worldwide" is not only incorrect but also potentially misleading to readers unfamiliar with epilepsy epidemiology. Regrettably, the assertion that "NCC is the main cause of epilepsy worldwide" has become a recurrent cliché in recent publications.1-4

This misconception primarily arises from methodological issues. Many studies identifying NCC as a cause of epilepsy rely on cross-sectional designs, employing prevalent rather than incident cases of epilepsy to establish etiology.5 Ideally, in the study of epilepsy etiology, incident cases should be utilized, as prevalent cases cannot reliably differentiate among potential etiological factors preceding epilepsy onset, complicating the establishment of causality.6 To date, there are no prospective long-term cohort studies examining risk factors, such as neurocysticercosis, for incident epilepsy cases.

Additionally, a bias inherent in these studies lies in the definition of epilepsy, often conflating one or multiple seizures with epilepsy. While seizures represent the most common clinical manifestation of NCC, the majority are acute symptomatic seizures resulting from transitional or degenerating cysts and the brain's acute inflammatory response.7 Conversely, individuals experiencing seizures with inactive, calcified cysts are classified as having unprovoked seizures. Thus, distinguishing acute symptomatic seizures from unprovoked seizures is pivotal in assessing the risk of subsequent epilepsy.8 Most individuals with NCC likely experience acute symptomatic seizures, which do not inevitably progress to epilepsy.7,8

A study published in the ILAE's Epilepsia Open journal9 presents findings from a prospective cohort study involving 180 adults presenting with seizures in emergency departments across five Latin American countries. Only 2.9% of the total cohort exhibited evidence of neurocysticercosis, indicating that NCC likely plays a minor role in seizure development and even less in epilepsy onset. This study underscores the importance of not misdiagnosing or overemphasizing NCC as a primary cause of epilepsy, as it may obscure other potential etiologies and result in inappropriate clinical management of individuals with epilepsy. Moreover, mislabeling individuals with NCC as “epileptic” could subject them to unnecessary long-term treatment, potentially leading to adverse effects and significant biopsychosocial and employment-related implications.10

In light of these considerations, it is imperative to exercise caution in attributing epilepsy mainly to neurocysticercosis and to promote a comprehensive understanding of epilepsy etiology among healthcare practitioners and researchers.

Sincerely,

Arturo Carpio, MD
Former Member of the ILAE Epidemiology Commission (2014-2018)
Professor of Neurology, School of Medicine, University of Cuenca, Ecuador
Email: arturo.carpio@ucuenca.edu.ec

Brenda Giagante
Member of the ILAE Argentinian Chapter
Professor, Arturo Jauretche University, Florencio Varela, Buenos Aires, Argentina
Head of Neurosciences Service, El Cruce Dr Nestor Kirchner Hospital
Email: brendagiagante@gmail.com

References

  1. Bustos JA, et al., Calcified Neurocysticercosis: Demographic, Clinical, and Radiological Characteristics of a Large Hospital-Based Patient Cohort. Pathogens. 2023;13(1):26. doi: 10.3390/pathogens13010026
  2. Ta R, Blond BN. The prevalence of and contributors to neurocysticercosis in endemic regions. J Neurol Sci. 2022; 441:120393.
  3. Garcia HH. Parasitic Infections of the Nervous System. Continuum (Minneap Minn). 2021;27(4):943-962. doi: 10.1212/CON.0000000000000986.
  4. Herrick JA, Bustos JA, Clapham P, Garcia HH, Loeb JA, for the Cysticercosis Working Group in Peru, 2020. Unique characteristics of epilepsy development in neurocysticercosis. Am J Trop Med Hyg 2020;103: 639–645.
  5. Thurman DJ, Begley CE, Carpio A, Helmers S, Hesdorffer DC et al. The primary prevention of epilepsy: A report of the Prevention Task Force of the International League Against Epilepsy. Epilepsia. 2018;59(5):905-914.
  6. Rothman KJ, Greenland S. Causation and causal inference in epidemiology. Am J Public Health. 2005; 95(S1 Suppl 1):S144–50
  7. Carpio A, Chang M, Zhang H, Romo ML, Hauser WA, et al. Exploring the complex associations over time among albendazole treatment, cyst evolution, and seizure outcomes in neurocysticercosis. Epilepsia. 2019;60(9):1820-1828.
  8. Beghi E, Carpio A, Forsgren L, Hesdorffer DC, Malmgren K, et al. Recommendation for a definition of acute symptomatic seizure. Epilepsia 2010;51(4):671–5.
  9. Carpio A, Salgado C, DiCapua D, Fleury A, Suastegui R, Giagante B, et al. Causes and prognosis of adults experiencing a first seizure in adulthood: A pilot cohort study conducted in five countries in Latin America. Epilepsia Open. 2024;00:1–9. https://doi.org/10.1002/epi4.12900
  10. de Boer HM. Epilepsy stigma: moving from a global problem to global solutions. Seizure. 2010;19:630–636.

Read a response to this letter from Dr. Hector H. Garcia