Cysticercosis - Taenia Solium

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • Seizures, hydrocephalus not caused by common etiologies
  • Calcitic cysts on CT

Criteria for Diagnosis

  • Proposed diagnostic criteria for human cysticercosis
    • Absolute criteria
      • Demonstration of cysticerci by histologic or microscopic examination of biopsy materials
      • Visualization of the parasite in the eye by funduscopy
      • Neuroradiologic demonstration of cystic lesions containing a characteristic scolex
    • Major criteria
      • Neuroradiologic lesions suggestive of neurocysticercosis
      • Demonstration of antibodies to cysticerci in serum by enzyme-linked immunoelectrotransfer blot
      • Resolution of intracranial cystic lesions spontaneously or after therapy with albendazole or praziquantel alone
    • Minor criteria
      • Lesions compatible with neurocysticercosis detected by neuroimaging studies
      • Clinical manifestations suggestive of neurocysticercosis
      • Demonstration of antibodies to cysticerci or cysticercal antigen in CSF by ELISA
      • Evidence of cysticercosis outside the CNS (eg, cigar-shaped soft-tissue calcifications)
    • Epidemiologic criteria
      • Residence in a cysticercosis-endemic area
      • Frequent travel to a cysticercosis-endemic area
      • Household contact with an individual infected with Taenia solium
    • Key for diagnostic interpretation
      • Confirmation
        • 1 absolute criteria
        • 2 major, 1 minor, and 1 epidemiologic criteria
      • Probable
        • 1 major and 2 minor
        • 1 major, 1 minor, and 1 epidemiologic
        • 3 minor and 1 epidemiologic

Laboratory Testing

Imaging Studies

  • Diagnosis is most often made by MRI or CT brain scans; addition of serologic screening by ELISA with confirmation by Western blot increases sensitivity of diagnosis of cysticercosis
    • CT scan – high sensitivity and specificity; lower for ventricular or cisternal forms
      • Single or multiple rounded lesions of low density with a small hyperdense mural nodule representing the scolex (starry night appearance)
    • MRI – more sensitive than CT; much more expensive

Differential Diagnosis

Cysticercosis is a parasitic infection caused by the larval stage of the pork tapeworm, Taenia solium.

Epidemiology

  • Incidence
    • Endemic in Mexico, Central and South America
    • Etiological agent in 10% of new onset seizures
  • Sex – M:F equal

Organism

  • Humans can be definitive host (adult worm in intestine) or dead-end intermediate host (cysticercosis)
  • Humans are incidental hosts by contact with contaminated water or undercooked pork
  • Human disease depends on site of infection
    • Tapeworm in intestine
    • Larval forms in tissues
  • Symptoms begin when cyst dies; depends on where the cysts are located
  • Dying cyst releases antigenic material, triggering the host inflammatory response

Clinical Presentation

  • Initial infection often asymptomatic
    • Rapid onset dependent on number of cysts and body site affected
  • Parenchymal
    • Most common form
    • Enhancing lesions
    • Often asymptomatic – found incidentally during imaging
    • Seizures
  • Extraparenchymal
  • Ocular cysts
    • Usually vitreous; can be subretinal
    • Blurry or disturbed vision, swelling or retinal detachment
Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Cysticercosis Antibody, IgG by ELISA 0055284
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Limitations 

Most sensitive in disseminated disease

Due to the cross-reactivity that exists between cysticercosis and echinococcus antibodies (approximately 23%) a positive result by ELISA should be confirmed by Western blot 

Follow-up 

CT or MRI suggested for neurologic presentations of the disease

Cysticercosis Antibody, IgG by ELISA (CSF) 0055285
Method: Semi-Quantitative Enzyme-Linked Immunosorbent Assay

Limitations 

Diagnosis of central nervous system infections can be accomplished by demonstrating the presence of intrathecally-produced specific antibody

Interpretation of results may be complicated by low antibody levels found in CSF, passive transfer of antibody from blood, and contamination via bloody taps

Follow-up 

CT or MRI suggested for neurologic presentations of the disease

General References

Brunetti E, White C. Cestode infestations: hydatid disease and cysticercosis. Infect Dis Clin North Am. 2012; 26(2): 421-35. PubMed

Del Brutto OH. Neurocysticercosis: a review. ScientificWorldJournal. 2012; 2012: 159821. PubMed

Kraft R. Cysticercosis: an emerging parasitic disease. Am Fam Physician. 2007; 76(1): 91-6. PubMed

Ramírez-Zamora A, Alarcón T. Management of neurocysticercosis. Neurol Res. 2010; 32(3): 229-37. PubMed

Sinha S, Sharma BS. Neurocysticercosis: a review of current status and management. J Clin Neurosci. 2009; 16(7): 867-76. PubMed

Sotelo J. Clinical manifestations, diagnosis, and treatment of neurocysticercosis. Curr Neurol Neurosci Rep. 2011; 11(6): 529-35. PubMed

Medical Reviewers

Last Update: August 2016