Cysticercosis - Taenia Solium

  • Diagnosis
  • Background
  • Lab Tests
  • References
  • Related Content

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

Indications for Laboratory Testing

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 Western Blot 0055283
Method: Qualitative Western Blot

Limitations

Consider testing for contamination by blood or transfer of serum antibodies across the blood-brain barrier

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

Cysticercosis Antibody, IgG by Western Blot (CSF) 0055282
Method: Qualitative Western Blot

Limitations

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 O. 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 B. 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: January 2016