Cysticercosis is a parasitic infection caused by the larval stage of the pork tapeworm, Taenia solium . Diagnosis usually involves both serological testing and brain imaging.
Tabs Content Clinical Overview Diagnosis
Indications for Testing
Seizures or hydrocephalus not caused by common etiologies
Calcitic cysts on CT scan
Criteria for Diagnosis
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 cerebrospinal fluid (CSF) by ELISA
Evidence of cysticercosis outside the central nervous system (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
One absolute criterion
Two major, one minor, and one epidemiologic criteria
Probable
One major and two minor criteria
One major, one minor, and one epidemiologic criteria
Three minor and one epidemiologic criteria
Laboratory Testing
CDC cysticercosis resources for health professionals and diagnosis recommendations Testing for consensus criteria
CSF antibody by ELISA with confirmation by Western blot
Serology – limited diagnostic use as a single test (variable sensitivity/specificity)
May be useful if used with imaging data
ELISA as initial testing in either serum or CSF
Confirm ELISA with Western blot – more sensitive (available at some laboratories; not currently available at ARUP Laboratories)
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
Background
Epidemiology
Incidence
Endemic in Mexico, Central America, 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
ARUP Lab Tests
Detect the presence of CSF IgG antibodies to T. solium if clinical suspicion of cysticercosis exists
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
Detect presence of IgG antibodies to T. solium in serum if clinical suspicion of cysticercosis exists
Patients with collagen vascular diseases, hepatic cirrhosis, schistosomiasis, and other parasitic infections can produce false-positive results
Related Topics Last Update: October 2019
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