Clinical Pearls & Morning Reports
Cysticercosis is the most common cause of acquired epilepsy worldwide. The disease results from ingestion of eggs from the tapeworm Taenia solium. At first, the disease is relatively indolent, because the eggs form cysts that do not generate a clinically significant immune response for approximately 5 years. Read the NEJM Case Records of the Massachusetts General Hospital here.
Q: Is cysticercosis prevalent in any locations in the United States?
A: This disease is endemic in areas of Asia and Central America; in these areas, 10 to 50% of patients with epilepsy have evidence of neurocysticercosis on cerebral imaging. There are also locations in the United States where cysticercosis is highly prevalent, including Southern California, Texas, and New York City.
Q: What regions of the central nervous system may be affected in cases of neurocysticercosis?
A: Neurocysticercosis can be present in intraparenchymal, intraventricular, meningeal, spinal, and ocular locations. The forms can be active (viable cysts with scolex, rarely associated with symptomatic disease), transitional (degenerating cysts in the colloidal and necrotic stages with adjacent edema, commonly associated with seizures), or inactive (calcifications or meningeal fibrosis).
A: The diagnosis usually relies on recognition of an appropriate clinical situation with supportive epidemiologic and neuroimaging features and less often relies on serologic testing. The consensus guidelines recommend that both CT and MRI, the latter with three-dimensional volumetric sequencing such as fast imaging employing steady-state acquisition (FIESTA) sequences, be performed for the evaluation of patients with probable neurocysticercosis. CT can delineate calcifications; MRI provides finer resolution, may allow for visualization of internal structures such as protoscolices, and assesses the degree of lesional enhancement and perilesional edema. The consensus guidelines suggest that the enzyme-linked immunoelectrotransfer blot assay is the preferred serologic test.
A: Four approaches should be considered in the treatment of patients with neurocysticercosis: use of antiparasitic agents such as albendazole and praziquantel, use of antiinflammatory agents such as glucocorticoids, use of antiseizure agents (if seizures are part of the clinical scenario), and mechanical interventions such as placement of a ventriculoperitoneal shunt or endoscopic removal of intraventricular cysts (if indicated). For each patient, the appropriate treatment is determined by the clinical situation and the type of parasitic involvement of the CNS. The consensus guidelines recommend that patients with three or more viable intraparenchymal cysts be treated with combination antiparasitic therapy (albendazole and praziquantel) and that patients with one or two viable cysts be treated with albendazole alone. For patients with a sole cyst that is degenerating, treatment with albendazole, glucocorticoids, and antiseizure agents is recommended. For patients with isolated calcifications, the consensus guidelines recommend against treatment with an antiparasitic agent.