This page focuses on neurocysticercosis, a globally important contributor to neurological illness. It is caused by infestation of the CNS with encysted larvae of Taenia solium. Humans get infected by raw vegetables contaminated with T. Solium eggs or foods carrying tapeworms.
NCC is classified into parenchymal and extra-parenchymal groups. Children mostly have single degenerating parenchymal cysts rather than multiple cysts. Commonly, NCC is seen after five years of age. Symptoms of parenchymal NCC are seizures, raised intracranial pressure, focal neuro-deficits, and cysticercal encephalitis. Most children present with complex partial seizures. Symptoms of extra-parenchymal NCC are ventricular and subarachnoid NCC, spinal cysticercosis, ophthalmic cysticercosis, etc. However, extra-parenchymal NCC is rare in children.
Since pathological confirmation of the parasite is hardly ever feasible, diagnosis rests mainly on neuroimaging. The appearance of cysts (such as vesicular cysts, degenerating or colloid cysts, scolex, etc.) on CT varies with the stage. Most lesions are single small enhancing computed tomographic lesions (SSECTL). Some children may have “starry-sky” parenchymal lesions (i.e., multiple lesions, disseminated NCC with numerous cysts). Subarachnoid NCC CT-image may show hydrocephalus, enhancement of tentorium, and basal cisterns. Identification of scolex and visualization of extra-parenchymal cysts is better with MRI. Additionally, an ETTB assay using purified glycoprotein antigens from T. Solium Cysticerci has shown highly specific results, whereas the widely used ELISA showed 65% specificity in CSF. However, sensitivity is less for patients with either single cysts or calcifications alone. Other tests include X-rays, stool examinations, blood and CSF tests, etc.
Therapeutic measures for NCC are considered symptomatic and surgical treatment for cysts. As most cases present with seizures, antiepileptic drugs (e.g., carbamazepine) are required. The rate of recurrence is generally higher in adults than in children. A short course of corticosteroids (e.g., Prednisolone) is generally used to ameliorate any adverse reaction from a host inflammatory response. However, use of steroids is rarely prescribed for children. Two definitive medical therapies are cyst destruction and seizure control. Praziquantel and albendazole have been found effective in destroying viable cysts. Albendazole is proven to be better than Praziquantel by expense and tolerance. Moreover, it has greater penetration into the subarachnoid space and its bioavailability increases with co-administration of steroids, and it’s not affected by phenytoin and carbamazepine. Albendazole is currently the drug of choice for the treatment of NCC.
A repeat CT after 3-6 months is suggested as a follow-up. The outcome is dependent on the type of NCC, cyst location, and number of cysts. Generally, parenchymal NCC has a better prognosis than extra-parenchymal NCC, and a single lesion has a better outcome as compared to multiple lesions. Most children with seizures and single lesions recover within 6 months. Cases with disseminated NCC have frequent seizure recurrences. Public awareness and insistence on sanitation and hygiene are of the utmost importance in prevention.
Reference:
Singhi, P., Singhi, S. Neurocysticercosis in children. Indian J Pediatr 76, 537–545 (2009).
https://doi.org/10.1007/s12098-009-0139-5
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