Ask the Experts - Treatment of Neurocysticercosis and Related Seizures?
A 45-year-old woman has a solitary cysticercosis lesion in the right parietal region (seen on MRI scan) leading to seizures. Her seizures have been controlled with phenytoin. Should she be given anthelmintics such as mebendazole or praziquantel? In view of possible hirsutism as a side effect of phenytoin, what other antiepileptics can be given and how should the medication be changed over?

Ramesh Rau, MD

Neurocysticercosis can be divided into active, transitional, and inactive stages based on the patient's clinical presentations and the radiologic appearance of the lesions (eg, MRI reveals perilesional gliosis in active stages and no lesions or calcification in inactive stages). Symptoms and treatment generally correspond to these stages: Those with active infections benefit from treatment with albendazole; patients with inactive lesions generally require no treatment other than standard anticonvulsant therapy for partial-onset epilepsy. There is controversy regarding whether patients require antiparasitic treatment at any stage of infection, because solitary lesions resolve with or without treatment in approximately 90% of patients.

Patients with persisting seizures despite antiparasitic treatment and anticonvulsant therapy may be candidates for focal surgical treatment. However, this patient's seizures have been controlled with phenytoin. Cosmetic side effects are much less common when phenytoin is taken at this age than when taken during childhood, and if the patient is experiencing no adverse effects, such as cognitive problems or gingival hyperplasia, then I would continue phenytoin. Other first-line anticonvulsants for partial-onset seizures, such as carbamazepine, are alternatives.

Patients whose seizures are controlled for several years may elect to discontinue their anticonvulsants, although seizures recur in approximately half of these patients. This risk decreases or increases by approximately 10% to 20%, depending on the presence of individual risk factors, eg, having a normal vs abnormal EEG, initially having single vs recurring seizures, having solitary vs multiple cysts demonstrated by initial head CT. A particularly negative prognostic sign is having a calcified cyst on head CT.