Anthelmintic Treatment of Neurocysticercosis

ANTHELMINTIC TREATMENT OF NEUROCYSTICERCOSIS

Cysticercosis of various organs, including brain, occurs in T. solium infestation due to migration of the larvae from the gut to various tissues via blood stream. Anthelmintic treatment of neurocysticercosis is considered optional, because the cysts do not cause any problem unless the larva dies and its products induce an intense focal reaction resulting in seizures and other neurological symptoms. The anthelmintic kills the larvae and precipitates a reaction, but prevents future episodes due to spontaneous death of the cysticerci. The decision whether or not to give the anthelmintic may be taken depending on the number, location and viability of the cysts. Multiple, live, parenchymal cysts are better treated; while solitary (or few), ventricular or calcified cysts are better left alone.

Out of the two anthelmintics effective in killing cysticerci, albendazole is now preferred over praziquantel for the following reasons:

The course of treatment is shorter (8–15 day) compared to praziquantel (15–30 days).

Cure rates in terms of resolution of symptoms and disappearance of cysts are higher (75–85% with albendazole) than praziquantel (50–60%).

Corticosteroids (which have to be given concurrently) enhance the absorption of albendazole, but lower the blood levels of praziquantel.

Albendazole is cheaper.

Whichever anthelmintic is used, corticosteroids (prednisolone 40–60 mg/day or dexamethasone 8–12 mg/day) must be started 2 days before and continued till 2 weeks after completing the anthelmintic course. This is necessary to suppress the neurological reaction to the products of killed larvae. Absorption of both albendazole and praziquantel is enhanced by ingesting them with food, particularly fatty food. For patients with seizures (as most of them are), adequate anticonvulsant treatment should be given beforehand and the fits controlled.

Phenytoin and carbamazepine are the most commonly used drugs. They induce the metabolism of praziquantel, which may necessitate use of higher doses. The anticonvulsant must be continued through the course of anthelmintic medication and for an indefinite period (mostly 1–6 months) after it. While parenchymal cysts respond to albendazole in 8–15 days, intraventricular and subarachnoid cysts may require treatment for a month or longer. It is very important to kill and expel the adult worm from the gut to eliminate the source of future cysticerci.