If people eat eggs from the pork tapeworm (Taenia solium), these eggs can move from the gut and then lodge in different tissues of the body forming cysts. When these cysts form in the brain, this is called neurocysticercosis. Some people may have no symptoms if this happens, but others may suffer from seizures, headaches, or more rarely from confusion, loss of balance or brain swelling. More rarely still, someone may die.
The condition is mainly found where people live in close contact with pigs and where the sanitation is poor. It affects around 50 million people worldwide, and in some areas is the leading cause of adult-onset epilepsy.
The number, size and location of the cysts help to guide treatment of neurocysticercosis, as do the patient’s symptoms; for example, giving anticonvulsants to someone with seizures. Two drugs, praziquantel and albendazole, can be used specifically in neurocysticercosis to help kill the parasite; these drugs are known as anthelmintics. Some cysts, called non-viable lesions are generally in the process of degenerating and resolving spontaneously; many experts recommend not treating this type of cyst. However, treating viable lesions (ie those lesions that may or may not resolve spontaneously) with these drugs may help kill the parasite, although treatment remains controversial due to the potential side effects and the fact the parasite may die without treatment.
In this review of 21 relevant randomized controlled trials, most studies examined the effects of albendazole. In patients with viable lesions, there is only evidence available for adult patients; this suggests that albendazole may reduce the number of lesions. In patients with non-viable lesions, there is only evidence available for children; this suggests that seizure recurrence was lower with albendazole, which goes against the opinions of some experts. There is insufficient evidence available to assess praziquantel.
In patients with viable lesions, evidence from trials of adults suggests albendazole may reduce the number of lesions. In trials of non-viable lesions, seizure recurrence was substantially lower with albendazole, which is counter-intuitive. It may be that steroids influence headache during treatment, but further research is needed to test this.
Neurocysticercosis is an infection of the brain by the larval stage of the pork tapeworm. In endemic areas it is a common cause of epilepsy. Anthelmintics (albendazole or praziquantel) may be given to kill the parasites. However, there are potential adverse effects, and the parasites may eventually die without treatment.
To assess the effectiveness and safety of anthelmintics for people with neurocysticercosis.
In May 2009 we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2009, Issue 2), MEDLINE, EMBASE, LILACS, and the mRCT.
Randomized controlled trials comparing anthelmintics with placebo, no anthelmintic, or other anthelmintic regimen for people with neurocysticercosis.
Two authors independently selected trials, extracted data, and assessed each trial's risk of bias. We calculated risk ratios (RR) for dichotomous variables, with 95% confidence intervals (CI). We pooled data from trials with similar interventions and outcomes.
For viable lesions in children, there were no trials. For viable lesions in adults, no difference was detected for albendazole compared with no treatment for recurrence of seizures (116 participants, one trial); but fewer participants with albendazole had lesions at follow up (RR 0.56, 95% CI 0.45 to 0.70; 192 participants, two trials).
For non-viable lesions in children, seizures recurrence was less common with albendazole compared with no treatment (RR 0.49, 95% CI 0.32 to 0.75; 329 participants, four trials). There was no difference detected in the persistence of lesions at follow up (570 participants, six trials). For non-viable lesions in adults, there were no trials.
In trials including viable, non-viable or mixed lesions (in both children and adults), headaches were more common with albendazole alone (RR 9.49, 95% CI 1.40 to 64.45; 106 participants, two trials), but no difference was detected in one trial giving albendazole with corticosteroids (116 participants, one trial).