Neurocysticercosis

A specific form of the infectious parasitic disease cysticercosis that is caused by the infection with Taenia solium, a tapeworm found in pigs. There is no correlation between the burden of lesions and the severity of the epilepsy.

Porcine tapeworm eggs
Hatch in gut and stretch their legs
Dot the CNS
Cloaked larvae spread at leisure
When revealed, swelling, seizure       Link to author

About

• A cause of epilepsy and CNS disease in those coming from endemic areas
• Treatment can cause an initial worsening
• One of the commonest parasitic infections in the world

Spread

• Eggs of Taenia solium are ingested via faecal-oral transmission from a tapeworm host.
• Encysted stage of the pork tapeworm, Taenia solium forms ova
• Cyst is ingested and penetrates the gut and develop into the cystic stage of the disease.

Epidemiology

• Commoner : those from South America, Mexico, India, Pakistan, Middle East
• Endemic in countries with poor sanitation
• Seen increasingly in developed countries due to globalization and immigration

Aetiology

• In addition to the localization of the parasite, inflammation is the main phenomenon responsible of symptomatology.
• The inflammatory reaction associated with NCC is complex and not completely understood.
• Children are more likely to have related seizures than adults

Spread

Clinical

• Seizures (focal or generalized), Nausea and vomiting
• Chronic headache and vision changes
• Muscle involvement leads to enlargement simulating hypertrophy
• Muscle weakness and, eventually, calcified deposits
• Focal neurological complaints and stroke
• Mental status changes, Hydrocephalus and raised ICP
• Absence of fever is typical for neurocysticercosis.
• In patients with advanced HIV disease and compromised cell-mediated immunity, it may exist without significant host response and is likely to be asymptomatic
• Fundoscopy is important - can show distinctive retinal changes with the presence of larval forms
• There may be muscle pseudohypertrophy and subcutaneous nodules

Investigations

• Immunoblot is the serologic investigation of choice. In individuals with multiple active lesions, it is 98% sensitive and 100% specific.
• CT scan or MRI scan shows cyst formation in the brain parenchyma associated with varying degrees of inflammatory reaction and oedema. Calcified neurocysticercal lesions (CNL) cause seizures but such lesions are frequently encountered on CT scans of asymptomatic individuals. The differential diagnosis is cystic tumor.
• MRI: techniques such as fluid-attenuated inversion recovery (FLAIR) performed 5 minutes after continuous inhalation of 100% oxygen and fast imaging employing steady-state acquisition (FIESTA) sequences permit better detection of the parasites
• CSF is normal in many cases. However Detection of specific antigens in sera by ELISA in patients with parasites located in the subarachnoid space or the ventricular system is a specific sign of parasite viability and may be used to evaluate treatment response

Management

• ABC, Supportive. Manage seizures and coma. Drugs used are praziquantel or albendazole
• After an initially expected increase in seizure activity, patients treated with Albendazole 15 mg/kg daily for 10 days and Prednisolone 30 mg per day for 14 days had significantly better long-term control of generalized seizures than those receiving placebos. Anticonvulsants should be continued until treated.
• Other choice is Praziquantel (50 mg/kg/day for 15 days)
• In some patients, in whom steroids cannot be successfully tapered, methotrexate and azathioprine have been used to reduce inflammation

References

• Neurocysticercosis Neurol Clin Pract. 2013 Apr; 3(2): 118–125.
• Neurocysticercosis
• Neurocysticercosis

Revisions

• Last updated 02/10/2017