Neurocysticercosis


Neurocysticercosis is a specific form of the infectious parasitic disease cysticercosis that is caused by the infection with Taenia solium, a tapeworm found in pigs. Neurocysticercosis occurs when cysts formed by the infection take hold within the brain, causing neurologic syndromes such as epileptic seizures. It is a common cause of seizures worldwide. It has been called a "hidden epidemic" and "arguably the most common parasitic disease of the human nervous system".
The infection of adult tapeworm often presents in different medical conditions depending on the body systems being affected. When humans are infected with Taenia solium, it causes an intestinal infection called taeniasis. Cysticerosis develops when multiple organs are affected, including the muscles, skin and eyes. Neurocysticerosis occurs when the larvae of Taenia solium invade the central nervous system. Common symptoms of neurocysticercosis include seizures, headaches, blindness, meningitis and dementia.

Pathophysiology

Neurocysticercosis most commonly involves the cerebral cortex followed by the cerebellum. The pituitary gland is very rarely involved in neurocysticercosis. The cysts may rarely coalesce and form a tree-like pattern which is known as racemose neurocysticercosis, which when involving the pituitary gland may result in multiple pituitary hormone deficiency.

Diagnosis

Neurocysticerosis is diagnosed by computed tomography scan. Diagnosis may be confirmed by detection of antibodies against cysticerci in CSF or serum through ELISA or imunoblotting techniques.

Treatment

Treatment of neurocysticerosis includes epileptic therapy and a long-course medication of praziquantel and/or albendazole. Steroid therapy may be necessary to minimize the inflammatory reaction to dying cysticerci. Surgical removal of brain cysts may be necessary, e.g. in cases of large parenchymal cysts, intraventricular cysts or hydrocephalus.
Albendazole can reduce the number of viable brain lesions and reduce seizures recurrence in those with non-viable brain lesions.
For seizures further randomized controlled trials are needed to evaluate the efficacy of antiepileptic drugs for seizure prevention in patients with symptoms other than seizures and the duration of AED treatment in these cases.

Epidemiology

The epidemiology of Taenia solium cysticercosis is solely associated with local cultural practices especially poor sanitation and is highly endemic in Sub-Saharan Africa, Latin America and Asia. Infection by Taenia solium cysticercosis, the pork tapeworm larvae in human, spares no ethnic group. Cysticercosis in the United States, which commonly presents in the form of neurocysticercosis, has been classified as a "neglected tropical disease", which commonly affects the poor and homeless, particularly those without access or in the habit of inadequate hand-washing and in the habit of eating with their hands.