Human Neurocysticercosis: An Overview

Abstract

Human cysticercosis is caused by ingestion of T. solium eggs from taenia carriers. Neurocysticercosis (NCC), defined as the infection of the CNS and the meninges by the larval stage of Taenia solium, is the most common helminthic infection of the CNS worldwide. Parasites may lodge in brain parenchyma, subarachnoid space, ventricular system, or spinal cord, causing pathological changes that account for the pleomorphism of this disease. Seizures/epilepsy are the most common clinical manifestation, but other patients present with headache, focal deficits, intracranial hypertension, or cognitive decline. Accurate diagnosis of NCC is possible after interpretation of clinical data together with findings of neuroimaging studies and results of immunological tests. However, neuroimaging studies are fundamental for diagnosis because immunological test and clinical manifestations only provide circumstantial evidence of NCC. The introduction of cysticidal drugs changed the prognosis of most NCC patients. These drugs have been shown to reduce the burden of infection and to improve the clinical course of the disease in many patients. Efforts should be directed to eradicate the disease through the implementation of control programs against all the steps in the life cycle of T. solium, including carriers of the adult tapeworm, infected pigs, and eggs in the environment.

Keywords: Taenia solium; albendazole; cysticercosis; epilepsy; headache; neurocysticercosis; praziquantel.

Figure 1

Neuroimaging characteristics of neurocysticercosis: (A) Parenchymal vesicular cysts showing the scolex (arrows) in T1-weighted MRI; (B) Vesicular cyst without scolex in contrast-enhanced CT scan; (C) Colloidal cysticerci appearing as ring-enhancing lesions in gadolinium-enhanced T1-weighted MRI; (D) Parenchymal brain calcifications in non-enhanced CT scan; (E) Multilobulated (racemose) subarachnoid cysticerci in FIESTA sequence MRI; and (F) Abnormal enhancement of basal leptomeninges and hydrocephalus in contrast-enhanced CT scan (Reproduced from Del Brutto et al, J Neurol Sci 2017, 371, 202-210) Copyright: the authors).

Figure 2

Fast Imaging Employing Steady-state Acquisition (FIESTA) MRI sequence showing massive cysticercal infection of the base of the brain and temporal pole by subarachnoid cysticerci (left) and their disappearance six months after cysticidal drug therapy (right). Courtesy of the Cysticercosis Working Group in Perú.