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Figure 1. MRI of a human brain showing multiple viable parenchymal cysts.
(Figure omitted. See article PDF.)
Figure 2. MRI of a human brain showing a cysticercal cyst in the lateral ventricle.
(Figure omitted. See article PDF.)
Figure 3. CT scan of a human brain showing numerous cysts in the cerebral parenchyma, giving a 'starry-night'appearance, as described in [14].
(Figure omitted. See article PDF.)
Neurocysticercosis is an infection resulting from the larval form of the pig tapeworm, Taenia solium . Neurocysticercosis is the most frequent parasitic disease affecting the CNS and is the most common cause of epilepsy in developing countries. Neurocysticercosis has also been recognized as an important parasitic disease in the USA and other developed nations. In developed nations, a higher risk of acquiring neurocysticercosis has been documented in patients who have traveled to endemic regions, are of Hispanic ethnicity and/or have had contact with T. solium carriers [1].
The cysticercus larva passes though several stages in the brain parenchyma. First, the cysticercus larva evolves into a fluid-filled and thin-walled cyst. This live viable cyst evokes only a minimal inflammatory reaction in the brain tissues and is known as the 'vesicular'cyst stage. Carpio et al. referred to this stage as the 'active'stage (Figure 1) [2]. Later, the cyst breaks down and its wall becomes thickened. Subsequent to this, hyaline degeneration and mineralization of the cyst occurs. At this stage, cysts are in the 'colloidal'stage and there is an intense inflammatory reaction in the surrounding brain tissue. Carpio et al. referred to this stage as the 'transitional-degenerative'stage [2]. Ultimately, the larva dies and the dead cyst becomes calcified. In the extraparenchymal form of neurocysticercosis, cysts are present in the cerebral ventricles, subarachnoid space and basal cisterns (Figure 2) [2,3].
Cerebral parenchymal neurocysticercosis frequently manifests as seizures. Other clinical manifestations include headaches, focal neurologic deficit, raised intracranial hypertension and obstructed hydrocephalus. Diagnosis is based on the diagnostic criteria given in (Boxes 1 & 2) [4,5].
The medical treatments for parenchymal neurocysticercosis include the administration of anticysticercal drugs and corticosteroids. In patients with hydrocephalus due to intraventricular, subarachnoid or racemose neurocysticercosis, surgery is indicated [6,7].
A recent meta-analysis (evaluating six controlled trials) suggests that anticysticercal treatment is effective and results in better resolution of colloidal...