Document downloaded from http://www.elsevier.es, day 09/07/2015. This copy is for personal use. Any transmission of this document by any media or format is strictly prohibited. Radiología. 2013;55(2):130---141 www.elsevier.es/rx UPDATE IN RADIOLOGY ଝ Imaging findings in neurocysticercosis ∗ S. Sarria Estrada , L. Frascheri Verzelli, S. Siurana Montilva, C. Auger Acosta, A. Rovira Canellas˜ Unitat de Ressonància Magnètica (IDI), Servei de Radiologia, Hospital Universitari Vall d’Hebron, Barcelona, Spain Received 2 September 2011; accepted 23 November 2011 KEYWORDS Abstract Neurocysticercosis, caused by the larvae of Taenia solium, is the parasitic infec- Taenia solium; tion that most commonly involves the central nervous system in humans. Neurocysticercosis is Cysticercosis; endemic in practically all developing countries, and owing to globalization and immigration it Neurocysticercosis; is becoming more common in developed countries like those in western Europe. Computed The most common clinical manifestations are epilepsy, focal neurologic signs, and intracranial tomography; hypertension. Magnetic resonance The imaging findings depend on the larval stage of Taenia solium, on the number and loca- imaging tion of the parasites (parenchymal, subarachnoid, or intraventricular), as well as on the host’s immune response (edema, gliosis, and arachnoiditis) and on the development of secondary lesions (arteritis, infarcts, or hydrocephalus). The diagnosis of this parasitosis must be established on the basis of the clinical and radiologi- cal findings, especially in the appropriate epidemiological context, with the help of serological tests. © 2011 SERAM. Published by Elsevier España, S.L. All rights reserved. PALABRAS CLAVE Neurocisticercosis. Hallazgos radiológicos Taenia solium; Cisticercosis; Resumen La neurocisticercosis es una parasitosis humana causada por las larvas de la Taenia Neurocisticercosis; solium, que es la que con mayor frecuencia afecta el sistema nervioso central. Esta infección es Tomografía endémica en prácticamente todos los países en vías de desarrollo, pero debido a la globalización computarizada; y a las migraciones humanas su frecuencia ha aumentado en países desarrollados como los de Imagen por Europa Occidental. resonancia magnética Las manifestaciones clínicas más frecuentes son la epilepsia, signos neurológicos focales e hipertensión intracraneal. ଝ Please cite this article: Sarria Estrada S, et al. Neurocisticercosis. Hallazgos radiológicos. Radiología. 2013;55:130-41. ∗ Corresponding author. E-mail address: [email protected] (S. Sarria Estrada). 2173-5107/$ – see front matter © 2011 SERAM. Published by Elsevier España, S.L. All rights reserved. Document downloaded from http://www.elsevier.es, day 09/07/2015. This copy is for personal use. Any transmission of this document by any media or format is strictly prohibited. Imaging findings in neurocysticercosis 131 Los hallazgos radiológicos dependen del estadio larvario de la Taenia solium, número y loca- lización de los parásitos (parenquimatosa, subaracnoidea e intraventricular), así como de la respuesta inmune del huésped (edema, gliosis, aracnoiditis) y del desarrollo de lesiones secun- darias (arteritis, infartos o hidrocefalia). El diagnóstico de esta parasitosis debe establecerse en función de los hallazgos clínicos y ra- diológicos, especialmente en un contexto epidemiológico adecuado, con apoyo de la serología. © 2011 SERAM. Publicado por Elsevier España, S.L. Todos los derechos reservados. Introduction Etiopathogenesis Cysticercosis is a parasitic disease caused by the larva of Tae- Taenia solium is one of the eight species of cestodes that nia solium. Human cysticercosis occurs after a person ingests infect humans. T. solium has a scolex and a body with eggs that are passed in the feces of a T. solium carrier (fecal- several hundreds of proglottids. Its life cycle includes the 1 --- 3 1 oral contamination). Although infection may develop in egg and larval stage and the adult stage. The hexacanth any organ, the central nervous system (parenchyma, sub- embryo (thin-walled larval cysts) measures 10---20 mm in arachnoid spaces, ventricles and spinal cord), eyes and length and contains an invaginated scolex (larval head). The 1 muscles are the most commonly involved. cyst, whose wall is rich in glycoproteins, is filled with a Cysticercosis is endemic in virtually all developing clear fluid during this phase, but it becomes cloudy after 1 countries (Latin America, South-East Asia and Africa), with the parasite dies. the exception of Muslim countries, where pork is not The adult Taenia is 2 --- 4 m long and inhabits the small 1 --- 3 consumed (Fig. 1). In recent years, the incidence of cysticer- intestine of humans, attached by the scolex. Proglotidds cosis has risen in developed countries due to immigration containing thousands of eggs detach daily and are passed 2,3 2 from endemic areas. in the feces, contaminating water and soil. The eggs are Neurocysticercosis is the most common parasitic disease eaten by pigs, and once in the pig’s intestine, they transform of the human central nervous system, being the main cause into oncosphere that enter the bloodstream and disseminate of acquired epilepsy in endemic areas and a major public to target organs where the larvae develop. In humans, the 1 --- 4 health problem worldwide. In 1993, the International Task larvae reaches the small intestine after the ingestion of con- Force for Disease Eradication declared that cysticercosis is taminated pork, raw or undercooked, the scolex attaches to potentially eradicable, and proposed to declare neurocys- the intestinal wall and begins to form proglotidds. Lastly, 5,6 ticercosis a reportable disease. cysticercosis occurs when humans become intermediate 1,2 The objective of this paper is to update the most impor- hosts by ingesting Taenia solium eggs (Fig. 2). tant radiologic features of neurocysticercosis and describe Humans acquire the infection through fecal-oral contami- the etiopathogenesis of the disease, clinical presentation, nation by infected individuals hosting the parasite. Humans and differential diagnosis. A brief description of the recom- are the only definitive hosts of Taenia solium, while both 1 --- 3 mended treatment is also provided. humans and pigs are intermediate hosts. High prevalence Moderate prevalence Low prevalence No information available Figure 1 Epidemiology. Cysticercosis is endemic to Africa, Asia and South America and particularly favored by poor socio-economic 6 conditions. Source: modified from Román et al. Document downloaded from http://www.elsevier.es, day 09/07/2015. This copy is for personal use. Any transmission of this document by any media or format is strictly prohibited. 132 S. Sarria Estrada et al. Ingestion of eggs of T. solium 2. Inflammatory response (edema). (human cysticercosis) 3. Presence of sequelae (fibrosis, granuloma, and calcifica- Eyes tions). Brain Lungs Muscles Ingestion of Clinical presentation of neurocysticercosis infected pork (taeniasis) Neurocysticercosis is a pleomorphic disease whose mani- festations depend on individual variation in the number, location, size, stage of parasites, and degree of the host 1,2,7,9 Eggs and inflammatory response. proglotidds Most symptomatic patients are 15---40 year old, and the Neurocysticercosis 1 disease shows no predilection for sex or race. The most common clinical findings include epilepsy, Ingestion of eggs of T.solium or proglotidds (swine cysticercosis) intracranial hypertension, encephalitis and meningitis. Epilepsy is the most common clinical manifestation, seen in more than 70% of patients. In endemic areas, neuro- Figure 2 Life cycle of Taenia solium. The cycle starts with cysticercosis is the leading cause of late-onset epilepsy. the ingestion of raw or undercooked meat containing larvae. Seizures are secondary to perilesional inflammation in The larvae reach the small intestine and attach to the intesti- degenerating cysts, although infarction and vasculitis may nal wall. The proglotidds containing thousands of eggs detach also act as predisposing factors. Calcified granulomas may daily, are passed with the feces, contaminating water and soil. 1,8,10,11 also cause epilepsy. Animals like pigs become infected by ingesting food contam- Clinical manifestations usually have a slowly progres- inated with eggs that develop in their intestine. They enter sive onset; however, an acute presentation such as cerebral the bloodstream and spread to muscle where larvae develop. 2,12 infarction secondary to vasculitis, may also occur. When humans ingest this undercooked or raw meat containing Tw o mechanisms can cause intracranial hypertension: the cysticerci, the life cycle starts over again. Lastly, cysticerco- (1) obstructive hydrocephalus secondary to intraventricular sis occurs when humans become intermediate hosts by ingesting cysts, arachnoiditis or granular ependymitis; and (2) mass the eggs of Taenia solium. 1,2,13 effect in cases of very large cysts. Patients with neu- rocysticercosis of the fourth ventricle may have transient obstruction of the Sylvian aqueduct, whose symptoms and Forms of infection with the cysticercus signs are known as Bruns’ syndrome. This syndrome is caused by an intraventricular mobile lesion, which leads to episodic Humans may develop two types of disease, taeniasis and obstructive hydrocephalus. This syndrome is characterized cysticercosis. Taeniasis is acquired by eating pork meat by headache, papilledema and loss of consciousness with infected