Neuroangiostrongyliasis: The "Subarachnoid Phase" and Its Implications for Anthelminthic Therapy.

Infection with the Rat Lungworm Angiostrongylus cantonensis is the leading cause of human eosinophilic meningoencephalitis worldwide. From its origins in southeastern Asia, the parasite was spread extensively throughout the twentieth century and is now established in many of the world's warmer regions. Its clinical effects range from mild and transient symptoms, usually headache with peripheral nerve dysfunction, to severe and permanent central nervous system (CNS) damage, occasionally fatal. The severity and prognosis of disease are determined by the larval dose, acquired by ingesting infected intermediate hosts (slugs and snails) or, less often, paratenic hosts, such as crabs, shrimps, frogs, and monitor lizards. Early diagnosis is critical for treatment and depends on clinical suspicion, for laboratory confirmation from blood and cerebrospinal fluid can be delayed and unreliable. Treatment is fraught with difficulty, compounded by conflicting published results. Corticosteroids play a useful role in suppressing early CNS inflammation, but their duration for maintenance becomes problematic in severe infections. Because most of the pathogenesis results from host immuno-inflammatory responses to migrating and dead larvae in the CNS, anthelminthic therapy remains controversial: if effective, it kills viable larvae, arresting them in the CNS and so exacerbating the pathology. In human infections, it is now clear that many larvae do leave the CNS and reach the pulmonary arteries, sometimes with clinical consequences. Pioneering life-cycle studies in rats demonstrated a "subarachnoid phase" in larval development and migration; recent autopsy findings, outlined here, show it also occurs in humans and has some bearing on treatment. One new and four previously reported cases of human infection are analyzed here, with findings indicating that anthelminthic treatment is effective only when given early and should not be commenced beyond 3 weeks after exposure to infection. In endemic areas, treatment should start as soon as this infection is suspected, even without a clear history of exposure, given the unacceptable risks of waiting for diagnostic laboratory confirmation.

[Giant racemose subarachnoid and intraventricular neurocysticercosis: A case report]. / Neurocisticercosis racemosa subaracnoidea gigante y ventricular: a propósito de un caso.

Neurocysticercosis is the most frequent parasitic disease of the central nervous system. It is caused by the larvae of Taenia solium, which can affect different anatomical sites. In Spain there is an increasing prevalence mainly due to immigration from endemic areas. The extraparenchymal forms are less common, but more serious because they usually develop complications. Neuroimaging plays a major role in the diagnosis and follow-up of this disease, supported by serology and a compatible clinical and epidemiological context. First-line treatments are cysticidal drugs such as albendazole and praziquantel, usually coadministered with corticosteroids, and in some cases surgery is indicated. We here report a case of neurocysticercosis with simultaneous intraventricular and giant racemose subarachnoid involvement.

Metabolic and histopathological profile of Rattus norvegicus (Wistar) experimentally infected by Angiostrongylus cantonensis (Chen, 1935).

Eosinophilic meningitis is a disease characterized by increased eosinophils in the cerebrospinal fluid (CSF), which is the most commonly caused by invasion of the central nervous system by helminths, as occurs in Angiostrongylus cantonensis infections. The rodent Rattus norvegicus is the definitive natural host and humans act as accidental hosts and can become infected by eating raw or undercooked snails or food contaminated with infective L3 larvae. Recently in Brazil there have been four cases of eosinophilic meningitis due to ingestion of infected Achatina fulica. To evaluate biochemical and histopathological changes caused by this parasite, R. norvegicus were experimentally infected with 100 L3 larvae of A. cantonensis. After the anesthetic procedure, serum from the rodents was collected from the inferior vena cava for evaluation of the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALKP), gamma-glutamyl transferase (GGT), total protein and its fractions. During the necropsy, the liver was collected and weighed. Then a 1-g fragment was extracted from the major lobe to quantify the hepatic glycogen and fragment remainder was taken from the same lobe and fixed in Milloning's formalin for histopathological examination. Additionally, helminths were collected from the brain and lungs of the rodents. The activities of AST, ALT, ALKP and GGT in the serum and hepatic glycogen increased in response to infection, while the levels of globulin and total protein increased only in the eighth week of infection and there was a reduction in the levels of serum glucose. Albumin and bilirubin concentrations remained stable during the experiment. Infection with A. cantonensis caused metabolic and histopathological changes in the rodents. This study can contribute to a better understanding of the relationship between A. cantonensis and R. norvegicus.

Extraparenchymal neurocysticercosis in the United States.

Neurocysticercosis (NCC) is endemic in the developing world but is becoming more common in the United States because of immigration. Although NCC is pleomorphic in its presentation, extraparenchymal NCC may be challenging to diagnose and treat. Extraparenchymal NCC is probably more frequent than previously thought. Neurologists and neuroradiologists in the United States are often unaware of the pretreatment/post-treatment radiographic patterns of extraparenchymal NCC and the potentially poor prognosis if not correctly diagnosed and managed. The review of this condition is important given increasing incidence in the United States.

Gurltia paralysans (Wolffhügel, 1933): description of adults and additional case reports of neurological diseases in three domestic cats from southern Chile.

Adults of Gurltia paralysans were obtained from veins of the spinal cord subarachnoid space from three domestic cats presenting with chronic paraparesis/paraplegia from rural areas of southern Chile. Four adult nematodes were collected (2 males and 2 females) were recovered from cat 1, 14 adult nematodes (12 females and 2 males) from cat 2, and 12 nematodes (10 females and 2 males) were collected from cat 3. Parasite induced lesions that compromised subarachnoid vein microvasculature at the thoracic, lumbar, sacral spinal cord segments extending to conus medularis. Female nematodes measured 25 mm long (range=25-30 mm) and 0.1mm wide. Male measured a mean of 16 mm length (range=13-18 mm) with a body diameter of 0.1mm (range=0.08-0.15 mm). The present study described structural features of G. paralysans, a rare parasite first reported in the 1930s, and provides additional reports on associated clinical and pathological findings in naturally infected domestic cats.

Subarachnoid basal neurocysticercosis: a focus on the most severe form of the disease.

Neurocysticercosis is an endemic disease in Latin America, Asia and Africa with growing occurrence in industrialized countries due to the increase in migration from low- and middle-income to high-income countries. The most severe clinical presentation is when the parasite is located in the subarachnoid space at the base of the brain (NCSAB). Aside from its clinical presentation, the severity of this form of the disease is due to the difficulties in diagnosis and treatment. Although NCSAB frequency is lower than that reported for the parenchymal location of the parasite, its clinical relevance must be emphasized. We provide a critical review of the central epidemiological, clinical, diagnostic and therapeutic features of this particular form of the disease, which is still associated with unacceptably high rates of morbidity and mortality.

Helminthic invasion of the central nervous system: many roads lead to Rome.

Invasion of the central nervous system (CNS) by parasitic worms often represents most severe complication of human helminthiasis. The pathways from the portal of entry to the CNS are manifold and differ from species to species. In this mini-review, we analysed the contemporary knowledge and current concepts of the routes pathogenic helminths take to gain access to brain, spinal cord and subarachnoid space.

Recurrent primary spinal subarachnoid neurocysticercosis.

STUDY DESIGN: Case description. OBJECTIVE: To describe a patient with a recurrent primary spinal subarachnoid neurocysticercosis (NCC) that was successfully treated with surgical decompression and medical therapy at our center. SUMMARY OF BACKGROUND DATA: Spinal subarachnoid NCC is thought to be the secondary result from larval migration through the ventricular system into the spinal subarachnoid space. However, this entity can develop as a primary infection through blood stream or direct larval migration. It can result in high recurrence and severe neurologic morbidity if it is not treated in an appropriate manner. METHODS: A 50-year-old woman with treatment history of spinal NCC presented with back pain and radicular pain. The lumbar magnetic resonance imaging showed a cystic lesion with septation and slight rim enhancement after gadolinium administration at the L4-S1 area. We performed surgical removal of this lesion and postoperative medical therapy for complete eradication of the parasite. RESULTS: The histopathology was diagnostic for a cysticercal cyst. Adjuvant medical therapy with albendazole was administered for 30 days after surgery. The patient remained symptom-free for 1 year after surgery without any evidence of recurrence. CONCLUSION: We report a rare case of recurrent primary spinal subarachnoid NCC at L4-S1 area. In cases of primary spinal subarachnoid NCC can be treated by adequate combined approach with surgery and medical therapy. Spinal subarachnoid NCC should be added to the differential diagnosis of primary spinal intradural cysts, because this lesion can occur primarily.

Meta-analysis: Cysticidal drugs for neurocysticercosis: albendazole and praziquantel.

BACKGROUND: Conflicting reports have caused controversy on whether cysticidal drugs modify the natural course of neurocysticercosis. PURPOSE: To perform a meta-analysis of randomized trials assessing the effect of cysticidal drugs on neuroimaging and clinical outcomes of patients with neurocysticercosis. DATA SOURCES: Search of MEDLINE, Cochrane Database of Systematic Reviews, and Literatura Latino-Americana y del Caribe en Ciencias de la Salud (LILACS) between 1979 and 2005. There were no language restrictions. STUDY SELECTION: Randomized trials of cysticidal drug therapy for neurocysticercosis that met predefined criteria designed to allow characterization of the disease and objective evaluation of therapy. The authors independently reviewed articles. Abstracted data included study design, number of randomly assigned patients and withdrawals, intervention, adverse events, timing of neuroimaging studies, and outcomes. DATA SYNTHESIS: Eleven studies met the inclusion criteria. Six trials randomly assigned 464 patients with cystic lesions (vesicular cysticerci), and 5 trials randomly assigned 478 patients with enhancing lesions (colloidal cysticerci). Parasites were located in the brain parenchyma or subarachnoid space at the convexity of the cerebral hemispheres. Cysticidal drug therapy was associated with complete resolution of cystic lesions (44% vs. 19%; P = 0.025). Trials on enhancing lesions showed a trend toward lesion resolution favoring the use of cysticidal drugs (72% vs. 63%; P = 0.38) that became statistically significant when an outlier trial was excluded from the analysis (69% vs. 55%; P = 0.006). Risk for seizure recurrence was lower after cysticidal treatment in patients with enhancing lesions (14% vs. 37%; P < 0.001). The single trial evaluating the frequency of seizures in patients with cystic lesions showed a 67% reduction in the rate of generalized seizures with treatment (P = 0.006). LIMITATIONS: Not all studies focused on the control of seizures as an outcome. CONCLUSIONS: Cysticidal drug therapy results in better resolution of colloidal and vesicular cysticerci, lower risk for recurrence of seizures in patients with colloidal cysticerci, and a reduction in the rate of generalized seizures in patients with vesicular cysticerci.

Subarachnoidal and intraventricular human neurocysticercosis: application of an antigen detection assay for the diagnosis and follow-up.

BACKGROUND: Neurocysticercosis (NC) is a parasitic disease of the central nervous system caused by the larval stage of Taenia solium. Although imaging studies are recommended for diagnosis and follow-up of patients, their high cost and restricted availability limit their use. Among various immunological tests, the detection of HP10 antigen in cerebral spinal fluid (CSF) has proved to be a useful tool for the diagnosis of NC in the case of viable but not dead parasites. OBJECTIVES: This study was designed to evaluate the usefulness of the detection of HP10 antigen for the diagnosis and follow-up of NC patients. METHODS: The effectiveness of this HP10 assay was analysed for the CSF of 46 confirmed NC cases (21 men, 25 women) who had been clinically and radiologically described. RESULTS: In 21 of 24 NC patients (87.5%) with viable parasites localized in the SA space at the base of the brain or in the ventricles these were detected by means of the HP10 assay, whilst none of the three patients with viable parasites in the parenchyma or sulci had these detected. Used for the follow-up of patients after cysticidal treatment, it was showed that levels of HP10 dropped significantly only among those patients whose cysticerci were clearly damaged. CONCLUSIONS: HP10 antigen assay is recommended as a support for diagnosis and follow-up in NC patients with viable parasites localized in the SA space at the base of the brain or in the ventricles, thereby potentially reducing the number of imaging studies required.

Albendazole trial at 15 or 30 mg/kg/day for subarachnoid and intraventricular cysticercosis.

Thirty-six patients with subarachnoid and intraventricular cysticercosis were randomly assigned to receive albendazole at 15 or 30 mg/kg/day plus dexamethasone for 8 days. Results favored a higher dose, with larger cyst reduction on MRI at 90 and 180 days and higher albendazole sulfoxide levels in plasma. An albendazole course at 30 mg/kg/day combined with corticosteroids is safe and more effective than the usual dose. A single treatment was insufficient in intraventricular and giant cysts.

Neurocysticercosis: updated concepts about an old disease.

Neurocysticercosis, the infection of the human brain by the larvae of Taenia solium, is a major cause of acquired epilepsy in most low-income countries. Cases of neurocysticercosis are becoming more common in high-income countries because of increased migration and travel. Diagnosis by neuroimaging and serological assessment has greatly improved over the past decade, and the natural progression of the disease and response to antiparasitic drugs is now much better understood. Neurocysticercosis is potentially eradicable, and control interventions are underway to eliminate this infection. Meanwhile, updated information on diagnosis and management of neurocysticercosis is required, especially for clinicians who are unfamiliar with its wide array of clinical presentations.

Symptomatic human neurocysticercosis--age, sex and exposure factors relating with disease heterogeneity.

OBJECTIVE: To evaluate the relevance of exposure and host biological factors in the heterogeneity of the clinical, radiological and inflammatory picture of neurocysticercosis (NCC). METHODS: 105 Mexican symptomatic NCC patients confirmed by imaging were studied before they received any specific treatment. The relationships studied were those between a) the patients' characteristics (gender, age and level of exposure), b) the type of clinical picture and c) the radiological and inflammatory characteristics of the disease (number, aspect, localization of the parasites, and CSF leukocyte counts). RESULTS: Seizures were the most frequent symptom and multiple subarachnoid cysticerci the most frequent localization. Symptomatology related to the developmental stage, number and localization of the parasites as well as the CSF leukocyte-counts. The total number of cysticercal lesions and of vesicular cysticerci increased with age,whereas the number of colloidal cysticerci decreased. CSF leukocyte-counts were higher in women than in men. Levels of exposure did not correlate with the clinical and radiological pictures. CONCLUSIONS: The variability found in the number, stage, localization and inflammation in the parasite lesions is strongly associated with the heterogeneity of NCC symptoms. The increased number of vesicular cysticerci and the decreased number of degenerating cysticerci with aging, as well as the prominence of inflammation in women suggest that immuno-endocrinological factors may play a role in susceptibility and pathogenesis. The data also show that with increasing age and exposure there is no increment in severity, a suggestion that there might be ways of regulating pathogenicity.

[Hydrocepahlia and subarachnoid cyst due to neurocysticercosis. A new case from rural Extremadura]. / Hidrocefalia y quiste subaracnoideo por neurocisticercosis. Un nuevo caso en una zona rural de Extremadura.

INTRODUCTION: Neurocystercicosis (NCC) is a disorder caused by the Taenia solium larva. It is the commonest parasitosis of the CNS. In Spain most patients are from countries where the condition is endemic. However, sporadic cases still occur amongst the non immigrant population of rural regions. We report a new case of NCC from the Valle del Jerte in rural Extremadura. CASE REPORT: A 51 year old man presented with intellectual impairment, motor aphasia, apraxia, right hemiparesia and sphincter incontinence for the past six months. On cranial CAT and MR hydorcephalia was seen together with a subarachnoid cyst in the left Sylvan fissure. Serology was positive for cysticercosis in both plasma and CSF. The patient was treated with albendazol after insertion of a ventriculo peritoneal shunt. Three months later there was both clinical and radiological improvement. CONCLUSION: NCC is still a condition which must be included in the differential diagnosis of patients in Spain who present with CNS involvement and cystic lesions on neuro imaging investigations, even when they are not from countries where the disease is endemic. Treatment with albendazol and steroids given after insertion of a ventriculo peritoneal shunt was effective in our patient.

Brain parenchymal, subarachnoid racemose, and intraventricular cysticercosis in an Indian man.

The coexistence of brain parenchymal cysts at various stages of evolution, both intraventricular and subarachnoid racemose, is reported in a patient with neurocysticercosis. The condition has a variety of presentations, depending on the location of the cyst. This case is of particular interest because of the rarity of this condition in India.

Albendazole therapy for subarachnoid cysticerci: clinical and neuroimaging analysis of 17 patients.

Seventeen patients with subarachnoid cysticerci received albendazole at doses of 15 mg/kg/day for eight days. All patients also received corticosteroids during the trial. Evaluation of the therapeutic response consisted of the comparison of the number of cysts shown by CT before and three months after treatment, and the evaluation of the clinical status of the patients before and after the trial. Before treatment, the 17 patients had 30 subarachnoid cysticerci, 11 of which were > 50 mm in diameter. Seventeen cysts were located at the convexity of cerebral hemispheres, seven at the sylvian fissure, five at the ambiens cisterns, and one at the cerebellopontine angle cistern. Fourteen patients had seizures, 10 had hemiparesis, three were demented, one had diminution of visual acuity, and one had hemifacial spasm. Brain CT obtained after therapy showed resolution of 27 cysts (90% effectiveness). Fourteen (82%) patients had total resolution of all cysts. All but three patients were asymptomatic. Remaining deficits included hemiparesis in two patients and diminution of visual acuity in one. It is concluded that albendazole is an effective treatment for subarachnoid cysticerci as it causes disappearance of most lesions on CT, and produces considerable improvement in the clinical manifestations of the patients.

Extraparenchymal neurocysticercosis: report of five cases and review of management.

Neurocysticercosis due to parenchymal cysts carries a good prognosis regardless of therapy. Extraparenchymal neurocysticercosis (including ventricular, spinal, and subarachnoid types) carries a poorer prognosis. Most extraparenchymal cases present with hydrocephalus. Medical treatment alone in doses and schedules developed for parenchymal disease is frequently unsuccessful. For ventricular disease, most cases can be managed with shunting procedures either alone or together with the administration of antiparasitic agents (e.g., praziquantel or albendazole), without extirpation of the cysts. Subarachnoid disease was formerly associated with a case fatality rate of about 50%. However, with the combination of shunting procedures for hydrocephalus, antiparasitic agents, and, in some cases, surgical extirpation of the cysts, the prognosis is much improved. Spinal cysticercosis can be either leptomeningeal (which responds like subarachnoid disease) or intramedullary. For all forms of neurocysticercosis, the role of antiparasitic agents needs to be better defined.