Academic literature on the topic 'Eosinophilic meningoencephalitis'

Eosinophilic meningoencephalitis is based on clinical manifestations and microscopic identification of eosinophils present in cerebrospinal fluid (CSF). It is caused by a variety of helminthic infections with most common being angiostrongyliasis, gnathostomiasis, toxocariasis, cysticercosis, schistosomiasis, baylisascariasis, and paragonimiasis. Many case reports are there in which parasites have been found responsible, but there are rare reports of CSF eosinophilia associated with the use of drugs. We report a case of drug-induced (ibuprofen) eosinophilic meningitis in a healthy female who presented to us with severe headache and improved dramatically after drug withdrawal.

SUMMARY Eosinophilic meningoencephalitis is caused by a variety of helminthic infections. These worm-specific infections are named after the causative worm genera, the most common being angiostrongyliasis, gnathostomiasis, toxocariasis, cysticercosis, schistosomiasis, baylisascariasis, and paragonimiasis. Worm parasites enter an organism through ingestion of contaminated water or an intermediate host and can eventually affect the central nervous system (CNS). These infections are potentially serious events leading to sequelae or death, and diagnosis depends on currently limited molecular methods. Identification of parasites in fluids and tissues is rarely possible, while images and clinical examinations do not lead to a definitive diagnosis. Treatment usually requires the concomitant administration of corticoids and anthelminthic drugs, yet new compounds and their extensive and detailed clinical evaluation are much needed. Eosinophilia in fluids may be detected in other infectious and noninfectious conditions, such as neoplastic disease, drug use, and prosthesis reactions. Thus, distinctive identification of eosinophils in fluids is a necessary component in the etiologic diagnosis of CNS infections.

The raccoon roundworm Baylisascaris procyonis (B. procyonis) may infect humans to cause severe or fatal meningoencephalitis, as well as ocular and visceral larva migrans. Young children are at greater risk for cerebral larva migrans with severe meningoencephalitis, and early empiric therapy may improve outcomes. Familiarity with characteristic brain imaging findings may prompt earlier diagnosis, particularly in the setting of CSF eosinophilia. We report a case of a 19-month-old boy who presented with truncal ataxia and was found to have peripheral and CSF eosinophilia. MRI demonstrated symmetric, confluent T2 hyperintense signal in the cerebral and cerebellar deep white mater, which helped differentiate B. procyonis meningoencephalitis from other infectious and non-infectious causes of eosinophilic meningoencephalitis. Early recognition and treatment of B. procyonis meningoencephalitis are important for improved outcomes, and careful review of neuroimaging can play a critical role in suggesting the diagnosis.

INTRODUCTION: Angiostrongylus cantonensis meningoencephalitis is an emergent disease in the Americas. METHOD: Twelve children suffering from eosinophilic meningoencephalitis due to this parasite aged between 6-10 years were studied. Cerebrospinal fluid (CSF) and serum samples were taken simultaneously in the first diagnostic puncture at admission. RESULTS: All cases showed typical findings on the routine CSF and serum analysis: increased CSF total protein, increased Q (CSF/serum) albumin accompanied by eosinophilia in CSF. No intrathecal synthesis of immunoglobulins was found. Mean serum and CSF sICAM-1 values were 337.4 and 3.97 ng/mL. Qalbumin and QsICAM-1 mean values were 4.1 and 6.2 respectively. In 50% of the patients an increased brain-derived fraction of sICAM-1 was found. CONCLUSION: It may be suggested that a dynamic of the sICAM-1 brain derived fraction is perhaps associated to the immune response in the evolution of the disease.sICAM-1 may be an agent in negative feedback for eosinophils passage through the blood-CSF barrier into the inflammatory brain response.

ABSTRACT Angiostrongylus cantonensis is the major cause of eosinophilic meningoencephalitis cases in Taiwan. Mice were orally infected with 35 infective larvae. One group of mice were given a single dose of mebendazole (20 mg/kg of body weight) per os at various times and examined at 14 days postinfection (dpi) for worm recovery rate and pathological studies. A 94 to 97% reduction in worm recovery was observed when medication was given at 4 to 5 dpi. Sections of the brains revealed that untreated infected mice developed typical severe eosinophilic meningoencephalitis. Meninges of these mice were thickened by massive infiltration of eosinophils, whereas only moderate pathological change was observed in the brains of mice that were treated with mebendazole at 4 dpi. Infected mice that received daily injections of 10 ng of interleukin-12 (IL-12) only for various numbers of days also exhibited moderate pathological changes in the brain. Eosinophil infiltration in the brains of these mice was low, and severe mechanical injuries in the parenchyma were observed. Treatment with mebendazole in combination with IL-12, however, resulted in low levels of worm recovery and dramatic lessening of the eosinophilic meningitis. A reverse transcriptase PCR assay of mRNA expression in the brain also revealed that the use of IL-12 had shifted the immune response of the mouse from Th2 type to Th1 type. This study could be used in developing strategies for the treatment of human angiostrongylosis.

Meningoencephalitis is not a rare disease in children. However, eosinophilic meningitis due to <i>Angiostrongylus cantonensis</i> is unusual in the pediatric population. We describe the case of a 12-year-old girl from the central area of Vietnam with eosinophilic meningitis due to <i>A. cantonensis</i>. The patient lived in a rural area, where farming is widespread, and presented with fever and headache. Laboratory results showed peripheral eosinophilia, a cerebrospinal fluid white blood cell count of 730/mm³ with 65% eosinophils. Cerebrospinal fluid ELISA was positive for <i>A. cantonensis</i>, and blood ELISA was positive for <i>A. cantonensis</i>. The presentation was consistent with a diagnosis of <i>A. cantonensis</i> eosinophilic meningitis. The patient recovered fully after administration of albendazole (200 mg/day for 2 weeks), as well as intravenous dexamethasone (0.6 mg/kg/day every 8 h) and mannitol (1.5 g/kg/day every 8 h) for the first 3 days, followed by 5 days of oral prednisolone (2 mg/kg/day).

Summary Canine Neural Angiostrongyliasis (CNA) is caused by the obligatory neural migration of Angiostrongylus cantonensis larvae in dogs. Characteristically, cases are juvenile dogs with progressive CNS dysfunction characterised by hyperaesthesia and often associated with eosinophilic pleocytosis of the CSF. In Australia, most cases occur between March and June. The rat lungworm, A cantonensis was first described by Chen in 1935 in Canton, China. While initially called Pulmonema cantonensis the parasite was later reclassified as A cantonensis. A disease diagnosed as eosinophilic meningoencephalitis was first described in 1944 in Taiwan. The same disease was reported in 1948 in the East Caroline Islands but it was not until 1961 that A cantonensis was confirmed as the aetiological agent when a patient in a Hawaiian mental institution, who had died of eosinophilic meningoencephalitis, had A cantonensis larvae recovered from the brain and spinal cord. The first reports of animals infected with A cantonensis were made by Mason in 1976 when he described a syndrome occurring in puppies in the Brisbane area, characterised by urinary incontinence, hind limb paresis and hyperaesthesia, often associated with eosinophilic pleocytosis of the CSF. Reports of infection in other species followed including macropods, bats, horses, primates and birds. Twenty-two cases of suspected CNA were collected prospectively to compare with those previously described, including 37 cases published by Mason in 1983, and to examine the accuracy of an ELISA used to diagnose human neural angiostrongyliasis in Australia. Samples were collected from two control populations in an attempt to validate the ELISA results. In the prospective series of cases, there was a significantly older subpopulation of dogs in addition to “classical” young dogs, suggesting that this syndrome can occur at any age and should be considered a differential in any dog with progressive neurological disease. The mortality rate in the prospective group was lower than in the published group, which is a reflection of the severity of the disease in younger animals as is the case with human patients. Definitive diagnosis of neural angiostrongyliasis in human patients has been achieved by identifying A cantonensis larvae within the CSF or aqueous humour. In dogs, the only definitive way to diagnose CNA has been via necropsy. While many cases of CNA are characteristic and presumptive diagnosis can be made based on typical history, signalment, clinical signs, CSF analysis and response to glucocorticoids, there appear to be an increasing number of cases occurring in older dogs, that displaying focal, atypical clinical signs or that develop permanent sequelae. Serology has been a useful tool in diagnosing neural angiostrongyliasis in humans. In its current form the ELISA is not sensitive or specific enough to allow a definitive diagnosis of CNA to be made using serum but is useful when applied to CSF specimens. Further refinement of the antigen or using monoclonal rather than polyclonal antibodies may improve the accuracy of the serology. Alternatively, methods such as Western Blot, Immuno-PCR or dot-blot ELISA, which have been successfully used to diagnoses angiostrongyliasis in humans, may be worthy of investigation The major differential diagnosis for CNA is neosporosis. Other differential diagnoses include idiopathic eosinophilic meningoencephalitis, parasitic infections including Toxoplasma gondii, Taenia solium, Gnathostoma spinigerum, visceral larval migrans (Toxocara canis) and schistosomiasis, fungal, bacterial, viral and rickettsial infections as well as neoplasia, trauma, drug reactions and toxicities. Treatment of CNA has been limited to glucocorticoids, however there may be adjunct therapies including anthelmintices, cyclosporine, and matrix metalloproteinase inhibitors. In Mason’s series of cases the use of anthelmintics significantly worsened the clinical outcome for patients. It does not appear, however, that the use of these agents in species other than the dog exacerbates clinical signs. Acquired immunity is short lived in rats and mice, which would suggest the same is true in dogs. Routine heartworm and intestinal parasite prophylaxis appears to have no influence on the occurrence of CNA.

博士
國立臺灣大學
微生物學研究所
91
Angiostrongylus cantonensis is the major cause of eosinophilic meningoencephalitis cases in Taiwan. Mice were orally infected with 35 infective larvae. One group of mice were given single dose mebendazole (20mg/kg) per os at various times and examined at 14 days postinfection (dpi) for worm recovery rate and pathological studies. A 94-97% reduction in worm recovery was observed if medication was given 4-5 dpi. Sections of the brains revealed that untreated infected mice developed typical severe eosinophilic meningoencephalitis. Meninges of these mice were thickened by massive infiltration of eosinophils, whereas only moderate pathological change was observed in the brains of mice that were treated with mebendazole at 4 dpi. Infected mice that received daily injections of 10 ng interleukin-12 (IL-12) for varying days only also exhibited moderate pathological change in the brains. Eosinophil infiltration in the brains of these mice were low and severe mechanical injuries in the parenchyma were observed. Treatment with mebendazole in combination with IL-12, however, resulted in low worm recovery and dramatic lessening of the eosinophilic meningitis. The reverse transcriptase-PCR assay on mRNA expression in the brain also revealed that the use of IL-12 had shifted the immune response of the mouse from Th2-type into Th1-type. In situ staining of the sections with TUNEL assay, anti-Akt or anti-caspase antibodies, revealed that infiltrated eosinophils in the meninges of infected but nontreated mice were resistant to apoptosis. Some of the infiltrated eosinophils in the meninges of various treatment groups, however, were undergoing programmed cell death.

碩士
中山醫學大學
醫學研究所
96
Angiostrongylus cantonensis, the rat lugworm, is the principal cause of eosinophilic meningitis or meningoencephalitis. In the previous study, matrix metalloproteinase-9 (MMP-9) has been proved involved in the pathogenesis of eosinophilic meningitis or meningoencephalitis. In this study, we used 5-week BALB/c male mice infected 50 A. cantonensis larvae. The results showed that MMP-12 is found in the brain tissues and cerebral spinal fruid (CSF) of infected mice and significantly increases from day 5 PI. Similarly, the expression of elastin, the substrate of MMP-12 is also increased. By immunohistochemistry, confirmed that MMP-12 distributed in leukocytes that infiltrated into subarachnoid space and mainly expressed in macrophages and eosinophils. The mice treated with albendazole (10mg/kg per day) alone, doxycycline (30mg/kg per day) alone, or a combination of albendazole (10mg/kg per day) and doxycycline (30mg/kg per day) for 7 consecutive days on day 5 and 15 post-inoculation (PI), respectively. The treatment of albendazole-doxycycline co-therapy on day 5 PI significantly reduced the infiltration of leukocytes and the expression of MMP-12 in infected mice. These results suggested that MMP-12 may contribute to the develop of eosinophilic meningitis or meningoencephalitis caused by A. cantonensis. This new approach may be beneficial to treat the parasitic meningitis or meningoencephalitis.

Master of Veterinary Clinical Studies
Summary Canine Neural Angiostrongyliasis (CNA) is caused by the obligatory neural migration of Angiostrongylus cantonensis larvae in dogs. Characteristically, cases are juvenile dogs with progressive CNS dysfunction characterised by hyperaesthesia and often associated with eosinophilic pleocytosis of the CSF. In Australia, most cases occur between March and June. The rat lungworm, A cantonensis was first described by Chen in 1935 in Canton, China. While initially called Pulmonema cantonensis the parasite was later reclassified as A cantonensis. A disease diagnosed as eosinophilic meningoencephalitis was first described in 1944 in Taiwan. The same disease was reported in 1948 in the East Caroline Islands but it was not until 1961 that A cantonensis was confirmed as the aetiological agent when a patient in a Hawaiian mental institution, who had died of eosinophilic meningoencephalitis, had A cantonensis larvae recovered from the brain and spinal cord. The first reports of animals infected with A cantonensis were made by Mason in 1976 when he described a syndrome occurring in puppies in the Brisbane area, characterised by urinary incontinence, hind limb paresis and hyperaesthesia, often associated with eosinophilic pleocytosis of the CSF. Reports of infection in other species followed including macropods, bats, horses, primates and birds. Twenty-two cases of suspected CNA were collected prospectively to compare with those previously described, including 37 cases published by Mason in 1983, and to examine the accuracy of an ELISA used to diagnose human neural angiostrongyliasis in Australia. Samples were collected from two control populations in an attempt to validate the ELISA results. In the prospective series of cases, there was a significantly older subpopulation of dogs in addition to “classical” young dogs, suggesting that this syndrome can occur at any age and should be considered a differential in any dog with progressive neurological disease. The mortality rate in the prospective group was lower than in the published group, which is a reflection of the severity of the disease in younger animals as is the case with human patients. Definitive diagnosis of neural angiostrongyliasis in human patients has been achieved by identifying A cantonensis larvae within the CSF or aqueous humour. In dogs, the only definitive way to diagnose CNA has been via necropsy. While many cases of CNA are characteristic and presumptive diagnosis can be made based on typical history, signalment, clinical signs, CSF analysis and response to glucocorticoids, there appear to be an increasing number of cases occurring in older dogs, that displaying focal, atypical clinical signs or that develop permanent sequelae. Serology has been a useful tool in diagnosing neural angiostrongyliasis in humans. In its current form the ELISA is not sensitive or specific enough to allow a definitive diagnosis of CNA to be made using serum but is useful when applied to CSF specimens. Further refinement of the antigen or using monoclonal rather than polyclonal antibodies may improve the accuracy of the serology. Alternatively, methods such as Western Blot, Immuno-PCR or dot-blot ELISA, which have been successfully used to diagnoses angiostrongyliasis in humans, may be worthy of investigation The major differential diagnosis for CNA is neosporosis. Other differential diagnoses include idiopathic eosinophilic meningoencephalitis, parasitic infections including Toxoplasma gondii, Taenia solium, Gnathostoma spinigerum, visceral larval migrans (Toxocara canis) and schistosomiasis, fungal, bacterial, viral and rickettsial infections as well as neoplasia, trauma, drug reactions and toxicities. Treatment of CNA has been limited to glucocorticoids, however there may be adjunct therapies including anthelmintices, cyclosporine, and matrix metalloproteinase inhibitors. In Mason’s series of cases the use of anthelmintics significantly worsened the clinical outcome for patients. It does not appear, however, that the use of these agents in species other than the dog exacerbates clinical signs. Acquired immunity is short lived in rats and mice, which would suggest the same is true in dogs. Routine heartworm and intestinal parasite prophylaxis appears to have no influence on the occurrence of CNA.