Eosinophilic meningitis following suboccipital craniotomy without bovine dural graft: illustrative case

BACKGROUND Eosinophilic meningitis is a rare known complication after brain surgery associated with duraplasty using artificial bovine graft. However, eosinophilic meningitis after craniotomy without bovine dural graft has not been reported. OBSERVATIONS A 48-year-old female presented with lateral medullary infarction caused by a vertebral artery dissecting aneurysm incorporating the posterior inferior cerebellar artery (PICA). The authors performed occipital artery–PICA anastomosis and repaired the dura by primary suture without bovine graft. Thereafter, endovascular internal trapping using coils was conducted. Severe headache developed at postoperative day 17, and the patient was diagnosed with eosinophilic meningitis. After administration of a high-dose corticosteroid for 2 weeks, her symptoms and laboratory findings were improved. LESSONS Postoperative eosinophilic meningitis is rarely related to craniotomy without using bovine graft. Neurosurgeons should consider the possibility of eosinophilic meningitis after craniotomy without a xenogeneic dural material.

Eosinophilic meningitis in New Caledonia: The role of Angiostrongylus cantonensis?

Introduction Eosinophilic meningitis is a rare form of meningitis with sequelae or death occurring in approximately 2–3% of cases. The most frequent etiological agent is the parasite Angiostrongylus cantonensis. The aim of this study was to characterize New Caledonian cases and to assess the extent to which of A. cantonensis was involved. Material and methods We performed a retrospective study of all cases of eosinophilic meningitis (EM) admitted to the Territorial Hospital of New Caledonia, from 2004 to 2019. We performed a descriptive and a multivariate analysis to identify association of variables with severe and fatal cases (or cases with sequelae). Conclusion Angiostrongyliasis was confirmed as being responsible for 17 of the 92 reported EM cases in New Caledonia from 2004 to 2019 with most being young adults and non-walking infants, and with two peaks of incidence one during the dry season and one during the rainy season. Considering the high incidence and regularity of cases, the potential reservoirs should be identified to target prevention campaigns.

Exosome-Depleted Excretory-Secretory Products of the Fourth-Stage Larval Angiostrongylus cantonensis Promotes Alternative Activation of Macrophages Through Metabolic Reprogramming by the PI3K-Akt Pathway

Angiostrongylus cantonensis (AC), which parasitizes in the brain of the non-permissive host, such as mouse and human, is an etiologic agent of eosinophilic meningitis. Excretory-secretory (ES) products play an important role in the interaction between parasites and hosts’ immune responses. Inflammatory macrophages are responsible for eosinophilic meningitis induced by AC, and the soluble antigens of Angiostrongylus cantonensis fourth stage larva (AC L4), a mimic of dead AC L4, aggravate eosinophilic meningitis in AC-infected mice model via promoting alternative activation of macrophages. In this study, we investigated the key molecules in the ES products of AC L4 on macrophages and observed the relationship between metabolic reprogramming and the PI3K-Akt pathway. First, a co-culture system of macrophage and AC L4 was established to define the role of AC L4 ES products on macrophage polarization. Then, AC L4 exosome and exosome-depleted excretory-secretory products (exofree) were separated from AC L4 ES products using differential centrifugation, and their distinct roles on macrophage polarization were confirmed using qPCR and ELISA experiments. Moreover, AC L4 exofree induced alternative activation of macrophages, which is partially associated with metabolic reprogramming by the PI3K-Akt pathway. Next, lectin blot and deglycosylation assay were done, suggesting the key role of N-linked glycoproteins in exofree. Then, glycoproteomic analysis of exofree and RNA-seq analysis of exofree-treated macrophage were performed. Bi-layer PPI network analysis based on these results identified macrophage-related protein Hexa as a key molecule in inducing alternative activation of macrophages. Our results indicate a great value for research of helminth-derived immunoregulatory molecules, which might contribute to drug development for immune-related diseases.

A RARE CASE OF EOSINOPHYLIC MENINGITIS BY PROBABLE ANGIOSTRONGYLUS CANTONENSIS, IN AN INFANT IN THE CITY OF MANAUS, IN THE AMAZON REGION OF BRAZIL

March 2021, a 12-month-old infant was brought to the HPS East Zone Little Jonh, in the capital of the State of Amazonas, Brazil, where she was admitted with fever, vomiting, intense prostration, little acceptance of breast milk, difficulty in walking, associated with left-facing strabismus and neck stiffness. At admission, the main author performed a lumbar puncture, and serological tests on the CSF to identify the causative agent were referred to a reference laboratory, which suggested that they be referred to the Central Laboratory - LACEN for suspecting the presence of agent Angionsytrongylis Canyonensis. Although, the identification of the causative agent is difficult to be detected and confirmed, this case report shows us the importance of the clinical laboratory in the identification of Eosinophilic Meningitis. The sub-detection of eosinophils in the CSF helps to underestimate the prevalence of eosinophilic meningitis. Thus, CSF analysis, slide preparation, sediment staining, as well as knowledge about the importance of adequate leukocyte differentiation in CSF are extremely important, to properly conduct the final diagnosis of the disease and prevent possible endemicity. The knowledge of this condition and early detection allows an effective therapy and improvement of public health actions. ? ?,

Infectious Causes of Eosinophilic Meningitis in Korean Patients: A Single-Institution Retrospective Chart Review from 2004 to 2018

Eosinophilic meningitis is defined as the presence of more than 10 eosinophils per μl in the cerebrospinal fluid (CSF), or eosinophils accounting for more than 10% of CSF leukocytes in patients with acute meningitis. Parasites are the most common cause of eosinophilic meningitis worldwide, but there is limited research on patients in Korea. Patients diagnosed with eosinophilic meningitis between January 2004 and June 2018 at a tertiary hospital in Seoul, Korea were retrospectively reviewed. The etiology and clinical characteristics of each patient were identified. Of the 22 patients included in the study, 11 (50%) had parasitic causes, of whom 8 (36%) were diagnosed as neurocysticercosis and 3 (14%) as Toxocara meningitis. Four (18%) patients were diagnosed with fungal meningitis, and underlying immunodeficiency was found in 2 of these patients. The etiology of another 4 (18%) patients was suspected to be tuberculosis, which is endemic in Korea. Viral and bacterial meningitis were relatively rare causes of eosinophilic meningitis, accounting for 2 (9%) and 1 (5%) patients, respectively. One patient with neurocysticercosis and 1 patient with fungal meningitis died, and 5 (23%) had neurologic sequelae. Parasite infections, especially neurocysticercosis and toxocariasis, were the most common cause of eosinophilic meningitis in Korean patients. Fungal meningitis, while relatively rare, is often aggressive and must be considered when searching for the cause of eosinophilic meningitis.

RPAcan3990: an ultrasensitive recombinase polymerase assay to detect Angiostrongylus cantonensis DNA

Angiostrongylus cantonensis (Ac) is one of the leading causes of eosinophilic meningitis worldwide. A field deployable molecular detection method could enhance both environmental surveillance and clinical diagnosis of this emerging pathogen. Accordingly, RPAcan3990, a recombinase polymerase assay (RPA) was developed to target a region predicted to be highly repeated in the Ac genome. The assay was then adapted to produce a visually interpretable fluorescent readout using an orange camera lens filter and a blue light. Using Ac genomic DNA, the limit of detection was found to be 1fg/μl by both fluorometer measurement and visual reading. All clinical samples known to be positive for Ac from various areas of the globe were positive by RPAcan3990. Cerebrospinal fluid samples from other etiologies of eosinophilic meningitis (i.e. Toxocara sp., Gnathostoma sp.) were negative in the RPAcan3990 assay. The optimal incubation temperature range for the reaction was between 35-40°C. The assay successfully detected 1fg/μl of Ac genomic DNA after incubation at human body temperature (in a shirt pocket). In conclusion, these data suggest RPAcan3990 is potentially a point of contact molecular assay capable of sensitively detecting Ac by producing visually interpretable results with minimal instrumentation.

A RARE CASE OF EOSINOPHYLIC MENINGITIS BY PROBABLE ANGIOSTRONGYLUS CANTONENSIS, IN AN INFANT IN THE CITY OF MANAUS, IN THE AMAZON REGION OF BRAZIL

March 2021, a 12-month-old infant was brought to the HPS East Zone Little Jonh, in the capital of the State of Amazonas, Brazil, where she was admitted with fever, vomiting, intense prostration, little acceptance of breast milk, difficulty in walking, associated with left-facing strabismus and neck stiffness. At admission, the main author performed a lumbar puncture, and serological tests on the CSF to identify the causative agent were referred to a reference laboratory, which suggested that they be referred to the Central Laboratory - LACEN for suspecting the presence of agent Angionsytrongylis Canyonensis. Although, the identification of the causative agent is difficult to be detected and confirmed, this case report shows us the importance of the clinical laboratory in the identification of Eosinophilic Meningitis. The sub-detection of eosinophils in the CSF helps to underestimate the prevalence of eosinophilic meningitis. Thus, CSF analysis, slide preparation, sediment staining, as well as knowledge about the importance of adequate leukocyte differentiation in CSF are extremely important, to properly conduct the final diagnosis of the disease and prevent possible endemicity. The knowledge of this condition and early detection allows an effective therapy and improvement of public health actions. ? ?,