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Diederik Van De Beek - One of the best experts on this subject based on the ideXlab platform.
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Delayed cerebral thrombosis complicating Pneumococcal Meningitis: an autopsy study.
Annals of intensive care, 2018Co-Authors: Jooyeon Engelen-lee, Matthijs C. Brouwer, Eleonora Aronica, Diederik Van De BeekAbstract:Delayed cerebral thrombosis (DCT) is a devastating cerebrovascular complication in patients with excellent initial recovery of Pneumococcal Meningitis. The aetiology is unknown, but direct bacterial invasion, activation of coagulation or post-infectious immunoglobulin deposition has been suggested. We studied histopathology of 4 patients with Pneumococcal Meningitis complicated by DCT. Results were compared with 8 patients who died of Pneumococcal Meningitis without DCT and 3 non-Meningitis control cases. Furthermore, we evaluated vascular immunoglobulin depositions (IgA, IgG and IgM) and the presence of Pneumococcal capsules by immunofluorescence. Patients who died after Pneumococcal Meningitis showed inflammation in the meninges and blood vessels with extensive infarction and thrombosis. We did not observe gross differences between DCT and non-DCT patients, except that 2 of 4 DCT patients had a basilar artery aneurysm compared to none of the non-DCT patients. We observed high density of IgM and IgG deposition in Meningitis cases as compared to controls, but no difference between DCT and non-DCT patients. Immunofluorescence staining of pneumococci demonstrated the presence of bacterial capsules in the meninges of all Meningitis patients, even 35 days after the initiation of antibiotic treatment. The aetiology of DCT complicating Pneumococcal Meningitis seems to be of multifactorial aetiology and includes vascular inflammation, thromboembolism of large arteries and infectious intracranial aneurysms. Pneumococcal cell wall components can be observed for weeks after Pneumococcal Meningitis and may be a source of resurging inflammation after the initial immunosuppression by dexamethasone.
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Variation of 46 Innate Immune Genes Evaluated for their Contribution in Pneumococcal Meningitis Susceptibility and Outcome.
EBioMedicine, 2016Co-Authors: Bart Ferwerda, Matthijs C. Brouwer, Frank Baas, Aeilko H. Zwinderman, Arie Van Der Ende, M. Geldhoff, Mercedes Valls Seron, Aldo Jongejan, Diederik Van De BeekAbstract:Pneumococcal Meningitis is the most common and severe form of bacterial Meningitis. Early recognition of the pathogen and subsequent innate immune response play a vital role in disease susceptibility and outcome. Genetic variations in innate immune genes can alter the immune response and influence susceptibility and outcome of Meningitis disease. Here we conducted a sequencing study of coding regions from 46 innate immune genes in 435 Pneumococcal Meningitis patients and 416 controls, to determine the role of genetic variation on Pneumococcal Meningitis susceptibility and disease outcome. Strongest signals for susceptibility were rs56078309 CXCL1 (p = 4.8e − 04) and rs2008521 in CARD8 (p = 6.1e − 04). For Meningitis outcome the rs2067085 in NOD2 (p = 5.1e − 04) and rs4251552 of IRAK4 were the strongest associations with unfavorable outcome (p = 6.7e − 04). Haplotype analysis showed a haplotype block, determined by IRAK4 rs4251552, significantly associated with unfavorable outcome (p = 0.004). Cytokine measurements from cerebrospinal fluid showed that with the IRAK4 rs4251552 G risk allele had higher levels of IL-6 compared to individuals with A/A genotype (p = 0.04). We show that genetic variation within exons and flanking regions of 46 innate immunity genes does not yield significant association with Pneumococcal Meningitis. The strongest identified signal IRAK4 does imply a potential role of genetic variation in Pneumococcal Meningitis.
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exome array analysis of susceptibility to Pneumococcal Meningitis
Scientific Reports, 2016Co-Authors: Anne T Kloek, Matthijs C. Brouwer, Arie Van Der Ende, Diederik Van De Beek, Jessica Van Setten, Michiel L Bots, Folkert W Asselbergs, Mercedes Valls Seron, Bart FerwerdaAbstract:Host genetic variability may contribute to susceptibility of bacterial Meningitis, but which genes contribute to the susceptibility to this complex disease remains undefined. We performed a genetic association study in 469 community-acquired Pneumococcal Meningitis cases and 2072 population-based controls from the Utrecht Health Project in order to find genetic variants associated with Pneumococcal Meningitis susceptibility. A HumanExome BeadChip was used to genotype 102,097 SNPs in the collected DNA samples. Associations were tested with the Fisher exact test. None of the genetic variants tested reached Bonferroni corrected significance (p-value <5 × 10(-7)). Our strongest signals associated with susceptibility to Pneumococcal Meningitis were rs139064549 on chromosome 1 in the COL11A1 gene (p = 1.51 × 10(-6); G allele OR 3.21 [95% CI 2.05-5.02]) and rs9309464 in the EXOC6B gene on chromosome 2 (p = 6.01 × 10(-5); G allele OR 0.66 [95% CI 0.54-0.81]). The sequence kernel association test (SKAT) tests for associations between multiple variants in a gene region and Pneumococcal Meningitis susceptibility yielded one significant associated gene namely COL11A1 (p = 1.03 × 10(-7)). Replication studies are needed to validate these results. If replicated, the functionality of these genetic variations should be further studied to identify by which means they influence the pathophysiology of Pneumococcal Meningitis.
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Exome Array Analysis of Susceptibility to Pneumococcal Meningitis.
Scientific reports, 2016Co-Authors: Anne T Kloek, Matthijs C. Brouwer, Arie Van Der Ende, Diederik Van De Beek, Jessica Van Setten, Michiel L Bots, Folkert W Asselbergs, Mercedes Valls Seron, Bart FerwerdaAbstract:Host genetic variability may contribute to susceptibility of bacterial Meningitis, but which genes contribute to the susceptibility to this complex disease remains undefined. We performed a genetic association study in 469 community-acquired Pneumococcal Meningitis cases and 2072 population-based controls from the Utrecht Health Project in order to find genetic variants associated with Pneumococcal Meningitis susceptibility. A HumanExome BeadChip was used to genotype 102,097 SNPs in the collected DNA samples. Associations were tested with the Fisher exact test. None of the genetic variants tested reached Bonferroni corrected significance (p-value
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Pneumococcal Meningitis: clinical-pathological correlations (MeninGene-Path)
Acta neuropathologica communications, 2016Co-Authors: Jooyeon Engelen-lee, Matthijs C. Brouwer, Eleonora Aronica, Diederik Van De BeekAbstract:Pneumococcal Meningitis is associated with substantial mortality and morbidity. We systematically assessed brain histopathology of 31 patients who died of Pneumococcal Meningitis from a nationwide study (median age 67 years; 21 (67 %) were male) using a pathology score including inflammation and vascular damage. Of the 27 patients with known time from the admission to death, 14 patients died within 7 days of admission and 13 after 7 days of admission. Eleven of 25 (44 %) patients had been treated with adjunctive dexamethasone therapy. Observed pathological processes were inflammation of medium-large arteries in 30 brains (97 %), cerebral haemorrhage in 24 (77 %), cerebritis in 24 (77 %), thrombosis in 21 (68 %), infarction in 19 (61 %) and ventriculitis in 19 (of 28 cases, 68 %). Inflammation of medium-large arteries led to obstruction of the vascular lumen in 14 (of 31 cases, 45 %). Vascular inflammation was associated with infarction and thrombosis of brain parenchymal vessels. Hippocampal dentate gyrus apoptosis between patients treated with and without dexamethasone was similar (p = 0.66); however, dexamethasone treated patients had higher total pathology score than non-dexamethasone treated patients (p = 0.003). Our study shows that vascular damage is key in the process of brain damage in Pneumococcal Meningitis. Data and material of this study will be made open-access for translational research in Pneumococcal Meningitis (MeninGene-Path).
Robert K. Shepherd - One of the best experts on this subject based on the ideXlab platform.
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Pneumococcal Meningitis post-cochlear implantation: potential routes of infection and pathophysiology.
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2010Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen J. O'learyAbstract:This review describes the current concept of Pneumococcal Meningitis in cochlear implant recipients based on recent laboratory studies. It examines possible routes of Streptococcus pneumoniae infection to the meninges in cochlear implant recipients. It also provides insights into fundamental questions concerning the pathophysiology of Pneumococcal Meningitis in implant recipients. Medline/PubMed database; English articles after 1960. Search terms: cochlear implants, Meningitis, pneumococcus, streptococcus pneumonia. Narrative review. All articles relating to post-implant Meningitis without any restriction in study designs were assessed and information extracted. The incidence of Pneumococcal Meningitis in cochlear implant recipients is greater than that of an age-matched cohort in the general population. Based on the current clinical literature, it is difficult to determine whether cochlear implantation per se increases the risk of Meningitis in subjects with no existing risk factors for acquiring the disease. As this question cannot be answered in humans, the study of implant-related infection must involve the use of laboratory animals in order for the research findings to be applicable to a clinical situation. The laboratory research demonstrated the routes of infection and the effects of the cochlear implant in lowering the threshold for Pneumococcal Meningitis. The laboratory data complement the existing clinical data on the risk of Pneumococcal Meningitis post-cochlear implantation. Copyright © 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.
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Pneumococcal Meningitis post-cochlear implantation: Potential routes of infection and pathophysiology
Otolaryngology - Head and Neck Surgery, 2010Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen J. O'learyAbstract:© 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.Objectives: This review describes the current concept of Pneumococcal Meningitis in cochlear implant recipients based on recent laboratory studies. It examines possible routes of S. pneumoniae infection to the meninges in cochlear implant recipients. It also provides insights into fundamental questions concerning the pathophysiology of Pneumococcal Meningitis in implant recipients. Data Sources: Medline search on topics related to Pneumococcal Meningitis post cochlear implantation. Review Methods: Comprehensive analysis of the published clinical and scientific laboratory research data. Results: The incidence of Pneumococcal Meningitis in cochlear implant recipients is greater than that of an age-matched cohort in the general population. Based on the current clinical literature, it is difficult to determine whether cochlear implantation per se increases the risk of Meningitis in subjects with no existing risk factors for acquiring the disease. As this question cannot be answered in humans, the study of implant-related infection must involve the use of laboratory animals in order for the research findings to be applicable to a clinical situation. The laboratory research demonstrated the routes of infection and the effects of the cochlear implant in lowering the threshold for Pneumococcal Meningitis. Conclusion: The laboratory data complements the existing clinical data on the risk of Pneumococcal Meningitis post cochlear implantation.Open Acces
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Effects of inner ear trauma on the risk of Pneumococcal Meningitis
Archives of Otolaryngology-head & Neck Surgery, 2007Co-Authors: Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen O'learyAbstract:Objective To examine the risk of Pneumococcal Meningitis in healthy rats that received a severe surgical trauma to the modiolus and osseous spiral lamina or the standard insertion technique for acute cochlear implantation. Design Interventional animal studies. Subjects Fifty-four otologically normal adult Hooded-Wistar rats. Interventions Fifty-four rats (18 of which received a cochleostomy alone; 18, a cochleostomy and acute cochlear implantation using standard surgical techniques; and 18, a cochleostomy followed by severe inner ear trauma) were infected 4 weeks after surgery with Streptococcus pneumoniae via 3 different routes (hematogenous, middle ear, and inner ear) to represent all potential routes of bacterial infection from the upper respiratory tract to the meninges in cochlear implant recipients with Meningitis. Results Severe trauma to the osseous spiral lamina and modiolus increased the risk of Pneumococcal Meningitis when the bacteria were given via the middle or inner ear (Fisher exact test, P Conclusions Severe inner ear surgical trauma to the osseous spiral lamina and modiolus can increase the risk of Pneumococcal Meningitis. Therefore, every effort should be made to ensure that cochlear implant design and insertion technique cause minimal trauma to the bony structures of the inner ear to reduce the risk of Pneumococcal Meningitis.
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Threshold shift: effects of cochlear implantation on the risk of Pneumococcal Meningitis
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2007Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen O'learyAbstract:Objectives The study goals were to examine whether cochlear implantation increases the risk of Meningitis in the absence of other risk factors and to understand the pathogenesis of Pneumococcal Meningitis post cochlear implantation. Study Design and Setting Four weeks following surgery, 54 rats (18 of which received a cochleostomy alone, 18 of which received a cochleostomy and acute cochlear implantation using standard surgical techniques, and 18 of which received a cochlear implant) were infected with Streptococcus pneumoniae via three different routes of bacterial inoculation (middle ear, inner ear, and intraperitoneal) to represent all potential routes of bacterial infection from the upper respiratory tract to the meninges. Results The presence of a cochlear implant reduced the threshold of bacteria required to cause Pneumococcal Meningitis from all routes of infection in healthy animals. Conclusion The presence of a cochlear implant increases the risk of Pneumococcal Meningitis regardless of the route of bacterial infection. Significance Early detection and treatment of Pneumococcal infection such as otitis media may be required, as cochlear implantation may lead to a reduction of infectious threshold for Meningitis.
Stephen J. O'leary - One of the best experts on this subject based on the ideXlab platform.
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Pneumococcal Meningitis post-cochlear implantation: Potential routes of infection and pathophysiology
Otolaryngology - Head and Neck Surgery, 2010Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen J. O'learyAbstract:© 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.Objectives: This review describes the current concept of Pneumococcal Meningitis in cochlear implant recipients based on recent laboratory studies. It examines possible routes of S. pneumoniae infection to the meninges in cochlear implant recipients. It also provides insights into fundamental questions concerning the pathophysiology of Pneumococcal Meningitis in implant recipients. Data Sources: Medline search on topics related to Pneumococcal Meningitis post cochlear implantation. Review Methods: Comprehensive analysis of the published clinical and scientific laboratory research data. Results: The incidence of Pneumococcal Meningitis in cochlear implant recipients is greater than that of an age-matched cohort in the general population. Based on the current clinical literature, it is difficult to determine whether cochlear implantation per se increases the risk of Meningitis in subjects with no existing risk factors for acquiring the disease. As this question cannot be answered in humans, the study of implant-related infection must involve the use of laboratory animals in order for the research findings to be applicable to a clinical situation. The laboratory research demonstrated the routes of infection and the effects of the cochlear implant in lowering the threshold for Pneumococcal Meningitis. Conclusion: The laboratory data complements the existing clinical data on the risk of Pneumococcal Meningitis post cochlear implantation.Open Acces
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Pneumococcal Meningitis post-cochlear implantation: potential routes of infection and pathophysiology.
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2010Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen J. O'learyAbstract:This review describes the current concept of Pneumococcal Meningitis in cochlear implant recipients based on recent laboratory studies. It examines possible routes of Streptococcus pneumoniae infection to the meninges in cochlear implant recipients. It also provides insights into fundamental questions concerning the pathophysiology of Pneumococcal Meningitis in implant recipients. Medline/PubMed database; English articles after 1960. Search terms: cochlear implants, Meningitis, pneumococcus, streptococcus pneumonia. Narrative review. All articles relating to post-implant Meningitis without any restriction in study designs were assessed and information extracted. The incidence of Pneumococcal Meningitis in cochlear implant recipients is greater than that of an age-matched cohort in the general population. Based on the current clinical literature, it is difficult to determine whether cochlear implantation per se increases the risk of Meningitis in subjects with no existing risk factors for acquiring the disease. As this question cannot be answered in humans, the study of implant-related infection must involve the use of laboratory animals in order for the research findings to be applicable to a clinical situation. The laboratory research demonstrated the routes of infection and the effects of the cochlear implant in lowering the threshold for Pneumococcal Meningitis. The laboratory data complement the existing clinical data on the risk of Pneumococcal Meningitis post-cochlear implantation. Copyright © 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.
Roy M. Robins-browne - One of the best experts on this subject based on the ideXlab platform.
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Pneumococcal Meningitis post-cochlear implantation: potential routes of infection and pathophysiology.
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2010Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen J. O'learyAbstract:This review describes the current concept of Pneumococcal Meningitis in cochlear implant recipients based on recent laboratory studies. It examines possible routes of Streptococcus pneumoniae infection to the meninges in cochlear implant recipients. It also provides insights into fundamental questions concerning the pathophysiology of Pneumococcal Meningitis in implant recipients. Medline/PubMed database; English articles after 1960. Search terms: cochlear implants, Meningitis, pneumococcus, streptococcus pneumonia. Narrative review. All articles relating to post-implant Meningitis without any restriction in study designs were assessed and information extracted. The incidence of Pneumococcal Meningitis in cochlear implant recipients is greater than that of an age-matched cohort in the general population. Based on the current clinical literature, it is difficult to determine whether cochlear implantation per se increases the risk of Meningitis in subjects with no existing risk factors for acquiring the disease. As this question cannot be answered in humans, the study of implant-related infection must involve the use of laboratory animals in order for the research findings to be applicable to a clinical situation. The laboratory research demonstrated the routes of infection and the effects of the cochlear implant in lowering the threshold for Pneumococcal Meningitis. The laboratory data complement the existing clinical data on the risk of Pneumococcal Meningitis post-cochlear implantation. Copyright © 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.
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Pneumococcal Meningitis post-cochlear implantation: Potential routes of infection and pathophysiology
Otolaryngology - Head and Neck Surgery, 2010Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen J. O'learyAbstract:© 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.Objectives: This review describes the current concept of Pneumococcal Meningitis in cochlear implant recipients based on recent laboratory studies. It examines possible routes of S. pneumoniae infection to the meninges in cochlear implant recipients. It also provides insights into fundamental questions concerning the pathophysiology of Pneumococcal Meningitis in implant recipients. Data Sources: Medline search on topics related to Pneumococcal Meningitis post cochlear implantation. Review Methods: Comprehensive analysis of the published clinical and scientific laboratory research data. Results: The incidence of Pneumococcal Meningitis in cochlear implant recipients is greater than that of an age-matched cohort in the general population. Based on the current clinical literature, it is difficult to determine whether cochlear implantation per se increases the risk of Meningitis in subjects with no existing risk factors for acquiring the disease. As this question cannot be answered in humans, the study of implant-related infection must involve the use of laboratory animals in order for the research findings to be applicable to a clinical situation. The laboratory research demonstrated the routes of infection and the effects of the cochlear implant in lowering the threshold for Pneumococcal Meningitis. Conclusion: The laboratory data complements the existing clinical data on the risk of Pneumococcal Meningitis post cochlear implantation.Open Acces
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Effects of inner ear trauma on the risk of Pneumococcal Meningitis
Archives of Otolaryngology-head & Neck Surgery, 2007Co-Authors: Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen O'learyAbstract:Objective To examine the risk of Pneumococcal Meningitis in healthy rats that received a severe surgical trauma to the modiolus and osseous spiral lamina or the standard insertion technique for acute cochlear implantation. Design Interventional animal studies. Subjects Fifty-four otologically normal adult Hooded-Wistar rats. Interventions Fifty-four rats (18 of which received a cochleostomy alone; 18, a cochleostomy and acute cochlear implantation using standard surgical techniques; and 18, a cochleostomy followed by severe inner ear trauma) were infected 4 weeks after surgery with Streptococcus pneumoniae via 3 different routes (hematogenous, middle ear, and inner ear) to represent all potential routes of bacterial infection from the upper respiratory tract to the meninges in cochlear implant recipients with Meningitis. Results Severe trauma to the osseous spiral lamina and modiolus increased the risk of Pneumococcal Meningitis when the bacteria were given via the middle or inner ear (Fisher exact test, P Conclusions Severe inner ear surgical trauma to the osseous spiral lamina and modiolus can increase the risk of Pneumococcal Meningitis. Therefore, every effort should be made to ensure that cochlear implant design and insertion technique cause minimal trauma to the bony structures of the inner ear to reduce the risk of Pneumococcal Meningitis.
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Threshold shift: effects of cochlear implantation on the risk of Pneumococcal Meningitis
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2007Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen O'learyAbstract:Objectives The study goals were to examine whether cochlear implantation increases the risk of Meningitis in the absence of other risk factors and to understand the pathogenesis of Pneumococcal Meningitis post cochlear implantation. Study Design and Setting Four weeks following surgery, 54 rats (18 of which received a cochleostomy alone, 18 of which received a cochleostomy and acute cochlear implantation using standard surgical techniques, and 18 of which received a cochlear implant) were infected with Streptococcus pneumoniae via three different routes of bacterial inoculation (middle ear, inner ear, and intraperitoneal) to represent all potential routes of bacterial infection from the upper respiratory tract to the meninges. Results The presence of a cochlear implant reduced the threshold of bacteria required to cause Pneumococcal Meningitis from all routes of infection in healthy animals. Conclusion The presence of a cochlear implant increases the risk of Pneumococcal Meningitis regardless of the route of bacterial infection. Significance Early detection and treatment of Pneumococcal infection such as otitis media may be required, as cochlear implantation may lead to a reduction of infectious threshold for Meningitis.
Graeme M. Clark - One of the best experts on this subject based on the ideXlab platform.
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Pneumococcal Meningitis post-cochlear implantation: potential routes of infection and pathophysiology.
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2010Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen J. O'learyAbstract:This review describes the current concept of Pneumococcal Meningitis in cochlear implant recipients based on recent laboratory studies. It examines possible routes of Streptococcus pneumoniae infection to the meninges in cochlear implant recipients. It also provides insights into fundamental questions concerning the pathophysiology of Pneumococcal Meningitis in implant recipients. Medline/PubMed database; English articles after 1960. Search terms: cochlear implants, Meningitis, pneumococcus, streptococcus pneumonia. Narrative review. All articles relating to post-implant Meningitis without any restriction in study designs were assessed and information extracted. The incidence of Pneumococcal Meningitis in cochlear implant recipients is greater than that of an age-matched cohort in the general population. Based on the current clinical literature, it is difficult to determine whether cochlear implantation per se increases the risk of Meningitis in subjects with no existing risk factors for acquiring the disease. As this question cannot be answered in humans, the study of implant-related infection must involve the use of laboratory animals in order for the research findings to be applicable to a clinical situation. The laboratory research demonstrated the routes of infection and the effects of the cochlear implant in lowering the threshold for Pneumococcal Meningitis. The laboratory data complement the existing clinical data on the risk of Pneumococcal Meningitis post-cochlear implantation. Copyright © 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.
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Pneumococcal Meningitis post-cochlear implantation: Potential routes of infection and pathophysiology
Otolaryngology - Head and Neck Surgery, 2010Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen J. O'learyAbstract:© 2010 American Academy of Otolaryngology–Head and Neck Surgery Foundation. Published by Mosby, Inc. All rights reserved.Objectives: This review describes the current concept of Pneumococcal Meningitis in cochlear implant recipients based on recent laboratory studies. It examines possible routes of S. pneumoniae infection to the meninges in cochlear implant recipients. It also provides insights into fundamental questions concerning the pathophysiology of Pneumococcal Meningitis in implant recipients. Data Sources: Medline search on topics related to Pneumococcal Meningitis post cochlear implantation. Review Methods: Comprehensive analysis of the published clinical and scientific laboratory research data. Results: The incidence of Pneumococcal Meningitis in cochlear implant recipients is greater than that of an age-matched cohort in the general population. Based on the current clinical literature, it is difficult to determine whether cochlear implantation per se increases the risk of Meningitis in subjects with no existing risk factors for acquiring the disease. As this question cannot be answered in humans, the study of implant-related infection must involve the use of laboratory animals in order for the research findings to be applicable to a clinical situation. The laboratory research demonstrated the routes of infection and the effects of the cochlear implant in lowering the threshold for Pneumococcal Meningitis. Conclusion: The laboratory data complements the existing clinical data on the risk of Pneumococcal Meningitis post cochlear implantation.Open Acces
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Effects of inner ear trauma on the risk of Pneumococcal Meningitis
Archives of Otolaryngology-head & Neck Surgery, 2007Co-Authors: Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen O'learyAbstract:Objective To examine the risk of Pneumococcal Meningitis in healthy rats that received a severe surgical trauma to the modiolus and osseous spiral lamina or the standard insertion technique for acute cochlear implantation. Design Interventional animal studies. Subjects Fifty-four otologically normal adult Hooded-Wistar rats. Interventions Fifty-four rats (18 of which received a cochleostomy alone; 18, a cochleostomy and acute cochlear implantation using standard surgical techniques; and 18, a cochleostomy followed by severe inner ear trauma) were infected 4 weeks after surgery with Streptococcus pneumoniae via 3 different routes (hematogenous, middle ear, and inner ear) to represent all potential routes of bacterial infection from the upper respiratory tract to the meninges in cochlear implant recipients with Meningitis. Results Severe trauma to the osseous spiral lamina and modiolus increased the risk of Pneumococcal Meningitis when the bacteria were given via the middle or inner ear (Fisher exact test, P Conclusions Severe inner ear surgical trauma to the osseous spiral lamina and modiolus can increase the risk of Pneumococcal Meningitis. Therefore, every effort should be made to ensure that cochlear implant design and insertion technique cause minimal trauma to the bony structures of the inner ear to reduce the risk of Pneumococcal Meningitis.
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Threshold shift: effects of cochlear implantation on the risk of Pneumococcal Meningitis
Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery, 2007Co-Authors: Benjamin P.c. Wei, Robert K. Shepherd, Graeme M. Clark, Roy M. Robins-browne, Stephen O'learyAbstract:Objectives The study goals were to examine whether cochlear implantation increases the risk of Meningitis in the absence of other risk factors and to understand the pathogenesis of Pneumococcal Meningitis post cochlear implantation. Study Design and Setting Four weeks following surgery, 54 rats (18 of which received a cochleostomy alone, 18 of which received a cochleostomy and acute cochlear implantation using standard surgical techniques, and 18 of which received a cochlear implant) were infected with Streptococcus pneumoniae via three different routes of bacterial inoculation (middle ear, inner ear, and intraperitoneal) to represent all potential routes of bacterial infection from the upper respiratory tract to the meninges. Results The presence of a cochlear implant reduced the threshold of bacteria required to cause Pneumococcal Meningitis from all routes of infection in healthy animals. Conclusion The presence of a cochlear implant increases the risk of Pneumococcal Meningitis regardless of the route of bacterial infection. Significance Early detection and treatment of Pneumococcal infection such as otitis media may be required, as cochlear implantation may lead to a reduction of infectious threshold for Meningitis.