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Primary Care Sep 2013Meningitis is defined as inflammation of the meninges, in almost all cases identified by an abnormal number of white blood cells in the cerebrospinal fluid and specific... (Review)
Review
Meningitis is defined as inflammation of the meninges, in almost all cases identified by an abnormal number of white blood cells in the cerebrospinal fluid and specific clinical signs/symptoms. Onset may be acute or chronic, and clinical symptoms of acute disease develop over hours to days. This article reviews the epidemiology, pathophysiology, clinical manifestations, diagnosis, and management of acute meningitis, and provides a list of key points for primary care practitioners. Aseptic and bacterial meningitis vary significantly and are discussed separately.
Topics: Age Factors; Anti-Infective Agents; Brain; Cerebrospinal Fluid; Haemophilus Vaccines; Humans; Meningism; Meningitis, Aseptic; Meningitis, Bacterial; Primary Health Care; Risk Factors; Tomography, X-Ray Computed; United States
PubMed: 23958365
DOI: 10.1016/j.pop.2013.06.001 -
Trends in Molecular Medicine Jun 2018The central nervous system (CNS) is an immunologically specialized tissue protected by a blood-brain barrier. The CNS parenchyma is enveloped by a series of overlapping... (Review)
Review
The central nervous system (CNS) is an immunologically specialized tissue protected by a blood-brain barrier. The CNS parenchyma is enveloped by a series of overlapping membranes that are collectively referred to as the meninges. The meninges provide an additional CNS barrier, harbor a diverse array of resident immune cells, and serve as a crucial interface with the periphery. Recent studies have significantly advanced our understanding of meningeal immunity, demonstrating how a complex immune landscape influences CNS functions under steady-state and inflammatory conditions. The location and activation state of meningeal immune cells can profoundly influence CNS homeostasis and contribute to neurological disorders, but these cells are also well equipped to protect the CNS from pathogens. In this review, we discuss advances in our understanding of the meningeal immune repertoire and provide insights into how this CNS barrier operates immunologically under conditions ranging from neurocognition to inflammatory diseases.
Topics: Animals; Central Nervous System; Disease Susceptibility; Homeostasis; Humans; Immune System; Immunity; Meninges; Meningitis
PubMed: 29731353
DOI: 10.1016/j.molmed.2018.04.003 -
Seminars in Neurology 2000In the past 10 years the epidemiology of bacterial meningitis has changed, with a decreased incidence of meningitis caused by Haemophilus influenzae and an increasing... (Review)
Review
In the past 10 years the epidemiology of bacterial meningitis has changed, with a decreased incidence of meningitis caused by Haemophilus influenzae and an increasing incidence of meningitis caused by penicillin- and cephalosporin-resistant strains of Streptococcus pneumoniae. Meningococcal meningitis has become an increasing threat to college students. Successful outcome from meningitis requires not only eradication of the bacterial pathogen but also management of the neurological complications of raised intracranial pressure, stroke, and seizure activity. In this article, the pathophysiology, etiology, clinical presentation, differential diagnosis, and management of acute bacterial meningitis are reviewed. The present recommendations for the use of dexamethasone in the treatment of this infection, the use of chemoprophylaxis, and the indications for vaccinations are included.
Topics: Acute Disease; Anti-Bacterial Agents; Bacterial Physiological Phenomena; Diagnosis, Differential; Humans; Meninges; Meningitis, Bacterial; Neisseria meningitidis; Streptococcus pneumoniae; Vaccines
PubMed: 11051294
DOI: 10.1055/s-2000-9393 -
Methods (San Diego, Calif.) Aug 2017A wide range of viral and microbial infections are known to cause meningitis, and there is evidence that the meninges are the gateway to pathogenic invasion of the brain... (Review)
Review
A wide range of viral and microbial infections are known to cause meningitis, and there is evidence that the meninges are the gateway to pathogenic invasion of the brain parenchyma. Hence observation of these regions has wide application to understanding host-pathogen interactions. Interactions between pathogens and cells of the immune response can be modified by changes in their environment, such as suppression of the flow of blood and lymph, and, particularly in the case of the meninges, with their unsupported membranes, invasive dissection can alter the tissue architecture. For these reasons, intravital imaging through the unperforated skull is the method of choice. We give a protocol for a simple method of two-photon microscopy through the thinned cortical skull of the anesthetized mouse to enable real-time imaging with sub-micron resolution through the meninges and into the superficial brain parenchyma. In reporter mice in which selected cell types express fluorescent proteins, imaging after infection with fluorescent pathogens (lymphocytic choriomeningitis virus, Trypanosoma brucei or Plasmodium berghei) has shown strong recruitment to the cortical meninges of immune cells, including neutrophils, T cells, and putative dendritic cells and macrophages. Without special labeling, the boundaries between the dura mater, the leptomeninx, and the parenchyma are not directly visualized in intravital two-photon microscopy, but other landmarks and characteristics, which we illustrate, allow the researcher to identify the compartment being imaged. While most infectious meningitides are localized mainly in the dura mater, others involve recruitment of immune cells to the leptomeninx.
Topics: Animals; Dendritic Cells; Host-Pathogen Interactions; Intravital Microscopy; Lymphocytic choriomeningitis virus; Macrophages; Meninges; Meningitis; Mice; Mice, Transgenic; Microorganisms, Genetically-Modified; Microscopy, Fluorescence, Multiphoton; Neutrophils; Plasmodium berghei; T-Lymphocytes; Trypanosoma brucei brucei
PubMed: 28351758
DOI: 10.1016/j.ymeth.2017.03.020 -
AJR. American Journal of Roentgenology Apr 1993Although the meninges are often thought of simplistically as a connective tissue sac that contains the CSF and the contents of the CNS, they are far more complex.... (Review)
Review
Although the meninges are often thought of simplistically as a connective tissue sac that contains the CSF and the contents of the CNS, they are far more complex. Anatomically, they comprise several layers. Pathologically, numerous disease processes may affect the meninges; different processes may even involve different areas of the meninges. These factors all influence the MR imaging characteristics of meningeal lesions. This review briefly discusses the anatomy of the meninges, the MR imaging technique when meningeal disease is suspected, and the appearance of the normal meninges. It then focuses on tumors, infections, cysts, and other lesions that primarily involve the meninges, excluding lesions that secondarily involve the meninges.
Topics: Arachnoid Cysts; Carcinoma; Humans; Magnetic Resonance Imaging; Meningeal Neoplasms; Meninges; Meningitis
PubMed: 8456653
DOI: 10.2214/ajr.160.4.8456653 -
Fortschritte Der Neurologie-Psychiatrie May 2018A thorough neurological examination in emergency situations requires the evaluation of meningeal signs. Even though in most settings, evaluation of meningism is... (Review)
Review
A thorough neurological examination in emergency situations requires the evaluation of meningeal signs. Even though in most settings, evaluation of meningism is technically not very demanding, the interpretation of findings may prove difficult. As opposed to a widely held belief, clinical signs of meningism are neither specific nor highly sensitive for detection of meningitis or subarachnoid hemorrhage. A meaningful evaluation of meningeal signs, therefore, requires careful consideration of both clinical findings and other accessory symptoms.
Topics: Diagnosis, Differential; Emergency Medical Services; Humans; Meningism; Neurologic Examination
PubMed: 29843178
DOI: 10.1055/a-0590-4296 -
Radiographics : a Review Publication of... Aug 2023Meningeal lesions can be caused by various conditions and pose diagnostic challenges. The authors review the anatomy of the meninges in the brain and spinal cord to...
Meningeal lesions can be caused by various conditions and pose diagnostic challenges. The authors review the anatomy of the meninges in the brain and spinal cord to provide a better understanding of the localization and extension of these diseases and summarize the clinical and imaging features of various conditions that cause dural and/or leptomeningeal enhancing lesions. These conditions include infectious meningitis (bacterial, tuberculous, viral, and fungal), autoimmune diseases (vasculitis, connective tissue diseases, autoimmune meningoencephalitis, Vogt-Koyanagi-Harada disease, neuro-Behçet syndrome, Susac syndrome, and sarcoidosis), primary and secondary tumors (meningioma, diffuse leptomeningeal glioneuronal tumor, melanocytic tumors, and lymphoma), tumorlike diseases (histiocytosis and immunoglobulin G4-related diseases), medication-induced diseases (immune-related adverse effects and posterior reversible encephalopathy syndrome), and other conditions (spontaneous intracranial hypotension, amyloidosis, and moyamoya disease). Although meningeal lesions may manifest with nonspecific imaging findings, correct diagnosis is important because the treatment strategy varies among these diseases. RSNA, 2023 and Quiz questions for this article are available through the Online Learning Center.
Topics: Humans; Posterior Leukoencephalopathy Syndrome; Meninges; Meningitis; Neuroimaging; Sarcoidosis; Meningeal Neoplasms; Magnetic Resonance Imaging
PubMed: 37535461
DOI: 10.1148/rg.230039 -
Radiology Nov 1996The structural organization of the dura and leptomeninges is reflected in its magnetic resonance (MR) imaging appearance in normal and disease states. Two distinct... (Review)
Review
The structural organization of the dura and leptomeninges is reflected in its magnetic resonance (MR) imaging appearance in normal and disease states. Two distinct enhancement patterns are characterized: dura-arachnoid enhancement and pia-subarachnoid space enhancement. The dura-arachnoid pattern consists of curvilinear enhancement overlying the brain and immediately deep to the inner table of the calvaria, as well as along the falx and tentorium. Pial enhancement closely follows the brain surface into sulci and outlines the basal cisterns. Recognition of these enhancement patterns and other MR imaging characteristics may enhance the role of MR imaging in the detection, diagnosis, and follow-up of neoplastic and nonneoplastic disorders affecting the meninges. The focus of this article (Part I) is the MR appearance of the normal meninges and nonneoplastic causes of meningeal disease. Part II of this series will discuss neoplastic conditions affecting the coverings of the brain and spinal cord with an emphasis on pathways of disease spread.
Topics: Cerebrovascular Disorders; Humans; Magnetic Resonance Imaging; Meninges; Meningitis
PubMed: 8888215
DOI: 10.1148/radiology.201.2.8888215 -
Journal of Postgraduate Medicine 2009"Tripod Sign" or "Amoss's Sign" is a sign of meningeal irritation. Although useful in diagnosing meningitis, it is not pathognomic and may be seen in a variety of... (Review)
Review
"Tripod Sign" or "Amoss's Sign" is a sign of meningeal irritation. Although useful in diagnosing meningitis, it is not pathognomic and may be seen in a variety of clinical conditions. Infants < 1 year of age and immunocompromised individuals may not demonstrate signs of meningeal irritation. Since elicitation of the sign requires voluntary sitting up, it is of limited use in patients with marked altered sensorium and young infants.
Topics: Diagnosis, Differential; Diagnostic Techniques, Neurological; Humans; Meningism; Posture
PubMed: 19884752
DOI: 10.4103/0022-3859.57408 -
Journal of the Neurological Sciences Apr 2020Central nervous system (CNS) metastasis from systemic cancers can involve the brain parenchyma, leptomeninges (pia, subarachnoid space and arachnoid mater), and dura.... (Review)
Review
Central nervous system (CNS) metastasis from systemic cancers can involve the brain parenchyma, leptomeninges (pia, subarachnoid space and arachnoid mater), and dura. Leptomeningeal metastases (LM), also known by different terms including neoplastic meningitis and carcinomatous meningitis, occur in both solid tumors and hematologic malignancies. This review will focus exclusively on LM arising from solid tumors with a goal of providing the reader an understanding of the epidemiology, pathophysiology, clinical presentation, prognostication, current management and future directions.
Topics: Arachnoid; Dura Mater; Humans; Meningeal Carcinomatosis; Meningeal Neoplasms; Meninges; Meningitis, Bacterial; Neoplasms
PubMed: 32007755
DOI: 10.1016/j.jns.2020.116706