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Cephalalgia : An International Journal... Nov 2019The exact mechanisms underlying the onset of a migraine attack are not completely understood. It is, however, now well accepted that the onset of the excruciating... (Review)
Review
BACKGROUND
The exact mechanisms underlying the onset of a migraine attack are not completely understood. It is, however, now well accepted that the onset of the excruciating throbbing headache of migraine is mediated by the activation and increased mechanosensitivity (i.e. sensitization) of trigeminal nociceptive afferents that innervate the cranial meninges and their related large blood vessels.
OBJECTIVES
To provide a critical summary of current understanding of the role that the cranial meninges, their associated vasculature, and immune cells play in meningeal nociception and the ensuing migraine headache.
METHODS
We discuss the anatomy of the cranial meninges, their associated vasculature, innervation and immune cell population. We then debate the meningeal neurogenic inflammation hypothesis of migraine and its putative contribution to migraine pain. Finally, we provide insights into potential sources of meningeal inflammation and nociception beyond neurogenic inflammation, and their potential contribution to migraine headache.
Topics: Afferent Pathways; Animals; Autonomic Fibers, Postganglionic; Capillary Permeability; Humans; Inflammation; Macrophages; Mast Cells; Meninges; Mice; Migraine Disorders; Models, Biological; Nociception; Nociceptors; Ophthalmic Nerve; Pituitary Adenylate Cyclase-Activating Polypeptide; Rats; T-Lymphocytes; Trigeminal Nerve; Vasodilation
PubMed: 29929378
DOI: 10.1177/0333102418771350 -
Cell Reports Nov 2022The trigeminal sensory innervation of the cranial meninges is thought to serve a nociceptive function and mediate headache pain. However, the activity of meningeal...
The trigeminal sensory innervation of the cranial meninges is thought to serve a nociceptive function and mediate headache pain. However, the activity of meningeal afferents under natural conditions in awake animals remains unexplored. Here, we used two- and three-dimensional two-photon calcium imaging to track the activity of meningeal afferent fibers in awake mice. Surprisingly, a large subset of afferents was activated during non-noxious conditions such as locomotion. We estimated locomotion-related meningeal deformations and found afferents with distinct dynamics and tuning to various levels of meningeal expansion, compression, shearing, and Z-axis motion. Further, these mechanosensitive afferents were often tuned to distinct directions of meningeal expansion or compression. Thus, in addition to their role in headache-related pain, meningeal sensory neurons track the dynamic mechanical state of the meninges under natural conditions.
Topics: Animals; Mice; Meninges; Neurons, Afferent; Headache; Locomotion
PubMed: 36384109
DOI: 10.1016/j.celrep.2022.111648 -
Acta Neurochirurgica Jun 2024The discovery of the glymphatic system has fundamentally altered our comprehension of cerebrospinal fluid transport and the removal of waste from brain metabolism. In... (Review)
Review
The discovery of the glymphatic system has fundamentally altered our comprehension of cerebrospinal fluid transport and the removal of waste from brain metabolism. In the past decade, since its initial characterization, research on the glymphatic system has surged exponentially. Its potential implications for central nervous system disorders have sparked significant interest in the field of neurosurgery. Nonetheless, ongoing discussions and debates persist regarding the concept of the glymphatic system, and our current understanding largely relies on findings from experimental animal studies. This review aims to address several key inquiries: What methodologies exist for evaluating glymphatic function in humans today? What is the current evidence supporting the existence of a human glymphatic system? Can the glymphatic system be considered distinct from the meningeal-lymphatic system? What is the human evidence for glymphatic-meningeal lymphatic system failure in neurosurgical diseases? Existing literature indicates a paucity of techniques available for assessing glymphatic function in humans. Thus far, intrathecal contrast-enhanced magnetic resonance imaging (MRI) has shown the most promising results and have provided evidence for the presence of a glymphatic system in humans, albeit with limitations. It is, however, essential to recognize the interconnection between the glymphatic and meningeal lymphatic systems, as they operate in tandem. There are some human studies demonstrating deteriorations in glymphatic function associated with neurosurgical disorders, enriching our understanding of their pathophysiology. However, the translation of this knowledge into clinical practice is hindered by the constraints of current glymphatic imaging modalities.
Topics: Humans; Glymphatic System; Neurosurgical Procedures; Meninges; Animals; Magnetic Resonance Imaging
PubMed: 38904802
DOI: 10.1007/s00701-024-06161-4 -
The Pediatric Infectious Disease Journal Jul 2016During the past several decades, researchers have shown that the eponymous signs of meningitis have reduced sensitivity and specificity compared with when they were... (Review)
Review
During the past several decades, researchers have shown that the eponymous signs of meningitis have reduced sensitivity and specificity compared with when they were originally described. This may be because of the changing epidemiology of meningitis and its treatment or it may be because of variations in performance of the maneuvers. For example, in the original descriptions, the Kernig sign (resistance of leg extension) is best elicited with the patient sitting and the Brudzinski nape of the neck sign involves holding down the patient's chest as the neck is flexed. These and other lesser-known signs of meningitis by Amoss, Bikeles and Edelmann all relate to the mechanics of stretching inflamed meninges, and this review will allow the clinician to understand how the history related to these maneuvers is still germane to clinical practice today.
Topics: Diagnosis, Differential; History, 19th Century; History, 20th Century; History, 21st Century; Humans; Meningitis; Neurologic Examination; Physical Examination; Reflex, Abnormal; Sensitivity and Specificity
PubMed: 27031257
DOI: 10.1097/INF.0000000000001152 -
Spinal Cord Sep 2015To summarize the incidence and spectrum of spinal cord-related complications in patients of tuberculous meningitis. (Review)
Review
OBJECTIVES
To summarize the incidence and spectrum of spinal cord-related complications in patients of tuberculous meningitis.
SETTING
Reports from multiple countries were included.
METHODS
An extensive review of the literature, published in English, was carried out using Scopus, PubMed and Google Scholar databases.
RESULTS
Tuberculous meningitis frequently affects the spinal cord and nerve roots. Initial evidence of spinal cord involvement came from post-mortem examination. Subsequent advancement in neuroimaging like conventional lumbar myelography, computed tomographic myelography and gadolinium-enhanced magnetic resonance-myelography have contributed immensely. Spinal involvement manifests in several forms, like tuberculous radiculomyelitis, spinal tuberculoma, myelitis, syringomyelia, vertebral tuberculosis and very rarely spinal tuberculous abscess. Frequently, tuberculous spinal arachnoiditis develops paradoxically. Infrequently, spinal cord involvement may even be asymptomatic. Spinal cord and spinal nerve involvement is demonstrated by diffuse enhancement of cord parenchyma, nerve roots and meninges on contrast-enhanced magnetic resonance imaging. High cerebrospinal fluid protein content is often a risk factor for arachnoiditis. The most important differential diagnosis of tuberculous arachnoiditis is meningeal carcinomatosis. Anti-tuberculosis therapy is the main stay of treatment for tuberculous meningitis. Higher doses of corticosteroids have been found effective. Surgery should be considered only when pathological confirmation is needed or there is significant spinal cord compression. The outcome in these patients has been unpredictable. Some reports observed excellent recovery and some reported unfavorable outcomes after surgical decompression and debridement.
CONCLUSIONS
Tuberculous meningitis is frequently associated with disabling spinal cord and radicular complications. Available treatment options are far from satisfactory.
Topics: Diagnosis, Differential; Humans; Incidence; Spinal Cord; Spinal Cord Injuries; Tuberculosis, Meningeal
PubMed: 25896347
DOI: 10.1038/sc.2015.58 -
Handbook of Clinical Neurology 2020The dura mater is the major gateway for accessing most extra-axial lesions and all intra-axial lesions of the central nervous system. It provides a protective barrier...
The dura mater is the major gateway for accessing most extra-axial lesions and all intra-axial lesions of the central nervous system. It provides a protective barrier against external trauma, infections, and the spread of malignant cells. Knowledge of the anatomical details of dural reflections around various corners of the skull bases provides the neurosurgeon with confidence during transdural approaches. Such knowledge is indispensable for protection of neurovascular structures in the vicinity of these dural reflections. The same concept is applicable to arachnoid folds and reflections during intradural excursions to expose intra- and extra-axial lesions of the brain. Without a detailed understanding of arachnoid membranes and cisterns, the neurosurgeon cannot confidently navigate the deep corridors of the skull base while safely protecting neurovascular structures. This chapter covers the surgical anatomy of dural and arachnoid reflections applicable to microneurosurgical approaches to various regions of the skull base.
Topics: Arachnoid; Cadaver; Dura Mater; Humans; Meninges; Skull Base
PubMed: 32553288
DOI: 10.1016/B978-0-12-804280-9.00002-0 -
Nature Reviews. Neurology Aug 2023Growing evidence from cerebrospinal fluid samples and post-mortem brain tissue from individuals with multiple sclerosis (MS) and rodent models indicates that the... (Review)
Review
Growing evidence from cerebrospinal fluid samples and post-mortem brain tissue from individuals with multiple sclerosis (MS) and rodent models indicates that the meninges have a key role in the inflammatory and neurodegenerative mechanisms underlying progressive MS pathology. The subarachnoid space and associated perivascular spaces between the membranes of the meninges are the access points for entry of lymphocytes, monocytes and macrophages into the brain parenchyma, and the main route for diffusion of inflammatory and cytotoxic molecules from the cerebrospinal fluid into the brain tissue. In addition, the meningeal spaces act as an exit route for CNS-derived antigens, immune cells and metabolites. A number of studies have demonstrated an association between chronic meningeal inflammation and a more severe clinical course of MS, suggesting that the build-up of immune cell aggregates in the meninges represents a rational target for therapeutic intervention. Therefore, understanding the precise cell and molecular mechanisms, timing and anatomical features involved in the compartmentalization of inflammation within the meningeal spaces in MS is vital. Here, we present a detailed review and discussion of the cellular, molecular and radiological evidence for a role of meningeal inflammation in MS, alongside the clinical and therapeutic implications.
Topics: Humans; Multiple Sclerosis; Gray Matter; Cerebral Cortex; Meninges; Inflammation; Disease Progression
PubMed: 37400550
DOI: 10.1038/s41582-023-00838-7 -
BMC Veterinary Research May 2021Bovine tuberculosis is a chronic inflammatory disease that causes granuloma formation mainly in retropharyngeal, tracheobronchial, mediastinal lymph nodes and lungs of...
BACKGROUND
Bovine tuberculosis is a chronic inflammatory disease that causes granuloma formation mainly in retropharyngeal, tracheobronchial, mediastinal lymph nodes and lungs of bovines. The presence of these lesions in other tissues such as the eyeball is very rare and difficult to diagnose. This study describes macroscopic and microscopic pathological findings in a calf with ocular and meningeal tuberculosis.
CASE PRESENTATION
March 2019, an eight-month-old Holstein Friesian calf was identified in a dairy farm located in central Mexico with a clinical cough, anorexia, incoordination, corneal opacity and vision loss. At necropsy, pneumonia, lymphadenitis, meningitis, and granulomatous iridocyclitis were observed. The histopathological examination revealed granulomatous lesions in lung tissue, lymph nodes, meninges and eyes with the presence of acid-fast bacilli associated with Mycobacterium spp.
CONCLUSION
To the best of our knowledge, this is the first report that describes macroscopic and microscopic pathological findings of ocular tuberculosis in cattle. This report highlights the importance of considering bovine tuberculosis in the differential diagnosis of corneal opacity and loss of vision in cattle.
Topics: Animals; Cattle; Eye Diseases; Granuloma; Meningitis; Mexico; Mycobacterium; Tuberculosis, Bovine; Tuberculosis, Ocular
PubMed: 33964902
DOI: 10.1186/s12917-021-02893-y -
Chinese Clinical Oncology Jun 2015Leptomeningeal dissemination of tumor cells, also referred to as neoplastic meningitis, is most frequently seen in patients with late-stage cancer and mostly associated... (Review)
Review
Leptomeningeal dissemination of tumor cells, also referred to as neoplastic meningitis, is most frequently seen in patients with late-stage cancer and mostly associated with a poor prognosis. Basically, neoplastic meningitis may affect all patients with a malignant tumor but is most common in patients affected by lung cancer, breast carcinoma, melanoma or hematologic neoplasms such as lymphoma and leukemia. Controlled clinical trials are largely lacking which results in various non-standardized treatment regimens. The presence of solid tumor manifestations in the CNS as well as the extracranial tumor load defines the most appropriate treatment approach. Radiation therapy, systemic chemotherapy and intrathecal treatment must be considered. For each patient, the individual situation needs to be carefully evaluated to determine the potential benefit as well as putative side effects associated with any therapy. A moderate survival benefit and particularly relief from pain and neurological deficits are the main treatment goals. Here, we summarize the management of patients with neoplastic meningitis and review the available treatment options.
Topics: Animals; Combined Modality Therapy; Humans; Meningeal Carcinomatosis; Meningitis; Neuroimaging; Patient Selection; Predictive Value of Tests; Risk Factors; Treatment Outcome
PubMed: 26112812
DOI: 10.3978/j.issn.2304-3865.2015.05.02 -
Trends in Immunology Apr 2023The emphasis on mechanisms driving multiple sclerosis (MS) symptomatic worsening suggests that we move beyond categorical clinical classifiers such as... (Review)
Review
The emphasis on mechanisms driving multiple sclerosis (MS) symptomatic worsening suggests that we move beyond categorical clinical classifiers such as relapsing-remitting MS (RR-MS) and progressive MS (P-MS). Here, we focus on the clinical phenomenon progression independent of relapse activity (PIRA), which begins early in the disease course. PIRA occurs throughout MS, becoming more phenotypically evident as patients age. The underlying mechanisms for PIRA include chronic-active demyelinating lesions (CALs), subpial cortical demyelination, and nerve fiber injury following demyelination. We propose that much of the tissue injury associated with PIRA is driven by autonomous meningeal lymphoid aggregates, present before disease onset and unresponsive to current therapeutics. Recently, specialized magnetic resonance imaging (MRI) has identified and characterized CALs as paramagnetic rim lesions in humans, enabling novel radiographic-biomarker-clinical correlations to further understand and treat PIRA.
Topics: Humans; Multiple Sclerosis; Meninges; Disease Progression; Multiple Sclerosis, Relapsing-Remitting
PubMed: 36868982
DOI: 10.1016/j.it.2023.02.002