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Neurologia Medico-chirurgica Feb 2021Among the various disorders that manifest with gait disturbance, cognitive impairment, and urinary incontinence in the elderly population, idiopathic normal pressure...
Among the various disorders that manifest with gait disturbance, cognitive impairment, and urinary incontinence in the elderly population, idiopathic normal pressure hydrocephalus (iNPH) is becoming of great importance. The first edition of these guidelines for management of iNPH was published in 2004, and the second edition in 2012, to provide a series of timely, evidence-based recommendations related to iNPH. Since the last edition, clinical awareness of iNPH has risen dramatically, and clinical and basic research efforts on iNPH have increased significantly. This third edition of the guidelines was made to share these ideas with the international community and to promote international research on iNPH. The revision of the guidelines was undertaken by a multidisciplinary expert working group of the Japanese Society of Normal Pressure Hydrocephalus in conjunction with the Japanese Ministry of Health, Labour and Welfare research project. This revision proposes a new classification for NPH. The category of iNPH is clearly distinguished from NPH with congenital/developmental and acquired etiologies. Additionally, the essential role of disproportionately enlarged subarachnoid-space hydrocephalus (DESH) in the imaging diagnosis and decision for further management of iNPH is discussed in this edition. We created an algorithm for diagnosis and decision for shunt management. Diagnosis by biomarkers that distinguish prognosis has been also initiated. Therefore, diagnosis and treatment of iNPH have entered a new phase. We hope that this third edition of the guidelines will help patients, their families, and healthcare professionals involved in treating iNPH.
Topics: Aged; Aged, 80 and over; Biomarkers; Cerebral Ventricles; Cerebrospinal Fluid Pressure; Cerebrospinal Fluid Shunts; Cerebrovascular Circulation; Cognitive Dysfunction; Dementia; Female; Gait Disorders, Neurologic; Humans; Hydrocephalus, Normal Pressure; Japan; Magnetic Resonance Imaging; Male; Neuroimaging; Neurologic Examination; Neuropsychological Tests; Nuclear Medicine; Prognosis; Subarachnoid Space; Urinary Incontinence
PubMed: 33455998
DOI: 10.2176/nmc.st.2020-0292 -
Child's Nervous System : ChNS :... Nov 2021Multiple names within the literature refer to a clinical picture affecting infants and consisting of a large or fast growing head circumference with enlarged cortical... (Review)
Review
PURPOSE
Multiple names within the literature refer to a clinical picture affecting infants and consisting of a large or fast growing head circumference with enlarged cortical subarachnoid spaces (CSAS) while cranial sutures are open. This myriad of terms demonstrates the confusion about the entity, that may even group together different etiological processes. In this review, we aim to shed light on this matter in an effort to restate the defining features of the clinical picture and sum the evidence and current understanding of its pathophysiology and related imaging findings.
METHODS
Extensive and updated review of the literature with special focus on defining features, clinical history with long term evaluation and pathophysiological process.
RESULTS
Functional and molecular CSF studies as well as clinical evidence challenges the common pathophysiological theory based on non-functional arachnoid villi. Conversely, there is increasing evidence supporting cerebro-venous system abnormalities as the main pathophysiological factor. Additionally, long term cohorts studies show that it may have subtle but irreversible neurodevelopmental consequences.
CONCLUSION
Subarachnomegaly is an age-related condition of the infancy with radiological enlargement of CSAS and often self limiting course. However, considering the evidence on pathophysiology as outlined herein and long term outcome reports, further research effort is needed to assess the consequences of venous outflow impairment and enlarged CSAS and how this relates to imaging findings and neurodevelopment test results later in life.
Topics: Humans; Hyperemia; Infant; Subarachnoid Space
PubMed: 34687332
DOI: 10.1007/s00381-021-05328-z -
The Journal of Physiology May 19741. To find the site where morphine acts when producing hyperglycaemia on injection into the cerebral ventricles in unanaesthetized cats, morphine sulphate was infused or...
1. To find the site where morphine acts when producing hyperglycaemia on injection into the cerebral ventricles in unanaesthetized cats, morphine sulphate was infused or injected through an implanted Collison cannula into different parts of the liquor space in an amount of 0.75 mg except on microinfusion into the posterior hypothalamus, when the amounts were 80 or 160 mug. The glucose was determined in blood samples collected from the inferior vena cava.2. Microinfusions of morphine into the posterior hypothalamus did not produce hyperglycaemia.3. Infusion of morphine into the liquor space at the entrance of the aqueduct or of the fourth ventricle produced hyperglycaemia. Any structures in the walls of the third ventricle as well as the peri-aqueductal grey are thus excluded as the site of action.4. Infusion of morphine into the subarachnoid space just above the corpora quadrigemina or below the ventral surface of the brain stem produced hyperglycaemia. With these routes the morphine does not enter any part of the ventricular cavities and the action would appear to be on structures at the ventral surface of the brain stem.5. Injection of morphine into the cisterna magna produces hyperglycaemia when the doses are larger than those already effective on injection into the cerebral ventricles. This also suggests an action on structures at the ventral surface of the brain stem, as this surface is reached more readily from the ventricles than from the cisterna.6. It is concluded that on injection into the cerebral ventricles, the morphine has to pass into the subarachnoid space, through the foramina of Luschka, in order to produce hyperglycaemia. It then reaches the ventral surface of the brain stem and probably acts there on structures in the upper part of the medulla oblongata.7. Infusion of morphine into the corpora quadrigemina near the caudal end of the superior corpora can produce profound hypoglycaemia.8. Anaesthesia depresses the morphine hyperglycaemia, but when the dose injected into the cerebral ventricles is increased four times or more, hyperglycaemia is also produced in pentobarbitone sodium anaesthesia.
Topics: Anesthesia; Animals; Blood Glucose; Brain Stem; Catheterization; Cats; Cerebral Ventricles; Consciousness; Dose-Response Relationship, Drug; Female; Hyperglycemia; Hypothalamus; Injections; Male; Morphine; Pentobarbital; Subarachnoid Space; Tectum Mesencephali
PubMed: 4853259
DOI: 10.1113/jphysiol.1974.sp010539 -
AJNR. American Journal of Neuroradiology Feb 2022The arachnoid membranes are projections of connective tissue in the subarachnoid space that connect the arachnoid mater to the pia mater. These are underappreciated and... (Review)
Review
The arachnoid membranes are projections of connective tissue in the subarachnoid space that connect the arachnoid mater to the pia mater. These are underappreciated and largely unrecognized by most neuroradiologists despite being found to be increasingly important in the pathogenesis, imaging, and treatment of communicating hydrocephalus. This review aims to provide neuroradiologists with an overview of the history, embryology, histology, anatomy, and normal imaging appearance of these membranes, as well as some examples of their clinical importance.
Topics: Arachnoid; Consciousness; Humans; Pia Mater; Radiology; Subarachnoid Space
PubMed: 34711549
DOI: 10.3174/ajnr.A7309 -
Journal of Neurosurgery. Spine Aug 2014
Topics: Female; Humans; Male; Subarachnoid Space; Syringomyelia
PubMed: 25221803
DOI: No ID Found -
Fluids and Barriers of the CNS Dec 2023Traditionally, the meninges are described as 3 distinct layers, dura, arachnoid and pia. Yet, the classification of the connective meningeal membranes surrounding the...
Traditionally, the meninges are described as 3 distinct layers, dura, arachnoid and pia. Yet, the classification of the connective meningeal membranes surrounding the brain is based on postmortem macroscopic examination. Ultrastructural and single cell transcriptome analyses have documented that the 3 meningeal layers can be subdivided into several distinct layers based on cellular characteristics. We here re-examined the existence of a 4 meningeal membrane, Subarachnoid Lymphatic-like Membrane or SLYM in Prox1-eGFP reporter mice. Imaging of freshly resected whole brains showed that SLYM covers the entire brain and brain stem and forms a roof shielding the subarachnoid cerebrospinal fluid (CSF)-filled cisterns and the pia-adjacent vasculature. Thus, SLYM is strategically positioned to facilitate periarterial influx of freshly produced CSF and thereby support unidirectional glymphatic CSF transport. Histological analysis showed that, in spinal cord and parts of dorsal cortex, SLYM fused with the arachnoid barrier layer, while in the basal brain stem typically formed a 1-3 cell layered membrane subdividing the subarachnoid space into two compartments. However, great care should be taken when interpreting the organization of the delicate leptomeningeal membranes in tissue sections. We show that hyperosmotic fixatives dehydrate the tissue with the risk of shrinkage and dislocation of these fragile membranes in postmortem preparations.
Topics: Mice; Animals; Meninges; Dura Mater; Arachnoid; Subarachnoid Space; Cerebral Cortex
PubMed: 38098084
DOI: 10.1186/s12987-023-00500-w -
Scientific Reports Jul 2023The cisterna magna has been defined as the space between the inferior margin of the cerebellar vermis to the level of the foramen magnum, while an enlarged dorsal...
The cisterna magna has been defined as the space between the inferior margin of the cerebellar vermis to the level of the foramen magnum, while an enlarged dorsal subarachnoid space at the occipito-cervical junction extending from the foramen magnum to the upper border of the axis (C2) is still ignored. Recently, the myodural bridge complex is proved to drive the cerebral spinal fluid flowing via this region, we therefore introduce the "occipito-atlantal cistern (OAC)" to better describe the subarachnoid space and provide a detailed rationale. The present study utilized several methods, including MRI, gross anatomical dissection, P45 sheet plastination, and three-dimensional visualization. OAC was observed to be an enlarge subarachnoid space, extending from the foramen magnum to the level of the C2. In the median sagittal plane, OAC was a funnel shape and its anteroposterior dimensions were 15.92 ± 4.20 mm at the level of the C0, 4.49 ± 1.25 mm at the level of the posterior arch of the C1, and 2.88 ± 0.77 mm at the level of the arch of the C2, respectively. In the median sagittal plane, the spino-dural angle of the OAC was calculated to be 35.10 ± 6.91°, and the area of OAC was calculated to be 232.28 ± 71.02 mm. The present study provides OAC is a subarachnoid space independent from the cisterna magna. Because of its distinctive anatomy, as well as theoretical and clinical significance, OAC deserves its own name.
Topics: Subarachnoid Space; Foramen Magnum; Neck; Spinal Cord; Cisterna Magna
PubMed: 37495633
DOI: 10.1038/s41598-023-38825-z -
Revue Medicale de Liege Sep 2020We report the case of a 28-year-old male admitted to the emergency department for generalized seizure. A brain computed tomography (CT) revealed a ruptured dermoid cyst...
We report the case of a 28-year-old male admitted to the emergency department for generalized seizure. A brain computed tomography (CT) revealed a ruptured dermoid cyst of the supra-tentorial stage (multiple drop-shaped fat structures were found in the subarachnoid space, basal cisterns and in ventricular system). An additional magnetic resonance imaging (MRI) was conducted to confirm the CT findings.
Topics: Adult; Dermoid Cyst; Humans; Magnetic Resonance Imaging; Male; Rupture, Spontaneous; Subarachnoid Space; Tomography, X-Ray Computed
PubMed: 32909404
DOI: No ID Found -
Journal of Cerebral Blood Flow and... Aug 2021The distribution and clearance of erythrocytes after subarachnoid hemorrhage (SAH) is poorly understood. We aimed to characterize the distribution of erythrocytes after...
The distribution and clearance of erythrocytes after subarachnoid hemorrhage (SAH) is poorly understood. We aimed to characterize the distribution of erythrocytes after SAH and the cells involved in their clearance. To visualize erythrocyte distribution, we injected fluorescently-labelled erythrocytes into the prechiasmatic cistern of mice. 10 minutes after injection, we found labelled erythrocytes in the subarachnoid space and ventricular system, and also in the perivascular spaces surrounding large penetrating arterioles. 2 and 5 days after SAH, fluorescence was confined within leptomeningeal and perivascular cells. We identified the perivascular cells as perivascular macrophages based on their morphology, location, Iba-1 immunoreactivity and preferential uptake of FITC-dextran. We subsequently depleted meningeal and perivascular macrophages 2 days before or 3 hours after SAH with clodronate liposomes. At day 5 after SAH, we found increased blood deposition in mice treated prior to SAH, but not those treated after. Treatment post-SAH improved neurological scoring, reduced neuronal cell death and perivascular inflammation, whereas pre-treatment only reduced perivascular inflammation. Our data indicate that after SAH, erythrocytes are distributed throughout the subarachnoid space extending into the perivascular spaces of parenchymal arterioles. Furthermore, meningeal and perivascular macrophages are involved in erythrocyte uptake and play an important role in outcome after SAH.
Topics: Animals; Brain; Disease Models, Animal; Erythrocytes; Gliosis; Glymphatic System; Macrophages; Male; Meninges; Mice; Neurons; Optical Imaging; Subarachnoid Hemorrhage; Subarachnoid Space
PubMed: 33444089
DOI: 10.1177/0271678X20980296 -
Investigative Ophthalmology & Visual... Dec 2023The purpose of this study was to examine the differences of optic nerve subarachnoid space (ONSAS) volume in patients with normal tension glaucoma (NTG) and healthy... (Randomized Controlled Trial)
Randomized Controlled Trial
PURPOSE
The purpose of this study was to examine the differences of optic nerve subarachnoid space (ONSAS) volume in patients with normal tension glaucoma (NTG) and healthy controls in different body positions.
METHODS
Eight patients with NTG and seven healthy controls underwent magnetic resonance imaging (MRI) examinations in head up tilt (HUT) +11 degrees and head down tilt (HDT) -5 degrees positions according to a randomized protocol determining the starting position. The ONSAS volume in both body positions was measured and compared between the two groups. The results were analyzed using a generalized linear model.
RESULTS
Between HDT and HUT, the postural ONSAS volume change was dependent on starting position (P < 0.001) and group (P = 0.003, NTG versus healthy). A subgroup analysis of those that were randomized to HUT examination first, coming directly from an upright position, showed that the patients with NTG had significantly larger positional ONSAS volume changes compared to the healthy controls; 121 ± 22 µL vs. 65 ± 37 µL (P = 0.049). Analysis of the ONSAS volume distribution showed different profiles for patients with NTG and healthy controls.
CONCLUSIONS
There was a significant difference in ONSAS volume change between patients with NTG and healthy subjects when subjected to posture changes, specifically when going from upright to head-down posture. This indicates that patients with NTG had been exposed to a lower ONSAS pressure when they came from the upright posture, which suggests an increased translaminar pressure difference in upright position. This may support the theory that NTG has a dysfunction in an occlusion mechanism of the optic nerve sheath that could cause abnormally negative ONSAS pressures in upright posture.
Topics: Humans; Low Tension Glaucoma; Magnetic Resonance Imaging; Posture; Optic Nerve; Subarachnoid Space
PubMed: 38099734
DOI: 10.1167/iovs.64.15.20