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Qvarlander S, Sundström N, Malm J, Eklund A. CSF formation rate-a potential glymphatic flow parameter in hydrocephalus? Fluids Barriers CNS 2024; 21:55. [PMID: 38987813 PMCID: PMC11234690 DOI: 10.1186/s12987-024-00560-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 06/29/2024] [Indexed: 07/12/2024] Open
Abstract
BACKGROUND Studies indicate that brain clearance via the glymphatic system is impaired in idiopathic normal pressure hydrocephalus (INPH). This has been suggested to result from reduced cerebrospinal fluid (CSF) turnover, which could be caused by a reduced CSF formation rate. The aim of this study was to determine the formation rate of CSF in a cohort of patients investigated for INPH and compare this to a historical control cohort. METHODS CSF formation rate was estimated in 135 (75 ± 6 years old, 64/71 men/women) patients undergoing investigation for INPH. A semiautomatic CSF infusion investigation (via lumbar puncture) was performed. CSF formation rate was assessed by downregulating and steadily maintaining CSF pressure at a zero level. During the last 10 min, the required outflow to maintain zero pressure, i.e., CSF formation rate, was continuously measured. The values were compared to those of a historical reference cohort from a study by Ekstedt in 1978. RESULTS Mean CSF formation rate was 0.45 ± 0.15 ml/min (N = 135), equivalent to 27 ± 9 ml/hour. There was no difference in the mean (p = 0.362) or variance (p = 0.498) of CSF formation rate between the subjects that were diagnosed as INPH (N = 86) and those who were not (N = 43). The CSF formation rate in INPH was statistically higher than in the reference cohort (0.46 ± 0.15 vs. 0.40 ± 0.08 ml/min, p = 0.005), but the small difference was probably not physiologically relevant. There was no correlation between CSF formation rate and baseline CSF pressure (r = 0.136, p = 0.115, N = 135) or age (-0.02, p = 0.803, N = 135). CONCLUSIONS The average CSF formation rate in INPH was not decreased compared to the healthy reference cohort, which does not support reduced CSF turnover. This emphasizes the need to further investigate the source and routes of the flow in the glymphatic system and the cause of the suggested impaired glymphatic clearance in INPH.
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Affiliation(s)
- Sara Qvarlander
- Department of Diagnostics and Intervention, Biomedical Engineering and Radiation Physics, Umeå University, Umeå, Sweden.
| | - Nina Sundström
- Department of Diagnostics and Intervention, Biomedical Engineering and Radiation Physics, Umeå University, Umeå, Sweden
| | - Jan Malm
- Department of Clinical Science, Neurosciences, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Diagnostics and Intervention, Biomedical Engineering and Radiation Physics, Umeå University, Umeå, Sweden
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Potter O, Menon V, Mollan SP. Risk factors and disease associations in people living with idiopathic intracranial hypertension. Expert Rev Neurother 2024; 24:681-689. [PMID: 38803205 DOI: 10.1080/14737175.2024.2359420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 05/21/2024] [Indexed: 05/29/2024]
Abstract
INTRODUCTION Idiopathic intracranial hypertension is a neurological condition characterized by a raised intracranial pressure and papilledema, leading to chronic headaches and visual disturbances. By recognizing modifiable risk factors and deploying evidence-based interventions, healthcare providers have the potential to mitigate the burden of the disease and improve patient outcomes. AREAS COVERED It is well known that the condition occurs in predominantly pre-menopausal females who live with obesity particularly in the context of recent weight gain. This review discusses what risk factors may contribute to the metabolic underpinnings of cerebrospinal fluid dysregulation. There are a number of disease associations that are important to screen for as they can alter management. EXPERT OPINION There is emerging evidence to suggest that idiopathic intracranial hypertension is a systemic metabolic disease and it is unknown what are all the risk factors are that precipitate the condition. Targeting certain hardwired risk factors is unachievable. However, as recent weight gain has been identified as a predominant risk factor for the development of the disease and relapse, modification of body weight should be the primary aim of management. Insightful research into the involvement of the neuroendocrine axis driving cerebrospinal fluid dysregulation now has the potential for the development of therapeutic targets.
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Affiliation(s)
- Olivia Potter
- Birmingham Neuro-Ophthalmology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Vaishnavi Menon
- Birmingham Neuro-Ophthalmology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Susan P Mollan
- Birmingham Neuro-Ophthalmology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Translational Brain Science, Institute of Metabolism and Systems Research, University of Birmingham, Edgbaston, UK
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Colman BD, Boonstra F, Nguyen MN, Raviskanthan S, Sumithran P, White O, Hutton EJ, Fielding J, van der Walt A. Understanding the pathophysiology of idiopathic intracranial hypertension (IIH): a review of recent developments. J Neurol Neurosurg Psychiatry 2024; 95:375-383. [PMID: 37798095 DOI: 10.1136/jnnp-2023-332222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/15/2023] [Indexed: 10/07/2023]
Abstract
Idiopathic intracranial hypertension (IIH) is a condition of significant morbidity and rising prevalence. It typically affects young people living with obesity, mostly women of reproductive age, and can present with headaches, visual abnormalities, tinnitus and cognitive dysfunction. Raised intracranial pressure without a secondary identified cause remains a key diagnostic feature of this condition, however, the underlying pathophysiological mechanisms that drive this increase are poorly understood. Previous theories have focused on cerebrospinal fluid (CSF) hypersecretion or impaired reabsorption, however, the recent characterisation of the glymphatic system in many other neurological conditions necessitates a re-evaluation of these hypotheses. Further, the impact of metabolic dysfunction and hormonal dysregulation in this population group must also be considered. Given the emerging evidence, it is likely that IIH is triggered by the interaction of multiple aetiological factors that ultimately results in the disruption of CSF dynamics. This review aims to provide a comprehensive update on the current theories regarding the pathogenesis of IIH.
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Affiliation(s)
- Blake D Colman
- Department of Neuroscience, Monash University Faculty of Medicine Nursing and Health Sciences, Clayton, Victoria, Australia
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Frederique Boonstra
- Department of Neuroscience, Monash University Faculty of Medicine Nursing and Health Sciences, Clayton, Victoria, Australia
| | - Minh Nl Nguyen
- Department of Neuroscience, Monash University Faculty of Medicine Nursing and Health Sciences, Clayton, Victoria, Australia
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | | | - Priya Sumithran
- Department of Surgery, Monash University Faculty of Medicine Nursing and Health Sciences, Clayton, Victoria, Australia
- Department of Endocrinology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Owen White
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
- Department of Neuroscience, Monash University Central Clinical School, Clayton, Victoria, Australia
| | - Elspeth J Hutton
- Department of Neuroscience, Monash University Faculty of Medicine Nursing and Health Sciences, Clayton, Victoria, Australia
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
| | - Joanne Fielding
- Department of Neuroscience, Monash University Faculty of Medicine Nursing and Health Sciences, Clayton, Victoria, Australia
| | - Anneke van der Walt
- Department of Neuroscience, Monash University Faculty of Medicine Nursing and Health Sciences, Clayton, Victoria, Australia
- Department of Neurology, Alfred Hospital, Melbourne, Victoria, Australia
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Khan DZ, Tariq K, Lee KS, Dyson EW, Russo V, Watkins LD, Russo A. Patient-specific automated cerebrospinal fluid pressure control to augment spinal wound closure: a case series using the LiquoGuard®. Br J Neurosurg 2024:1-9. [PMID: 38174716 PMCID: PMC11013023 DOI: 10.1080/02688697.2023.2290101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/26/2023] [Indexed: 01/05/2024]
Abstract
OBJECTIVE Spinal cerebrospinal fluid (CSF) leaks are common, and their management is heterogeneous. For high-flow leaks, numerous studies advocate for primary dural repair and CSF diversion. The LiquoGuard7® allows automated and precise pressure and volume control, and calculation of patient-specific CSF production rate (prCSF), which is hypothesized to be increased in the context of durotomies and CSF leaks. METHODS This single-centre illustrative case series included patients undergoing complex spinal surgery where: 1) a high flow intra-operative and/or post-operative CSF leak was expected and 2) lumbar CSF drainage was performed using a LiquoGuard7®. CSF diversion was tailored to prCSF for each patient, combined with layered spinal wound closure. RESULTS Three patients were included, with a variety of pathologies: T7/T8 disc prolapse, T8-T9 meningioma, and T4-T5 metastatic spinal cord compression. The first two patients underwent CSF diversion to prevent post-op CSF leak, whilst the third required this in response to post-op CSF leak. CSF hyperproduction was evident in all cases (mean >/=140ml/hr). With patient-specific CSF diversion regimes, no cases required further intervention for CSF fistulae repair (including for pleural CSF effusion), wound breakdown or infection. CONCLUSIONS Patient-specific cerebrospinal fluid drainage may be a useful tool in the management of high-flow intra-operative and post-operative CSF leaks during complex spinal surgery. These systems may reduce post-operative CSF leakage from the wound or into adjacent body cavities. Further larger studies are needed to evaluate the comparative benefits and cost-effectiveness of this approach.
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Affiliation(s)
- Danyal Z. Khan
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, London, UK
| | - Kanza Tariq
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK
- Department of Brain Repair & Rehabilitation, UCL Queen Square Institute of Neurology, London, UK
| | - Keng Siang Lee
- Bristol Medical School, Faculty of Health Sciences, University of Bristol, Bristol, UK
| | - Edward W Dyson
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK
- Department of Brain Repair & Rehabilitation, UCL Queen Square Institute of Neurology, London, UK
| | - Vittorio Russo
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK
| | - Laurence D Watkins
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK
- Department of Brain Repair & Rehabilitation, UCL Queen Square Institute of Neurology, London, UK
| | - Antonino Russo
- Department of Neurosurgery, National Hospital for Neurology and Neurosurgery, London, UK
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Yiangou A, Mollan SP, Sinclair AJ. Idiopathic intracranial hypertension: a step change in understanding the disease mechanisms. Nat Rev Neurol 2023; 19:769-785. [PMID: 37957260 DOI: 10.1038/s41582-023-00893-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2023] [Indexed: 11/15/2023]
Abstract
The understanding of idiopathic intracranial hypertension (IIH) has evolved over the past few years. Previously, IIH was considered a disease exclusively affecting the neuro-ophthalmic axis, characterized by raised intracranial pressure, headache and papilloedema, and resulting in the risk of severe and permanent visual loss and life-changing disabling headaches. Recent advances have begun to redefine IIH as a probable metabolic disease involving a range of systemic manifestations. More than 95% of individuals affected by the disease are women of reproductive age with obesity. The incidence is rapidly rising and parallels the escalating worldwide obesity rates. Contemporary insights identify associations with insulin resistance, type 2 diabetes and a twofold increased risk of cardiovascular disease in excess of that driven by obesity alone. Adipose distribution in people with IIH, like that in other metabolic diseases, is preferentially centripetal and is associated with changes in intracranial pressure. Evidence now demonstrates adipose tissue dysfunction in people with IIH, involving transcriptional and metabolic priming for lipogenesis and weight gain. Hormonal perturbations are also observed, including a unique phenotype of androgen excess that promotes cerebrospinal fluid secretion. Knowledge of these additional disease features is driving research into novel therapeutic targets and altering the approach to multidisciplinary care.
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Affiliation(s)
- Andreas Yiangou
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- Department of Neurology, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Susan P Mollan
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- Birmingham Neuro-Ophthalmology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Alexandra J Sinclair
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.
- Department of Neurology, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK.
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