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Hladky SB, Barrand MA. Regulation of brain fluid volumes and pressures: basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus. Fluids Barriers CNS 2024; 21:57. [PMID: 39020364 PMCID: PMC11253534 DOI: 10.1186/s12987-024-00532-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 03/21/2024] [Indexed: 07/19/2024] Open
Abstract
The principles of cerebrospinal fluid (CSF) production, circulation and outflow and regulation of fluid volumes and pressures in the normal brain are summarised. Abnormalities in these aspects in intracranial hypertension, ventriculomegaly and hydrocephalus are discussed. The brain parenchyma has a cellular framework with interstitial fluid (ISF) in the intervening spaces. Framework stress and interstitial fluid pressure (ISFP) combined provide the total stress which, after allowing for gravity, normally equals intracerebral pressure (ICP) with gradients of total stress too small to measure. Fluid pressure may differ from ICP in the parenchyma and collapsed subarachnoid spaces when the parenchyma presses against the meninges. Fluid pressure gradients determine fluid movements. In adults, restricting CSF outflow from subarachnoid spaces produces intracranial hypertension which, when CSF volumes change very little, is called idiopathic intracranial hypertension (iIH). Raised ICP in iIH is accompanied by increased venous sinus pressure, though which is cause and which effect is unclear. In infants with growing skulls, restriction in outflow leads to increased head and CSF volumes. In adults, ventriculomegaly can arise due to cerebral atrophy or, in hydrocephalus, to obstructions to intracranial CSF flow. In non-communicating hydrocephalus, flow through or out of the ventricles is somehow obstructed, whereas in communicating hydrocephalus, the obstruction is somewhere between the cisterna magna and cranial sites of outflow. When normal outflow routes are obstructed, continued CSF production in the ventricles may be partially balanced by outflow through the parenchyma via an oedematous periventricular layer and perivascular spaces. In adults, secondary hydrocephalus with raised ICP results from obvious obstructions to flow. By contrast, with the more subtly obstructed flow seen in normal pressure hydrocephalus (NPH), fluid pressure must be reduced elsewhere, e.g. in some subarachnoid spaces. In idiopathic NPH, where ventriculomegaly is accompanied by gait disturbance, dementia and/or urinary incontinence, the functional deficits can sometimes be reversed by shunting or third ventriculostomy. Parenchymal shrinkage is irreversible in late stage hydrocephalus with cellular framework loss but may not occur in early stages, whether by exclusion of fluid or otherwise. Further studies that are needed to explain the development of hydrocephalus are outlined.
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Affiliation(s)
- Stephen B Hladky
- Department of Pharmacology, Tennis Court Rd, Cambridge, CB2 1PD, UK.
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Berman G, Mollan SP. The Pressure of Headache at the United Kingdom CSF Disorders Day 2023. Neuroophthalmology 2024; 48:204-209. [PMID: 38756340 PMCID: PMC11095568 DOI: 10.1080/01658107.2023.2290539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 11/18/2023] [Indexed: 05/18/2024] Open
Abstract
Headache in intracranial disorders drives significant disability in our patients. Management principles for secondary headaches require a multidisciplinary approach with expertise from the neurological, neuro-ophthalmological, neuroradiological, and neurosurgical specialities. The Pressure of Headache was the theme of the annual United Kingdom CSF Disorders Day and saw speakers and panellists from Australia, Europe, and the United States. Among the topics presented were the newest concepts underpinning idiopathic intracranial hypertension management and spontaneous intracranial hypotension. Advances in our knowledge of cerebrospinal fluid secretion and the visual snow syndrome debate were particular highlights. This review provides a summary of the research on headache disorders that overlap the neuro-ophthalmological axis of care for patients.
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Affiliation(s)
- Gabriele Berman
- 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, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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Westgate CSJ, Kamp-Jensen C, Israelsen IME, Toft-Bertelsen T, Wardman JH, Jensen CA, Styrishave B, MacAulay N, Jensen RH, Eftekhari S. Acetazolamide and topiramate lower intracranial pressure through differential mechanisms: The effect of acute and chronic administration. Br J Pharmacol 2024; 181:70-86. [PMID: 37553842 DOI: 10.1111/bph.16213] [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: 09/19/2022] [Revised: 05/24/2023] [Accepted: 07/20/2023] [Indexed: 08/10/2023] Open
Abstract
BACKGROUND AND PURPOSE Diseases of raised intracranial pressure (ICP) cause severe morbidity and mortality. Multiple drugs are utilised to lower ICP including acetazolamide and topiramate. However, the evidence for their use is unclear. We aimed to assess the ICP modulatory effects and molecular effects at the choroid plexus (CP) of acetazolamide and topiramate. EXPERIMENTAL APPROACH Female rats were implanted with telemetric ICP probes for physiological, freely moving 24/7 ICP recordings. Randomised cross-over studies were performed, where rats received acute (24 h) high doses of acetazolamide and topiramate, and chronic (10 days) clinically equivalent doses of acetazolamide and topiramate, all via oral gavage. Cerebrospinal fluid (CSF) secretion assays, and RT-qPCR and western blots on in vitro and in vivo CP, were used to investigate drug actions. KEY RESULTS We demonstrate that acetazolamide and topiramate achieved maximal ICP reduction within 120 min of administration, and in combination doubled the ICP reduction over a 24-h period. Chronic administration of acetazolamide or topiramate lowered ICP by 25%. Topiramate decreased CSF secretion by 40%. Chronic topiramate increased the gene expression of Slc12a2 and Slc4a10 and protein expression of the sodium-dependent chloride/bicarbonate exchanger (NCBE), whereas chronic acetazolamide did not affect the expression of assessed genes. CONCLUSIONS AND IMPLICATIONS Acetazolamide and topiramate are effective at lowering ICP at therapeutic levels. We provide the first evidence that topiramate lowers CSF secretion and that acetazolamide and topiramate may lower ICP via distinct molecular mechanisms. Thus, the combination of acetazolamide and topiramate may have utility for treating raised ICP.
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Affiliation(s)
- Connar Stanley James Westgate
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Christina Kamp-Jensen
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Ida Marchen Egerod Israelsen
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
| | | | | | - Christian Ahm Jensen
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bjarne Styrishave
- Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Rigmor Højland Jensen
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
| | - Sajedeh Eftekhari
- Danish Headache Center, Department of Neurology, Glostrup Research Institute, Rigshospitalet-Glostrup, University of Copenhagen, Copenhagen, Denmark
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Huda F, Abdelmonem A, Dehghani Firouzabadi F, Srinivas Dola VN, Sheikhy A, Taheri MR. The role of arachnoid granulations in idiopathic intracranial hypertension. Neuroradiol J 2023; 36:651-656. [PMID: 37102274 PMCID: PMC10649532 DOI: 10.1177/19714009231173109] [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] [Indexed: 04/28/2023] Open
Abstract
OBJECTIVES Idiopathic intracranial hypertension (IIH) is a disease defined by elevated intracranial pressure (ICP) without an established etiology. Arachnoid granulations (AG) are conduits for CSF resorption from the subarachnoid space to the venous system. AG have been implicated to play a central role in maintaining CSF homeostasis. We tested the hypothesis that patients with fewer visible AG on MRI are more likely to present with IIH. METHODS In this institutional review board (Institutional Review Board)-approved retrospective chart review study, 65 patients with a clinical diagnosis of idiopathic intracranial hypertension were compared to 144 control patients who met inclusion/exclusion criteria. Patients' signs and symptoms pertaining to IIH were obtained through the electronic medical record Brain MR images were reviewed for the number and distribution of AGs indenting the dural venous sinuses. The presence of imaging and clinical findings associated with long standing increased ICP was noted. Propensity score method (with inverse probability weighting technique) was used to compare case and control groups. RESULTS In the control group, the number of AG indenting the dural venous sinuses on MRI (NAG) was lower in women compared to men when matched for age (20-45 yo) and BMI (>30 kg/m2). The NAG was lower in 20-45 yo females in the IIH group as compared to the 20-45 yo females in the control group. This statistically significant difference persists when controlled for BMI. In contrast, the NAG in >45 yo females in the IIH group trended higher compared to the >45 yo females in the control group. CONCLUSION Our results suggest that alterations in arachnoid granulations could play a role in the development of IIH.
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Affiliation(s)
- Fahimul Huda
- Department of Radiology, The George Washington University Hospital, Washington, DC, USA
| | - Ahmed Abdelmonem
- Department of Radiology, The George Washington University Hospital, Washington, DC, USA
| | | | | | - Ali Sheikhy
- Tehran University of Medical Sciences Non-Communicable Disease Research Center, Tehran, Iran
| | - M Reza Taheri
- Department of Radiology, The George Washington University Hospital, Washington, DC, USA
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Wardman JH, Jensen MN, Andreassen SN, Styrishave B, Wilhjelm JE, Sinclair AJ, MacAulay N. Modelling idiopathic intracranial hypertension in rats: contributions of high fat diet and testosterone to intracranial pressure and cerebrospinal fluid production. Fluids Barriers CNS 2023; 20:44. [PMID: 37328884 DOI: 10.1186/s12987-023-00436-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 04/29/2023] [Indexed: 06/18/2023] Open
Abstract
BACKGROUND Idiopathic intracranial hypertension (IIH) is a condition characterized by increased intracranial pressure (ICP), impaired vision, and headache. Most cases of IIH occur in obese women of childbearing age, though age, BMI, and female sex do not encompass all aspects of IIH pathophysiology. Systemic metabolic dysregulation has been identified in IIH with a profile of androgen excess. However, the mechanistic coupling between obesity/hormonal perturbations and cerebrospinal fluid dynamics remains unresolved. METHODS Female Wistar rats were either fed a high fat diet (HFD) for 21 weeks or exposed to adjuvant testosterone treatment for 28 days to recapitulate IIH causal drivers. Cerebrospinal fluid (CSF) and blood testosterone levels were determined with mass spectrometry, ICP and CSF dynamics with in vivo experimentation, and the choroid plexus function revealed with transcriptomics and ex vivo isotope-based flux assays. RESULTS HFD-fed rats presented with increased ICP (65%), which was accompanied by increased CSF outflow resistance (50%) without altered CSF secretion rate or choroid plexus gene expression. Chronic adjuvant testosterone treatment of lean rats caused elevated ICP (55%) and CSF secretion rate (85%), in association with increased activity of the choroid plexus Na+,K+,2Cl- cotransporter, NKCC1. CONCLUSIONS HFD-induced ICP elevation in experimental rats occurred with decreased CSF drainage capacity. Adjuvant testosterone, mimicking the androgen excess observed in female IIH patients, elevated the CSF secretion rate and thus ICP. Obesity-induced androgen dysregulation may thus contribute to the disease mechanism of IIH.
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Affiliation(s)
- Jonathan H Wardman
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark
| | - Mette N Jensen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark
| | - Søren N Andreassen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark
| | - Bjarne Styrishave
- Department of Pharmacy, University of Copenhagen, Copenhagen, Denmark
| | - Jens E Wilhjelm
- Department of Health Technology, The Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Alexandra J Sinclair
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
| | - Nanna MacAulay
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.
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Piccus R, Thaller M, Sinclair AJ, Mollan SP. Current and emerging diagnostic and management approaches for idiopathic intracranial hypertension. Expert Rev Neurother 2023; 23:457-466. [PMID: 37114519 DOI: 10.1080/14737175.2023.2206567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
INTRODUCTION Idiopathic intracranial hypertension is characterized by raised intracranial pressure that triggers disabling headaches and can cause permanent visual loss. There is an increased incidence and prevalence of the condition linked to location-specific obesity rates. There are no licensed treatments for the condition. The majority of approaches to managing the disease prioritize resolution of papilledema. However, evidence is emerging that idiopathic intracranial hypertension is a systemic metabolic disease. AREAS COVERED The aim of this review is to present the emerging pathophysiology evidence which is leading to novel targeted therapeutics. The diagnostic pathway is outlined. The current and potential management approaches for idiopathic intracranial hypertension are also discussed. EXPERT OPINION Idiopathic intracranial hypertension is a condition with metabolic dysregulation with systemic manifestations that are present over and above what can be expl.ained by obesity alone. While most of the current management of this condition focuses on the eyes, future management needs to address the disabling headaches and the systemic risks of preeclampsia, gestational diabetes, and major cardiovascular events.
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Affiliation(s)
- Ravi Piccus
- Medical school, University of Birmingham, Birmingham, UK
| | - Mark Thaller
- Translational Brain Science, Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Alexandra J Sinclair
- Translational Brain Science, Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Susan P Mollan
- Translational Brain Science, Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK
- Birmingham Neuro-Ophthalmology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
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Kassubek R, Weinstock D, Behler A, Müller HP, Dupuis L, Kassubek J, Ludolph AC. Morphological alterations of the hypothalamus in idiopathic intracranial hypertension. Ther Adv Chronic Dis 2022; 13:20406223221141354. [PMID: 36479140 PMCID: PMC9720803 DOI: 10.1177/20406223221141354] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 11/07/2022] [Indexed: 11/15/2023] Open
Abstract
BACKGROUND The pathophysiology of idiopathic intracranial hypertension (IIH), a condition characterized by raised intracranial pressure, is not well understood. OBJECTIVES We hypothesized that the hypothalamus might exhibit alterations in patients with IIH, based on its established association with obesity and the potential role of hormonal and metabolic factors in IIH. DESIGN Retrospective single-center cohort study. METHODS Thirty-three individuals with IIH and 40 matched healthy individuals were studied, including levels of the hormones and proteins leptin, adiponectin, ghrelin, insulin, growth/differentiation factor 15 (GDF15), somatostatin, and melatonin. In vivo high-resolution T1-weighted magnetic resonance imaging (MRI) data were analyzed by quantification of hypothalamic volumes using a well-established segmentation method, separate for the anterior and the posterior hypothalamic subvolumes. An additional analysis was performed using age, gender, and BMI-matched subgroups of 20 IIH patients and 20 controls. RESULTS The analysis of laboratory values showed significantly increased insulin, leptin, and melatonin levels for IIH patients in comparison to controls, while adiponectin levels were decreased in IIH; however, only melatonin level differences could be confirmed in the analysis with BMI matching. There was no statistical difference in total hypothalamus volumes between IIH and controls, but the hypothalamic morphology was altered in IIH patients with a lower volume of the anterior part of the hypothalamus and a higher volume of the posterior part; these results were identical in the analysis of the BMI-matched groups. The correlation analyses between hormonal changes and hypothalamic morphology did not achieve significant results. CONCLUSION In this exploratory study, morphological abnormalities of the hypothalamus were observed to be associated with the IIH complex, although the mechanism remains to be unraveled. These findings expand the metabolic phenotype of IIH, but further functional studies are necessary to corroborate these data.
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Affiliation(s)
- Rebecca Kassubek
- Department of Neurology, University of Ulm,
Oberer Eselsberg 45, 89081 Ulm, Germany
| | | | - Anna Behler
- Department of Neurology, University of Ulm,
Ulm, Germany
| | | | - Luc Dupuis
- Université de Strasbourg, INSERM, Mécanismes
centraux et périphériques de la neurodégénérescence, Strasbourg,
France
| | - Jan Kassubek
- Department of Neurology, University of Ulm,
Ulm, Germany; German Center for Neurodegenerative Diseases (DZNE), Ulm,
Germany
| | - Albert C. Ludolph
- Department of Neurology, University of Ulm,
Ulm, Germany; German Center for Neurodegenerative Diseases (DZNE), Ulm,
Germany
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Mollan SP, Sinclair AJ. Outcomes measures in idiopathic intracranial hypertension. Expert Rev Neurother 2021; 21:687-700. [PMID: 34047224 DOI: 10.1080/14737175.2021.1931127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Introduction: Idiopathic intracranial hypertension is a condition characterized by raised intracranial pressure, papilledema, and normal neuroimaging (aside from radiological signs of raised intracranial pressure). Symptoms of idiopathic intracranial hypertension include chronic headaches and for some, visual loss. New treatments are unmet clinical needs.Areas covered: The aim of this review is to present the evidence base and considered opinion on outcome measures to determine successful management of idiopathic intracranial hypertension.Expert opinion: Less invasive measures of disease activity such as optical coherence tomography will continue to grow in this field, both as a measure of papilledema, and potentially as a surrogate for intracranial pressure and visual function. As a highly disabling aspect of the disease is headache, treatment outcomes for headache morbidity need to be appropriately chosen and standardized to allow comparison between trials.
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Affiliation(s)
- Susan P Mollan
- Birmingham Neuro-Ophthalmology, Queen Elizabeth Hospital, Birmingham, United Kingdom (UK)
| | - Alexandra J Sinclair
- Birmingham Neuro-Ophthalmology, Queen Elizabeth Hospital, Birmingham, United Kingdom (UK).,Metabolic Neurology, Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK.,Department of Neurology, University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital, Birmingham, UK
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Naseri Kouzehgarani G, Feldsien T, Engelhard HH, Mirakhur KK, Phipps C, Nimmrich V, Clausznitzer D, Lefebvre DR. Harnessing cerebrospinal fluid circulation for drug delivery to brain tissues. Adv Drug Deliv Rev 2021; 173:20-59. [PMID: 33705875 DOI: 10.1016/j.addr.2021.03.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/10/2021] [Accepted: 03/01/2021] [Indexed: 12/31/2022]
Abstract
Initially thought to be useful only to reach tissues in the immediate vicinity of the CSF circulatory system, CSF circulation is now increasingly viewed as a viable pathway to deliver certain therapeutics deeper into brain tissues. There is emerging evidence that this goal is achievable in the case of large therapeutic proteins, provided conditions are met that are described herein. We show how fluid dynamic modeling helps predict infusion rate and duration to overcome high CSF turnover. We posit that despite model limitations and controversies, fluid dynamic models, pharmacokinetic models, preclinical testing, and a qualitative understanding of the glymphatic system circulation can be used to estimate drug penetration in brain tissues. Lastly, in addition to highlighting landmark scientific and medical literature, we provide practical advice on formulation development, device selection, and pharmacokinetic modeling. Our review of clinical studies suggests a growing interest for intra-CSF delivery, particularly for targeted proteins.
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Mondejar V, Patsalides A. The Role of Arachnoid Granulations and the Glymphatic System in the Pathophysiology of Idiopathic Intracranial Hypertension. Curr Neurol Neurosci Rep 2020; 20:20. [DOI: 10.1007/s11910-020-01044-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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