Idiopathic intracranial hypertension

Regulation of brain fluid volumes and pressures: basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus

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.

Cerebrospinal Fluid Diversion from the Cisterna Magna in Patients with Idiopathic Intracranial Hypertension and Slit Ventricles: Long-Term Effectiveness, Revision Rates, and Clinical Outcomes

OBJECTIVE

Idiopathic intracranial hypertension (IIH) is a cerebrospinal fluid (CSF) disorder defect that is frequently treated with CSF shunts. Shunts utilizing the cisterna magna as a proximal reservoir have been described in literature; however, long-term outcomes are unknown. The present study aims to describe the long-term effectiveness, revision rates, and clinical outcomes of this shunt in 14 patients with IIH and slit ventricles.

METHODS

A single-center retrospective review of 14 IIH patients treated by cisterna magna shunts was performed. Shunt histories, including revision rate and time until first shunt failure for ventricular, lumbar, and cisterna magna shunts were recorded. "Revision rate" was calculated as the total number of shunt revisions over years of total shunt placement. The average follow-up time was 12.08 years.

RESULTS

The mean age at first cisterna magna shunt placement was 18.1 years (6.6-43.3 years) and all patients had radiological evidence of slit ventricles. Cisterna magna shunts improved or resolved clinical symptoms for all 14 patients and had a lower rate of revisions (0.42 revision/year) compared to ventricular (0.72 revision/year) and lumbar (1.30 revision/year) shunts. Of the 11 patients still requiring CSF diversion at the end of the study, eight had functioning shunts that utilized the cisterna magna.

CONCLUSIONS

The cisterna magna shunt may be a suitable option for patients with IIH and slit ventricles. Further study is needed to understand the clinical utility of this shunt for the population in which it is indicated.

Establishing continuum in Transcranial Doppler characteristics of IIH, migraine and healthy controls- An exploratory study

BACKGROUND

IIH is a severe form of headache that often has superimposed migraine and often it is very difficult to distinguish the two forms of headache. Intracranial hemodynamics is a relatively unexplored means of distinguishing between the two forms of headache.

OBJECTIVES

We aimed to study intracranial flow dynamics using Transcranial Doppler in patients with IIH, migraine, and normal controls.

MATERIALS AND METHODS

It was a hospital-based observational study that included 51 people with IIH, 87 people with migraine, and 101 healthy controls and all were subjected to TCD study after detailed clinical examination.

RESULTS

Mean age of patients in three groups were similar with the mean age in IIH being 33.41 ± 10.75 (age in years ± SD). Vision loss was present in 66.67% of patients with IIH, and most common field defect was generalized constriction (27.5%). Neuroimaging was abnormal in 94.11% of patients of IIH with mean CSF pressure was 31.27±5.32 cm of water. Of all the TCD-measured velocities, mean flow velocity (MFV) showed a significant difference in all three groups with (p-value <0.001). The pulsatility index, both for middle cerebral arteries as well as ophthalmic arteries showed a significant difference in the three groups with the highest values in IIH patients (p-value<.001). The mean VMR in IIH (1.11±0.32) was lower than the mean VMR in migraine (1.34±0.43) as well as controls (1.49±0.46).

CONCLUSION

TCD parameters like MFV and PI are useful parameters that show considerable variation and can be used to differentiate between IIH and migraine.

Effectiveness and Safety of Ventriculoperitoneal Shunt Versus Lumboperitoneal Shunt for Idiopathic Intracranial Hypertension: A Systematic Review and Comparative Meta-Analysis

INTRODUCTION

Idiopathic Intracranial Hypertension (IIH) is a condition characterized by elevated intracranial pressure. Although several mechanisms have been proposed as underlying causes of IIH, no identifiable causative factor has been determined for this condition. Initial treatments focus on weight or CSF reduction, but severe cases may require surgery. This study compares outcomes in IIH patients treated with lumboperitoneal shunts (LPSs) versus ventriculoperitoneal shunts (VPSs).

METHODS

This systematic-review and meta-analysis follows Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines and includes studies about VPS and LPS patients, reporting one of the outcomes of interest. We conducted searches on PubMed, Embase, Web of Science, and Cochrane Library.

RESULTS

Our analysis involved twelve studies, comprising 5990 patients. The estimated odds ratio (OR) for visual improvement was 0.97 (95% CI 0.26-3.62; I2 = 0%) and for headache improvement was 0.40 (95% CI 0.20-0.81; I2 = 0%), favoring LPS over VPS. Shunt revision analysis revealed an OR of 1.53 (95% CI 0.97-2.41; I2 = 77%). The shunt complications showed an OR of 0.91 (95% CI 0.68-1.22; I2 = 0%). The sub-analyses for shunt failure uncovered an OR of 1.41 (95% CI 0.92-2.18; I2 = 25%) and for shunt infection events an OR of 0.94 (95% CI 0.50-1.75; I2 = 0%).

CONCLUSIONS

The interventions showed general equivalence in complications, shunt failure, and other outcomes, but LPS seems to hold an advantage in improving headaches. Substantial heterogeneity highlights the need for more conclusive evidence, emphasizing the crucial role for further studies. The findings underscore the importance of considering a tailored decision between VPS and LPS for the management of IIH patients.

Systemic lupus erythematosus with chronic persistent intracranial hypertension: A case report

OBJECTIVE

The aim is to investigate the clinical characteristics of systemic lupus erythematosus with intracranial hypertension.

METHODS

The clinical characteristics of one case of systemic lupus erythematosus with chronic persistent intracranial hypertension were analyzed, and related literature was reviewed by searching Medline and Wanfang databases.

RESULTS

Intracranial hypertension in SLE patients may occur at the onset or during the course of the disease. Our patient was diagnosed with IH 3 years after the onset of SLE. Headache and papilledema were the most common symptoms of intracranial hypertension, followed by nausea or vomiting, vision changes, and cerebral palsy. Our patient had a headache and cranial hypertension that lasted for years, but no papilledema was found. Corticosteroid is currently the mainstay of the treatment of IIH in patients with SLE, and immunosuppressive agents, acetazolamide, intravenous mannitol and furosemide are also used. However, our patient did not respond to these treatments and presents the characteristics of chronic persistent intracranial hypertension.

CONCLUSION

Systemic lupus erythematosus with intracranial hypertension is a rare manifestation of SLE, which is not completely parallel to SLE activity. Headache and papilledema were the most common presenting symptoms. Different from previous reported cases, our patient had poor response to treatments, showing chronic and persistent characteristics.

Idiopathic intracranial hypertension in two twin sisters

Idiopathic intracranial hypertension (IIH) is a condition of unknown aetiology characterised by an increase in the intracranial pressure. Familial cases of IIH are rare and not well-understood. We present two monozygotic twins who developed IIH two years apart. The case involves two monozygotic female twins developing IIH in their 50s. They presented with a history of blurry vision and headaches. The diagnosis included the neurological, radiological and ophthalmological examination, excluding other causes. Both patients received treatment with acetazolamide, successfully resolving the papilloedema and restoring a normal visual field. This case highlights the occurrence of IIH among twins presenting at similar periods, emphasising the potential genetic influence. Clinicians should alert and educate the family regarding the risk factors and potential symptoms of this condition in the unlikely occurrence that other family members are affected.

The manifestations of metabolic acidosis during acetazolamide treatment in a cohort of pediatric idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension is characterized by increased intracranial pressure with unidentified pathology. Despite its use as the first-line treatment, data on acetazolamide's effectiveness and safety in pediatric idiopathic intracranial hypertension is sparse. This study's objective was to assess those issues and the need for routine blood gas monitoring during treatment.

METHODS

Retrospective observational cohort study, based on multicenter computerized medical charts of pediatric patients with idiopathic intracranial hypertension diagnosed between 2007-2018 in three medical centers serving one metropolitan area (an estimated population of 400,000 children). Clinical and laboratory data of children up to 18 years old, fulfilling the Friedman criteria and taking acetazolamide, were collected and analyzed.

RESULTS

Sixty-eight patients were included with a mean acetazolamide treatment duration of 8.5 months and a median maximal dose 18 mg/kg/d. Sixty-two children had mild (76%), moderate (13%), or severe (1.5%) metabolic acidosis. At least one adverse effect (neurologic, gastrointestinal, renal) was recorded among 27% of patients. No significant difference was found between the mean pH of children with or without clinical adverse effects (p = 0.35). No correlation was found between laboratory acidosis and adverse effect severity (p = 0.3), or between median acetazolamide dose and acidosis level (p = 0.57).

CONCLUSIONS

Although laboratory finding of metabolic acidosis is common among patients with idiopathic intracranial hypertension treated with acetazolamide, it is not correlated with clinics. Therefore, we recommend sending blood tests during acetazolamide treatment based on clinical judgment. A higher resolution version of the Graphical abstract is available as Supplementary information.

Transorbital sonography in idiopathic intracranial hypertension: Single-center study, systematic review and meta-analysis

BACKGROUND AND PURPOSE

Transorbital sonography (TOS) provides a noninvasive tool to detect intracranial pressure by assessing optic nerve sheath diameter (ONSD) and optic disc elevation (ODE). The utility of TOS in the diagnosis of idiopathic intracranial hypertension (IIH) has been increasingly recognized.

METHODS

A single-center case-control study sought to compare TOS-acquired ONSD and ODE among IIH-cases versus patients with other neurological diseases (controls). Furthermore, a systematic review and meta-analysis was conducted to present pooled mean differences and diagnostic measures of ONSD and ODE between IIH-cases and controls.

RESULTS

In the single-center study, consisting of 31 IIH-cases and 34 sex- and age-matched controls, ONSD values were higher among IIH-cases than controls (p<.001), while ODE was more prevalent in cases (65% vs. 15%; p<.001). The receiver-operating characteristic (ROC)-curve analysis revealed that the optimal cutoff value of ONSD for predicting IIH was 5.15 mm, with an area under the curve (AUC) of 0.914 (95% confidence interval [CI]: 0.861-0.967) and sensitivity and specificity values of 85% and 90%, respectively. In a meta-analysis of 14 included studies with 415 IIH-cases, ONSD and ODE values were higher in IIH-cases than controls (mean difference in ONSD 1.20 mm; 95% CI: 0.96-1.44 mm and in ODE 0.3 mm; 95% CI: 0.33-0.67 mm). With regard to ONSD, pooled sensitivity, specificity, and diagnostic odds ratio were calculated at 85.5% (95% CI: 77.9-90.8%), 90.7% (95% CI: 84.6-94.5%), and 57.394 (95% CI: 24.597-133.924), respectively. The AUC in summary ROC-curve analysis was 0.878 (95% CI: 0.858-0.899) with an optimal cutoff point of 5.0 mm.

CONCLUSIONS

TOS has a high diagnostic utility for the noninvasive diagnosis of IIH and may deserve wider implementation in everyday clinical practice.

Multiple skull base defects in the setting of spontaneous cerebrospinal fluid rhinorrhea; a dual institution view

PURPOSE

Idiopathic intracranial hypertension (IIH) is a condition of high cerebrospinal fluid (CSF) pressure that presents with CSF leak. The implications of multiple skull base defects (SBD) and associated synchronous CSF leaks have not been previously explored.

MATERIALS AND METHODS

A dual institutional case-control study examined multiple SBD's and encephaloceles on the risk of CSF leak and postoperative failures post-repair. IIH patients with CSF leaks and IIH controls without leaks were selected retrospectively. Chi square analysis evaluated for statistically significant alterations in probability with CSF leak development.

RESULTS

192 patients were selected with 108 IIH controls and 84 spontaneous CSF leak cases. Signs and symptoms for IIH controls and CSF leak cases respectively were pulsatile tinnitus (60.2 % and 29.8 %), headaches (96.3 % and 63.1 %), papilledema (74.1 % and 12.5 %), visual field defects (60.8 % and 13 %) (p < 0.001). Encephalocele formation in controls was 3.7 % compared to cases at 91.6 % (p < 0.001). Multiple SBD's in controls compared cases was 0.9 % and 46.4 % respectively (p < 0.001). Subgroup analysis of CSF leak cases showed 15 patients with two CSF leak repairs due to a recurrence. 27 (39.1 %) single leak cases had multiple SDB's while 12 (80 %) recurrent leaks had multiple SDB's (p = 0.004).

CONCLUSIONS

Patients with radiographic evidence of multiple SBD's and encephaloceles represent a high-risk population with a propensity for CSF leaks. Secondary SBD's are common in patients with spontaneous CSF rhinorrhea and higher in patients with a recurrence.

B-mode transorbital ultrasonography for the diagnosis of idiopathic intracranial hypertension: an updated systematic review and meta-analysis

OBJECTIVES

This systematic review and meta-analysis aimed to evaluate the role of B-mode transorbital ultrasonography (TOS) for the diagnosis of idiopathic intracranial hypertension (IIH) in adults.

METHODS

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL) (1966-May 2022) were searched to identify studies reporting ultrasonographic data about the optic nerve sheath diameter (ONSD) and optic disc elevation (ODE) in adults with IIH compared to subjects without IIH. The quality of the included studies was evaluated by the Newcastle-Ottawa Quality.

RESULTS

Fifteen studies were included (total of 439 patients). The values of ODE ranged from 0.6 to 1.3 mm in patients with IIH. The values of ONSD ranged from 4.7 to 6.8 mm in IIH patients and from 3.9 to 5.7 mm in controls. In IIH patients, the ONSD was significantly higher compared to controls (standardized mean difference: 2.5 mm, 95% confidence interval (CI): 1.6-3.4 mm). Nine studies provided data about the presence of papilledema and the pooled prevalence was 95% (95% CI, 92-97%).

CONCLUSIONS

In adults, the thickness of ONSD and the entity of ODE were significantly associated with IIH. B-mode TOS enables to noninvasively detect increased ICP and should be performed, potentially routinely, in any patient with suspected IIH.

Evaluation of Optic Disc Edema in Long-Duration Spaceflight Crewmembers Using Retinal Photography

BACKGROUND

Long-duration spaceflight crewmembers are at risk for spaceflight-associated neuro-ocular syndrome (SANS). One of the earliest manifestations of SANS is optic disc edema (ODE), which could be missed using the subjective Frisén scale. The primary objective of this study is to determine the inter-rater and intrarater reliability of Frisén grade for SANS-induced ODE among a trained observer cohort. The secondary objective is to propose a standardized evaluation process for SANS-induced ODE across International Space Station Partner Agencies.

METHODS

Retrospective, double-blinded diagnostic study. Preflight and postflight fundus photographs were presented to subject matter experts who identified and graded ODE. Pairs of images were also compared side-by-side for disc ranking. Grader concordance was assessed for Frisén grading and disc ranking.

RESULTS

Expert graders identified Grade 1 ODE in 17.35% of images from 62 crewmembers (9 female, mean [SD] age, 47.81 [5.19] years). Grades 2 and 3 were identified less than 2% of the time. Concordance in Frisén grades among pairs of graders was 70.99%. Graders identified a difference in preflight and postflight fundus photographs 17.21% of the time when using disc ranking. Pairs of graders had complete concordance in disc ranking 79.79% of the time. Perfect intrarater agreement between Frisén grade and disc ranking occurred 77.7% of the time.

CONCLUSIONS

These findings demonstrate intergrader and intragrader variability when using the Frisén scale to identify SANS-induced ODE, which is typically milder in presentation than terrestrial cases of idiopathic intracranial hypertension. It is possible to miss early ODE on fundoscopy alone, making it insufficient as a sole criterion for the diagnosis of SANS. A more sensitive and objective method of surveillance is necessary to monitor international crewmembers for ODE, perhaps using a multimodal approach that includes technology such as optical coherence tomography.

Intraoperative ultrasound-guided ventricular cannulation in patients with normal-sized ventricles

INTRODUCTION

Many pathologies require normal-sized ventricle cannulation, which may be technically challenging even with neuronavigation guidance. This study presents a series of ventricular cannulation of normal-sized ventricles using intraoperative ultrasound (iUS) guidance and the outcomes of patients treated by this technique, for the first time.

METHODS

The study included patients who underwent ultrasound-guided ventricular cannulation of normal-sized ventricles (either ventriculoperitoneal (VP) shunting or Ommaya reservoir) between January 2020 and June 2022. All patients underwent iUS-guided ventricular cannulation from the right Kocher's point. The inclusion criteria for normal-sized ventricles were as follows: (1) Evans index <30%, and (2) widest third ventricle diameter <6mm. Medical records and pre-, intra- and post-operative imaging were retrospectively analyzed.

RESULTS

Nine of the 18 included patients underwent VP shunt placement; 6 had idiopathic intracranial hypertension (IIH), 2 had resistant cerebrospinal fluid fistula following posterior fossa surgery, and 1 had iatrogenic intracranial pressure elevation following foramen magnum decompression. Nine patients underwent Ommaya reservoir implantation, 6 of whom had breast carcinoma and leptomeningeal metastases and 3 hematologic disease and leptomeningeal infiltration. All catheter tip positions were achieved in a single attempt, and none were placed suboptimally. Mean follow-up was 10 months. One IIH patient (5.5%) had early shunt infection which necessitated shunt removal.

CONCLUSION

iUS is a simple and safe method for accurate cannulation of normal-sized ventricles. It provides an effective real-time guidance option for challenging punctures.

Intracranial venous stenting for idiopathic intracranial hypertension

INTRODUCTION

There is increasing evidence in the literature to support venous sinus stenting in patients with idiopathic intracranial hypertension who fail first-line therapy. Venous sinus stenting is a safe and successful technique compared with cerebrospinal fluid diversion procedures. This study examines the clinical outcomes of patients post intracranial venous stenting for intracranial hypertension across three tertiary hospitals in Western Australia.

METHODS

A retrospective analysis was performed on 83 consecutive patients treated with intracranial venous stenting for IIH at three tertiary hospitals from October 2013 to March 2020. Data were collected from outpatient clinic letters, electronic discharge letters, electronic radiological imaging and procedural reports.

RESULTS

89.2% patients were able to cease Acetazolomide post stenting. 78.3% patients reported resolution of headaches. 84.3% patients demonstrated resolution of their papilloedema. 91.6% patients demonstrated improvement of their visual acuity. Compared with a recent meta-analysis by Satti and Chaudry in 2015, our results demonstrated a higher technical success rate and lower complication rates.

CONCLUSION

Our study findings support the paradigm shift from CSF diversion procedures to venous sinus stenting in patients with IIH who fail first-line therapy. Venous sinus stenting has a high technical success rate and significantly lower complication rates than other invasive treatments.

A Case of Bilateral Papilledema With Improved Clinical Symptoms by Venous Stenting for Superior Sagittal Sinus Stenosis

Superior sagittal sinus (SSS) obstruction causes intracranial hypertension, often requiring surgical stenting. Consensus on treating brain venous sinus stenosis, another cause, is lacking. This study reports a case of SSS stenosis and intracranial hypertension treated with venous stenting, improving bilateral papilledema. A 51-year-old with a headache and visual disturbance had papilledema and visual field loss. MR venography showed SSS stenosis, leading to a neurosurgery referral. Lumbar puncture confirmed intracranial hypertension (>35 cmH2O), prompting venous stenting. Post-procedure, papilledema, headache, and visual field loss improved. Venous stenting could be effective for SSS stenosis with clinically proven or recurrent pressure differences. Further cases are needed for standardization.

Neurofilament light chain marks severity of papilledema in idiopathic intracranial hypertension

BACKGROUND

Neurofilament light chain (NfL) reflects axonal damage in neurological disorders. It has recently been evaluated in idiopathic intracranial hypertension (IIH). A biomarker indicating the severity of optic nerve damage in IIH could support diagnostic accuracy and therapeutic decisions.

METHODS

We retrospectively reviewed NfL concentrations in the cerebrospinal fluid (CSF) of 35 IIH patients and 12 healthy controls, who had received diagnostic workup for IIH in our clinic. The diagnosis of IIH was made according to the modified Friedman criteria for IIH and for IIH without papilledema Friedman DI et al Neurol 81:1159-1165 (2013) [1]. NfL in the CSF (CSF-NfL) was correlated with the severity of papilledema and with CSF opening pressure.

RESULTS

CSF-NfL correlated with CSF opening pressure at the time of collection. In patients with IIH and moderate or severe papilledema, CSF-NfL was significantly increased compared to patients with mild or no papilledema. Healthy controls with raised intracranial pressure showed no relevant elevation of CSF-NfL.

CONCLUSION

CSF-NfL appears to correlate with the severity of papilledema in IIH and with CSF opening pressure and may therefore be a predictor of optic nerve damage in IIH patients.

Improving pediatric idiopathic intracranial hypertension care: a retrospective cohort study

To describe the clinical course and prognosis of pediatric idiopathic intracranial hypertension (IIH) and examine the preferred management setting. IIH is characterized by increased intracranial pressure and is often associated with headaches and visual complaints. IIH is a preventable cause of vision loss in children. Hence, a rapid diagnosis followed by prompt treatment and follow-up is essential. However, standardization of the management of IIH in the pediatric population is not well established. Computerized medical charts of all 82 pediatric (< 18 years) patients diagnosed with IIH between 2007 and 2018 in the metropolitan area of Jerusalem were reviewed. Comparison was made between children followed in a multidisciplinary clinic in tertiary centers and those followed elsewhere. Detailed demographic and clinical data, as well as data regarding the follow-up setting and clinical course of the disease, were collected and analyzed. Recurrent IIH-related hospital returns were selected as a measurable marker for the uncontrolled disease. Recurrent IIH-related hospital return rate was significantly lower and occurred later among children followed by multidisciplinary teams compared to individual experts. Follow-up in multidisciplinary clinics improve the quality of life, and financial burden and may prevent permanent visual impairment in children with IIH.

A New Perspective on the Pathophysiology of Idiopathic Intracranial Hypertension: Role of the Glia-Neuro-Vascular Interface

Idiopathic intracranial hypertension (IIH) is a neurological disease characterized by symptoms and signs of increased intracranial pressure (ICP) of unknown cause. Most attention has been given to the role of cerebrospinal fluid (CSF) disturbance and intracranial venous hypertension caused by sinus vein stenosis. We previously proposed that key pathophysiological processes take place within the brain at the glia-neuro-vascular interface. However, the relative importance of the proposed mechanisms in IIH disease remains unknown. Modern treatment regimens aim to reduce intracranial CSF and venous pressures, but a substantial proportion of patients experience lasting complaints. In 2010, the first author established a database for the prospective collection of information from individuals being assessed for IIH. The database incorporates clinical, imaging, physiological, and biological data, and information about treatment/outcome. This study retrieved information from the database, asking the following research questions: In IIH subjects responding to shunt surgery, what is the occurrence of signs of CSF disturbance, sinus vein stenosis, intracranial hypertension, and microscopic evidence of structural abnormalities at the glia-neuro-vascular interface? Secondarily, do semi-quantitative measures of abnormal ultrastructure at the glia-neurovascular differ between subjects with definite IIH and non-IIH (reference) subjects? The study included 13 patients with IIH who fulfilled the diagnostic criteria and who improved following shunt surgery, i.e., patients with definite IIH. Comparisons were done regarding magnetic resonance imaging (MRI) findings, pulsatile and static ICP scores, and immune-histochemistry microscopy. Among these 13 IIH subjects, 6/13 (46%) of patients presented with magnetic resonance imaging (MRI) signs of CSF disturbance (empty sella and/or distended perioptic subarachnoid spaces), 0/13 (0%) of patients with IIH had MRI signs of sinus vein stenosis, 13/13 (100%) of patients with IIH presented with abnormal preoperative pulsatile ICP [overnight mean ICP wave amplitude (MWA) above thresholds], 3/13 (23%) patients showed abnormal static ICP (overnight mean ICP above threshold), and 12/13 (92%) of patients with IIH showed abnormal structural changes at the glia-neuro-vascular interface. Comparisons of semi-quantitative structural variables between IIH and aged- and gender-matched reference (REF) subjects showed IIH abnormalities in glial cells, neurons, and capillaries. The present data suggest a key role of disease processes affecting the glia-neuro-vascular interface.

Potential Surgical Implications of Internal Jugular Stenosis in a Craniocervical Junction Meningioma

We report a case of a 61-year-old lady presenting with several weeks of progressive left-sided weakness, and found to have a foramen magnum meningioma. She was counselled on surgical resection of the tumour, and a preoperative computed tomography angiogram (CTA) was obtained for operative planning purposes. CTA demonstrated incidental bilateral internal jugular vein (IJV) stenosis, with enlarged extracranial collateral vessels and elongated styloid processes. The main surgical concern was potential injury of the extracranial collateral vessels during operative exposure, which may compromise her intracranial venous outflow in light of the IJV stenosis. A doppler ultrasound scan of the IJVs was performed, which demonstrated that blood flow was still present through both vessels. Through careful soft tissue dissection during surgery, potential complications and injury to the extracranial collaterals were avoided.

We performed a literature review of the incidence of IJV stenosis, its associated conditions, and potential surgical implications. Complications from injury to vital collateral extracranial vessels should be considered during preoperative planning in patients with anatomical variants or risk factors for IJV stenosis, as seen in this case.

MRI findings differentiating tonsillar herniation caused by idiopathic intracranial hypertension from Chiari I malformation

PURPOSE

Some patients with idiopathic intracranial hypertension (IIH) have cerebellar tonsillar herniation ≥ 5 mm mimicking Chiari malformation I (CMI), which can result in misdiagnosis and unjustified treatment. Our purpose was to identify IIH patients with tonsillar herniation ≥ 5 mm (IIH_TH) and compare with CMI patients to assess imaging findings that could distinguish the two conditions.

METHODS

Ninety-eight patients with IIH, 81 patients with CMI, and 99 controls were retrospectively assessed. Two neuroradiologists blindly reviewed MR images. IIH_TH patients were compared with CMI patients and controls regarding the extent of tonsillar herniation (ETH), bilateral transverse sinus stenosis (BTSS), hypophysis-sella ratio (HSR), and bilateral tortuosity of optic nerve (BTON).

RESULTS

13/98 (13.2%) IIH patients had tonsillar herniation ≥ 5 mm (IIH_TH) and were significantly younger and had higher BMI compared with CMI patients and controls. ETH was significantly less in the IIH_TH than CMI (6.5 ± 2.4 mm vs. 10.9 ± 4.4 mm; p < 0.001). BTSS and HSR < 0.5 were more common in IIH_TH than CMI (p < 0.001 and p = 0.003, respectively). No differences were seen between CMI and controls. BTON was significantly more common in IIH_TH compared to control (p = 0.01) but not to the CMI (p = 0.36). Sensitivity and specificity to differentiate IIH_TH from CMI were 69.2% and 96.1% for BTSS and 69.2% and 75.3% for HSR < 0.5.

CONCLUSION

The presence of BTSS and/or HSR < 0.5 in patients with ETH ≥ 5 mm should suggest further evaluation to exclude IIH before considering CMI surgery.

Idiopathic Intracranial Hypertension: A Case Study of Patient Engagement in the Treatment of a Chronic Disease

Idiopathic intracranial hypertension is a rare neurological disorder characterized by increased intracranial pressure, which can lead to visual loss and headaches. While medical therapy exists, weight loss is the only disease-modifying treatment. Weight loss is the only therapy that leads to sustained resolution of papilledema. Involving the patient in their disease management through patient engagement is a way to improve disease outcomes, and strengthen the therapeutic relationship. This feature discusses an overview of the disease, a patient's experience, and a physician's perspective.

Case Report: Cerebrospinal Fluid Dynamics in the Optic Nerve Subarachnoid Space and the Brain Applying Diffusion Weighted MRI in Patients With Idiopathic Intracranial Hypertension—A Pilot Study

Purpose

The aim of this study was to examine the cerebrospinal fluid (CSF) flow rates in the subarachnoid space (SAS) of the optic nerve (ON) and the brain in patients with idiopathic intracranial hypertension (IIH) and papilledema (PE) compared to healthy controls by applying non-invasive diffusion-weighted MRI.

Methods

A retrospective analysis of diffusion-weighted MR images of 5 patients with IIH (10 ONs), mean age: 31 ± 10 years (5 women), and 11 healthy controls (22 ONs, mean age: 60 ± 13 years, 5 women) was performed. The flow velocity flow-range ratio (FRR) between the intracranial cavity and the SAS of the ON was calculated in both groups and then compared.

Results

The mean FRR was 0.55 ± 0.08 in patients with IIH and 0.63 ± 0.05 in healthy controls. The difference between patients with IIH and healthy controls was statistically significant (p < 0.05).

Conclusions

The CSF flow velocity was decreased in patients with IIH with PE compared to healthy controls. The reduced CSF flow dynamics might be involved in the pathophysiology of PE in IIH and diffusion-weighted MRI can be a useful non-invasive tool to study the CSF flow dynamics within the SAS ON.

Summary

Idiopathic intracranial hypertension is a neurological disease, where vision loss is the most feared complication of this disorder. The pathophysiology of IIH is not fully understood but is strongly linked to a reduced uptake of CSF into the central dural sinus veins. In this study, we examined the CSF flow rates in the SAS ON and the brain in patients with IIH and PE compared to healthy controls by applying non-invasive diffusion-weighted MRI. Knowing about the flow ratio of CSF may be of clinical relevance for the treatment decisions of IIH. If medical treatment fails, surgical options for lowering the ICP pressure need to be taken into consideration. As the primary goal of treatment is to prevent the loss of vision and visual field, it is important to know whether the communication of CSF between the intracranial CSF and the CSF in the perioptic space is intact. We showed that the CSF flow velocity was decreased in IIH patients with PE compared to healthy controls. The reduced CSF flow might be involved in the pathophysiology of PE in IIH, and diffusion-weighted MRI can be a useful non-invasive tool to study the CSF flow dynamics within the SAS ON.

The Influence of the Ventricular-Lumbar Gradient on Cerebrospinal Fluid Analysis in Serial Samples

Background: Cerebrospinal fluid (CSF) samples from patients with non-inflammatory neurological diseases are used for control groups in biomarker studies. Since large amounts of CSF are withdrawn, patients with idiopathic intracranial hypertension (IIH) or normal pressure hydrocephalus (NPH) are especially suitable. The serially taken CSF portions are usually collected in different tubes. We aimed to investigate whether the later random choice of one of these tubes for CSF investigations might harbor the risk of different CSF protein findings due to the so-called ventriculo-lumbar CSF gradient. Methods: Patients with IIH (9) and NPH (7) were included. CSF was serially taken and collected in six tubes of 5 mL each. Concentrations and CSF-serum quotients of immunoglobulins, albumin and the virus-specific antibody index (AI) were determined in the first, fourth and sixth CSF fraction. Results: CSF immunoglobulin and albumin concentrations and CSF-serum protein quotients were significantly lower in the fourth and sixth CSF fraction compared with the first CSF fraction. Virus-specific AI did not significantly differ in the different CSF fractions. Conclusions: CSF protein analytics should be performed in the first CSF fraction in order to avoid different measurement results and achieve comparability within a control group and between different control and patient groups.

Deep breathing couples CSF and venous flow dynamics

Venous system pathologies have increasingly been linked to clinically relevant disorders of CSF circulation whereas the exact coupling mechanisms still remain unknown. In this work, flow dynamics of both systems were studied using real-time phase-contrast flow MRI in 16 healthy subjects during normal and forced breathing. Flow evaluations in the aqueduct, at cervical level C3 and lumbar level L3 for both the CSF and venous fluid systems reveal temporal modulations by forced respiration. During normal breathing cardiac-related flow modulations prevailed, while forced breathing shifted the dominant frequency of both CSF and venous flow spectra towards the respiratory component and prompted a correlation between CSF and venous flow in the large vessels. The average of flow magnitude of CSF was increased during forced breathing at all spinal and intracranial positions. Venous flow in the large vessels of the upper body decreased and in the lower body increased during forced breathing. Deep respiration couples interdependent venous and brain fluid flow—most likely mediated by intrathoracic and intraabdominal pressure changes. Further insights into the driving forces of CSF and venous circulation and their correlation will facilitate our understanding how the venous system links to intracranial pressure regulation and of related forms of hydrocephalus.

Clinical features and the role of magnetic resonance imaging in pediatric patients with intracranial hypertension

Increased intracranial hypertension (IIH) is a defined clinical condition; however, an unsolved pathophysiologic background usually creates problems in its diagnosis and proper approach. The aim of this study was to emphasize the clinical conditions and brain magnetic resonce imaging (MRI) clues of pediatric patients, especially this clinical entity with high morbidity. Here, we review the etiology, clinical presentation, brain MRI findings, and prognosis of IIH in children. The symptoms' onset age ranged from 9 months to 16 years. Headache (81%), vomiting (37%), and diplopia (33.3%) were the most frequent symptoms. The most common etiologic factors were found to be obesity and dural venous sinus thrombosis. Cerebrospinal fluid (CSF) opening pressure had mean a mean value of 615.2 ± 248 mm H₂O. A significant relationship was found between visual field impairment and height of CSF pressure (p < 0.001). Optic nerve sheath enlargement (88.8%) and optic nerve tortuosity (85.1%) were found as the most common brain MRI findings. Slit-like ventricle (37%), venous sinus thrombosis (29.6%), posterior globe sclera flattening (29.6%), empty sella (25.9%), and intraocular protrusion of the optic nerve (14.8%) were the other findings. A significant relationship was found between CSF opening pressure and the presence of optic nerve tortuosity (p = 0.002), and distension of the optic nerve sheath (p = 0.006). All patients received acetazolamide, only one patient underwent lumboperitoneal shunt, and only one received steroids. In children, IIH can present with different etiologies and symptoms. Brain MRI provides crucial clues in diagnosis. Urgent diagnosis and treatment planning are required to protect vision functions.

Long-term telemetric intracranial pressure monitoring for diagnosis and therapy optimisation of idiopathic intracranial hypertension

Background

Idiopathic intracranial hypertension (IIH) is a disease which is difficult to diagnose and moreover difficult to treat. We developed a strategy for long-term telemonitoring of intracranial pressure (ICP), by incorporation of the NEUROVENT®-P-tel System, with the goal of improved diagnosis and consequent therapy of this disease. We highlight the results obtained through this approach.

Methods

Twenty patients with suspected IIH who were treated in our hospital from August 2014 to October 2020 (16 females, 4 males, median age 36,6 years), were assigned to one of two ICP monitoring settings, “Home-Telemonitoring” (n = 12) and “Home-Monitoring” (n = 8). The ICP data were analysed and used conjointly with the accompanying clinical picture for establishment of IIH diagnosis, and telemonitoring was resumed for therapy optimisation of confirmed cases.

Results

The diagnosis of IIH was confirmed in 18 of the 20 patients. Various surgical/interventional treatments were applied to the confirmed cases, including ventriculoperitoneal (VP) shunting (n = 15), stenting of the transvers venous sinus (n = 1), endoscopic third ventriculostomy (ETV) (n = 1), and ETV in combination with endoscopic laser-based coagulation of the choroid Plexus (n = 1). Optimal adjustment of the implanted shunt valves was achieved with an average valve opening pressure of 6,3 ± 2,17 cm H₂O for differential valves, and of 29,8 ± 3,94 cm H₂O for gravitational valves. The Home-Telemonitoring setting reduced consequent outpatient visits, compared to the Home-Monitoring setting, with an average of 3,1 visits and 4,3 visits, respectively. No complications were associated with the surgical implantation of the P-tel catheter.

Conclusion

This study offers insight into the use of long-term ICP monitoring for management of IIH patients in combination with dual-valve VP shunts. The use of NEUROVENT® P-tel system and potentially other similar fully implantable ICP-monitoring devices, albeit invasive, may be justified in this complex disease. The data suggest recommending an initial adjustment of dual-valve VP-shunts of 30 and 6 cm H₂O, for gravitational and differential valves, respectively. Further research is warranted to explore potential integration of this concept in IIH management guidelines.

Bariatric Surgery as a Viable Treatment for Idiopathic Intracranial Hypertension: a Case Series and Review of Literature

Purpose

Idiopathic intracranial hypertension is a significant cause of preventable blindness. Patients suffer from debilitating headaches, pulsatile tinnitus, nausea, vomiting, photophobia and radicular pain. At this rate, treatment cost will increase to 462.7 million pounds sterling annually by 2030. Weight loss is the only proven disease-modifying therapy for reversal of idiopathic intracranial hypertension. Bariatric surgery leads to superlative weight loss and reversal of related comorbidities. The case series and literature review aim to raise awareness of bariatric surgery as a safe and effective treatment modality for idiopathic intracranial hypertension.

Material and Methods

The literature review comprises three systematic analysis and one randomised control trial which were identified after a PubMed search. In the case series, we have included four patients with a preoperative diagnosis of long-standing idiopathic intracranial hypertension. They were referred to our department for bariatric surgery by the neuro-ophthalmologist between January and December 2018. They were followed up for 2 years after bariatric surgery.

Results

All four patients were women with a mean age of 34 years. Mean body mass index reduced from 47.3 kg/m² before surgery to 30 kg/m² at the end of 2 years after surgery. They showed significant improvement or resolution in their symptoms related to idiopathic intracranial hypertension, and none of them required further cerebrospinal fluid pressure reducing procedures.

Conclusion

Bariatric surgery is a safe and effective method of treating idiopathic intracranial hypertension. It is superior compared to medical management and cerebrospinal fluid pressure reducing procedures which have high rates of recurrence.

Case series of idiopathic intracranial hypertension in three patients with immune-complex glomerulonephritis

BACKGROUND

Idiopathic intracranial hypertension (IIH) is defined by an increased cerebrospinal fluid pressure in the absence of inflammation, structural obstructions, or mass lesions. Although the underlying pathogenesis of IIH is not fully understood, associations with specific risk factors as obesity, obstruction of cerebral venous sinuses, medications, endocrine or systemic conditions and chronic kidney disease have been described. Immune-complex glomerulonephritis as IgA-nephropathy is a frequent cause of chronic kidney failure, which was reported previously in one IIH patient. To date, there is no knowledge about the variable relation of immune-complex nephritis, kidney function and the course of IIH.

CASE PRESENTATION

We report three cases (two females) of concurrent diagnosis of IIH and immune-complex glomerulonephritis. All patients presented with typical IIH symptoms of headache and visual disturbances. Two patients had been diagnosed with IgA-nephropathy only few weeks prior to IIH diagnosis. The third patient had been diagnosed earlier with terminal kidney failure due to a cryoglobulin glomerulonephritis.

CONCLUSION

We propose a possible link between renal deposition of immune-complexes and increased cerebrospinal fluid pressure. Pathophysiological hypotheses and clinical implications are discussed. We recommend clinical awareness and further systematic research to obtain more information on the association of IIH and immune-complex glomerulonephritis.

Measurement of Choroid Thickness Using Optical Coherence Tomography to Monitor Intracranial Pressure in an Idiopathic Cranial Hypertension Model

Background

Idiopathic intracranial hypertension (IIH) is a condition with increased intracranial pressure (ICP) without mass lesion or a known etiology with normal cerebrospinal fluid (CSF) composition. With optical coherence tomography (OCT), which is a noninvasive imaging technique, cross-sectional scans of the retina, choroid, and optic nerve head can be obtained with a resolution that is close to histological resolution.

Aim

The study aimed to evaluate the efficacy of OCT in providing practical and sensitive measurements to follow-up patients with IIH.

Materials and Methods

This retrospective study included 22 patients with IIH and 22 healthy controls. OCT was used to measure peripapillary retinal nerve fiber layer thickness (RNFLT), ganglion cell layer (GCL) thickness and inner plexiform layer (IPL) thickness, and subfoveal choroidal thickness (CT). Lumbar puncture (LP) was performed to evaluate ICP. An association between subfoveal CT and ICP was noted in patients with IIH-a finding that has not been reported previously.

Results

Patients with IIH had increased RNFLT (P < 0.000) and CT (P < 0.000) compared with healthy controls. In addition, subfoveal CT was significantly correlated with ICP (r_s= 0.851; P < 0.000).

Conclusion

Measurement of CT by OCT, which reflects ICP, allows for the follow-up of patients with IIH. In addition, it can be used to monitor other diseases with high ICP.

Abnormal Intracranial Pulse Pressure Amplitude Despite Normalized Static Intracranial Pressure in Idiopathic Intracranial Hypertension Refractory to Conservative Medical Therapy

Idiopathic intracranial hypertension (IIH) incorporates symptoms and signs of increased intracranial pressure (ICP) and is diagnosed by increased lumbar cerebrospinal fluid pressure. However, our knowledge about the characteristics of ICP abnormality, e.g., changes in pulsatile versus static ICP, remains scarce. This study questioned how overnight pulsatile ICP (mean ICP wave amplitude, MWA) associates with static ICP (mean ICP) in IIH patients who were refractory to conservative medical treatment. The material included 80 consecutive IIH patients undergoing ICP monitoring prior to shunt, as part of work-up for failed conservative medical therapy. In this group, the overnight mean ICP was normalized in 52/80 patients, but with abnormal overnight MWA in 45 of the 52 patients. Even though there was a positive correlation between MWA and mean ICP at group level and within individual ICP recordings, the levels of MWA were abnormal in a high proportion of patients despite normalized mean ICP. Taken together, the present results disclosed lasting abnormal pulsatile ICP despite normalized static ICP in IIH patients refractory to conservative medical therapy, which may reflect the underlying pathophysiology. It is tentatively suggested that abnormal pulsatile ICP in IIH may reflect alterations at the glia-neurovascular interface, resulting in impaired astrocytic pulsation absorber mechanisms.

MRI-findings in idiopathic intracranial hypertension (Pseudotumor cerebri)

BACKGROUND

 Pseudotumor cerebri, also known as idiopathic intracranial hypertension, is a disorder of increased intracranial pressure of unknown etiology. Main symptom is headache which has a characteristic similar to other headache diseases, therefore the idiopathic intracranial hypertension often remains undetected. The incidence is 1/100 000 with the number of unreported cases being much higher. This article highlights the essential role of MRI in the differential diagnosis.

METHODS

 A literature search was carried out on idiopathic intracranial hypertension and Pseudotumor cerebri in English and German. Original and Review articles as well as case reports were taken into account. Since the main focus of the article is MRI diagnostics, some images were selected to illustrate the characteristic MRI morphological features.

RESULTS AND CONCLUSION

 The diagnosis of idiopathic intracranial hypertension is based on an exclusion procedure. Most common syndromes are headache, transient visual obscurations, pulsatile tinnitus and nausea. In the presence of an underlying cause for the increased intracranial pressure one speaks of a secondary intracranial hypertension. The diagnostics include a detailed medical history, neurological and ophthalmic examination, lumbar puncture, and neuroradiological imaging procedures. MRI, in particular, has become increasingly important in recent years, since signs for changes in cerebrospinal fluid pressure are now detectable and well-defined. The therapeutic approaches are symptom-oriented and aim to lower the pressure. With a precise diagnosis and timely start of therapy, idiopathic intracranial hypertension has a good prognosis, especially with regard to the preservation of eyesight.

KEY POINTS

  · The idiopathic intracranial hypertension is an important differential diagnosis for unspecific headache and impaired vision. · Overweight women in childbearing age are particularly affected. · The most important component in diagnostics is MRI.

CITATION FORMAT

· Juhász J, Hensler J, Jansen O. MRT-Befunde bei der idiopathischen intrakraniellen Hypertension (Pseudotumor cerebri). Fortschr Röntgenstr 2021; DOI: 10.1055/a-1447-0264.

Neurosurgical CSF Diversion in Idiopathic Intracranial Hypertension: A Narrative Review

The prevalence of idiopathic intracranial hypertension (IIH), a complex disorder, is increasing globally in association with obesity. The IIH syndrome occurs as the result of elevated intracranial pressure, which can cause permanent visual impairment and loss if not adequately managed. CSF diversion via ventriculoperitoneal and lumboperitoneal shunts is a well-established strategy to protect vision in medically refractory cases. Success of CSF diversion is compromised by high rates of complication; including over-drainage, obstruction, and infection. This review outlines currently used techniques and technologies in the management of IIH. Neurosurgical CSF diversion is a vital component of the multidisciplinary management of IIH.

Prepontine Shunting for Pseudotumor Cerebri in Previously Failed Shunt Patients: A 5-Year Analysis

BACKGROUND

Shunting procedures have a high failure rate when used to treat pseudotumor cerebri (PTC) patients who have failed medical therapy. This failure is believed to be attributable to the collapsibility of the ventricular system when exposed to increased differential pressure gradients in the cerebral spinal fluid compartments caused by ventriculoperitoneal shunts (VPS).

OBJECTIVE

To investigate whether prepontine/interpeduncular cistern shunting may be a reasonable alternative to VPS intervention in PTC patients with history of shunt failure. There have been no large series of cisternal-peritoneal shunt (CPS) patients in the PTC population.

METHODS

A retrospective review of 49 patients with placement of CPS for PTC with 2 failed prior shunting procedures was performed. Shunt survivability was based on shunt patency and resolution of ophthalmologic symptoms and cranial nerve deficits. All patients were followed for a minimum of 3 yr with serial ophthalmologic and neurosurgical evaluations.

RESULTS

At 3 yr, 44 of the 49 (88.9%) patients had working CPS. Three patients in this group had infections requiring complete shunt removal. Excluding infections, 44 of 46 (95.5%) shunts were functional at 3 yr. There were 3 small, asymptomatic hemorrhages that did not increase patient length of stay, and there were no catastrophic hemorrhages or strokes. There were also no abdominal complications related to shunt placement.

CONCLUSION

CPS is a viable alternative to VPS in PTC patients who have failed traditional shunting methods to give these patients a persistent benefit of a working shunt. The procedure provides this solution with low operative and perioperative morbidity.

Impaired glymphatic function in idiopathic intracranial hypertension

Idiopathic intracranial hypertension is a brain disease incorporating cerebrospinal fluid disturbance, increased intracranial pressure and visual failure, but with unknown cause. This study examined a hypothesis that glymphatic function is impaired in idiopathic intracranial hypertension patients. The MRI contrast agent gadobutrol was utilized as a cerebrospinal fluid tracer following intrathecal administration. Consecutive standardized T1 MRI acquisitions over 48 h were done to assess tracer distribution within brain of 15 idiopathic intracranial hypertension patients and 15 reference individuals who were comparable in age and gender distribution. Using FreeSurfer software, we semi-quantified tracer level in multiple brain regions as T1 MRI signal change. The tracer enriched the entire brain of idiopathic intracranial hypertension and reference subjects. In idiopathic intracranial hypertension, tracer enrichment was increased and clearance of tracer delayed from a wide range of brain regions, including both grey and white matter. Differences were most evident in frontal and temporal regions. The pulsatile intracranial pressure was measured overnight and tracer propagation in brain compared between individuals with pathological and normal pulsatile intracranial pressure. In individuals with pathological pulsatile intracranial pressure, tracer enrichment was stronger and clearance from brain delayed, particularly in regions nearby large artery trunks at the brain surface. The present in vivo observations provide evidence for impaired glymphatic function in several brain regions of idiopathic intracranial hypertension patients. Glymphatic failure may imply altered clearance of metabolic byproducts, which may precede neurodegeneration. Further studies are needed to characterize glymphatic failure in idiopathic intracranial hypertension.

MRI CSF flowmetry in evaluation of different neurological diseases

Background

Phase contrast MR imaging is a rapid and non-invasive technique which is sensitive in diagnosis and follow-up of different neurological diseases that cause CSF flow abnormality. MRI CSF flowmetry will be currently assessed in different neurological diseases that may cause CSF flow abnormalities.

Results

This study includes 39 patients with their ages ranging from 1 to 65 years; they were referred from the neurology department, with nine individuals of matched age and sex as a control group. Based on clinical history and conventional MRI, patients were subdivided into five subgroups; normal pressure hydrocephalus (NPH), hydrocephalus, idiopathic intracranial hypertension (IIH), brain atrophy (BA), and Chiari malformation type I (CM-I). All patients and control were subjected to MRI CSF flowmetry evaluation with stress on peak diastolic velocity (PDV), peak systolic velocity (PSV), stroke volume (SV), and maximum velocity (Vmax). PDV, PSV, and SV were found significantly higher in NPH, CM-I, and hydrocephalus compared to control (4.2, 4.96, and 83.23 for NPH; 3.95, 4.93, and 37.38 for CM-I; and 4.2, 5.6, and 125 in hydrocephalus versus 2.11, 2.73, and 75.33 in control, respectively; P = 0.0004, 0.0008, and 0.0009 for NPH; 0.03, 0.003, and 0.06 for CM-I; and 0.0005, 0.0002, and 0.0003, respectively). On the other hand, patients with BA showed significantly lower values (1.37, 1.66, and 1.53, respectively) compared to control (P = 0.001, 0.001, and 0.004, respectively).

Conclusion

MRI CSF flowmetry provides an easy, accurate, and non-invasive method for diagnosis of different neurological diseases that cause CSF flow abnormality. Moreover, this diagnostic modality could be helpful in selecting the therapeutic option.

Association between Optical Coherence Tomography Measurements and Clinical Parameters in Idiopathic Intracranial Hypertension

Purpose

To correlate optical coherence tomography (OCT) measurements with clinical parameters in idiopathic intracranial hypertension (IIH).

Methods

A cross-sectional study was conducted with 22 patients with IIH and 11 controls. All participants underwent comprehensive ophthalmological examination followed by spectral-domain OCT (SD-OCT) and standard automated perimetry using the 30–2 program of the Humphrey visual field analyzer. Correlations between ganglion cell complex (GCC) thickness and retinal nerve fiber layer (RNFL) thickness, as measured by SD-OCT, and clinical parameters were assessed using generalized estimating equations.

Result

The mean age of the participants was 35.0 ± 10.83 years. The groups were similar regarding age, but were significantly different regarding sex and visual acuity (p=0.001 and p=0.038, respectively). The GCC was significantly thinner in the IIH group, with a mean of 90.535 ± 9.766 μm compared to 98.119 ± 6.988 μm for the controls (p=0.023). There was a significant association between GCC thickness and optic disc pallor (p=0.016) and between edema and visual acuity (p=0.037). No significant difference was found in RNFL thickness between patients and controls.

Conclusion

The GCC was thinner in the patients with IIH compared to the controls, and there was an association between GCC and optic disc pallor. This might suggest a role for OCT parameters when the structural changes that occur in IIH are investigated, possibly guiding clinical decision making.

Pseudotumor cerebri syndrome in a child with Alagille syndrome: intracranial pressure dynamics and treatment outcome after ventriculoperitoneal shunting

Alagille syndrome (AS) is a rare multisystem disease of the liver, heart, eyes, face, skeleton, kidneys, and vascular system. The occurrence of pseudotumor cerebri syndrome (PTCS) in patients with AS has been reported only exceptionally. Owning to its rarity and a mostly atypical presentation, the diagnosis and natural history of affected patients remain uncertain. We report an atypical case of PTCS in a 4-year-old boy with a known history of AS who presented with bilateral papilledema (PE) on a routine ophthalmological examination. Visual findings deteriorated after treatment with acetazolamide. Continuous intracranial pressure (ICP) monitoring was then utilized to investigate ICP dynamics. Successful treatment with resolution of PE was achieved after ventriculoperitoneal shunting but relapsed due to growth-related dislocation of the ventricular catheter. This report brings new insights into the ICP dynamics and the resulting treatment in this possibly underdiagnosed subgroup of PTCS patients. It also demonstrates that ventriculoperitoneal shunting can provide long-term improvement of symptoms for more than 10 years.

Familial Idiopathic Intracranial Hypertension in Two Non-obese Chinese Sisters

Background: Familial idiopathic intracranial hypertension (FIIH) is a rare condition, the etiology of which is unclear.

Aims: To describe two non-obese Chinese sisters who met the criteria of FIIH and to analyze the clinical features and prognosis of FIIH.

Methods: The clinical course, treatment, and prognosis of these two patients were analyzed retrospectively. Meanwhile, all the literature of familial IIH (FIIH) was reviewed.

Results: These two sisters presented with headaches and visual impairment in their mid-thirties. Magnetic resonance imaging (MRI) of the brain was unremarkable except for partial empty sella. No comorbidities or defined causes were detected. Headaches were partially relieved by dehydrated medicine, whereas the visual impairment persisted.

Conclusion: In cases where patients present with headaches, empty sella are found on an MRI, and there is visual impairment with or without papilla edema, intracranial hypertension should be excluded. Furthermore, we should pay more attention to the relatives of those patients with increased intracranial hypertension.

Increased occurrence of pathological mitochondria in astrocytic perivascular endfoot processes and neurons of idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) primarily affects fertile, overweight women, and presents with the symptoms of raised intracranial pressure. The etiology is unknown but has been thought to relate to cerebrospinal fluid disturbance or cerebral venous stenosis. We have previously found evidence that IIH is also a disease of the brain parenchyma, evidenced by alterations at the neurogliovascular interface, including astrogliosis, pathological changes in the basement membrane and pericytes, and alterations of perivascular aquaporin‐4. The aim of this present electron microscopic study was to examine whether mitochondria phenotype was changed in IIH, particularly focusing on perivascular astrocytic endfeet and neurons (soma and pre‐ and postsynaptic terminals). Cortical brain biopsies of nine reference individuals and eight IIH patients were analyzed for subcellular distribution and phenotypical features of mitochondria using transmission electron microscopy. We found significantly increased prevalence of pathological mitochondria and reduced number of normal mitochondria in astrocytic endfeet of IIH patients. The degree of astrogliosis correlated negatively with the number of normal mitochondria in astrocytic endfoot processes. Moreover, we found significantly increased number of pathological mitochondria in pre‐ and postsynaptic neuronal terminals, as well as significantly shortened distance between mitochondria and endoplasmic reticulum contacts. Finally, the length of postsynaptic density, a marker of synaptic strength, was on average reduced in IIH. The present data provide evidence of pathological mitochondria in perivascular astrocytes endfeet and neurons of IIH patients, highlighting that impaired metabolism at the neurogliovascular interface may be a facet of IIH.

Blood-Brain Barrier Dysfunction in Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is traditionally considered benign and characterized by symptoms related to increased intracranial pressure, including headache and impaired vision. We have previously demonstrated that brains of IIH patients exhibit patchy astrogliosis, increased perivascular expression of the water channel aquaporin-4 (AQP4) as well as degenerating pericyte processes and capillary basement membranes. Given the established association between pericyte degeneration and blood-brain barrier (BBB) dysfunction, we investigated blood protein leakage by light microscopic immunohistochemistry. We also assessed perivascular AQP4 expression by immunogold transmission electron microscopy. The study included 14 IIH patients and 14 reference (REF) subjects undergoing neurosurgery for epilepsy, aneurysm, or tumor. Evidence of BBB dysfunction, measured as area extravasated fibrinogen/fibrin, was significantly more pronounced in IIH than REF individuals. The extent of extravasated fibrinogen was positively correlated with increasing degree of astrogliosis and vascular AQP4 immunoreactivity, determined by light microscopy. Immunogold transmission electron microscopy revealed no overall changes in AQP4 expression at astrocytic vascular endfeet in IIH (n = 8) compared to REF (n = 11) individuals. Our results provide evidence of BBB leakage in IIH, signifying that IIH is a more serious neurodegenerative disease than previously considered.

Cerebrospinal Fluid Pressure Reduction Results in Dynamic Changes in Optic Nerve Angle on Magnetic Resonance Imaging

BACKGROUND

Optic nerve sheath tortuosity is a previously reported, but incompletely characterized, finding in idiopathic intracranial hypertension (IIH). We hypothesized that optic nerve angle (ONA), as a quantitative measure of tortuosity, would change dynamically with cerebrospinal fluid (CSF) pressure status of patients with IIH immediately before and after lumbar puncture (LP).

METHODS

Consecutive patients with suspected IIH referred for MRI and diagnostic LP were prospectively enrolled in this single institution, institutional review board-approved study. Each patient underwent a pre-LP MRI, diagnostic LP with opening pressure (OP) and closing pressure (CP), and then post-LP MRI all within 1 session. Sagittal and axial ONAs were measured on multiplanar T2 SPACE images by 2 neuroradiologists on pre- and post-LP MRI. Effects of measured pressure and CSF volume removal on changes in ONA were analyzed as was interrater reliability for ONA measurement.

RESULTS

Ten patients with IIH were included {all female, median age 29 (interquartile range [IQR] 25-32)}. All patients had elevated OP (median 37, IQR 34-41 cm H2O), and significantly reduced CP (median 18, IQR 16-19 cm H2O, P < 0.001) after CSF removal (IQR 13-16 mL). Within patients, mean ONAs (sagittal and axial) were significantly lower before (162 ± 9°, 163 ± 10°) than after (168 ± 7°, 169 ± 5°) LP (P = 0.001, 0.008, respectively). Interrater reliability was higher with sagittal ONA measurements (0.89) than axial (0.72).

CONCLUSIONS

ONA changes with short-term CSF pressure reduction in patients with IIH, establishing optic nerve tortuosity as a dynamic process related to CSF status.

An update on idiopathic intracranial hypertension in adults: a look at pathophysiology, diagnostic approach and management

Idiopathic intracranial hypertension is a neurological syndrome determined by a rise in intracranial pressure without a detectable cause. Course and prognosis may be changeable, requiring a multidisciplinary approach for its diagnosis and management. Although its precise pathogenesis is still unknown, many studies have been carried out to define the possible causal and associated factors, such as retinoids, steroid hormones, body mass index and recent weight gains, cytokines and adipokines levels. The clinical presentation can be variable including chronic headache, disturbance of vision, diplopia and tinnitus. Even if papilloedema is considered the most specific sign, it could not be observed in more than 5% of patients during the evaluation of the fundus oculi. Neuroradiological signs acquire greater importance in patients who do not present papilloedema and may suggest the diagnosis of idiopathic intracranial hypertension. Other assessments can be useful in the diagnostic process, such as optical coherence tomography, visual evoked potentials, ocular ultrasonography and fundus fluorescein angiography and autofluorescence. Nonetheless, cerebrospinal fluid pressure measurement is required to establish a definite diagnosis. Management may be different, since surgical procedures or lumbar punctures are often required when symptoms develop rapidly leading to a loss of visual function. Apart from these cases, patients can be treated with a pharmacological approach and low-calorie diet, but they also need to be monitored over time since relapses years later are not uncommon.

Idiopathic intracranial hypertension and bariatric surgery: a systematic review

Background

Idiopathic intracranial hypertension (IIH) is a rare condition typically affecting women with obesity who are of child-bearing age. Patients commonly present with headaches, visual disturbances, pulsatile tinnitus and papilledema. The association between IIH and obesity has been well established in the literature, suggesting that weight loss may contribute to improving IIH. For patients with severe obesity for whom conservative management is not successful, bariatric surgery is an effective modality for weight loss. We aimed to systematically review the literature to determine the efficacy of bariatric surgery in the treatment of IIH

Methods

We conducted a comprehensive search of MEDLINE, Embase, Scopus, the Cochrane Library and Web of Science (limited to studies in humans published in English between January 1946 and July 2015).

Results

Twelve primary studies (n = 39 patients) were included in the systematic review. All patients had a preoperative diagnosis of IIH. Preoperative body mass index (BMI) was 47.4 ± 3.6 kg/m2 ; BMI improved to 33.7 ± 2.1 kg/m2 and 33.9 ± 11.6 kg/m2 at 6 and 12 months postoperatively, respectively. Lumbar puncture opening pressures decreased from 34.4 ± 6.9 cmH2O to 14.0 ± 3.6 cmH2O after surgery. Common symptoms of IIH improved after bariatric surgery: headaches (100% preoperatively v. 10% postoperatively), visual complaints (62% v. 44%), tinnitus (56% v. 3%) and papilledema (62% v. 8%).

Conclusion

Bariatric surgery appears to lead to considerable improvement in IIH. Idiopathic intracranial hypertension is not a well-publicized comorbidity of obesity, but its presence may be considered as an indication for bariatric surgery.

Aquaporin 1 and the Na+/K+/2Cl- cotransporter 1 are present in the leptomeningeal vasculature of the adult rodent central nervous system

Background

The classical view of cerebrospinal fluid (CSF) production posits the choroid plexus as its major source. Although previous studies indicate that part of CSF production occurs in the subarachnoid space (SAS), the mechanisms underlying extra-choroidal CSF production remain elusive. We here investigated the distributions of aquaporin 1 (AQP1) and Na⁺/K⁺/2Cl⁻ cotransporter 1 (NKCC1), key proteins for choroidal CSF production, in the adult rodent brain and spinal cord.

Methods

We have accessed AQP1 distribution in the intact brain using uDISCO tissue clearing technique and by Western blot. AQP1 and NKCC1 cellular localization were accessed by immunohistochemistry in brain and spinal cord obtained from adult rodents. Imaging was performed using light-sheet, confocal and bright field light microscopy.

Results

We determined that AQP1 is widely distributed in the leptomeningeal vasculature of the intact brain and that its glycosylated isoform is the most prominent in different brain regions. Moreover, AQP1 and NKCC1 show specific distributions in the smooth muscle cell layer of penetrating arterioles and veins in the brain and spinal cord, and in the endothelia of capillaries and venules, restricted to the SAS vasculature.

Conclusions

Our results shed light on the molecular framework that may underlie extra-choroidal CSF production and we propose that AQP1 and NKCC1 within the leptomeningeal vasculature, specifically at the capillary level, are poised to play a role in CSF production throughout the central nervous system.

“Benign intracranial hypertension” is a misleading name for a more serious disease: analysis of the visual outcome in cases with idiopathic intracranial hypertension

Objective

Assessment of visual field outcomes following the medical or surgical management of increased intracranial pressure in patients with idiopathic intracranial hypertension.

Patient and methods

Thirty-two patients diagnosed with idiopathic intracranial hypertension who met all the modified Dandy criteria were included in this study. Magnetic resonance brain imaging with contrast and magnetic resonance venography were performed to exclude the presence of secondary causes of intracranial hypertension. Following normal neuroimaging, a lumbar puncture was performed for all patients with papilledema to measure the cerebrospinal fluid opening pressure. The assessment of visual function, including visual acuity, fundus examination (dilated fundus examination to confirm the presence and the grade of papilledema and to exclude the other ocular causes of optic disc swelling), and formal visual field assessment by perimetry when visual acuity was more than 1/60 were performed by the ophthalmologist before and after medical or surgical treatment.

Results

Thirty-two patients were included, the majority of whom were females of childbearing age (29/32; 90.6%). All patients complained of headache. Visual assessment revealed the presence of blurry vision in all patients. Papilledema with different grades was observed in 31/32 (96.9%) patients, while the other patient (3.1%) showed optic atrophy; 30/32 (93.8%) patients had visual acuity ˃ 1/60. The average visual field was − 18 dB ± 9.97 SD in the right eye and − 19.47 dB ± 5.43 SD in the left eye. Twenty-nine patients received medical treatment in the form of acetazolamide, which succeeded in controlling idiopathic intracranial hypertension in 24/29 (82.7%) patients, while a theco-peritoneal shunt was inserted in 8/32 (25%) patients. After management, statistically significant improvements in cerebrospinal fluid opening pressure, presenting manifestation, visual acuity, and field were noticed.

Conclusions

Permanent visual loss is the most feared complication of idiopathic intracranial hypertension; therefore, early diagnosis and multidisciplinary treatment are necessary to improve visual acuity and visual field.