Assessment of glymphatic dysfunction in pediatric idiopathic intracranial hypertension: insights from quantitative diffusivity and perivascular spaces analysis-a case-control study

Background

The impaired drainage of cerebrospinal fluid through the glymphatic system is thought to play a role in the idiopathic intracranial hypertension (IIH) pathophysiology. Limited data exist regarding the glymphatic system's involvement in pediatric patients with IIH. Therefore, the study's objective was to quantitatively evaluate alterations in parenchymal diffusivity and magnetic resonance imaging (MRI)-visible dilated perivascular spaces (PVS) as imaging indicators of glymphatic dysfunction in pediatric patients with IIH.

Methods

Patients diagnosed with IIH in 2017-2022 in a single tertiary center (Sheba Medical Center, Israel) were retrospectively reviewed. Twenty-four pediatric patients were enrolled. All patients underwent clinical 3-T brain MRI. The control group included 24 age- and gender-matched healthy subjects with a normal-appearing brain on imaging. We used automatic atlas-based diffusion-weighted imaging analysis to determine regional diffusivity of the thalamus, caudate, putamen, globus pallidus, hippocampus, amygdala, and brain stem. PVS were evaluated using a semi-quantitative rating scale on T2-weighted images. Variables were compared using the Mann-Whitney test. Multivariate analysis of covariance was used to test for differences between controls and IIH patients.

Results

No significant differences in regional brain diffusivity were observed between individuals with IIH and healthy controls (P=0.14-0.91 for various brain regions). The number of visible PVS was comparable between patients with IIH and the control group across all evaluated sites (P=0.12-0.74 for various brain regions).

Conclusions

Pediatric IIH patients exhibited similar patterns of parenchymal diffusivity and PVS compared to age-matched controls. These findings do not support the hypothesis that the glymphatic system may play a role in the pathophysiology of pediatric IIH, although previously postulated. However, employing more sophisticated magnetic resonance (MR) techniques could enhance the sensitivity in uncovering underlying glymphatic dysfunction. Further research is warranted to validate and explore this association in larger cohorts and investigate the underlying mechanisms involved in IIH.

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 peripheral and central olfactory regions by MRI in patients with idiopathic intracranial hypertension

OBJECTIVES

We investigated the peripheral and central smell regions in patients with idiopathic intracranial hypertension (IIH) by cranial MRI.

METHODS

In this retrospective study, cranial MRI images of 43 adult patients with IIH (Group 1) and 43 healthy adults without IIH (Group 2) were included. In both groups, peripheral [Olfactory bulb (OB) volume and Olfactory sulcus (OS) depth] and central smell regions (insular gyrus and corpus amygdala area, and thalamus volume) were measured in cranial MRI.

RESULTS

Bilateral OB volume and insular gyrus area, and right corpus amygdala and thalamus volumes of the IIH group were significantly lower than those of the control group (p < 0.05). In the IIH group, OB volume of the right side was significantly lower, and insular gyrus area of the right side was significantly higher than those of the left side (p < 0.05). In the IIH group, there were positive correlations between OB volumes; OS depths; insular gyrus areas; corpus amygdala areas; and thalamus volumes bilaterally (p < 0.05). In older patients, right OS depth and right corpus amygdala area decreased (p < 0.05).

CONCLUSION

In conclusion, IIH may be related to olfactory impairment. Cranial MRI images showed a decrease in peripheral (OB volume) and central (insular gyrus and corpus amygdala area and thalamus volume) smell regions. To prevent olfactory impairment in IIH patients, treatment should be done in IIH patients to decrease intracranial pressure. It is very important to prevent the circulation of CSF with increased pressure between the sheets of the olfactory nerve in IIH patients.

Sleep Disturbances in Adolescents With Idiopathic Intracranial Hypertension

BACKGROUND

We aimed to assess the presence of sleep disturbances in adolescents with idiopathic intracranial hypertension (IIH) and to determine whether demographic, anthropometric, and clinical factors are associated with disrupted sleep.

METHODS

Sleep disturbances and patterns were evaluated in a cohort of adolescents (aged 12 to 18 years) with ongoing IIH and compared with a healthy age- and sex-matched control group. All participants responded to three self-rating questionnaires: the School Sleep Habits Survey (SSHS), the Pediatric Sleep Questionnaire (PSQ), and the Depression, Anxiety, and Stress Scale. The study group's demographic, clinical, laboratory, and radiological data were documented, and their association with sleep patterns was examined.

RESULTS

Thirty-three adolescents with ongoing IIH and 71 healthy controls were included. There was a significantly higher prevalence of sleep disturbances in the IIH group compared with the controls (SSHS, P < 0.001 and PSQ, P < 0.001), as well as of their independent subscales: sleep-related breathing disorders (P = 0.006), daytime sleepiness (P = 0.04), sleep/wake disruptions (P < 0.001), and sleep-related depressive tendencies (P < 0.001). According to subgroup analyses, these differences were also present between the normal-weight adolescents but not between the overweight IIH and control adolescents. No differences were found in the demographic, anthropometric, and IIH disease-related clinical measures between individuals with IIH with disrupted and normal sleep patterns.

CONCLUSIONS

Sleep disturbances are common among adolescents with ongoing IIH, irrespective of their weight and disease-related characteristics. Screening adolescents with IIH for sleep disturbances is recommended as part of their multidisciplinary management.

Anatomic Variation of the Lateral Sinus in Patients With Idiopathic Intracranial Hypertension: Delineation With Black-Blood Contrast-Enhanced MRI

Objectives: The purpose of this study was to describe the peculiar anatomic variations in the lateral sinus and analyze the patterns of cerebrospinal fluid (CSF) drainage by using high-resolution (HR) black-blood (BB) contrast-enhanced magnetic resonance imaging (MRI) in patients with idiopathic intracranial hypertension (IIH).

Methods: Total 33 IIH patients who were found cerebral venous sinus stenosis (CVSS) by MR venography (MRV) were enrolled in this study. HR-BB contrast-enhanced MRI was used to assess the features of anatomical variations in transverse sinus and sigmoid sinus. The development of bilateral sinuses was firstly evaluated, including unilateral hypoplasia with contralateral dominance or bilateral balanced development. Then, four kinds of anatomical variations were eventually recorded, including circumscribed stenosis, arachnoid granulation (AG), fibrous septum (FS), and brain herniation (BH) into dural venous sinus (DVS).

Results: Bilateral venous drainage dysfunction was found in 30(90.9%) patients, whereas only 3(9.1%) patients presented unilateral venous drainage dysfunction. There was no difference in clinical symptoms between the two groups. The most common case is hypoplasia in unilateral sinus combined with anatomic variation in the contralateral dominant transverse sinus such as AG and BH into DVS. Total of 52 anatomic variations were finally found in bilateral sinuses in 33 enrolled patients, including 19(36.5%)AGs, 12(23.1%)FS, 7(13.5%) BH into DVS and 14(26.9%) circumscribed stenoses. Moreover, 41(62.1%) lateral sinuses showed enhancement in T1-weight-enhanced MRI.

Conclusions: Patients with CVSS almost had CSF outflow disorders, whatever bilateral equalization or unilateral hypoplasia with contralateral dominance. Four types of main anatomic variations, including circumscribed stenosis, AG, FS, and BH into DVS, caused venous reflux obstruction by elevating the intracranial press (ICP).

Diagnosis and treatment of idiopathic intracranial hypertension

Objective

To review and discuss the clinical presentation and treatment of idiopathic intracranial hypertension.

Discussion

Visual alterations and headache are the two main symptoms of idiopathic intracranial hypertension, although additional features including cranial nerve palsies, cognitive deficits, olfactory deficits and tinnitus are not uncommon. The headache associated with idiopathic intracranial hypertension frequently has a migrainous phenotype. The underlying cause of the disorder has not yet been elucidated. Several hypotheses have been postulated but none of them can explain the full clinical picture. Therapeutic options remain limited, focusing mainly on reduction in body weight and the reduction of CSF production with carbonic anhydrase inhibitors.

Conclusion

The accurate diagnosis of idiopathic intracranial hypertension is essential as visual deterioration due to papilledema may be irreversible. Given its phenotypic similarity and frequent overlap with chronic migraine it is essential to consider idiopathic intracranial hypertension in the diagnostic workup of chronic headache; in particular, when considering its increasing prevalence. Understanding in detail the pathophysiological mechanisms behind the associated headache would also allow study of current and future therapeutic options in a structured way.

Outcome of idiopathic intracranial hypertension after laparoscopic sleeve gastrectomy

BACKGROUND

Idiopathic intracranial hypertension (IIH) predominantly affects young, obese women and presents with signs and symptoms of increased intracranial pressure, such as headaches and visual impairment.

OBJECTIVE

We aim to present our experience in the management of IIH.

SETTING

University Hospital.

METHODS

Obese IIH patients who had a laparoscopic sleeve gastrectomy during the study period (2 years) were included. Data were retrieved from prospectively collected database. Headaches, visual alterations, and medications or interventions used to treat are discussed.

RESULTS

The study included 16 obese women with IIH. Mean age was 31 ± 2 years (range, 25-44 yr) and mean body mass index was 46 ± 4 kg/m² (range, 42-53 kg/m²). Main symptoms and signs were chronic headaches (14), impaired vision (15), vision loss (1), papilledema (6), and field defects in 4 patients. Symptoms were present for a mean of 5 years (4-11). History of medical treatment with carbonic anhydrase inhibitor (acetazolamide) and thecoperitoneal shunting was present in 12 and 9 patients, respectively. Mean lumbar puncture opening pressure was 41.2 ± 21- (range, 30-64) cm water. At 12 months after laparoscopic sleeve gastrectomy, body mass index and percentage excess weight loss were 27.8 ± 1 kg/m² and 75.2 ± 2%, respectively. Symptoms gradually improved with complete resolution in all but 2 patients (87.5%).

CONCLUSION

The present work emphasizes the role of bariatric surgery in the management of obese patients with IIH. Larger, prospective, controlled studies are needed.

Psychiatric disorders are a common prognostic marker for worse outcome in patients with idiopathic intracranial hypertension

OBJECTIVE

Idiopathic intracranial hypertension (IIH) is aetiologically unknown disorder that associates with endocrinological disturbances, including dysfunction of hypothalamic-pituitary-adrenal-axis. Neuroendocrinological dysfunctions have also been characterized in psychiatric disorders, and therefore we investigated the presence of psychiatric disorders of patients with IIH in a well-defined cohort.

PATIENTS AND METHODS

A total of 51 patients with IIH were included. Patient demographics, symptoms, imaging data, ophthalmological and clinical findings were collected.

RESULTS

At the time of diagnosis the mean age was 32.5years (SD 10.7), the body mass index was 37.1 kg/m² (SD 7.4), and the opening pressure 29.1 mmHg (SD 6.2). A total of 88.2% of patients were female and 45.1% were diagnosed with a psychiatric co-morbidity prior to IIH diagnosis. The mean follow-up time was 4.4 years (SD 5.4). The overall treatment outcome was significantly poorer on a group of patients with psychiatric diagnosis when compared to individuals without such history (p = 0.001), but there were no differences in the resolution of papilledema (p = 0.405). Patients with IIH and psychiatric disorders had more often empty sella on their imaging at diagnosis when compared to patients without psychiatric co-morbidity (p = 0.044).

CONCLUSION

Psychiatric disorders are highly prevalent in patients with IIH and associate with worse subjective outcomes. These findings advocate for monitoring the mental health of patients with IIH and warrant further multidisciplinary research to understand the potentially underlying psychosocial and neuroendocrinological mechanisms.

Dural venous sinus stenting for idiopathic intracranial hypertension: An updated review

BACKGROUND

Dural venous sinus stenting (DVSS) is an accepted treatment option in selected patients with medically refractory idiopathic intracranial hypertension and obstructive venous outflow physiology prior to cerebrospinal flow diversion (CSFD) surgery. There are no randomized controlled studies focusing on outcomes and complication rates for dural venous sinus stenting.

PURPOSE

We present the largest comprehensive meta-analysis on DVSS for idiopathic intracranial hypertension (IIH) focusing on success rates, complications, and re-stenting rates to date. We also present a simplified approach to direct retrograde internal jugular vein (IJ) access for DVSS that allows for expedited procedures.

MATERIALS AND METHODS

We performed a retrospective electronic PubMed query of all peer-reviewed articles in the last 15 years between 2003 to 2018. We included all patients who underwent dural venous sinus stenting for a medically refractive IIH and excluded articles without sufficient data on outcomes, complication rates and re-stenting rates. We also evaluated and compared outcomes in patients undergoing direct retrograde IJ access DVSS to traditional transfemoral vein access.

RESULTS

A total of 29 papers and 410 patients who underwent DVSS met criteria for inclusion. DVSS was associated with high technical success [99.5%], low rates of repeated procedure [10%], and low major complication rates [1.5%].

CONCLUSION

Our retrospective comprehensive review of DVSS for medically refractory IIH suggests that stenting in appropriately chosen patients is associated with low complication rates, high technical success, and low repeat procedure rates.

Magnetic resonance elastography to estimate brain stiffness: Measurement reproducibility and its estimate in pseudotumor cerebri patients

This study determines the reproducibility of magnetic resonance elastography (MRE) derived brain stiffness in normal volunteers and compares it against pseudotumor patients before and after lumbar puncture (LP). MRE was performed on 10 normal volunteers for reproducibility and 14 pseudotumor patients before and after LP. During LP, opening and closing cerebrospinal fluid (CSF) pressures were recorded before and after removal of CSF and correlated to brain stiffness. Stiffness reproducibility was observed (r > 0.78; p < 0.008). Whole brain opening LP stiffness was significantly (p = 0.04) higher than normals, but no significant difference (p = 0.11) in closing LP measurements. No significant correlation was observed between opening and closing pressure and brain stiffness.

Imaging of Cerebrospinal Fluid Rhinorrhea and Otorrhea

As the obesity epidemic grows in the United States, rhinorrhea and otorrhea from spontaneous cerebrospinal fluid (CSF) leaks secondary to untreated idiopathic intracranial hypertension are increasing in prevalence. CSF rhinorrhea and otorrhea should also be carefully evaluated in posttraumatic and postsurgical settings, because untreated CSF leaks often have serious consequences. The work-up, diagnosis, and characterization of a CSF leak can be complex, often requiring a multimodality approach to optimize surgical planning. This article reviews the causes of CSF leaks, describes the methodology used to work up a suspected leak, and discusses the challenges of making an accurate diagnosis.

Intracranial hypertension secondary to high dose cytosine arabinoside - A case study

We report a rare case of intracranial hypertension following high dose cytosine arabinoside (HiDAC) in a 20-year-old man, with precursor B-cell acute lymphoblastic leukemia (ALL). A five drug induction protocol for ALL was initiated; post induction consolidation was with HiDAC (3 g/m² IV every 12 h on days 1, 3 and 5). Post consolidation, cytogenetic remission was attained and he received an intensification and maintenance regimen for ALL, for a period of approximately 24 months. Four months following the completion of his treatment, the patient relapsed within the central nervous system (CNS). Intravenous salvage chemotherapy was initiated using a combination of fludarabine 30 mg/m², followed by cytarabine 2 g/m² 4 h later on days 1 through 5 (FA). On day # 23 of FA, he developed a severe headache. A gadolinium-enhanced brain magnetic resonance imaging (MRI) revealed increased intracranial pressure. On day # 25, ophthalmology examination suggested bilateral papilledema. He was started on acetazolamide 250 mg twice daily. He had spontaneous resolution of his symptoms. The patient had no recurrence of papilledema or any other neurological symptoms. Intracranial hypertension secondary to HiDAC, is an exceedingly rare complication and is not regularly associated as a common side effect of cytarabine administration. Prompt action in diagnosing and treating intracranial hypertension will save the patient from consequences, such as loss of vision, that are prevalent in this condition.

Elevated intracranial pressure causes optic nerve and retinal ganglion cell degeneration in mice

The purpose of this study was to develop a novel experimental system for the modulation and measurement of intracranial pressure (ICP), and to use this system to assess the impact of elevated ICP on the optic nerve and retinal ganglion cells (RGCs) in CD1 mice. This system involved surgical implantation of an infusion cannula and a radiowave based pressure monitoring probe through the skull and into the subarachnoid space. The infusion cannula was used to increase ICP, which was measured by the probe and transmitted to a nearby receiver. The system provided robust and consistent ICP waveforms, was well tolerated, and was stable over time. ICP was elevated to approximately 30 mmHg for one week, after which we assessed changes in optic nerve structure with transmission electron microscopy in cross section and RGC numbers with antibody staining in retinal flat mounts. ICP elevation resulted in optic nerve axonal loss and disorganization, as well as RGC soma loss. We conclude that the controlled manipulation of ICP in active, awake mice is possible, despite their small size. Furthermore, ICP elevation results in visual system phenotypes of optic nerve and RGC degeneration, suggesting that this model can be used to study the impact of ICP on the visual system. Potentially, this model can also be used to study the relationship between ICP and IOP, as well diseases impacted by ICP variation such as glaucoma, idiopathic intracranial hypertension, and the spaceflight-related visual impairment intracranial pressure syndrome.

Idiopathic intracranial hypertension in the Middle East: A growing concern

Idiopathic Intracranial Hypertension (IIH) is a disorder of increased intracranial pressure without any identifiable etiology. It is defined by elevated intracranial pressure (ICP) with normal neuroimaging and normal cerebrospinal fluid (CSF) contents. IIH typically affects young obese women and produces symptoms and signs related to high ICP. Headache and blurred vision are the most common symptoms, and papilledema is the major clinical sign. In this review we examine the epidemiology and demographic features of IIH in Middle Eastern countries and compare and contrast them with the published IIH literature from Western countries. The incidence of IIH in several Middle East countries has been estimated at 2.02-2.2/100,000 in the general population, which is higher than the Western rate. Obesity is a major risk factor globally and it is associated with an increased risk of severe vision loss due to IIH. There has been an increase in obesity prevalence in the Middle East countries mainly affecting the Gulf Council Countries (GCC), which parallels increased industrial development. This rise may be contributing to the increasing incidence of IIH in these countries. Other risk factors may also be contributing to IIH in Middle East countries and the differences and similarities to Western IIH merit further study.

Bilateral transverse sinus stenosis in patients with tinnitus

Tinnitus is a frequent complaint in patients affected by intracranial hypertension (IH). Recently, some studies have reported an association between idiopathic intracranial hypertension (IIH) and bilateral transverse sinus stenosis (BTSS). We investigated the relationship between BTSS and monosymptomatic tinnitus, regardless of its clinical characteristics, in subjects without clinical evidence of IH. We selected 78 subjects (all women, mean age 49.5 ± 10.36) affected by tinnitus, without clinical history of audiological and otological pathologies, enrolled among outpatients of the Institute of Audiology and Phoniatrics in Catanzaro, Italy, over a 2 year period. All subjects underwent psychometric evaluation, psychoacoustic assessment, neurological and ophthalmological examination, cerebral magnetic resonance venography (MRV) and brain magnetic resonance imaging (MRI). MRV identified BTSS in 17.9% (14 patients). In the BTSS group, tinnitus was bilateral/central in 21%, and monolateral in the remaining patients (50% left; 29% right ear). It was more frequently pulsating in the BTSS group, but 64.9% of BTSS subjects described their tinnitus as stable. No features of tinnitus showed statistical significance in association with BTSS. In BTSS subjects, we found values suggesting IH by lumbar puncture (LP) in 40% of cases. In these patients, LP gave immediate improvement of tinnitus. The association between BTSS and tinnitus, regardless of its features, must be considered when other causes of tinnitus are excluded.