The incidence of idiopathic intracranial hypertension in Israel from 2005 to 2007: results of a nationwide survey

Role of diffusion tensor imaging in the evaluation of white matter integrity in idiopathic intracranial hypertension

OBJECTIVES

To determine whether idiopathic intracranial hypertension (IIH) may affect white matter integrity and optic pathways by using diffusion tensor imaging (DTI) and to correlate the DTI metrics with intracranial pressure (ICP).

METHODS

This study is a retrospective case-control study. A total of 42 patients who underwent lumbar puncture and those with elevated ICP, meeting the diagnostic criteria for IIH, were included in the study. All patients had supportive magnetic resonance imaging findings for the diagnosis of IIH. The headache control group comprised 36 patients who presented to the Neurology Department with infrequent episodic tension-type headache, had a normal neurologic examination, and had clinical and radiological findings suggestive of normal ICP. For each patient with IIH, clinical findings and ophthalmological measurements were recorded. The apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) values were calculated using a region of interest-based method in different white matter tracts and optic pathways and compared.

RESULTS

A total of 42 patients diagnosed with IIH (three males, 39 females), with a mean (standard deviation [SD] age of 38.1 (8.9) years), and 36 headache controls (10 males, 26 females, mean [SD] age; 38.1 [9.4] years) were included in the study. The mean (SD) body mass index (BMI) of the patients with IIH was 25.2 (1.9) kg/m2, and the mean (SD) BMI of the headache controls was 23.3 (1.5) kg/m2 (p < 0.001). Decreased FA values and increased RD values in the cingulum were detected in patients with IIH compared to the headache controls (p = 0.003, Cohen's d = 0.681; p = 0.002 Cohen's d = -0.710). Decreased AD values in the left and right superior cerebellar peduncle and increased ADC values in the middle cerebellar peduncle were detected in patients with IIH compared to the headache controls (p < 0.001, Cohen's d = 0.961; p = 0.009, Cohen's d = 0.607; p = 0.015, Cohen's d = -0.564). Increased ADC and RD values and decreased FA values in optic nerve were detected in patients with IIH (p = 0.010, Cohen's d = -0.603; p = 0.004, Cohen's d = -0.676; p = 0.015 Cohen's d = 0.568). A positive correlation was found between the cerebrospinal fluid pressure and ADC values of the left and right superior and left inferior longitudinal fasciculus, genu of the corpus callosum, and right optic radiation (r = 0.43, p = 0.005; r = 0.31, p = 0.044; r = 0.39, p = 0.010; r = 0.35, p = 0.024; r = 0,41, p = 0.007). There was a positive correlation between the retinal nerve fiber layer thickness and the ADC values of the optic nerve (r = 0.32, p = 0.039).

CONCLUSIONS

Intracranial hypertension can be associated with deteriorated DTI values, which might be interpreted as a sign of impaired white matter microstructural integrity in many brain regions beyond the periventricular white matter. Pressure-induced edema and axonal degeneration may be the potential underlying mechanisms of this microstructural damage.

Idiopathic intracranial hypertension in Asians: a retrospective dual-center study

BACKGROUND

There have been limited data on idiopathic intracranial hypertension (IIH) in Asians and there remain uncertainties whether a cerebrospinal fluid (CSF) pressure of 250 mm CSF is an optimum diagnostic cutoff. The aims of the present study included (1) characterization of IIH patients in Taiwan, (2) comparisons among different diagnostic criteria for IIH, and (3) comparisons between patients with CSF pressures of > 250 and 200-250 mm CSF.

METHODS

This retrospective study involved IIH patients based on the modified Dandy criteria from two tertiary medical centers in Taiwan. Clinical manifestations were retrieved from electronic medical records, and findings on ophthalmologic examination and magnetic resonance images (MRIs) were reviewed.

RESULTS

A total of 102 patients (71 F/31 M, mean age 33.4 ± 12.2 years, mean CSF pressure 282.5 ± 74.5 mm CSF) were identified, including 46 (45.1%) with obesity (body-mass index ≥ 27.5), and 57 (62.6%) with papilledema. Overall, 80 (78.4%), 55 (53.9%), 51 (50.0%), and 58 (56.9%) patients met the Second and Third Edition of International Classification of Headache Disorders, Friedman, and Korsbæk criteria, respectively. Patients in the 200-250 mm CSF group (n = 40) were less likely to have papilledema (48.5% vs. 70.7%, p = 0.035), transient visual obscuration (12.5% vs. 33.9%, p = 0.005), and horizontal diplopia (10.0% vs. 30.6%, p = 0.006), and had fewer signs on MRIs (2.2 ± 1.3 vs. 2.8 ± 1.0, p = 0.021) when compared with those with CSF pressures > 250 mm CSF (n = 62). However, the percentages of patients with headache (95.0% vs. 87.1%, p = 0.109) at baseline, chronic migraine at six months (31.6% vs. 25.0%, p = 0.578), and visual field defect (86.7% vs. 90.3%, p = 0.709) were similar.

CONCLUSIONS

It was found that obesity and papilledema were less common in Asian IIH patients when compared with Caucasian patients. Although patients with CSF pressures of 200-250 mm CSF had a less severe phenotype, the risks of having headache or visual loss were comparable to those in the > 250 mm CSF group. It is possible that a diagnostic cutoff of > 200 mm CSF could be more suitable for Asians, although further studies are still needed.

Arachnoid granulations in idiopathic intracranial hypertension: Do they have an influence?

OBJECTIVE

The aim of this study was to investigate whether the relative narrowing of the dural venous sinuses by arachnoid granulations (AGs) is more pronounced in patients with idiopathic intracranial hypertension (IIH) compared to healthy controls.

BACKGROUND

IIH is characterized by increased intracranial pressure, which is associated with symptoms such as headache and visual disturbances. The role of cerebral venous drainage obstruction in IIH is the subject of ongoing research.

MATERIALS AND METHODS

In this retrospective case-control study, 3D contrast-enhanced magnetic resonance images of a cohort of 43 patients with IIH were evaluated for (1) the number of AGs per venous sinus and (2) the diameters of the dural venous sinuses at the site of an AG and at standardized measurement points. In addition, the minimum width of the transverse/sigmoid sinus was measured. All data were compared to the same data from a cohort of 43 control participants.

RESULTS

Patients with IIH showed less relative sinus narrowing by AG compared to controls (median: 7%, interquartile range [IQR] 10% vs. 11%, IQR 9% in controls; p = 0.009). In patients with IIH, sinus diameter was larger at the site of an AG (70 ± 25 mm2) compared to its diameter at the standardized measurement point (48 ± 23 mm2; p = 0.010). In the superior sagittal sinus (SSS), patients with IIH had smaller AGs (median: 3 mm2, IQR 2 mm2 vs. 5 mm2, IQR 3 mm2 in controls; p = 0.023) while the respective sinus segment was larger (median: 69 mm2; IQR 21 mm2 vs. 52 mm2, IQR 26 mm2 in controls; p = 0.002). The right transverse sinus was narrower in patients with IIH (41 ± 21 mm vs. 57 ± 20 mm in controls; p < 0.001).

CONCLUSIONS

In contrast to our hypothesis, patients with IIH showed less pronounced relative sinus narrowing by AG compared to controls, especially within the SSS, where AGs were smaller and the corresponding sinus segment wider. Smaller AGs could result in lower cerebrospinal fluid resorption, favoring the development of IIH. Conversely, the smaller AGs could also be a consequence of IIH due to backpressure in the SSS because of the narrower transverse/sigmoid sinus, which widens the SSS and compresses the AG.

A Case of Idiopathic Intracranial Hypertension Complicated with both Infratentorial and Supratentorial Cortical Superficial Siderosis: Novel Imaging Findings on Intravoxel Incoherent Motion Magnetic Resonance Imaging Offering Clues to Pathophysiology

The pathology of idiopathic intracranial hypertension (IIH), a disease characterized by papillary edema and increased intracranial pressure (IICP), is not yet understood; this disease significantly affects quality of life due to symptoms including vision loss, headache, and pulsatile tinnitus. By contrast, superficial siderosis (SS), a disorder in which hemosiderin is deposited on the surface of the cerebral cortex and cerebellum, potentially causes cerebellar ataxia or hearing loss. So far, no cases of IIH with infratentorial and supratentorial cortical SS have been reported. Herein, we report a case of a 31-year-old woman with obesity who developed this condition. The patient suddenly developed headache and dizziness, had difficulty walking, and subsequently became aware of diplopia. Fundus examination revealed bilateral optic nerve congestive papillae and right eye abducens disturbance. Head magnetic resonance imaging (MRI) showed prominent SS on the cerebellar surface and cerebral cortex. Lumbar puncture revealed IICP of 32 cmH2O, consistent with the diagnostic criteria for IIH, and treatment with oral acetazolamide was started; subsequently, the intracranial pressure decreased to 20 cmH2O. Her abduction disorder disappeared, and the swelling of the optic papilla improved. She was now able return to her life as a teacher without any sequelae. SS is caused by persistent slight hemorrhage into the subarachnoid space. In this case, both infratentorial and supratentorial cortical superficial SS was observed. Although cases of IIH complicated by SS are rare, it should be kept in mind that a causal relationship between IIH and SS was inferred from our case. Our findings also suggest that cerebrospinal fluid dynamic analysis using MRI is effective in diagnosing IIH and in determining the efficacy of treatment.

Long Term Effects of Metabolic and Bariatric Surgery on Idiopathic Intracranial Hypertension

BACKGROUND

Idiopathic Intracranial Hypertension (IIH) is a rare disorder, linked to severe obesity. The study aimed to evaluate long-term effects of metabolic and bariatric surgery (MBS) on IIH outcomes.

METHODS

Retrospective study of patients with IIH and severe obesity who underwent MBS. Data were retrieved from prospectively maintained databases of two bariatric surgeons.

RESULTS

Thirteen patients were included, of them 12 women. Median age was 36 (interquartile range;IQR 21,47) years and body mass index (BMI) was 40.4 (IQR 37.8,41.8) kg/m2. All patients had visual disturbances,12/13 had headaches, and 6/13 had tinnitus. The mean opening pressure on lumbar puncture was 45 cmH2O, and 11/13 patients had papilledema. Medications for IIH were consumed by 11/13 patients, and 2/13 patients had prior surgical intervention for IIH. MBS types included sleeve gastrectomy (n=7), adjustable gastric banding (n=2), roux-en-y gastric bypass (n=2), one anastomosis gastric bypass (n=1), duodenal switch (n=1). At a median follow-up of 10 years (IQR 8,13), the median BMI and total weight loss were 29.7 kg/m2 and 27%, respectively. Remission of symptoms was achieved in 9/13 patients.

CONCLUSIONS

MBS results in significant and sustainable weight loss, with subsequent resolution or improvement of IIH. It may be considered as a preventive measure for IIH in patients with severe obesity.

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.

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.

Recovery of Vision after Optic Nerve Sheath Fenestration in Children and Adolescents with Elevated Intracranial Pressure

PURPOSE

To evaluate the effect of optic nerve sheath fenestration (ONSF) on the recovery of visual function in pediatric patients with optic disc swelling owing to increased intracranial pressure.

DESIGN

Retrospective case series.

METHODS

Medical chart review of all pediatric patients who underwent ONSF between 2009 and 2020 at the Children's Hospital of Philadelphia. Visual function was assessed at pre and postoperative visits. The main outcome measures were visual acuity, color vision, extraocular motility, visual field mean deviation, retinal nerve fiber layer thickness measured by optical coherence tomography.

RESULTS

Fourteen pediatric patients (10 females; mean ± SD age of 14 ± 2.6 years; range, 8.5-17.5 years) were included. Five patients underwent bilateral surgeries. Ten patients were diagnosed with idiopathic intracranial hypertension. Of the 10 idiopathic intracranial hypertension patients, 3 had a previous history of weight gain and 2 of systemic steroid treatment; these can be referred to as pseudotumor cerebri. The mean ± SD follow-up length was 16.4 ± 12.3 months. VA improved from 20/138 to 20/68 in the operated eye (P = .0003) and from 20/78 to 20/32 in the nonoperated eye (P = .02). Color vision improved in the operated eye (P = .04), extraocular motility improved in the operated and nonoperated eye (P = .002 and P = .04 respectively). Visual field mean deviation improved in the operated (-23.4 dB to -11.5 dB, P < .0001) and nonoperated eye (-19.8 dB to -6.8 dB, P = .02). Retinal nerve fiber layer thickness improved in the operated eye (349.1 to 66.2 µm; P < .0001). The postoperative improvement was observed as early as the postoperative day 1.

CONCLUSIONS

ONSF produces a rapid and persistent vision improvement in both the operated eye and the nonoperated eye. In children and young adults with papilledema and elevated intracranial pressure causing vision loss that is severe at presentation or refractory to standard medical management, ONSF should be considered.

Sex hormones, CSF and serum leptin in patients with idiopathic intracranial hypertension

Background

Idiopathic intracranial hypertension (IIH) is typically seen in females of childbearing period; therefore, it is possible that female sex hormones have a pathogenic role in IIH. Obesity is considered as a strong risk factor for IIH, Leptin levels in the serum and CSF were found to be positively correlated with anthropological measures of obesity. The role of leptin and sex hormones in the pathogenesis of idiopathic intracranial hypertension is not fully understood. The aim of this work was to assess CSF leptin, serum leptin, estradiol, testosterone, Dehydroepiandrosterone sulfate (DHEAS) levels in idiopathic intracranial hypertension (IIH) patients.

Results

This is a case control study which was conducted on 38 IIH female patients and 38 females as controls. IIH patients had significantly higher levels of serum Leptin, CSF Leptin, serum estradiol and serum testosterone than controls (P value < 0.001, < 0.001, 0.005 and < 0.001, respectively), whereas there was no statistically significant difference between IIH patients and controls in serum DHEAS (P value = 0.142). IIH patients with body mass index (BMI) ≥ 30 kg/m2 had significantly higher levels of serum Leptin, CSF Leptin, serum estradiol, serum testosterone, and serum DHEAS than IIH patients with BMI < 30 kg/m2 (P value < 0.001, < 0.001, 0.009, < 0.001, and < 0.001, respectively).

Conclusions

Patients with IIH express a characteristic elevation in CSF leptin, serum leptin, estradiol and testosterone levels. These hormones are significantly elevated in patients with high BMI.

Idiopathic intracranial hypertension: Pathophysiology, diagnosis and management

Idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure, manifested by papilledema and radiological findings, in the absence of an identifiable casual factor. The primary symptoms include headache, vision loss, and pulsatile tinnitus, and are recognized to have profound impacts on quality of life and visual function. IIH demonstrates a strong predilection towards obese women of reproductive age, and the population incidence is rising with the growing prevalence of obesity worldwide. The pathophysiology involves dysregulation of cerebrospinal fluid (CSF) dynamics and venous sinus pressure, and recent studies highlighting the pathogenic role of metabolic and hormonal factors have led to the identification of several pharmacological targets and development of novel therapeutic agents. The overarching treatment goals include symptomatic alleviation and prevention of permanent vision loss. The Idiopathic Intracranial Hypertension Treatment Trial, the first of its kind randomized controlled trial on IIH, provides class I evidence for treatment with weight loss and acetazolamide. In medically refractive or fulminant cases, optic nerve sheath fenestration, CSF diversion, and venous sinus stenting, have been successfully implemented. However, there are few high-quality prospective studies investigating the treatment and natural history of IIH, highlighting the compelling need for further research to determine the optimal treatment regimen.

Incidence of idiopathic intracranial hypertension in Southern Tasmania, Australia

Introduction

Anecdotally, the incidence of idiopathic intracranial hypertension (IIH) is increasing, linked to an increase in the obesity rate in Australian society. However, formal incidence and prevalence studies are rare. We therefore sought to determine the incidence and clinical features of IIH in Southern Tasmania, Australia.

Method

Neurology discharge summaries and lumbar puncture referrals from the single tertiary referral centre in this region were screened for an IIH diagnosis. All regional neurologists were surveyed to capture patients diagnosed through private neurology clinics. A retrospective review of medical records was conducted to confirm the diagnosis and determine whether patients met the Modified Dandy Criteria (MDC). Patients were included if they were above the age of 18 years and received a new diagnosis of IIH between June 2016 and June 2018. Population statistics were obtained from the Australian Bureau of Statistics.

Results

IIH incidence was 5.4/100 000. All patients were females, aged between 18 and 45 years. Headache was the most commonly reported symptom, with high rates of pre-existing or concurrent migraine diagnoses. Weight loss and commencement of oral acetazolamide were the most common treatment approaches. Four patients were medically refractory and required surgical intervention.

Conclusion

The incidence of IIH in Southern Tasmania is comparable with the incidence reported in subgroups of females of childbearing age in recent prior studies. The demographic, diagnostic and therapeutic data presented can inform future local health service provision and serve as a baseline for ongoing assessment of change in incidence and treatment of IIH at a community level.

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.

Emerging themes in idiopathic intracranial hypertension

PURPOSE

Idiopathic intracranial hypertension (IIH) is a rare disorder characterised by raised intracranial pressure. The underlying pathophysiology is mostly unknown and effective treatment is an unmet clinical need in this disease. This review evaluates key emerging themes regarding disease characteristics, mechanisms contributing to raised intracranial pressure and advances in potential therapeutic targets.

FINDINGS

IIH is becoming more common, with the incidence rising in parallel with the global obesity epidemic. Current medical management remains centred around weight management, which is challenging. Metabolic investigations of patients have identified specific androgen profiles in cerebrospinal fluid (CSF), which suggest an endocrine dysfunction impacting CSF secretion in IIH. Glucagon-like peptide-1 (GLP-1) and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) have been found to play a role in CSF dynamics in IIH and have formed the basis of the first clinical trials looking at new treatments.

CONCLUSIONS

Identification of novel molecular targets thought to underlie IIH pathology is now being translated to clinical trials.

Reviewing the Recent Developments in Idiopathic Intracranial Hypertension

There is increasing evidence and appreciation of idiopathic intracranial hypertension (IIH) in medicine. The pathological processes underlying raised intracranial pressure are being studied, with new insights found in both hormonal dysregulation and the metabolic neuroendocrine axis. These will potentially lead to novel therapeutic targets for IIH. The first consensus guidelines have been published on the investigation and management of adult IIH, and the International Headache Society criteria for headache attributable to IIH have been modified to reflect our evolving understanding of IIH. Randomized clinical trials have been published, and a number of studies in this disease area are ongoing.

Idiopathic Intracranial Hypertension in the United States: Demographic and Socioeconomic Disparities

Background: Obesity's risk increases for low-income, female, young, and Black patients. By extrapolation, idiopathic intracranial hypertension (IIH)-a disease associated with body mass index-would potentially display socioeconomic and demographic disparities. Methods: IIH incidence (per 100,000) was investigated with respect to sex, age, income, residence, and race/ethnicity, by querying the largest United States (US) healthcare administrative dataset (1997-2016), the National (Nationwide) Inpatient Sample. Results: Annual national incidence (with 25th and 75th quartiles) for IIH was 1.15 (0.91, 1.44). Females had an incidence of 1.97 (1.48, 2.48), larger (p = 0.0000038) than males at 0.36 (0.26, 0.38). Regarding age, largest incidence was among those 18-44 years old at 2.47 (1.84, 2.73). Low-income patients had an incidence of 1.56 (1.47, 1.82), larger (p = 0.00024) than the 1.21 (1.01, 1.36) of the middle/high. No differences (χ2 = 4.67, p = 0.097) were appreciated between urban (1.44; 1.40, 1.61), suburban (1.30; 1.09, 1.40), or rural (1.46; 1.40, 1.48) communities. For race/ethnicity (χ2 = 57, p = 2.57 × 10-12), incidence was largest for Blacks (2.05; 1.76, 2.74), followed by Whites (1.04; 0.79, 1.41), Hispanics (0.67; 0.57, 0.94), and Asian/Pacific Islanders (0.16; 0.11, 0.19). Year-to-year, incidence rose for all strata subsets except Asian/Pacific Islanders (τ = -0.84, p = 0.00000068). Conclusion: IIH demonstrates several sociodemographic disparities. Specifically, incidences are larger for those low-income, Black, 18-44 years old, or female, while annually increasing for all subsets, except Asian/Pacific Islanders. Hence, IIH differentially afflicts the US population, yielding in healthcare inequalities.

Demographics, Clinical Characteristics, and Management of Idiopathic Intracranial Hypertension in Kuwait: A Single-Center Experience

Background: Idiopathic intracranial hypertension (IIH) affects predominantly obese females during their reproductive age period. The demographics of this condition has not been studied in Kuwait before. Objectives: To determine the demographics, clinical features, risk factors, and treatment modalities of IIH in the main neurology tertiary referral hospital in Kuwait and to compare our data with literature. Methods: A retrospective study was conducted to identify cases of IIH seen between January 1, 2018, and December 31, 2018. Patients were diagnosed in and referred from the neurology and neuro-ophthalmology clinics. Results: Our cohort consisted of 139 patients. We estimated a crude annual incidence rate of IIH of 3.28 per 100,000 population. Female-to-male ratio was 9.6:1. Mean age was 32.1 ± 10.8 years. Mean age of males was 31.46 ± 12.63 and that of females was 32.11 ± 10.67. The median of the duration from the first symptoms till diagnosis was 6 weeks (2-10 weeks). Headache was the most common symptom in 134 (96.4%) patients, followed by visual disturbances in 85 (61.2%) patients, transient visual obscurations (TVOs) in 84 (60.4%) patients, pulsatile tinnitus in 72 (51.8%) patients, diplopia in 22 (15.8%) patients, other symptoms (e.g., nausea, vomiting, radicular neck, and back pain) in 19 (13.7%) patients, and 1 (0.7%) patient had facial weakness. High body mass index (BMI) was seen in 89.9% of patients, either overweight or obese, and it was the most common risk factors in both males (46.2%) and females (61.1%). Anemia was found in 38.1%; 21.6% of patients used OCPs and 7.9% used vitamin A. Bilateral transverse sinus stenosis (BTSS) was detected in 47 (33.8%) patients. Only 2 (1.4%) patients developed "fulminant IIH" characterized by rapidly progressive disease. All the patients received medical treatment and only 12 (8.6%) needed surgical management. Conclusion: Incidence of IIH in Kuwait is similar to other regional studies but higher than Western studies. Demographics and clinical features of IIH in our study are comparable to international and regional figures. Most of our patients had a benign course. IIH is more prevalent in females and strongly associated with obesity.

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.

Patients with pulse-synchronous tinnitus should be suspected to have elevated cerebrospinal fluid pressure

Objective

This study was performed to evaluate the prevalence and clinical importance of elevated cerebrospinal fluid (CSF) pressure among patients with pulse-synchronous tinnitus.

Methods

Nineteen patients underwent height and weight measurements, routine otologic examinations, ear computed tomography, brain magnetic resonance imaging, fundus examination, and tinnitus score assessment. We analyzed the data with Fisher’s exact test, the t-test, and Pearson’s correlation.

Results

The mean age of the 19 patients was 39.2 ± 8.1 years (range, 27–54 years), and the mean body mass index was 22.2 ± 1.6 kg/m² (range, 19.9–24.6 kg/m²). The proportion of patients with elevated CSF pressure was 68%. No significant correlation between the severity of tinnitus and CSF pressure was found. Lumbar puncture and oral administration of diuretics resulted in significant improvement in tinnitus.

Conclusions

If detailed physical and imaging examinations fail to detect the definite cause of pulse-synchronous tinnitus, a routine lumbar puncture should be performed to measure the CSF pressure. Elevated CSF pressure should be suspected in patients with pulse-synchronous tinnitus.

The effect of CSF drain on the optic nerve in idiopathic intracranial hypertension

Background

Elevation of intracranial pressure in idiopathic intracranial hypertension induces an edema of the prelaminar section of the optic nerve (papilledema). Beside the commonly observed optic nerve sheath distention, information on a potential pathology of the retrolaminar section of the optic nerve and the short-term effect of normalization of intracranial pressure on these abnormalities remains scarce.

Methods

In this exploratory study 8 patients diagnosed with idiopathic intracranial hypertension underwent a MRI scan (T2 mapping) as well as a diffusion tensor imaging analysis (fractional anisotropy and mean diffusivity). In addition, the clinical presentation of headache and its accompanying symptoms were assessed. Intracranial pressure was then normalized by lumbar puncture and the initial parameters (MRI and clinical features) were re-assessed within 26 h.

Results

After normalization of CSF pressure, the morphometric MRI scans of the optic nerve and optic nerve sheath remained unchanged. In the diffusion tensor imaging, the fractional anisotropy value was reduced suggesting a tissue decompression of the optic nerve after lumbar puncture. In line with these finding, headache and most of the accompanying symptoms also improved or remitted within that short time frame.

Conclusion

The findings support the hypothesis that the elevation of intracranial pressure induces a microstructural compression of the optic nerve impairing axoplasmic flow and thereby causing the prelaminar papilledema. The microstructural compression of the optic nerve as well as the clinical symptoms improve within hours of normalization of intracranial pressure.

Predictive role of presenting symptoms and clinical findings in idiopathic intracranial hypertension

BACKGROUND

The aim of the study was to evaluate the presenting symptoms and signs of idiopathic intracranial hypertension (IIH) in a large cohort of patients and to estimate their possible role in establishing the diagnosis of IIH.

METHODS

This prospective cohort study in two tertiary centers, the Danish Headache Center in Rigshospitalet-Glostrup and the Neurology Clinic of the Clinical Center of Serbia, included 286 patients referred by attending specialists for possible IIH evaluation. Patients were divided into two groups: one with confirmed IIH diagnosis and one with rejected IIH diagnosis.

RESULTS

The diagnosis of IIH was confirmed in 219 (76.6%) patients. It was more often confirmed if the patient was referred by an ophthalmologist than if the referral was from a neurologist (83.6% vs. 69.8%, p = .029) and in patients with higher body mass index (BMI) (p = .032). Transient visual obscurations (p = .006), double vision (p = .033), neck pain (p = .025), and tinnitus (p = .013) were presenting symptoms more frequently reported by patients with IIH diagnosis. In the same group of patients, papilledema (p < .001) and sixth nerve palsy (p = .010) were noted significantly more often. Papilledema was extracted by multivariate analysis as an independent predictor of IIH diagnosis (p < .001).

CONCLUSION

Although studies investigating IIH report an abundance of presenting symptoms, our results indicate that these symptoms are not diagnostic for IIH. Papilledema is the most reliable clinical sign predicting the correct IIH diagnosis in patients with suspected IIH.

The expanding burden of idiopathic intracranial hypertension

Objective

To quantify the hospital burden and health economic impact of idiopathic intracranial hypertension.

Methods

Hospital Episode Statistics (HES) national data was extracted between 1st January 2002 and 31st December 2016. All those within England with a diagnosis of idiopathic intracranial hypertension were included. Those with secondary causes of raised intracranial pressure such as tumours, hydrocephalus and cerebral venous sinus thrombosis were excluded.

Results

A total of 23,182 new IIH cases were diagnosed. Fifty-two percent resided in the most socially deprived areas (quintiles 1 and 2). Incidence rose between 2002 and 2016 from 2.3 to 4.7 per 100,000 in the general population. Peak incidence occurred in females aged 25 (15.2 per 100,000). 91.6% were treated medically, 7.6% had a cerebrospinal fluid diversion procedure, 0.7% underwent bariatric surgery and 0.1% had optic nerve sheath fenestration. Elective caesarean sections rates were significantly higher in IIH (16%) compared to the general population (9%), p < 0.005. Admission rates rose by 442% between 2002 and 2014, with 38% having repeated admissions in the year following diagnosis. Duration of hospital admission was 2.7 days (8.8 days for those having CSF diversion procedures). Costs rose from £9.2 to £50 million per annum over the study period with costs forecasts of £462 million per annum by 2030.

Conclusions

IIH incidence is rising (by greater than 100% over the study), highest in areas of social deprivation and mirroring obesity trends. Re-admissions rates are high and growing yearly. The escalating population and financial burden of IIH has wide reaching implications for the health care system.

Meta-analysis and systematic review of population-based epidemiological studies in idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is positively associated with obesity, mostly in young women. The global increase in obesity may influence the burden of IIH. Using the PubMed, Embase, MEDLINE and Web of Science databases, a meta-analysis and systematic review of epidemiological studies of IIH were performed up to June 2017. Temporal changes in IIH incidence were measured, and incidence rates of IIH were correlated with country-specific World Health Organization obesity rates. Prevalence data and shunting rates of IIH were recorded. The quality of epidemiological studies was assessed using the Standards of Reporting of Neurological Disorders (STROND) criteria. In 15 identified studies, there were 889 patients (87% women), mean age 29.8 years. The incidence of IIH ranged from 0.03 to 2.36 per 100 000 per year. The pooled incidence of IIH was 1.20 per 100 000 per year although there was very high heterogeneity (I² 98%). The incidence rates of IIH were correlated with country-specific prevalence of obesity (Spearman's correlation 0.82, P < 0.01). The prevalence of IIH was rarely recorded. A shunting procedure was reported in 8% of patients. STROND criteria were variably reported, median of 26.5 of 43 (range 16-35). IIH is a public health concern as increased obesity prevalence is associated with increased incidence of IIH. A better quality of epidemiological studies is required to improve understanding of IIH and inform health policy for IIH management.

Update on Idiopathic Intracranial Hypertension

PURPOSE OF REVIEW

This review presents a critical appraisal of current therapeutic strategies for patients with idiopathic intracranial hypertension (IIH). We present the reader with the most recent evidence to support medical and surgical interventions in patients with IIH and provide recommendations about treatment initiation and escalation. We also indicate areas where knowledge gaps exist regarding therapeutic efficacy and superiority of one intervention over another.

RECENT FINDINGS

A double-masked, randomized prospective study of medical management of patients with mild IIH (Idiopathic Intracranial Hypertension Treatment Trial-IIHTT) has established that acetazolamide therapy has additional efficacy when compared to weight loss alone. Furthermore, management of IIH-related headache, even in patients with papilledema, may require treatment other than ICP lowering for patients to experience symptomatic relief. Finally, a number of uncontrolled interventional studies have shown transverse sinus stenting to be a potentially effective treatment for medically refractory IIH. Medical therapy with acetazolamide should be considered in addition to structured weight loss in patients with mild IIH. Surgical treatment for patients with vision-threatening disease IIH can be performed by either optic nerve sheath fenestration or cerebrospinal fluid diversion, with venous sinus stenting emerging as an alternate therapy. Headache relief from ICP lowering therapy is variable and often not sustained.

Improving identification of idiopathic intracranial hypertension patients in Swedish patient register

OBJECTIVE

Idiopathic intracranial hypertension (IIH) is often misdiagnosed. This can cause problems if conducting register-based studies. The study purpose was to produce algorithms that better identify patients with correct diagnosis of IIH in the Swedish National Patient Register (NPR).

METHODS

Patients with ICD-10 code G93.2 for IIH registered in the NPR (2006-2013, Stockholm County) were included and diagnosis validated by medical record reviews. Patients were randomized into two groups: one used to produce the algorithm (n = 105) and one for validation (n = 102). We tested variables possible to extract from registries and used forward stepwise logistic regression which provided a predicted probability of correct diagnosis for each patient.

RESULTS

We included 207 patients of which 135 had confirmed IIH. This gave a positive predictive value of 65.2% (CI: 58.4-71.4). The algorithm produced with variables extracted from registries, that is, age, number of times with diagnosis code G93.2 recorded (>2 times), and acetazolamide treatment, predicted the diagnosis correctly 88.2% (CI: 80.3-93.3) of the time. Excluding treatment data from the algorithm did not change the prediction notably, 86.3% (CI: 78.1-91.7).

CONCLUSION

We produced two algorithms that with improved accuracy predict whether an IIH diagnosis in the NPR is correct. This can be a useful tool when performing register-based studies.

Bariatric surgery as a treatment for pseudotumor cerebri: case study and narrative review of the literature

CONTEXT

Pseudotumor cerebri occurs when there is an increase in intracranial pressure without an underlying cause, usually leading to loss of vision. It is most commonly observed in obese women of child-bearing age.

CASE REPORT

A 46-year-old woman presented at our service with idiopathic intracranial hypertension that had been diagnosed two years earlier, which had led to chronic refractory headache and an estimated 30% loss of visual acuity, associated with bilateral papilledema. She presented partial improvement of the headache with acetazolamide, but the visual loss persisted. Her intracranial pressure was 34 cmH2O. She presented a body mass index of 39.5 kg/m2, also associated with high blood pressure. Computed tomography of the cranium with endovenous contrast did not show any abnormalities. She underwent Roux-en-Y gastric bypass with uneventful postoperative evolution. One month following surgery, she presented a 24% excess weight loss. An ophthalmological examination revealed absence of visual loss and remission of the papilledema. There were no new episodes of headache following the surgery. There was also complete resolution of high blood pressure. The intracranial pressure decreased to 24 cmH2O, six months after the surgery.

CONCLUSION

Although the condition is usually associated with obesity, there are few reports of bariatric surgery among individuals with pseudotumor cerebri. In cases studied previously, there was high prevalence of resolution or improvement of the disease following bariatric surgery. There is no consensus regarding which technique is preferable. Thus, further research is necessary in order to establish a specific algorithm.

Cerebral microvascular abnormalities in patients with idiopathic intracranial hypertension

AIM

Idiopathic intracranial hypertension (IIH) is characterized by symptoms indicative of increased intracranial pressure (ICP), such as headache and visual impairment. We have previously reported that brain biopsies from IIH patients show patchy astrogliosis and increased expression of the water channel aquaporin-4 (AQP4) at perivascular astrocytic endfeet.

METHODS

The present study was undertaken to investigate for ultrastructural changes of the cerebral capillaries in individuals with IIH. We examined by electron microscopy (EM) biopsies from the cortical parenchyma of 10 IIH patients and 8 reference subjects (patients, not healthy individuals), in whom tissue was retrieved from other elective and necessary brain surgeries (epilepsy, tumors or vascular diseases). IIH patients were diagnosed on the basis of typical clinical symptoms and abnormal intracranial pressure wave amplitudes during overnight ICP monitoring.

RESULTS

All 10 IIH patients underwent shunt surgery followed by favorable clinical outcome. EM revealed abnormal pericyte processes in IIH. The basement membrane (BM) showed more frequently evidence of degeneration in IIH, but neither the BM dimensions nor the pericyte coverage differed between IIH and reference tissue. The BM thickness increased significantly with increasing age. Reference individuals were older than IIH cases; observations may to some extent be age-related.

CONCLUSION

The present study disclosed marked changes of the cerebral cortical capillaries in IIH patients, suggesting that microvascular alterations are involved in the evolvement of IIH.

Cerebrospinal fluid circulation and hydrocephalus

Hydrocephalus (HC) is classically defined as dynamic imbalance between the production and absorption of cerebrospinal fluid (CSF) leading to enlarged ventricles. Potential causative factors include various brain disorders like tumors causing obstruction of CSF flow within the ventricular system or the subarachnoid space. Classification of HC is based on the site of CSF flow obstruction guiding optimal treatment, with endoscopic third ventriculostomy in intraventricular obstruction and CSF shunt in communicating HC. Another clinically relevant classification is acute and chronic; the most frequent chronic form is idiopathic normal-pressure hydrocephalus (iNPH). The reported incidence of HC varies according to the study population and classification used. The incidence of congenital HC is approximately 0.4-0.6/1,000 newborns and the annual incidence of iNPH varies from 0.5/100,000 to 5.5/100,000. Radiologically, ventricular dilatation may be nonspecific, and differentiation of iNPH from other neurodegenerative diseases may be ambiguous. There are no known specific microscopic findings of HC but a systematic neuropathologic examination is needed to detect comorbid diseases and possible etiologic factors of HC. Depending on the etiology of HC, there are several nonspecific signs potentially to be seen.

Impaired cerebrospinal fluid pressure

Abnormalities of cerebrospinal fluid (CSF) pressure are relatively common and may lead to a variety of symptoms, with headache usually being the most prominent one. The clinical presentation of alterations in CSF pressure may vary significantly and show a striking similitude to several primary headache syndromes. While an increase in CSF pressure may be of primary or secondary origin, a pathologic decrease of CSF pressure is usually the result of a meningeal rupture with a resulting leakage of CSF. The pathophysiologic mechanisms of idiopathic intracranial hypertension (IIH) remain largely unknown. However recent evidence indicates that an abnormality in CSF outflow and absorption is likely to play a significant role. Treatment usually consists of a combination of weight loss and a pharmacologic approach using carbonic anhydrase inhibitors. Recent results of the first randomized, double-blind, placebo-controlled trial (RCT) with acetazolamide proved its efficacy in reducing headache and visual disturbances. Clinical evidence suggests efficacy for topiramate and furosemide but no RCT has been conducted to date to confirm these results. In contrast to IIH, spontaneous intracranial hypotension frequently remits spontaneously without specific treatment. If necessary, treatment options range from conservative methods to epidural blood or fibrin sealant patches and surgical interventions.

Population-based incidence and clinical characteristics of idiopathic intracranial hypertension

OBJECTIVE

To validate the diagnosis of idiopathic intracranial hypertension (IIH) from the Swedish National Patient Register (NPR) and investigate the incidence of IIH, as well as co-morbidities and medication use in a large Swedish population-based sample.

METHODS

We searched the NPR to find all patients ≥18 years old with the ICD-10 diagnosis code (G93.2) for IIH in Stockholm County from Jan 1, 2006, to Dec 31, 2013. All medical records were reviewed to validate the diagnosis and to collect additional information.

RESULTS

We included 207 patients with an IIH diagnosis, of which 135 (65%) were correctly diagnosed when validated by charts review. Eighty-three patients had disease onset during the study period. This gave a yearly incidence of 0.65/100 000. Female-to-male ratio was 6.1:1. Females, mean age 31.0 (CI 28.8-33.1), were younger at time of diagnosis compared to males, mean age 42.9 (CI 36.4-49.5), P<.001. The most common co-morbidities were obesity (92%), hormonal conditions (21%) and recent infections preceding the diagnosis (21%). Prior treatment with tetracycline derivatives were seen in 9%.

CONCLUSION

The incidence of IIH in Stockholm is in the lower range of previously reported rates, possibly due to a lower prevalence of obesity. A substantial proportion of patients (35%) did not fulfill diagnostic criteria. Disease onset occurs at younger age in females. Co-morbidities were mainly associated with diseases affecting hormonal balance or causing inflammatory activation. These findings raise new hypothetical theories regarding mechanisms involved in IIH pathogenesis.

Assessing the Efficacy and Safety of an 11β-Hydroxysteroid Dehydrogenase Type 1 Inhibitor (AZD4017) in the Idiopathic Intracranial Hypertension Drug Trial, IIH:DT: Clinical Methods and Design for a Phase II Randomized Controlled Trial

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a condition with few effective management options. So far, there have been no randomized controlled trials evaluating new treatments in IIH.

OBJECTIVES

The purpose of this paper is to outline the trial design for the Idiopathic Intracranial Hypertension Drug Trial (IIH:DT), assessing an innovative medical treatment in IIH and the rationale for the chosen trial methodology.

METHODS

IIH:DT is a phase II double-blind randomized placebo-controlled trial recruiting 30 female participants with active IIH (intracranial pressure >25cm H₂ O and papilledema). Participants are randomized in a 1:1 ratio to 12 weeks of either AZD4017, an 11β-hydroxysteroid dehydrogenase type 1 inhibitor, or a matching placebo. They receive either 400 mg of AZD4017 or placebo twice daily. Participants are followed up at Weeks 1, 2, 3, 4, 6, 8, 10, 12, and 16 postrandomization. The primary outcome is to examine the effect of AZD4017 on intracranial pressure, measured by lumbar puncture, over 12 weeks. Secondary outcome measures include IIH symptoms, visual function, papilledema, headache measures, safety, and tolerability. Cerebrospinal fluid, serum, plasma, urine, and adipose tissue are also taken for exploratory outcomes.

RESULTS

All participants were recruited between April 2014 and August 2016.

CONCLUSIONS

IIH:DT is the first phase II double-blind randomized placebo-controlled trial assessing the efficacy and safety of the novel pharmacological intervention, AZD4017, for the treatment of IIH.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02017444; https://clinicaltrials.gov/ct2/show/NCT02017444 (Archived by WebCite at http://www.webcitation.org/6tVHesN6s).

Pseudotumor cerebri syndrome in childhood: incidence, clinical profile and risk factors in a national prospective population-based cohort study

AIM

To investigate the epidemiology, clinical profile and risk factors of pseudotumor cerebri syndrome (PTCS) in children aged 1-16 years.

METHODS

A national prospective population-based cohort study over 25 months. Newly diagnosed PTCS cases notified via British Paediatric Surveillance Unit were ascertained using classical diagnostic criteria and categorised according to 2013 revised diagnostic criteria. We derived national age, sex and weight-specific annual incidence rates and assessed effects of sex and weight categories.

RESULTS

We identified 185 PTCS cases of which 166 also fulfilled revised diagnostic criteria. The national annual incidence (95% CI) of PTCS in children aged 1-16 years was 0.71 (0.57 to 0.87) per 100 000 population increasing with age and weight to 4.18 and 10.7 per 100 000 in obese boys and girls aged 12-15 years, respectively. Incidence rates under 7 years were similar in both sexes. From 7 years onwards, the incidence in girls was double that in boys, but only in overweight (including obese) children. In children aged 12-15 years, an estimated 82% of the incidence of PTCS was attributable to obesity. Two subgroups of PTCS were apparent: 168 (91%) cases aged from 7 years frequently presented on medication and with headache and were predominantly female and obese. The remaining 17 (9%) cases under 7 years often lacked these risk factors and commonly presented with paralytic squint.

CONCLUSIONS

This uniquely large population-based study of childhood PTCS will inform the design of future intervention studies. It suggests that weight reduction is central to the prevention of PTCS.

Cortical astrogliosis and increased perivascular aquaporin-4 in idiopathic intracranial hypertension

The syndrome idiopathic intracranial hypertension (IIH) includes symptoms and signs of raised intracranial pressure (ICP) and impaired vision, usually in overweight persons. The pathogenesis is unknown. In the present prospective observational study, we characterized the histopathological changes in biopsies from the frontal brain cortical parenchyma obtained from 18 IIH patients. Reference specimens were sampled from 13 patients who underwent brain surgery for epilepsy, tumors or acute vascular diseases. Overnight ICP monitoring revealed abnormal intracranial pressure wave amplitudes in 14/18 IIH patients, who underwent shunt surgery and all responded favorably. A remarkable histopathological observation in IIH patients was patchy astrogliosis defined as clusters of hypertrophic astrocytes enclosing a nest of nerve cells. Distinct astrocyte domains (i.e. no overlap between astrocyte processes) were lacking in most IIH biopsy specimens, in contrast to their prevalence in reference specimens. Evidence of astrogliosis in IIH was accompanied with significantly increased aquaporin-4 (AQP4) immunoreactivity over perivascular astrocytic endfeet, compared to the reference specimens, measured with densitometry. Scattered CD68 immunoreactive cells (activated microglia and macrophages) were recognized, indicative of some inflammation. No apoptotic cells were demonstrable. We conclude that the patchy astrogliosis is a major finding in patients with IIH. We propose that the astrogliosis impairs intracranial pressure-volume reserve capacity, i.e. intracranial compliance, and contributes to the IIH by restricting the outflow of fluid from the cranium. The increased perivascular AQP4 in IIH may represent a compensatory mechanism to enhance brain fluid drainage.

Idiopathic intracranial hypertension, hormones, and 11β-hydroxysteroid dehydrogenases

Idiopathic intracranial hypertension (IIH) results in raised intracranial pressure (ICP) leading to papilledema, visual dysfunction, and headaches. Obese females of reproductive age are predominantly affected, but the underlying pathological mechanisms behind IIH remain unknown. This review provides an overview of pathogenic factors that could result in IIH with particular focus on hormones and the impact of obesity, including its role in neuroendocrine signaling and driving inflammation. Despite occurring almost exclusively in obese women, there have been a few studies evaluating the mechanisms by which hormones and adipokines exert their effects on ICP regulation in IIH. Research involving 11β-hydroxysteroid dehydrogenase type 1, a modulator of glucocorticoids, suggests a potential role in IIH. Improved understanding of the complex interplay between adipose signaling factors such as adipokines, steroid hormones, and ICP regulation may be key to the understanding and future management of IIH.

A case series of dural venous sinus stenting in idiopathic intracranial hypertension: association of outcomes with optical coherence tomography

Purpose/Aim: Pseudotumor cerebri or idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure of unknown etiology. A subset of patients has shown benefit from endovascular dural venous sinus stenting (DVSS). We sought to identify a population of IIH patients who underwent DVSS to assess outcomes.

MATERIALS AND METHODS

A retrospective study was performed to identify IIH patients with dural sinus stenosis treated with DVSS. Outcome measures included dural sinus pressure gradients, peripapillary retinal nerve fiber layer (RNFL) thickness using optical coherence tomography and improvement in symptoms.

RESULTS

Seventeen patients underwent DVSS. Average pre- and post-intervention pressure gradients were 23.06 and 1.18 mmHg, respectively (p < 0.0001). Sixteen (94%) noted improvement in headache, fourteen (82%) had visual improvement and all (100%) patients had improved main symptom. Of 11 patients with optical coherence tomography, 8 showed decreased RNFL thickness and 3 remained stable; furthermore, these 11 patients had improved vision with improved papilledema in 8, lack of pre-existing papilledema in 2 and stable, mild edema in 1 patient.

CONCLUSIONS

Our series of patients with dural sinus stenosis demonstrated improvement in vision and reduction in RNFL thickness. DVSS appears to be a useful treatment for IIH patients with dural sinus stenosis.

Understanding idiopathic intracranial hypertension: mechanisms, management, and future directions

Idiopathic intracranial hypertension is a disorder characterised by raised intracranial pressure that predominantly affects young, obese women. Pathogenesis has not been fully elucidated, but several causal factors have been proposed. Symptoms can include headaches, visual loss, pulsatile tinnitus, and back and neck pain, but the clinical presentation is highly variable. Although few studies have been done to support evidence-based management, several recent advances have the potential to enhance understanding of the causes of the disease and to guide treatment decisions. Investigators of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) reported beneficial effects of acetazolamide in patients with mild visual loss. Studies have also established weight loss as an effective disease-modifying treatment, and further clinical trials to investigate new treatments are underway. The incidence of idiopathic intracranial hypertension is expected to increase as rates of obesity increase; efforts to reduce diagnostic delays and identify new, effective approaches to treatment will be key to meeting the needs of a growing number of patients.

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.