Elevated cerebrospinal fluid (CSF) leptin in idiopathic intracranial hypertension (IIH): evidence for hypothalamic leptin resistance?

Risk factors and disease associations in people living with idiopathic intracranial hypertension

INTRODUCTION

Idiopathic intracranial hypertension is a neurological condition characterized by a raised intracranial pressure and papilledema, leading to chronic headaches and visual disturbances. By recognizing modifiable risk factors and deploying evidence-based interventions, healthcare providers have the potential to mitigate the burden of the disease and improve patient outcomes.

AREAS COVERED

It is well known that the condition occurs in predominantly pre-menopausal females who live with obesity particularly in the context of recent weight gain. This review discusses what risk factors may contribute to the metabolic underpinnings of cerebrospinal fluid dysregulation. There are a number of disease associations that are important to screen for as they can alter management.

EXPERT OPINION

There is emerging evidence to suggest that idiopathic intracranial hypertension is a systemic metabolic disease and it is unknown what are all the risk factors are that precipitate the condition. Targeting certain hardwired risk factors is unachievable. However, as recent weight gain has been identified as a predominant risk factor for the development of the disease and relapse, modification of body weight should be the primary aim of management. Insightful research into the involvement of the neuroendocrine axis driving cerebrospinal fluid dysregulation now has the potential for the development of therapeutic targets.

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.

Understanding the pathophysiology of idiopathic intracranial hypertension (IIH): a review of recent developments

Idiopathic intracranial hypertension (IIH) is a condition of significant morbidity and rising prevalence. It typically affects young people living with obesity, mostly women of reproductive age, and can present with headaches, visual abnormalities, tinnitus and cognitive dysfunction. Raised intracranial pressure without a secondary identified cause remains a key diagnostic feature of this condition, however, the underlying pathophysiological mechanisms that drive this increase are poorly understood. Previous theories have focused on cerebrospinal fluid (CSF) hypersecretion or impaired reabsorption, however, the recent characterisation of the glymphatic system in many other neurological conditions necessitates a re-evaluation of these hypotheses. Further, the impact of metabolic dysfunction and hormonal dysregulation in this population group must also be considered. Given the emerging evidence, it is likely that IIH is triggered by the interaction of multiple aetiological factors that ultimately results in the disruption of CSF dynamics. This review aims to provide a comprehensive update on the current theories regarding the pathogenesis of IIH.

High CCL2 Levels Detected in CSF of Patients with Pediatric Pseudotumor Cerebri Syndrome

Pseudotumor cerebri (PTC) is a disorder characterized by increased intracranial pressure in the absence of a structural lesion or other identifiable cause. Cytokines, which are involved in the regulation of immune responses and inflammation, have been implicated in the pathogenesis of PTC. In a prospective, cross-sectional study at three centers in Israel, we analyzed cerebrospinal fluid (CSF) samples from 60 children aged 0.5-18 years, including 43 children with a definitive diagnosis of PTC and a control group of 17 children. Levels of IL-4, IL-10, IL-17, CCL2, CCL7, CCL8, CCL13, BDNF, and IFN-γ were measured using ELISA kits. Levels of CCL2 were significantly higher in the PTC group compared to the control group (p < 0.05), with no other significant differences in the measured cytokines between the two groups. The groups did not differ significantly in clinical presentation, imaging, treatment, or ophthalmic findings. Our findings provide preliminary evidence that CCL2 may be involved in the pathogenesis of PTC and may serve a potential target for therapy in PTC.

Magnetic Resonance Imaging Findings in Idiopathic Intracranial Hypertension With and Without Pulsatile Tinnitus: An Age-Matched Cohort Study

OBJECTIVE

Many but not all patients with idiopathic intracranial hypertension (IIH) have pulsatile tinnitus (PT). However, little is known about why some patients with IIH develop PT and others do not. The purpose of this study was to determine if any of the classic magnetic resonance imaging (MRI)-detectable markers of IIH differ between patients with and without PT, thereby shedding light on potential pathophysiology.

METHODS

A retrospective age-matched cohort study of patients with documented IIH (diagnosed by neuro-ophthalmologist) was performed. All patients had MRI performed around the time of diagnosis. MRIs were assessed for 16 variables known to be associated with IIH (e.g., pituitary displacement/empty sella, optic nerve tortuosity, transverse sinus stenosis, inferior cerebellar tonsils, arachnoid granulations, slit-like ventricles) by two blinded neuroradiologists. All binary variables were analyzed via χ2 test with Yates correction, or Fisher exact when appropriate. Continuous variables were analyzed via Student t test. Inter-rater reliability for binary variables was assessed by Cohen κ. For continuous variables, intraclass correlation coefficient was calculated.

RESULTS

Forty age-matched patients with IIH met the inclusion criteria (20 with PT, 20 without PT). For all known binary MRI findings associated with IIH, there were no statistically significant differences between groups. Likewise, there were no statistically significant differences for continuous variables.

CONCLUSIONS

The classic MRI findings associated with IIH do not differ between patients with and without PT, suggesting that systemic (rather than localized intrinsic or extrinsic) factors may play a critical role in the pathophysiology.

Cerebrospinal fluid levels of sortilin-1, lipocalin-2, autotaxin, decorin and interleukin-33 in patients with idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension (IIH) is characterized by increased cerebrospinal fluid (CSF) pressure of unknown cause. It has been suggested that the inflammatory process plays a role in the pathophysiology of the disease. Sortilin-1, lipocalin-2, autotaxin, decorin, and interleukin-33 (IL-33) are among the factors involved in inflammatory processes.

OBJECTIVE

To investigate the CSF levels of sortilin-1, lipocalin-2, autotaxin, decorin, and IL-33 in patients with IIH.

METHODS

A total of 24 IIH patients and 21 healthy controls were included in the study. Demographic characteristics of the patients and of the control group as well as CSF pressures were evaluated. Sortilin-1, lipocalin-2, autotaxin, decorin and IL-33 levels in the CSF were measured.

RESULTS

The CSF levels lipocalin-2, sortilin-1, autotaxin, IL-33 and CSF pressure were significantly higher in the patients group compared with the control group (p < 0.001). Decorin levels were reduced in patients (p < 0.05). There was no correlation between the autotaxin and IL-33 levels and age, gender, CSF pressure, and body mass index. The results of our study showed that inflammatory activation plays an important role in the development of the pathophysiology of IIH. In addition, the fact that the markers used in our study have never been studied in the etiopathogenesis of IIH is important in explaining the molecular mechanism of this disease.

CONCLUSION

Studies are needed to evaluate the role of these cytokines in the pathophysiology of the disease. It is necessary to evaluate the effects of these molecules on this process.

Cerebrospinal fluid (CSF) and idiopatic intracranial hypertension (IIH): a critical review

Pseudotumor cerebri is a syndrome that results from increased intracranial pressure. The main symptoms are headache, vision disturbances, and pulsatile tinnitus. Definitive diagnosis requires the presence of clinical and/or radiological signs of intracranial hypertension, high opening pressure on lumbar puncture (LP), and normal CSF constitution. Several studies have evaluated new contributions of CSF in the clinical evaluation and the in understanding of the pathophysiology of pseudotumor cerebri. Such studies have included the analysis of inflammatory biomarkers, adipokines, proteomic analysis, and CSF flow studies. In this review, we present the main results obtained so far and critically discuss the present status and the potential role of research involving the CSF in this condition. Based on current knowledge, it is possible to conclude that CSF research with new biomarkers has not yet provided information that can be employed in clinical practice at this moment. However, a better understanding of the constitution and dynamics of CSF circulation in patients with pseudotumor cerebri has brought some information about this condition and can potentially improve our knowledge about this condition in the future.

Idiopathic intracranial hypertension imaging approaches and the implications in patient management

Idiopathic intracranial hypertension (IIH) represents a clinical disease entity without a clear etiology, that if left untreated, can result in severe outcomes, including permanent vision loss. For this reason, early diagnosis and treatment is necessary. Historically, the role of cross-sectional imaging has been to rule out secondary or emergent causes of increased intracranial pressure, including tumor, infection, hydrocephalus, or venous thrombosis. MRI and MRV, however, can serve as valuable imaging tools to not only rule out causes for secondary intracranial hypertension but can also detect indirect signs of IIH resultant from increased intracranial pressure, and demonstrate potentially treatable sinus venous stenosis. Digital subtraction venographic imaging also plays a central role in both diagnosis and treatment, providing enhanced anatomic delineation and temporal flow evaluation, quantitative assessment of the pressure gradient across a venous stenosis, treatment guidance, and immediate opportunity for endovascular therapy. In this review, we discuss the multiple modalities for imaging IIH, their limitations, and their contributions to the management of IIH.

A Systematic Review on Whether an Association Exists Between Adolescent Obesity and Idiopathic Intracranial Hypertension

Pseudotumor cerebri syndrome (PTCS)/idiopathic intracranial hypertension (IIH) is a clinical presentation appertaining to signs/symptoms of raised intracranial pressure, like headache and papilledema. It is an uncommon but clinically significant cause of morbidity such as permanent vision loss. It is crucial to understand if idiopathic intracranial hypertension (IIH) is on the rise in adolescents, it is probably due to the rising prevalence of obesity worldwide. Our study aimed to find an association between obesity and IIH in adolescents. We utilized Preferred Reporting Items for Systematic Review and Meta-Analysis 2020 (PRISMA) guidelines to run this systematic review. Many publications related to the topic in the discussion were scrutinized through a comprehensive database search. We filtered them down to a final count of 10 articles after utilizing our inclusion/exclusion criteria and assessing the quality of work. In these final papers, we identified several possibilities to explain the link between obesity and IIH in adolescents. Overweight and obese adolescents were found to have a significantly increased risk of IIH development, with a more severe clinical picture seen in morbidly obese female patients.

Idiopathic Intracranial Hypertension: A Comprehensive Overview

Idiopathic intracranial hypertension (IIH), also called pseudotumor cerebri syndrome, is a disorder defined as elevated intracranial pressure (ICP) of unknown cause. It is a diagnosis of exclusion in most cases, and all other forms of elevated ICP must be ruled out. With its increasing prevalence, it is much more likely for physicians, otolaryngologists included, to encounter this condition. It is important to have a clear understanding of the typical and atypical presentation of this disease, along with its evaluative workup and management options. This article reviews IIH with a focus on those factors that are specifically relevant to otolaryngologic care.

Idiopathic Intracranial Hypertension: Implications for the Otolaryngologist

Idiopathic intracranial hypertension (IIH) is a triad of headaches, visual changes, and papilledema in the absence of a secondary cause for elevated intracranial pressure. There is an association with obesity, and the incidence is rising in parallel with the obesity epidemic. Sometimes these patients present to an otolaryngologist with complaints like tinnitus, dizziness, hearing loss, and otorrhea or rhinorrhea from cerebrospinal fluid leak. IIH diagnosis in conjunction with neurology and ophthalmology, including neuroimaging and lumbar puncture with opening pressure, is key to managing of this condition. Otolaryngologists should recognize IIH as a possible diagnosis and initiate appropriate referrals and treatment.

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.

Role of tumor necrosis factor-alpha in the pathophysiology of idiopathic intracranial hypertension

BACKGROUND

Although the pathogenesis of idiopathic intracranial hypertension (IIH) is still poorly understood, the contribution of inflammatory mechanisms has been proposed in its pathophysiology.

OBJECTIVE

This study aimed to measure serum tumor necrosis factor-α (TNF-α) levels in patients with IIH and to examine its relationship with clinical and ophthalmological parameters and cerebrospinal fluid (CSF) opening pressure.

SUBJECTS AND METHODS

Thirty-six IIH patients and 30 healthy subjects were enrolled in the study. Patients were subjected to complete neurological, general, and ophthalmological assessments. Serum TNF-α levels were measured for patients and controls using the enzyme-linked immunosorbent assay.

RESULTS

Serum TNF-α levels were significantly higher in IIH patients compared to healthy controls (p value <.001). Serum TNF-α level was significantly negatively correlated with grade of perimetry and CSF opening pressure (r = -.36, p value = .02), (r = -.37, p value = .02) respectively. However, serum TNF-α was not significantly correlated either with age at onset, disease duration, BMI, headache severity, relapse rate, visual acuity, or papilloedema grade. Serum TNF-α was found to be a significant predictor of the severity of the visual field affection in IIH patients, as one-grade increase of the perimetric grading was associated with a decrease in serum TNF-α by 13.96 ng/ml.

CONCLUSION

Altered serum TNF-α levels may suggest the potential involvement of pro-inflammatory mechanisms in the pathogenesis of IIH. Serum TNF-α level may be an indicator of the severity of the visual field affection in IIH.

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios as inflammation markers in patients with papilledema due to idiopathic intracranial hypertension

Purpose:

The aim of this study was to investigate the role of inflammation in the pathogenesis of idiopathic intracranial hypertension (IIH) using the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) as inflammation markers.

Methods:

The files of 33 IIH patients and 33 controls were screened for this retrospective study. For each patient, the NLR and PLR values were calculated using a single fasting blood sample. For both eyes, papilledema (PE) grades, best-corrected visual acuity (BCVA), retinal nerve fiber layer thickness (RNFLT), and ganglion cell layer thickness (GCLT) measurements were recorded along with the demographic data, including body mass index (BMI), and complete neurological and ophthalmological findings. Comparisons between the two groups and between the IIH patients with and without PE were made. The associations of NLR and PLR with all other parameters were analyzed independently from age, gender, and BMI.

Results:

NLR and PLR were higher in patients with IIH than controls (P < 0.05). They were also higher in patients with PE (P < 0.05) in the IIH group. NLR and PLR were found to be associated with BCVA (P < 0.001 and P = 0.023, respectively), global RNFLT (P = 0.004 and 0.012, respectively), RNFLT of the temporal quadrant (P < 0.001 and P = 0.042, respectively) and PE grade (P < 0.001 and P = 0.035, respectively).

Conclusion:

The NLR and PLR values and their associations with BCVA, RNFLT, and PE support the hypothesis that inflammation is a very important component of the pathogenesis of IIH.

Systemic and adipocyte transcriptional and metabolic dysregulation in idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a condition predominantly affecting obese women of reproductive age. Recent evidence suggests that IIH is a disease of metabolic dysregulation, androgen excess, and an increased risk of cardiovascular morbidity. Here we evaluate systemic and adipose specific metabolic determinants of the IIH phenotype.

METHODS

In fasted, matched IIH (n = 97) and control (n = 43) patients, we assessed glucose and insulin homeostasis and leptin levels. Body composition was assessed along with an interrogation of adipose tissue function via nuclear magnetic resonance metabolomics and RNA sequencing in paired omental and subcutaneous biopsies in a case-control study.

RESULTS

We demonstrate an insulin- and leptin-resistant phenotype in IIH in excess of that driven by obesity. Adiposity in IIH is preferentially centripetal and is associated with increased disease activity and insulin resistance. IIH adipocytes appear transcriptionally and metabolically primed toward depot-specific lipogenesis.

CONCLUSION

These data show that IIH is a metabolic disorder in which adipose tissue dysfunction is a feature of the disease. Managing IIH as a metabolic disease could reduce disease morbidity and improve cardiovascular outcomes.

FUNDING

This study was supported by the UK NIHR (NIHR-CS-011-028), the UK Medical Research Council (MR/K015184/1), Diabetes UK, Wellcome Trust (104612/Z/14/Z), the Sir Jules Thorn Award, and the Midlands Neuroscience Teaching and Research Fund.

Dural venous sinus stenting in the treatment of idiopathic intracranial hypertension: A systematic review and critique of literature

Idiopathic intracranial hypertension (IIH) is increased intracranial pressure without a known cause. Dural venous sinus stenting (DVSS) is a relatively new intervention for treatment of IIH refractory to medical therapy and lifestyle modifications. In this review, we outline various hypotheses of IIH pathogenesis and describe the role of venous sinus stenosis and the technical details of DVSS. We also present a summary and critique of the available evidence describing the outcomes of DVSS in IIH and review the evidence-based guidelines for this procedure. We conclude that, although many studies have shown generally favorable outcomes of DVSS in patients with IIH, most have serious limitations, the most common one being paucity of pre- and postprocedure ophthalmological data. Thus, there is not enough available evidence to conclude whether DVSS is an effective procedure for treatment of IIH. We also present the most commonly used indications for DVSS as described in the literature and stress the importance of neuro-ophthalmological assessment before and after the procedure to monitor response and potential complications.

A Natural History of Silent Brain Syndrome over 36 Years: A case report

A 34-year-old Caucasian male who underwent a ventricular shunt at age 21 presented with bilateral enophthalmos, poor eyelid-globe apposition and exposure keratopathy characteristic of silent brain syndrome. Progressive enophthalmos and corneal decompensation were documented in serial photographs and radiographic studies over 36 years. Over this period, no sequelae of shunt over-drainage were observed. A lumbar puncture at the last follow-up measured CSF opening pressure to be within the normal range. Additional systemic findings included pneumosinus dilatans, loss of adipose tissue in the temporalis fossa and atrophy of the dorsal interossei of the hand. Surgical interventions to preserve ocular function included insertion of orbital floor wedge and sheet implants, sheet orbital roof implants, and retroplacement of canthal tendons. This report chronicles the long-term clinical course of a patient with silent brain syndrome. The systemic changes suggest factors beyond low intracranial pressure may contribute to the pathogenesis of the condition in our patient.

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.

Guide to preclinical models used to study the pathophysiology of idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is characterised by raised intracranial pressure (ICP) and papilloedema in the absence of an identifiable secondary cause typically occurring in young women with obesity. The impact is considerable with the potential for blindness, chronic disabling headaches, future risk of cardiovascular disease and marked healthcare utilisation. There have been marked advances in our understanding the pathophysiology of IIH including the role of androgen excess. Insight into pathophysiological underpinnings has arisen from astute clinical observations, studies, and an array of preclinical models. This article summarises the current literature pertaining to the pathophysiology of IIH. The current preclinical models relevant to gaining mechanistic insights into IIH are then discussed. In vitro and in vivo models which study CSF secretion and the effect of potentially pathogenic molecules have started to glean important mechanistic insights. These models are also useful to evaluate novel therapeutic targets to abrogate CSF secretion. Importantly, in vitro CSF secretion assays translate into relevant changes in ICP in vivo. Models of CSF absorption pertinent to IIH, are less well established but highly relevant and of future interest. There is no fully developed in vivo model of IIH but this remains an area of importance. Progress is being made to improve our understanding of the underlying aetiology in IIH including the characterisation of disease biomarkers and their mechanistic role in driving disease pathology. Preclinical models, used to evaluate IIH mechanisms are yielding important mechanistic insights. Further work to refine these techniques will provide translatable insights into disease aetiology.

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.

Pseudotumor Cerebri Syndrome: From Childhood to Adulthood Risk Factors and Clinical Presentation

INTRODUCTION

Although considered uncommon, pseudotumor cerebri syndrome (PTC) is a significant cause of headache among children and adults. However, the presenting symptoms may be different among diverse age groups. In the present study, we compared the risk factors and clinical presentation of PTC across life-from childhood to adulthood.

METHODS

A retrospective survey of PTC patients aged 7 years or older between 2011 and 2013 was carried out. Pooled analyses were performed comparing characteristics from our data with those of published data subdivided into 3 age groups: pre-young children, adolescents, and adults.

RESULTS

Our cohort consisted of 72 patients: 32 children (10 pre-young children, 22 adolescents) and 40 adults. Within the pre-young children age group: 20% were females versus 82% in the adolescent age group and 85% of the adult age group. Obesity was found in 10% of the young children group, 64% of the adolescents, and 80% of the adults. Headache was reported in 70% young children, 82% adolescents, and 83% adults. Pooled analysis of 1499 patients showed that young children with PTC tend to complain less about headache compared with older ones. Vomiting and visual impairment were most common among adolescents, and dizziness and tinnitus were most common in adults.

CONCLUSION

PTC has different risk factors and clinical presentation throughout life. In young children, there is no gender preference and most patients are not obese. Risk factors in adolescents resemble those of adults.

Metabolic Concepts in Idiopathic Intracranial Hypertension and Their Potential for Therapeutic Intervention

BACKGROUND

Traditional risk factors associated with idiopathic intracranial hypertension (IIH) include obesity, weight gain, and female sex. The incidence of IIH is increasing and yet the underlying trigger and the fueling pathological mechanisms are still poorly understood.

EVIDENCE ACQUISITION

Review of ophthalmology, neurology, general surgery, obesity, endocrinology, nutrition, and neurosurgery literature was made.

RESULTS

The facts that implicate sex and obesity in IIH and headache are examined. The role of fat distribution in IIH is questioned, and the concept of adipose tissue functioning as an endocrine organ driving IIH is discussed. The impact of androgen metabolism in IIH is reviewed as is the emerging role of glucagon-like-peptide-1 analogues in modulating intracranial pressure. This introduces the concept of developing targeted disease-modifying therapeutic strategies for IIH.

CONCLUSIONS

This review will discuss the possible role of the adipose/gut/brain metabolism axis in IIH and speculate how this may impact the pathogenesis of IIH and therapeutic opportunities.

Eye Conditions in Women

Changes in vision can have significant impact on health and quality of life. Differences between women and men have been identified in the incidence of several eye conditions. Some of these differences are a result of the greater longevity of women. However, the eye, like other organs, is susceptible to the impacts of inflammation and sex steroids. Conditions, such as thyroid eye disease, optic neuritis, and dry eye disease are related to autoimmune or inflammatory conditions and are, thus, more common among women. Idiopathic intracranial hypertension occurs disproportionately in women of childbearing age; the etiology of this condition appears to be related to both inflammatory and sex hormone fluctuations.

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.

Obesity and Weight Loss in Idiopathic Intracranial Hypertension: A Narrative Review

BACKGROUND

Most patients with idiopathic intracranial hypertension (IIH) are obese. Weight loss is felt to be an important factor in improving IIH. The mechanism by which weight loss leads to a reduction in elevated intracranial pressure is unclear. Evidence from prospective studies evaluating the role of weight loss in IIH is lacking.

EVIDENCE ACQUISITION

We performed a detailed review of the published literature regarding the association of IIH and obesity, including proposed pathogenetic mechanisms, and the effect of weight loss and weight-loss interventions in IIH. References were identified by searching PubMed with the terms idiopathic intracranial hypertension and weight loss. Additional citations were found in the identified references.

RESULTS

Over 90% of IIH patients are obese or overweight. The risk of IIH increases as a function of body mass index (BMI) and weight gain over the preceding year. The risk of IIH-induced vision loss also increases with increasing BMI, especially with BMI >40 kg/m. Several mechanisms have been proposed linking obesity to the development of IIH but the pathophysiology remains unknown. Published studies and clinical observations strongly support weight loss as an effective treatment, although there are no prospective controlled trials. Weight loss in the range of 6%-10% often leads to IIH remission. Weight loss of ≥5% at 1 year is achieved in roughly 50%-70% of patients if they are enrolled in a high-intensity lifestyle modification program and in 20%-35% of patients if they direct their own weight loss. Weight is typically regained over 1-3 years but about a third of patients maintain ≥5% weight loss over the long term. Patients treated initially with lifestyle modification therapy show a modest persisting benefit over self-directed patients. Selected commercial weight loss programs also may improve long-term maintenance of weight loss. New antiobesity drugs significantly improve the proportion of obese patients who have ≥5% loss of weight at 1 year.

CONCLUSIONS

Obesity is an important contributing factor for the development of IIH, although the pathophysiological mechanism linking obesity to IIH is unknown. The risk of developing IIH and associated visual loss increases with increasing BMI. Weight loss is an effective treatment for IIH. Long-term maintenance of initial weight loss is helped modestly by lifestyle modification programs and possibly by selected commercial weight loss programs. New antiobesity drugs may provide further options for IIH therapy in the future.

An update on idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension (IIH) is still a grey area in the knowledge of the aetiology, diagnosis and management of neurosurgical diseases. The definition of IIH has been reviewed over time and many hypotheses have been expressed as cause of the disease. The literature supplies very little evidence-based information to guide our decision-making process when it comes to treat the disease. In this review we sum up the latest information regarding the aetiology and therapy of IIH. Additionally, we make an attempt to unify the diagnostic criteria of Dandy, Friedman and Wall established from 1937 to date.

METHOD

In this narrative review, we attempt to update the current standpoint to IIH, evaluate the input until now and consider future directions for research. The vast majority of the literature consisted of cohort studies, case control studies, systematic reviews and other narrative reviews.

RESULTS

Pathophysiology: The incidence of IIH is steadily increasing. Several pathophysiological theories have been proposed in the literature based on the flow of cerebrospinal fluid.

DIAGNOSIS

We attempt to fuse all the three diagnostic approaches published in the literature that detect IIH, while preserving the individual characteristics of each approach.

TREATMENT

Based on evidence-based trials, the current use of acetazolamide in comparison with placebo or with topiramate has been evaluated. In the interventions' field, there seems to be a consonance about the alarming symptoms and what the most suitable operation is in each case. There is some disagreement about the indications for venous sinus transversus stenting and its risk/benefit ratio.

CONCLUSIONS

Until now there is no class I guideline to which our decision-making can be based on for the management of IIH. A lack of systematic reviews and randomised control trials has been noted. If we focused our research on that, we could develop a standardised treatment protocol.

Idiopathic Intracranial Hypertension: Prognostic Factors and Multidisciplinary Management

BACKGROUND

Idiopathic intracranial hypertension (IIH) mostly affects young obese women and can lead to permanent visual impairment. However, prognostic factors and therapeutic strategy remain unclear.

METHODS

We retrospectively collected data from all patients diagnosed and managed for IIH in our university center from January 2001 to December 2016.

RESULTS

Seventy-nine patients were diagnosed with IIH. Bilateral transverse sinus stenosis (TSS) was found in 74% of the population. Visual outcome at 6 months was poor for 46% of patients, including all patients presenting weight gain of at least 5% since diagnosis (p < 0.001), whereas mean body mass index at diagnosis was not different between patients with poor versus good outcome (32.9 ± 7.7 versus 34.6 ± 9.4 kg·m^-2). Other significant factors of poor prognosis were bilateral TSS (OR = 5.2; 95 CI: 1.24-24.9; p = 0.024). Thirteen patients with poor outcome after 6-month assessment underwent unilateral TSS stenting leading to visual improvement in 11 cases.

CONCLUSION

Weight gain, rather than initial weight, emerged as the leading factor of poor visual outcome in patients with IIH, followed by presence of bilateral TSS. Consequently, first-line treatment must include dietary measures to control weight. Unilateral stenting appears to be a safe second-line treatment option for patients with bilateral TSS.

Evolving evidence in adult idiopathic intracranial hypertension: pathophysiology and management

Idiopathic intracranial hypertension (IIH) is a rare but important disease associated with significant morbidity. There is an expected rise in prevalence in line with the escalating global burden of obesity. Modern revisions in the terminology and diagnostic criteria for IIH help guide clinicians in investigations and researchers in standardising recruitment criteria for clinical trials. The pathophysiology of IIH is incompletely characterised; suggested underpinning mechanisms include the role of cerebrospinal fluid regulation as well as metabolic and endocrinological perspectives. Recent treatment trials are providing insights into the management but debate still surrounds key areas in treatment. This review will provide an up-to-date discussion on the potential pathogenic mechanisms and management of IIH.

Evidence for potential involvement of pro-inflammatory adipokines in the pathogenesis of idiopathic intracranial hypertension

Background Although specific role players are currently unknown, contribution of inflammatory mediators has been suggested in the pathophysiology of idiopathic intracranial hypertension (IIH), which is a disease more prevalent in obese female individuals of childbearing age. We aimed to investigate the levels of adipokines and cytokines to demonstrate possible markers for inflammation that participate in IIH pathophysiology and their association with clinical features of IIH. Methods IIH patients, diagnosed according to the revised criteria, and age-, gender- and body mass index (BMI)-matched healthy controls were enrolled in this study. Serum samples were evaluated for insulin-like growth factor 1, insulin, nesfatin, adiponectin, interleukin (IL)-1β, IL-6, IL-8, leptin, plasminogen activator inhibitor type-1, resistin, tumour necrosis factor-alpha (TNF-α) and monocyte chemotactic protein 1 via enzyme-linked immunosorbent assay or multiplex immunoassays. Results IL-1β level was significantly higher ( p = 0.012), and IL-8 and TNF-α levels were significantly lower in the IIH group ( p < 0.001 and p = 0.008, respectively) compared to the control group. There were no correlations between the cytokine/adipokine levels and age, BMI, disease duration, and cerebrospinal fluid oligoclonal bands. There were also no significant differences in cytokine and adipokine levels between IIH patients regarding visual impairment. However, statistically significant differences were found between IIH patients with relapse versus healthy controls regarding IL-1β ( p = 0.007), IL-8 ( p = 0.001) and TNF-α ( p = 0.017) levels. Other investigated cytokines and adipokines showed no significant alterations in IIH patients investigated in the remission period. Conclusion Altered serum levels of IL-1β, IL-8 and TNF-α seem to be associated with IIH pathogenesis, and these cytokines may be used as prognostic markers in IIH to predict relapse.

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.

Decreased levels of aquaporin-4 in the cerebrospinal fluid of patients with idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension is characterized by increased intracranial pressure. Its pathogenesis is largely unknown. Aquaporins may play a role in the homeostasis of cerebrospinal fluid.

METHODS

We aimed to elucidate the role of aquaporins in idiopathic intracranial hypertension by measuring the level of aquaporin-1 and aquaporin-4 in the cerebrospinal fluid and plasma of 28 patients and 29 controls by enzyme-linked immunosorbent assay. The adipokines leptin and retinol-binding protein 4 were also measured.

RESULTS

We found a reduction in aquaporin-4 in the cerebrospinal fluid of patients. Leptin levels were increased in the cerebrospinal fluid and plasma of patients and were correlated with weight, body mass index and body fat. There was no difference between patients and controls in the levels of aquaporin-1 and retinol-binding protein 4.

CONCLUSION

Our data suggest that an imbalance of aquaporin-4 in the cerebrospinal fluid of patients with idiopathic intracranial hypertension may contribute to the pathogenesis of this disorder.

Osmolality of Cerebrospinal Fluid from Patients with Idiopathic Intracranial Hypertension (IIH)

INTRODUCTION

Idiopathic intracranial hypertension (IIH) is a disorder of increased intracranial fluid pressure (ICP) of unknown etiology. This study aims to investigate osmolality of cerebrospinal fluid (CSF) from patients with IIH.

METHODS

We prospectively collected CSF from individuals referred on suspicion of IIH from 2011-2013. Subjects included as patients fulfilled Friedman and Jacobson's diagnostic criteria for IIH. Individuals in whom intracranial hypertension was refuted were included as controls. Lumbar puncture with ICP measurement was performed at inclusion and repeated for patients after three months of treatment. Osmolality was measured with a Vapor Pressure Osmometer.

RESULTS

We collected 90 CSF samples from 38 newly diagnosed patients and 28 controls. At baseline 27 IIH-samples and at 3 months follow-up 35 IIH-samples were collected from patients. We found no significant differences in osmolality between 1) patients at baseline and controls (p = 0. 86), 2) patients at baseline and after 3 months treatment (p = 0.97), and 3) patients with normalized pressure after 3 months and their baseline values (p = 0.79). Osmolality in individuals with normal ICP from 6-25 cmH2O (n = 41) did not differ significantly from patients with moderately elevated ICP from 26-45 cmH2O (n = 21) (p = 0.86) and patients with high ICP from 46-70 cmH2O (n = 4) (p = 0.32), respectively. There was no correlation between osmolality and ICP, BMI, age and body height, respectively. Mean CSF osmolality was 270 mmol/kg (± 1 SE, 95% confidence interval 267-272) for both patients and controls.

CONCLUSIONS

CSF osmolality was normal in patients with IIH, and there was no relation to treatment, ICP, BMI, age and body height. Mean CSF osmolality was 270 mmol/kg and constitutes a reference for future studies. Changes in CSF osmolality are not responsible for development of IIH. Other underlying pathophysiological mechanisms must be searched.

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.

Quantification and regulation of the adipokines resistin and progranulin in human cerebrospinal fluid

BACKGROUND

Adipokines bearing the potential to cross the blood-brain barrier (BBB) are promising candidates for the endocrine regulation of central nervous processes and of a postulated fat-brain axis. Resistin and progranulin concentrations in paired serum and cerebrospinal fluid (CSF) samples of patients undergoing neurological evaluation and spinal puncture were investigated.

MATERIALS AND METHODS

Samples of n = 270 consecutive patients with various neurological diseases were collected without prior selection. Adipokine serum and CSF concentrations were measured by enzyme-linked immunosorbent assay and serum and CSF routine parameters by standard procedures. Anthropometric data, medication and patient history were available.

RESULTS

Serum levels of resistin and progranulin were positively correlated among each other, with respective CSF levels, low-density lipoprotein cholesterol levels and markers of systemic inflammation. CSF resistin concentrations were generally low. Progranulin CSF concentrations and CSF/serum progranulin ratio were significantly higher in patients with infectious diseases, with disturbed BBB function and with elevated CSF cell count and presence of oligoclonal bands. Both adipokines are able to cross the BBB depending on a differing patency that increases with increasing grade of barrier dysfunction. Whereas resistin represents a systemic marker of inflammation, CSF progranulin levels strongly depend on the underlying disease and dysfunction of blood-CSF barrier.

CONCLUSIONS

Resistin and progranulin represent novel and putative regulators of the fat-brain axis by their ability to cross the BBB under physiological and pathophysiological conditions. The presented data provide insight into the characteristics of BBB function regarding progranulin and resistin and the basis for future establishment of normal values for CSF concentrations and CSF/serum ratios.

Over-drainage and persistent shunt-dependency in patients with idiopathic intracranial hypertension treated with shunts and bariatric surgery

Background:

Idiopathic intracranial hypertension (IIH) may lead to visual impairment. Shunt surgery is indicated for refractory IIH-related symptoms that persist despite medical treatment, or those presenting with significant visual decline. Obesity is a risk factor for IIH; a reduction in weight has been shown to improve papilledema. Bariatric surgery (BS) has been suggested for treating IIH associated with morbid obesity. In this study, we describe a high rate of over-drainage (OD) seen in patients following shunts and BS.

Methods:

The study cohort includes 13 patients with IIH that underwent shunt surgery for treatment of the IIH-related symptoms. Six patients underwent BS in addition to the shunt surgery (but not concomitantly). Seven patients had only shunt surgeries with no BS. Data were collected retrospectively.

Results:

BS effectively led to weight reduction (body mass index decreasing from 43 ± 4 to 28 ± 5). Patients undergoing BS had 1–6 (2.5 ± 1.9) shunt revisions for OD following BS, as opposed to 0–3 (1.4 ± 1.1) revisions prior to BS over similar time spans (statistically insignificant difference), and 0–6 (1.6 ± 2.5) revisions among the non-BS patients over a longer time span (statistically insignificant difference). Two patients in the BS group underwent shunt externalization and closure; however, they proved to be shunt-dependent.

Conclusions:

Patients with IIH that undergo shunt surgery and BS (not concomitantly) may suffer from OD symptoms, necessitating multiple shunt revisions, and valve upgrades. Despite BS being a valid primary treatment for some patients with IIH, among shunted patients, BS may not lead to resolution of IIH-related symptoms and patients may remain shunt-dependent.

An integrated mechanism of pediatric pseudotumor cerebri syndrome: evidence of bioenergetic and hormonal regulation of cerebrospinal fluid dynamics

Pseudotumor cerebri syndrome (PTCS) is defined by the presence of elevated intracranial pressure (ICP) in the setting of normal brain parenchyma and cerebrospinal fluid (CSF). Headache, vision changes, and papilledema are common presenting features. Up to 10% of appropriately treated patients may experience permanent visual loss. The mechanism(s) underlying PTCS is unknown. PTCS occurs in association with a variety of conditions, including kidney disease, obesity, and adrenal insufficiency, suggesting endocrine and/or metabolic derangements may occur. Recent studies suggest that fluid and electrolyte balance in renal epithelia is regulated by a complex interaction of metabolic and hormonal factors; these cells share many of the same features as the choroid plexus cells in the central nervous system (CNS) responsible for regulation of CSF dynamics. Thus, we posit that similar factors may influence CSF dynamics in both types of fluid-sensitive tissues. Specifically, we hypothesize that, in patients with PTCS, mitochondrial metabolites (glutamate, succinate) and steroid hormones (cortisol, aldosterone) regulate CSF production and/or absorption. In this integrated mechanism review, we consider the clinical and molecular evidence for each metabolite and hormone in turn. We illustrate how related intracellular signaling cascades may converge in the choroid plexus, drawing on evidence from functionally similar tissues.

Idiopathic intracranial hypertension and obesity

Idiopathic intracranial hypertension (IIH), also known as primary pseudotumor cerebri syndrome (PTCS), is a condition of unknown etiology which affects primarily overweight, reproductive-aged women and causes increased intracranial pressure (ICP). This review discusses the recently revised diagnostic criteria for PTCS for adults and children. Additionally, the role of obesity in the epidemiology, etiology, and management of IIH as well as the current knowledge of obesity profiles and markers in IIH are reviewed. We also highlight the emerging, unifying theory of the neuroendocrine effects on the mineralocorticoid receptor to explain a possible mechanism for the increased cerebrospinal fluid production and ICP in secondary PTCS.

Clinical characterization of idiopathic intracranial hypertension in children presenting to the emergency department: the experience of a large tertiary care pediatric hospital

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a syndrome characterized by elevated intracranial pressure, without evidence of intracranial mass lesion or venous thrombosis on brain imaging. The syndrome occurs mainly in young, fertile, and overweight women but may present in any age group. The aim of this study was to report the presentation, course, and outcomes of older versus younger children presenting with IIH to the emergency department of our large tertiary care hospital during an 8-year period.

METHODS

Retrospective chart review (January 2000-December 2008) of all patients younger than 17 years with IIH was performed on the basis of modified Dandy Criteria. The patients were analyzed according to age (<11 years and 11-17 years) and weight centile (<90%, 90%-97%, >97%).

RESULTS

Ages ranged from 2 to 16.5 years (mean [SD], 9.71 [4.56] years). Thirty males (46.8%) and 33 females (53.2%) were identified: 30 were prepubertal with a male-female ratio of 1:0.56 and 33 were pubertal with a male-female ratio of 1:2 (P < 0.05). There were no significant differences between the 2 age groups in proportions of children in the 3 predefined weight categories The most common presenting symptom was headache (75%), which was significantly less common in the younger age group compared with the older group (P < 0.01). Papilledema was present in 51 patients (82.3%). Mean (SD) cerebrospinal fluid opening pressure was 378 (16) mm H2O. Findings of brain imaging (mostly computed tomographic scan), performed in all patients, were normal in 42 (67.7%); the most common finding in the remainder was swelling of the optic nerves.

CONCLUSIONS

Our results indicate that IIH should be considered in any child with new-onset headache or visual disturbance, irrespective of age, sex, weight, or the presence of known predisposing factors. When IIH is suspected, neuroimaging should be performed promptly to exclude secondary causes of this condition because IIH in children remains a diagnosis of exclusion. Early diagnosis and prompt treatment for IIH can prevent potential visual loss.

Idiopathic intracranial hypertension

Background

Idiopathic intracranial hypertension or pseudotumour cerebri is primarily a disorder of young obese women characterised by symptoms and signs associated with raised intracranial pressure in the absence of a space-occupying lesion or other identifiable cause.

Summary

The overall incidence of idiopathic intracranial hypertension is approximately two per 100,000, but is considerably higher among obese individuals and, given the global obesity epidemic, is likely to rise further. The pathophysiology of this condition is poorly understood, but most theories focus on the presence of intracranial venous hypertension and/or increased cerebrospinal fluid outflow resistance and how this relates to obesity. A lack of randomised clinical trials has resulted in unsatisfactory treatment guidelines and although weight loss is important, especially when used in conjunction with drugs that reduce cerebrospinal fluid production, resistant cases remain difficult to manage and patients invariably undergo neurosurgical shunting procedures. The use of transverse cerebral sinus stenting remains contentious and long-term benefits are yet to be determined.

Conclusion

An understanding of the clinical features, diagnostic work-up and therapeutic options available for patients with idiopathic intracranial hypertension is important both for neurologists and ophthalmologists as visual loss maybe permanent if untreated.

Idiopathic intracranial hypertension; research progress and emerging themes

Idiopathic intracranial hypertension (IIH) is a condition characterised by increased intracranial pressure of unknown cause predominantly seen in obese women of childbearing age and associated with a history of recent weight gain. The aetiology is poorly understood and there are no evidence-based guidelines on the management of the disease. We aim to provide a review of the recent literature outlining the latest advances in this field over the past few years. Areas of emerging interest related to the pathophysiology of IIH will be discussed, such as the role of obesity, adipose tissue and 11β-hydroxysteroid dehydrogenase type 1. We consider the latest research on the role of venous sinus stenosis in IIH and ex vivo advances into cerebrospinal fluid drainage via the arachnoid granulation tissue. The latest techniques for optic nerve head evaluation and the role of optical coherence tomography will be summarised. Finally, we will discuss recent advances in the management of IIH, including weight loss, and medical and surgical treatment strategies.

Is the brain water channel aquaporin-4 a pathogenetic factor in idiopathic intracranial hypertension? Results from a combined clinical and genetic study in a Norwegian cohort

PURPOSE

Idiopathic intracranial hypertension (IIH) is a condition of increased intracranial pressure of unknown aetiology. Patients with IIH usually suffer from headache and visual disturbances. High intracranial pressure despite normal ventricle size and negative MRI indicate perturbed water flux across cellular membranes, which is provided by the brain water channel aquaporin-4 (AQP4). IIH could be associated with malfunctioning intracerebral water homeostasis and cerebrospinal fluid (CSF) reabsorption based on functional or regulatory alterations of AQP4.

METHODS

Clinical data, blood and CSF samples were collected from 28 patients with IIH. Clinical characteristics were assessed, and a genetic association study was performed by sequencing the AQP4 gene on chromosome 18. Genetic data were compared with 52 healthy controls and matched by age, sex and ethnicity. Chi-square test and linear discriminant analysis (LDA) were used in the search of a genotype-phenotype association.

RESULTS

While the majority of patients responded to medical treatment, four required shunt application. All, except one, had a good visual outcome. The 24 AQP4 gene SNPs showed no association with IIH. Full cross-validation of the LDA modelling resulted in only 55.1% correct classification of the cases and controls, with a corresponding estimated p-value 0.37.

CONCLUSIONS

Our genetic case-control study did not indicate an association between AQP4 gene variants and IIH. However, the theory of an etiopathogenic link between IIH and AQP4 is tempting, and discussed in this article. Association studies with large sample size are difficult to perform owing is the rarity of the condition.

Proteomic analysis of cerebrospinal fluid from obese women with idiopathic intracranial hypertension: a new approach for identifying new candidates in the pathogenesis of obesity

Body weight control is tightly regulated in the hypothalamus. The inaccessibility of human brain tissue can be partially solved by using cerebrospinal fluid (CSF) as a tool for assessing the central nervous system's production of orexigen and anorexigen factors. Using proteomic analysis, the present study investigated the differentially displayed proteins in human CSF from obese and non-obese subjects. We designed a case-control study conducted in a reference hospital where eight obese (cases) and eight non-obese (controls) women with idiopathic intracranial hypertension were included. Intracranial hypertension was normalised through the placement of a ventriculo- or lumboperitoneal shunt in the 12 months before their inclusion in the study. Isotope-coded protein label (for proteins > 10 kDa) and label-free liquid chromatography (for proteins < 10 kDa) associated with mass spectrometry analysis were used. Eighteen differentially expressed proteins were identified. Many of them fall into three main groups: inflammation (osteopontin, fibrinogen γ and β chain, α1 acid glycoprotein 2 and haptoglobin), neuroendocrine mediators (neurosecretory protein VGF, neuroendocrine protein 7B2, chromogranin-A and chromogranin B), and brain plasticity (testican-1, isoform 10 of fibronectin, galectin-3 binding protein and metalloproteinase inhibitor type 2). The differential production of osteopontin, neurosecretory protein VGF, chromogranin-A and fibrinogen γ chain was further confirmed by either enzyme-linked immunosorbent assay or western blotting. In conclusion, we have identified potential candidates that could be involved in the pathogenesis of obesity. Further studies aiming to investigating the precise role of these proteins in the pathogenesis of obesity and their potential therapeutic implications are needed.

The syndrome of pseudotumour cerebri and idiopathic intracranial hypertension

PURPOSE OF REVIEW

Idiopathic intracranial hypertension (IIH) is a condition in which raised intracranial pressure is associated with a high body mass index, and in those societies in which the prevalence of obesity is increasing the disorder is of increasing importance. It is one cause of the syndrome of pseudotumour cerebri but the cause and the link with a rise in body weight are not understood. Furthermore the treatment of the more severe, sight-threatening cases is controversial.

RECENT FINDINGS

A major theme in recent years has been an attempt to identify the underlying mechanism of IIH. Some theories - such as the dural sinus stenosis theory - seem to ignore the relationship with weight gain; others have proposed a direct link between obesity and raised intracranial pressure through a specific fat distribution in the body; others through the production of lipokines; and yet others have suggested a converse causation with raised intracranial pressure giving rise to obesity. Uncontrolled case series continue to demonstrate the success of interventions such as cerebrospinal fluid diversion procedures, venous sinus stenting and bariatric surgery but there are no level 1 clinical trials.

SUMMARY

Interest in IIH is increasing and currently generating numerous studies but there is no consensus view on either cause or management.

The incidence and prevalence of idiopathic intracranial hypertension in Sheffield, UK

BACKGROUND AND PURPOSE

The purpose of this study was to identify the incidence and prevalence of idiopathic intracranial hypertension (IIH) in Sheffield, UK.

METHODS

A retrospective review of case notes was conducted to identify cases of IIH seen between 1 January 2007 and 31 December 2008.

RESULTS

Sixteen (15 women and 1 man) new patients were identified to give an incidence within Sheffield of 1.56/100,000/year and 2.86/100,000/year for women. The incidence of IIH in obese women was 11.9/100,000/year. The prevalence of IIH was calculated as 10.9/100,000, and 85.7/100,000 in obese women.

CONCLUSION

A higher incidence of IIH than previously reported UK data was found, which may be because of increasing obesity within the population, or improved case ascertainment.