Visual Field Outcomes for the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT)

The Psychological and Cognitive Landscape of Adult Idiopathic Intracranial Hypertension: A Scoping Review

Purpose of Review

Idiopathic intracranial hypertension (IIH) is a chronic headache disorder with increasing prevalence. Although characterized by raised intracranial pressure causing papilledema with a risk of visual impairment, psychological symptoms such as depression, anxiety, and cognitive impairment are frequently seen but are understudied and under-reported. Together, these can negatively affect quality of life. These were explored through a systematic PRISMA scoping review. OVID, EMBASE, Cochrane, and PubMed databases were searched in April 2023, limited to those in English and published during January 2000-March 2023. PROSPERO ID CRD42023399410.

Recent Findings

From 454 identified studies, 24 relevant articles were identified from a range of countries including the United Kingdom, the United States, Israel, Egypt, Canada, Germany, and Brazil. Data on study design, participants, tests performed, and outcomes were collated. There is a considerable burden of psychiatric, affective, and cognitive conditions, as well as impaired quality of life, in adult patients with IIH. Notably, these were independently correlated with the presence of headache in a number of studies and with obesity in others.

Summary

Aside from optimizing symptom control, including reducing the severity of headaches and protecting visual function, clinicians should be mindful of the biopsychosocial difficulties and potential cognitive impairments patients with IIH face. Assistance may be required with managing concurrent depression and anxiety, as well as optimizing cognitive function. Incorporating neuropsychological assessment and individualized management strategies may be beneficial at the point of diagnosis and throughout the illness.

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.

Longitudinal optical coherence tomography indices in idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) may result in optic nerve fiber loss and even atrophy. The timing of the optical coherence tomography (OCT) indices reaching the lowest point (nadir) and the factors that predict the patient's anatomical outcome are not known. We aimed to determine the timing and the factors that affect nadir retinal nerve fiber layer (RNFL) thickness. The medical records of 99 IIH patients who were treated from December 2009 to January 2020 were retrospectively reviewed. The mean RNFL thickness at presentation was 263.5 ± 106.4 µm. The mean time to nadir was 7.9 ± 6.3 months. The average RNFL and ganglion cell complex (GCC) thickness at the nadir were 92.6 ± 14.5 µm (47% showed thinning) and 77.9 ± 27.8 µm (70% showed thinning), respectively. The Frisén disc edema stage and average RNFL thickness at baseline correlated with a longer time to nadir, (r = 0.28 P = 0.003 and r = 0.24, P = 0.012, respectively). The nadir average RNFL thickness and the nadir average GCC thickness (r = 0.32, P = 0.001, r = 0.29, P = 0.002, respectively) correlated with the baseline visual field mean deviation. The final anatomical outcome of IIH episodes in this study resulted in RNFL and GCC thinning. The time to RNFL nadir and its values correlated with IIH severity at presentation.

Interpretation of the Visual Field in Neuro-ophthalmic Disorders

PURPOSE OF REVIEW

In this review, we will describe current methods for visual field testing in neuro-ophthalmic clinical practice and research, develop terminology that accurately describes patterns of field deficits, and discuss recent advances such as augmented or virtual reality-based perimetry and the use of artificial intelligence in visual field interpretation.

RECENT FINDINGS

New testing strategies that reduce testing times, improve patient comfort, and increase sensitivity for detecting small central or paracentral scotomas have been developed for static automated perimetry. Various forms of machine learning-based tools such as archetypal analysis are being tested to quantitatively depict and monitor visual field abnormalities in optic neuropathies. Studies show that the combined use of optical coherence tomography and standard automated perimetry to determine the structure-function relationship improves clinical care in neuro-ophthalmic disorders. Visual field assessment must be performed in all patients with neuro-ophthalmic disorders affecting the afferent visual pathway. Quantitative visual field analysis using standard automated perimetry is critical in initial diagnosis, monitoring disease progression, and guidance of therapeutic plans. Visual field defects can adversely impact activities of daily living such as reading, navigation, and driving and thus impact quality of life. Visual field testing can direct appropriate occupational low vision rehabilitation in affected individuals.

Guidelines of the International Headache Society for Controlled Clinical Trials in Idiopathic Intracranial Hypertension

The quality of clinical trials is essential to advance treatment, inform regulatory decisions and meta-analysis. With the increased incidence of idiopathic intracranial hypertension and the emergence of clinical trials for novel therapies in this condition, the International Headache Society Guidelines for Controlled Clinical Trials in Idiopathic Intracranial Hypertension aims to establish guidelines for designing state-of-the-art controlled clinical trials for idiopathic intracranial hypertension.

MRI features of idiopathic intracranial hypertension are not prognostic of visual and headache outcome

BACKGROUND

In idiopathic intracranial hypertension (IIH), certain MRI features are promising diagnostic markers, but whether these have prognostic value is currently unknown.

METHODS

We included patients from the Vienna-Idiopathic-Intracranial-Hypertension (VIIH) database with IIH according to Friedman criteria and cranial MRI performed at diagnosis. Presence of empty sella (ES), perioptic subarachnoid space distension (POSD) with or without optic nerve tortuosity (ONT), posterior globe flattening (PGF) and transverse sinus stenosis (TSS) was assessed and multivariable regression models regarding visual outcome (persistent visual impairment/visual worsening) and headache outcome (headache improvement/freedom of headache) were fitted.

RESULTS

We included 84 IIH patients (88.1% female, mean age 33.5 years, median body mass index 33.7). At baseline, visual impairment was present in 70.2% and headache in 84.5% (54.8% chronic). Persistent visual impairment occurred in 58.3%, visual worsening in 13.1%, headache improvement was achieved in 83.8%, freedom of headache in 26.2%. At least one MRI feature was found in 78.6% and 60.0% had ≥3 features with POSD most frequent (64.3%) followed by TSS (60.0%), ONT (46.4%), ES (44.0%) and PGF (23.8%). In multivariable models, there was no association of any single MRI feature or their number with visual impairment, visual worsening, headache improvement or freedom. Visual impairment at baseline predicted persistent visual impairment (odds ratio 6.3, p<0.001), but not visual worsening. Chronic headache at baseline was significantly associated with lower likelihood of headache freedom (odds ratio 0.48, p=0.013), but not with headache improvement.

CONCLUSIONS

MRI features of IIH are neither prognostic of visual nor headache outcome.

Archetypal analysis of longitudinal visual fields for idiopathic intracranial hypertension patients presenting in a clinic setting

We previously applied archetypal analysis (AA) using visual fields (VF) from the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) to derive a model, which quantified patterns (or archetypes [ATs] of VF loss), anticipated recovery, and identified residual VF deficits. We hypothesized that AA could produce similar results using IIH VFs collected in clinical practice. We applied AA to 803 VFs from 235 eyes with IIH from an outpatient neuro-ophthalmology clinic and created a clinic-derived model of ATs, with the relative weight (RW) and average total deviation (TD) for each AT. We also created a combined-derived model from an input dataset containing the clinic VFs and 2862 VFs from the IIHTT. We used both models to decompose clinic VF into ATs of varying percent weight (PW), correlated presentation AT PW with mean deviation (MD), and evaluated final visit VFs considered "normal" by MD ≥ -2.00 dB for residual abnormal ATs. The 14-AT clinic-derived and combined-derived models revealed similar patterns of VF loss previously identified in the IIHTT model. AT1 (a normal pattern) was most prevalent in both models (RW = 51.8% for clinic-derived; 35.4% for combined-derived). Presentation AT1 PW correlated with final visit MD (r = 0.82, p < 0.001 for the clinic-derived model; r = 0.59, p < 0.001 for the combined-derived model). Both models showed ATs with similar patterns of regional VF loss. The most common patterns of VF loss in "normal" final visit VFs using each model were clinic-derived AT2 (mild global depression with enlarged blind spot; 44/125 VFs; 34%) and combined-derived AT2 (near-normal; 93/149 VFs; 62%). AA provides quantitative values for IIH-related patterns of VF loss that can be used to monitor VF changes in a clinic setting. Presentation AT1 PW is associated with the degree of VF recovery. AA identifies residual VF deficits not otherwise indicated by MD.

Visual Field Pointwise Analysis of the Idiopathic Intracranial Hypertension Weight Trial (IIH:WT)

Purpose

This study was designed to determine if point analysis of the Humphrey visual field (HVF) is an effective outcome measure for people with idiopathic intracranial hypertension (IIH) compared with mean deviation (MD).

Methods

Using the IIH Weight Trial data, we performed a pointwise analysis of the numerical retinal sensitivity. We then defined a medically treated cohort as having MDs between -2 dB and -7 dB and calculated the number of points that would have the ability to change by 7 dB.

Results

The HVF 24-2 mean ± SD MD in the worse eye was -3.5 ± 1.1 dB (range, -2.0 to -6.4 dB). Total deviation demonstrated a preference for the peripheral and blind spot locations to be affected. Points between 0 dB and -10 dB demonstrated negligible ability to improve, compared with those between -10 dB and -25 dB. For the evaluation of the feasibility for a potential medical intervention trial, only 346 points were available for analysis between -10 dB and -25 dB bilaterally, compared with 4123 points in baseline sensitivities of 0 to -10 dB.

Conclusions

Patients with IIH have mildly affected baseline sensitivities in the visual field based on HVF analyzer findings, and the majority of points do not show substantial change over 24 months in the setting of a randomized clinical trial. Most patients with IIH who are eligible for a medical treatment trial generally have the mildest affected baseline sensitivities. In such patients, pointwise analysis offers no advantage over MD in detection of visual field change.

Idiopathic intracranial hypertension presenting with migraine phenotype is associated with unfavorable headache outcomes

OBJECTIVE

To assess the prognostic impact of migraine headache in idiopathic intracranial hypertension (IIH).

BACKGROUND

Migraine headache is common in IIH, but it is unclear whether it has prognostic relevance.

METHODS

We investigated patients with IIH from the Vienna-IIH-database and differentiated migraine (IIH-MIG) from non-migraine headache (IIH-nonMIG) and without headache (IIH-noHA). Using multivariable models, we analyzed the impact of IIH-MIG on headache and visual outcomes 12 months after diagnosis.

RESULTS

Among 97 patients (89% female, mean [SD] age 32.9 [11.1] years, median body mass index 32.0 kg/m2 , median cerebrospinal fluid opening pressure 310 mm), 46% were assigned to IIH-MIG, 37% to IIH-nonMIG (11% tension-type, 26% unclassifiable), and 17% to IIH-noHA. Overall, headache improvement was achieved in 77% and freedom of headache in 28%. The IIH-MIG group showed significantly lower rates for headache improvement (67% vs. 89% in IIH-nonMIG, p = 0.019) and freedom of headache (11% vs. 33% in IIH-nonMIG and 63% in IIH-noHA, p = 0.015). These differences persisted when only analyzing patients with resolved papilledema at follow-up. In contrast, visual worsening was significantly less common in IIH-MIG (9% vs. 28% in IIH-nonMIG and 31% in IIH-noHA, p = 0.045). In multivariable models, IIH-MIG was associated with a significantly lower likelihood of achieving headache improvement (odds ratio [OR] 0.57, 95% confidence interval [CI] 0.40-0.78, p < 0.001) and freedom of headache (OR 0.29, 95% CI 0.12-0.46, p < 0.001), but also a lower risk for visual worsening (OR 0.26, 95% CI 0.04-0.82, p < 0.001).

CONCLUSIONS

In IIH, migraine headache is associated with unfavorable outcomes for headache, even when papilledema has resolved, and possibly favorable visual outcome.

Management of recurrent cerebrospinal fluid leak, current practices and open challenges. A systematic literature review

Cerebrospinal fluid leak (CSFL) is a rare pathological condition which requires prompt and adequate management due to the high rate of associated major complications. At present, CSFL can be successfully treated through endoscopic endonasal approaches with success rates higher than 90%. Despite this, CSFL recurrence may occur, and its management is critical and still represents a matter of debate. A systematic review of the literature on the management of recurrent CSFL was conducted. It included a cohort of 1,083 cases of CSFL treated with surgical or conservative approaches; 112 cases of recurrence were reported for an overall recurrence rate of 10.3%. Most of the leaks were localised in the anterior skull base (68.3%) and identification of recurrent CSFL may be troublesome. Therefore, the entire skull base must be meticulously examined and long-term follow-up is mandatory. The risk for CSFL recurrence is higher in patients affected by idiopathic intracranial hypertension (IIH), but its role in CSFL recurrence is yet to be understood. Recurrent CSFL must be repaired as soon as possible in order to reduce the risk of intracranial complications. The use of early post-operative CSF diversion by lumbar drain (LD) is currently a matter of debate even in case of CSFL recurrences.

A Consensus Statement on the Terminology for Automated Visual Field Abnormalities

BACKGROUND

A multitude of terms have been used to describe automated visual field abnormalities. To date, there is no universally accepted system of definitions or guidelines. Variability among clinicians creates the risk of miscommunication and the compromise of patient care. The purposes of this study were to 1) assess the degree of consistency among a group of neuro-ophthalmologists in the description of visual field abnormalities and 2) to create a consensus statement with standardized terminology and definitions.

METHODS

In phase one of the study, all neuro-ophthalmologists in Israel were asked to complete a survey in which they described the abnormalities in 10 selected automated visual field tests. In phase 2 of the study, the authors created a national consensus statement on the terminology and definitions for visual field abnormalities using a modified Delphi method. In phase 3, the neuro-ophthalmologists were asked to repeat the initial survey of the 10 visual fields using the consensus statement to formulate their answers.

RESULTS

Twenty-six neuro-ophthalmologists participated in the initial survey. On average, there were 7.5 unique descriptions for each of the visual fields (SD 3.17), a description of only the location in 24.6% (SD 0.19), and an undecided response in 6.15% (SD 4.13). Twenty-two neuro-ophthalmologists participated in the creation of a consensus statement which included 24 types of abnormalities with specific definitions. Twenty-three neuro-ophthalmologists repeated the survey using the consensus statement. On average, in the repeated survey, there were 5.9 unique descriptions for each of the visual fields (SD 1.79), a description of only the location in 0.004% (SD 0.01), and an undecided response in 3.07% (SD 2.11%). Relative to the first survey, there was a significant improvement in the use of specific and decisive terminology.

CONCLUSIONS

The study confirmed a great degree of variability in the use of terminology to describe automated visual field abnormalities. The creation of a consensus statement was associated with improved use of specific terminology. Future efforts may be warranted to further standardize terminology and definitions.

Unsupervised Machine Learning Shows Change in Visual Field Loss in the Idiopathic Intracranial Hypertension Treatment Trial

PURPOSE

We previously reported that archetypal analysis (AA), a type of unsupervised machine learning, identified and quantified patterns of visual field (VF) loss in idiopathic intracranial hypertension (IIH), referred to as archetypes (ATs). We assessed whether AT weight changes over time are consistent with changes in conventional global indices, whether visual outcome or treatment effects are associated with select AT, and whether AA reveals residual VF defects in eyes deemed normal after treatment.

DESIGN

Analysis of data collected from a randomized controlled trial.

PARTICIPANTS

Two thousand eight hundred sixty-two VFs obtained from 165 participants during the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT).

METHODS

We applied a 14-AT model derived from IIHTT VFs. We examined changes in individual AT weights over time for all study eyes and evaluated differences between treatment groups. We created an AT change score to assess overall VF change from baseline. We tested threshold baseline AT weights for association with VF outcome and treatment effect at 6 months. We determined the abnormal ATs with meaningful weight at outcome for VFs with a mean deviation (MD) of -2.00 dB or more.

MAIN OUTCOME MEASURES

Individual AT weighting coefficients and MD.

RESULTS

Archetype 1 (a normal VF pattern) showed the greatest weight change for all study eyes, increasing from 11.9% (interquartile range [IQR], 0.44%-24.1%) at baseline to 31.2% (IQR, 16.0%-45.5%) at outcome (P < 0.001). Archetype 1 weight change (r = 0.795; P < 0.001) and a global score of AT change (r = 0.988; P < 0.001) correlated strongly with MD change. Study eyes with baseline AT2 (a mild diffuse VF loss pattern) weight of 44% or more (≥ 1 standard deviation more than the mean) showed higher AT2 weights at outcome than those with AT2 weight of < 44% at baseline (P < 0.001). Only the latter group showed a significant acetazolamide treatment effect. Archetypal analysis revealed residual VF loss patterns, most frequently representing mild diffuse loss and an enlarged blind spot in 64 of 66 study eyes with MD of -2.00 dB or more at outcome.

CONCLUSIONS

Archetypal analysis provides a quantitative approach to monitoring VF changes in IIH. Baseline AT features may be associated with treatment response and VF outcome. Archetypal analysis uncovers residual VF defects not otherwise revealed by MD.

Idiopathic Intracranial Hypertension - Challenges and Pearls

Idiopathic intracranial hypertension (IIH) is defined as a syndrome of raised intracranial pressure with normal imaging of the brain and cerebrospinal fluid (CSF) composition. There is a rising incidence and prevalence of this disease related to the increased prevalence of obesity. It typically affects women of working age, and headache is the predominant morbidity in over 90%. The disease is also more prevalent in young males. There are many controversies and myths that surround IIH. There are currently few treatment options for IIH, management is typically medical with those experiencing progressive visual loss undergoing surgical procedures. Weight loss and venous sinus stenting are a few therapies directed at the etiology.

[Idiopathic intracranial hypertension (case study)]

Idiopathic intracranial hypertension (IIH) is a rare pathological condition that without proper therapy often results in permanent vision loss. Diagnosis of IIH is often difficult, since it is characterized by a combination of numerous specific and non-specific ophthalmological and neurological criteria. Difficulties in diagnosis significantly delay the prescription of treatment, which affects the visual prognosis. The description of this clinical case is intended to present our own experience in the diagnosis and management tactics of a patient with this pathology, which will be useful for practicing ophthalmologists.

Unsupervised Machine Learning Identifies Quantifiable Patterns of Visual Field Loss in Idiopathic Intracranial Hypertension

Purpose

Archetypal analysis, a form of unsupervised machine learning, identifies archetypal patterns within a visual field (VF) dataset such that any VF is described as a weighted sum of its archetypes (ATs) and has been used to quantify VF defects in glaucoma. We applied archetypal analysis to VFs affected by nonglaucomatous optic neuropathy caused by idiopathic intracranial hypertension (IIH).

Methods

We created an AT model from 2862 VFs prospectively collected from 330 eyes in the IIH Treatment Trial (IIHTT). We compared baseline IIH AT patterns with their descriptive VF classifications from the IIHTT.

Results

The optimum IIH AT model yielded 14 ATs resembling VF patterns reported in the IIHTT. Baseline VFs contained four or fewer meaningful ATs in 147 (89%) of study eyes. AT2 (mild general VF depression pattern) demonstrated the greatest number of study eyes with meaningful AT weight at baseline (n = 114), followed by AT1 (n = 91). Other ATs captured patterns of blind spot enlargement, hemianopia, arcuate, nasal defects, and more nonspecific patterns of general VF depression. Of all ATs, AT1 (normal pattern) had the strongest correlation with mean deviation (r = 0.69, P < 0.001). For 65 of the 93 VFs with a dominant AT, this AT matched the expert classification.

Conclusions

Archetypal analysis identifies quantifiable, archetypal VF defects that resemble those commonly seen in IIH.

Translational Relevance

Archetypal analysis provides a quantitative, objective method of measuring and monitoring disease-specific regional VF defects in IIH.

Outcomes measures in idiopathic intracranial hypertension

Introduction: Idiopathic intracranial hypertension is a condition characterized by raised intracranial pressure, papilledema, and normal neuroimaging (aside from radiological signs of raised intracranial pressure). Symptoms of idiopathic intracranial hypertension include chronic headaches and for some, visual loss. New treatments are unmet clinical needs.Areas covered: The aim of this review is to present the evidence base and considered opinion on outcome measures to determine successful management of idiopathic intracranial hypertension.Expert opinion: Less invasive measures of disease activity such as optical coherence tomography will continue to grow in this field, both as a measure of papilledema, and potentially as a surrogate for intracranial pressure and visual function. As a highly disabling aspect of the disease is headache, treatment outcomes for headache morbidity need to be appropriately chosen and standardized to allow comparison between trials.

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.

Artifactual Visual Field Defects Identified on Technically "Reliable" Visual Field Studies in a Neuro-Ophthalmology Practice

Purpose

To assess the reliability of automated visual field studies with neurological abnormalities and normal reliability indices that were inconsistent with the remainder of the neuro-ophthalmic assessment.

Methods

Retrospective observational study from the clinical practice of a neuro-ophthalmologist at a tertiary referral center.

Results

From 2230 patient charts, ten cases were identified that met the inclusion criteria. In eight of the cases repeat visual field testing had no reproducible abnormality. Four of these cases were concerning for a bitemporal or homonymous hemianopia. None of the patients, including the two cases with a reproducible defect, developed any convincing manifestations of an organic disease related to the visual field defect.

Conclusion

Our findings suggest that even marked neurological abnormalities on reliable automated visual field tests can be false. When the remainder of the neuro-ophthalmic evaluation is inconsistent with the test result, we recommend that clinicians attempt to immediately repeat the visual field study.

Modeling a potential SANS countermeasure by experimental manipulation of the translaminar pressure difference in mice

The spaceflight-associated neuro-ocular syndrome (SANS), which may present after prolonged exposure to microgravity, is thought to occur due to elevated intracranial pressure (ICP). Intracranial pressure interacts with intraocular pressure (IOP) to define the translaminar pressure difference (TLPD; IOP-ICP). We combined inducible models of ICP and IOP elevation in mice to interrogate the relationships among ICP, IOP, and TLPD, and to determine if IOP elevation could mitigate the phenotypes typically caused by elevated ICP and thereby serve as a countermeasure for SANS. Ten C57BL6J mice of both genders underwent experimental elevation of ICP via infusion of artificial cerebrospinal fluid into the subarachnoid space. One eye also underwent experimental elevation of IOP using the bead injection model. Intraocular pressure and ICP were monitored for 2 weeks. Optokinetic-based contrast sensitivity was measured at baseline and after 2 weeks, and post-mortem studies of optic nerve and retina anatomy were performed. Photopic contrast sensitivity was reduced more in IOP elevated than control eyes. Scotopic contrast sensitivity was reduced similarly in IOP elevated and control eyes. However, the pattern of scotopic vision loss was not uniform in IOP elevated eyes; there was minimal loss in eyes that most closely approximated the normal TLPD. Optic nerve axon loss, increased optic nerve disorganization, and retinal ganglion cell loss all occurred similarly between IOP elevated and control eyes. Elevation of IOP in eyes with elevated ICP may counterbalance some effects on vision loss but exacerbate others, suggesting complex relationships among IOP, ICP, and TLPD.

A systematic review of surgical treatments of idiopathic intracranial hypertension (IIH)

Idiopathic intracranial hypertension denotes raised intracranial pressure in the absence of an identifiable cause and presents with symptoms relating to elevated ICP, namely headaches and visual deterioration. Treatment of IIH aims at reducing intracranial pressure, relieving headache and salvaging patients' vision. Surgical interventions are recommended for medically refractory IIH and include CSF diversion techniques, optic nerve sheath fenestration, bariatric surgery and venous sinus stenting. Prospective studies on the surgical options for IIH are scant and no evidence-based guidelines for the surgical management of medically refractory IIH have been established. A search in Cochrane Library, MEDLINE and EMBASE from 1 January 1985 to 19 April 2019 for controlled or observational studies on the surgical treatment of IIH (defined in accordance with the modified Dandy or the modified Friedman criteria) in adults yielded 109 admissible studies. VSS improved papilledema, visual fields and headaches in 87.1%, 72.7% and 72.1% of the patients respectively, with a 2.3% severe complication rate and 11.3% failure rate. CSF diversion techniques diminished papilledema, visual field deterioration and headaches in 78.9%, 66.8% and 69.8% of the cases and are associated with a 9.4 severe complication rate and a 43.4% failure rate. ONSF ameliorated papilledema, visual field defects and headaches in 90.5, 65.2% and 49.3% of patients. Severe complication rate was 2.2% and failure rate was 9.4%. This is currently the largest systematic review for the available operative modalities for IIH. VSS provided the best results in headache resolution and visual outcomes, with low failure rates and a very favourable complication profile. In light of this, VSS ought to be regarded as the first-line surgical modality for the treatment of medically refractory IIH.

Spontaneous cerebrospinal fluid leak and idiopathic intracranial hypertension

PURPOSE OF REVIEW

To review the most recent literature on the relationship of spontaneous cerebrospinal fluid (CSF) leak with idiopathic intracranial hypertension (IIH) and considerations in management of these conditions.

RECENT FINDINGS

A link has been proposed between spontaneous CSF leak and IIH based on similar demographics, radiologic, and clinical findings in these patients, and on a plausible mechanism of skull base erosion in the setting of high CSF pressure over time. IIH patients with CSF leak may not present with classic IIH signs and symptoms as the leak can alleviate excess pressure; however, they may develop these after a leak is repaired. There may also be a higher risk of leak recurrence if intracranial hypertension is not treated postoperatively.

SUMMARY

A growing body of evidence supports an association between IIH and spontaneous CSF leak. However, this relationship is still not fully elucidated, and there is no current agreement on how to incorporate screening, management, or counseling guidelines for CSF leak into the care of IIH patients. There are also no specific guidelines for evaluation/management of IIH in patients with spontaneous CSF leak. Further interdisciplinary research is needed to explore this connection and to establish screening, evaluation, and management guidelines.

Threshold Static Automated Perimetry of the Full Visual Field in Idiopathic Intracranial Hypertension

Purpose

To characterize visual loss across the full visual field in idiopathic intracranial hypertension (IIH) patients with mild central visual loss.

Methods

We tested the full visual field (50° nasal, 80° temporal, 30° superior, 45° inferior) of 1 eye of 39 IIH patients by using static perimetry (size V) with the Open Perimetry Interface. Participants met the Dandy criteria for IIH and had at least Frisén grade 1 papilledema with better than -5 dB mean deviation (MD) centrally. Two observers (MW and AS) evaluated the visual field defects, adjudicated any differences, and reviewed optical coherence tomography data.

Results

We found a greater MD loss peripherally than centrally (central 26°). The median MD (and corresponding median absolute deviations) was -1.37 dB (1.61 dB) for the periphery and -0.77 dB (0.87 dB) for the central 26°, P < 0.001. There were about 30% more abnormal test locations identified in the periphery (P = 0.12), and the mean defect depth increased with eccentricity (P < 0.001). The most frequent defect found was a temporal wedge (23% of cases) in the periphery with another 23% that included this sector with inferior temporal loss. Although the presence of papilledema limited correlation, 55% of the temporal wedge defects had optical coherence tomography retinal nerve fiber layer deficits in the corresponding superonasal location. Other common visual field defects were inferonasal loss, superonasal loss, and superior and inferior arcuate defects. Seven patients (18%) had visual field defects in the periphery with normal central visual field testing.

Conclusion

In IIH patients, we found substantial visual loss both outside 30° of the visual field and inside 30° with the depth of the defect increasing linearly with eccentricity. Temporal wedge defects were the most common visual field defect in the periphery. Static threshold perimetry of the full visual field appears to be clinically useful in IIH patients.

Decreased retinal nerve fiber layer thickness in patients with cerebral venous thrombosis

Background

To identify thickness variations in the retinal nerve fiber layer around the optic disc and macula in patients with cerebral vein thrombosis (CVT) without papilledema.

Methods

This study included 28 patients with CVT diagnosis and appropriate treatment. Detailed ophthalmologic examination found bilateral vision 10/10, vision field test normal and fundus examination found no papilledema images. The patients had macular and optic retinal nerve fiber layer thickness (RNFL) measured with spectral domain-optical coherence tomography (SD-OCT) (Optovue, Fremont, CA). Patients had retinal nerve fiber thickness compared with a control group.

Results

When the effect on the macula and RNFL near the optic nerve disk is investigated, there was significant thinning identified in the macula inferior inner, temporal inner, superior inner and temporal outer quadrants (p = 0.009, 0.001, 0.026, 0.014, respectively) and in the inferior temporal quadrant of the optic nerve disk (p = 0.020) in CVT patients compared to normal individuals.

Conclusions

Even after appropriate treatment of CVT patients, axonal loss was identified with OCT. As a result, it may be important to use OCT measurements to monitor CVT treatment.

Intracranial hypertension: a current review

PURPOSE OF REVIEW

To provide a current review of recent publications with regards to intracranial hypertension.

RECENT FINDINGS

Attempts were made to provide pediatric data; however, the recent completion of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) has provided a wealth of data with regards to adult intracranial hypertension.The pediatric incidence of intracranial hypertension ranges between 0.63 and 0.71 per 100 000 children. A majority of pediatric cases responded to acetazolamide, with resolution of headache averaging 3.8 weeks. Most patients require less than 1 year of treatment with male sex, older age at diagnosis, primary intracranial hypertension, and lack of headache being predictors of good response. Fluorescein angiography has the highest accuracy in distinguishing true papilledema from pseudopapilledema. The IIHTT found Frisen grade of papilledema was within 1 grade in 92.8% of patients. Monitoring of potassium levels is not required and aplastic anemia was not seen in patients taking acetazolamide.

SUMMARY

Although the newer pediatric studies report incidence rates in pediatric intracranial hypertension are lower than seen in adults, intracranial hypertension is still a concern in pediatrics. There has been a wealth of information with regards to symptomatology, treatment, and outcomes from the IIHTT that will hopefully assist with management in the pediatric population.

Ganglion Cell Complex Analysis as a Potential Indicator of Early Neuronal Loss in Idiopathic Intracranial Hypertension

Reliable visual field testing is the gold standard in identifying future vision loss in patients with Idiopathic Intracranial hypertension (IIH). However, when field performance is unreliable, GCC analysis may be useful. We evaluated IIH patients over three visits: initial visit, follow-up visit and a third visit, almost 1 year later. We evaluated mean deviation (MD), GCC and RNFL at presentation and the second visit and compared it to the mean deviation (MD) on fields at the third visit. As early as the second visit, GCC loss correlated with visual field results seen at the third visit.

Characterization of Retinal Ganglion Cell and Optic Nerve Phenotypes Caused by Sustained Intracranial Pressure Elevation in Mice

Elevated intracranial pressure (ICP) can result in multiple neurologic sequelae including vision loss. Inducible models of ICP elevation are lacking in model organisms, which limits our understanding of the mechanism by which increased ICP impacts the visual system. We adapted a mouse model for the sustained elevation of ICP and tested the hypothesis that elevated ICP impacts the optic nerve and retinal ganglion cells (RGCs). ICP was elevated and maintained for 2 weeks, and resulted in multiple anatomic changes that are consistent with human disease including papilledema, loss of physiologic cupping, and engorgement of the optic nerve head. Elevated ICP caused a loss of RGC somas in the retina and RGC axons within the optic nerve, as well as a reduction in both RGC electrical function and contrast sensitivity. Elevated ICP also caused increased hypoxia-inducible factor (HIF)-1 alpha expression in the ganglion cell layer. These experiments confirm that sustained ICP elevation can be achieved in mice and causes phenotypes that preferentially impact RGCs and are similar to those seen in human disease. With this model, it is possible to model human diseases of elevated ICP such as Idiopathic Intracranial Hypertension and Spaceflight Associated Neuro-ocular Syndrome.

Chronic Headaches After a Concussion in an Obese 16-Year-Old Girl

Jennifer is a 16-year-old Latina girl who is new to your practice. During her first well visit, she mentions that she has had daily headaches for 2 years. They began after sustaining a concussion in a car accident. Typically, her headaches are bilateral and "squeezing"; they occur in the afternoons and last for a few hours. Her concussion also resulted in depressed mood, which has improved over time.When you ask if her headaches have changed recently, she says that they have been worse for the last few days. The quality and severity are unchanged; however, they now occur first thing in the morning, are worse when supine, and no longer remit. In the last 2 days, she has developed new-onset blurry vision, nausea, dizziness, photophobia, and sonophobia. Although she previously experienced sadness with her concussion, she now feels irritable. She has never used tobacco, alcohol, or drugs, and she takes no medications.On examination, her body mass index is above the 99th percentile. You note mild papilledema bilaterally. She has no focal neurological deficits. The remainder of her examination is normal.You send her to an emergency department. Her head computed tomography is normal. A lumbar puncture demonstrates an opening pressure of 32 cm H2O; she feels relief after the procedure. She is admitted with a diagnosis of benign intracranial hypertension and is started on acetazolamide. What is the differential diagnosis of chronic headaches in an obese adolescent? How should a busy community pediatrician manage Jennifer acutely? What follow-up care should Jennifer receive?

The Idiopathic Intracranial Hypertension Treatment Trial: A Review of the Outcomes

OBJECTIVE

The Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) was the first large, randomized study on the use of acetazolamide and weight loss for treatment of idiopathic intracranial hypertension-associated vision loss. The multicenter trial also examined a number of secondary outcomes. This review summarizes all available results of the study published in the literature since 2014.

BACKGROUND

Prior to the IIHTT, clinicians managed idiopathic intracranial hypertension based on data from small, unmasked trials, expert opinion, and clinical experience. Due to the lack of empiric evidence, there were no official treatment protocols to guide treatment of the disorder.

METHODS

We performed a PubMed literature search for all articles with data from the IIHTT Study Group. After review of each article and any relevant supporting literature, the results were compiled into a summary of the literature.

RESULTS

The PubMed search identified 14 articles with primary and/or secondary outcome data from the IIHTT. We summarized the findings for the primary outcome of visual field outcomes in the acetazolamide treatment group compared to the placebo group, as well as secondary outcomes for the safety and tolerability of acetazolamide, cerebrospinal fluid opening pressure, quality of life, fundus photography, and optical coherence tomography. While both groups demonstrated improvement on most outcomes, acetazolamide had a greater effect even when controlling for its effect on weight loss.

CONCLUSIONS

As the first large, randomized, prospective trial, the IIHTT extensively expanded the available data on idiopathic intracranial hypertension treatment. Most importantly, it provided support for the safe use of acetazolamide up to 4 g daily with weight loss for effective treatment of mild vision loss in IIH, with associated improvements in papilledema, increased intracranial pressure, and quality of life.

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.