The idiopathic intracranial hypertension treatment trial: design considerations and methods

Novel Approaches to the Treatment of Idiopathic Intracranial Hypertension

PURPOSE OF REVIEW

Idiopathic intracranial hypertension (IIH) typically affects women of childbearing age, is associated with recent weight gain, and can result in debilitating headache as well as papilledema that can cause vision loss. There have been advances in the medical and surgical treatment of affected patients with IIH that can improve outcomes and tolerability of therapy.

RECENT FINDINGS

Medical treatment with agents that lower intracranial pressure through pathways other than carbonic anhydrase inhibition are being developed, and medically-directed weight loss as well as bariatric surgery now may be considered as primary therapy. New surgical options including venous sinus stenting have shown efficacy even with cases of severe vision loss. Our treatment options for IIH patients are becoming more diverse, and individualized treatment decisions are now possible to address specific components of the patient's disease manifestations and to lead to IIH remission.

Classifying and quantifying changes in papilloedema using machine learning

Background

Machine learning (ML) can differentiate papilloedema from normal optic discs using fundus photos. Currently, papilloedema severity is assessed using the descriptive, ordinal Frisén scale. We hypothesise that ML can quantify papilloedema and detect a treatment effect on papilloedema due to idiopathic intracranial hypertension.

Methods

We trained a convolutional neural network to assign a Frisén grade to fundus photos taken from the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT). We applied modified subject-based fivefold cross-validation to grade 2979 longitudinal images from 158 participants' study eyes (ie, the eye with the worst mean deviation) in the IIHTT. Compared with the human expert-determined grades, we hypothesise that ML-estimated grades can also demonstrate differential changes over time in the IIHTT study eyes between the treatment (acetazolamide (ACZ) plus diet) and placebo (diet only) groups.

Findings

The average ML-determined grade correlated strongly with the reference standard (r=0.76, p<0.001; mean absolute error=0.54). At the presentation, treatment groups had similar expert-determined and ML-determined Frisén grades. The average ML-determined grade for the ACZ group (1.7, 95% CI 1.5 to 1.8) was significantly lower (p=0.0003) than for the placebo group (2.3, 95% CI 2.0 to 2.5) at the 6-month trial outcome.

Interpretation

Supervised ML of fundus photos quantified the degree of papilloedema and changes over time reflecting the effects of ACZ. Given the increasing availability of fundus photography, neurologists will be able to use ML to quantify papilloedema on a continuous scale that incorporates the features of the Frisén grade to monitor interventions.

Assessment of the relationship between structural and functional tests in patients with idiopathic intracranial hypertension

PURPOSE

To assess the relationship between structural and functional tests in mild and moderate idiopathic intracranial hypertension (IIH).

METHODS

Patients with mild and moderate IIH and a control group were enrolled. Best-corrected visual acuity (BCVA), macular ganglion cell layer (MGCL) thickness, peripapillary retinal nerve fiber layer (pp RNFL) thickness, perimetric mean deviation (MD), and photopic negative responses (PhNR) of the electroretinogram were recorded. The associations between structural (pp RNFL and MGCL thickness) and functional (PhNR amplitude, MD and BCVA) parameters were assessed.

RESULTS

154 eyes from 78 subjects (74 eyes from IIH patients and 80 eyes from healthy subjects) were included in this comparative observational study. The MGCL thickness, VA, pp RNFL, and PhNR base-to-trough (BT) amplitude were significantly worse in moderate IIH. The BCVA and MD were associated with MGCL thickness only in moderate IIH. The relationship between MD and MGCL thickness started when MD fell below -5.7 dB.

CONCLUSIONS

The association between functional and structural parameters varies between mild and moderate IIH. The MD and MGCL thickness outperformed in assessing disease severity in mild and moderate IIH, respectively. The association between MD and MGCL thickness could be considered in IIH severity categorization.

Visualization of Optic Nerve Structural Patterns in Papilledema Using Deep Learning Variational Autoencoders

Purpose

To visualize and quantify structural patterns of optic nerve edema encountered in papilledema during treatment.

Methods

A novel bi-channel deep-learning variational autoencoder (biVAE) model was trained using 1498 optical coherence tomography (OCT) scans of 125 subjects over time from the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) and 791 OCT scans of 96 control subjects from the University of Iowa. An independent test dataset of 70 eyes from 70 papilledema subjects was used to evaluate the ability of the biVAE model to quantify and reconstruct the papilledema spatial patterns from input OCT scans using only two variables.

Results

The montage color maps of the retinal nerve fiber layer (RNFL) and total retinal thickness (TRT) produced by the biVAE model provided an organized visualization of the variety of morphological patterns of optic disc edema (including differing patterns at similar thickness levels). Treatment effects of acetazolamide versus placebo in the IIHTT were also demonstrated in the latent space. In image reconstruction, the mean signed peripapillary retinal nerve fiber layer thickness (pRNFLT) difference ± SD was -0.12 ± 17.34 µm, the absolute pRNFLT difference was 13.68 ± 10.65 µm, and the RNFL structural similarity index reached 0.91 ± 0.05.

Conclusions

A wide array of structural patterns of papilledema, integrating the magnitude of disc edema with underlying disc and retinal morphology, can be quantified by just two latent variables.

Translational Relevance

A biVAE model encodes structural patterns, as well as the correlation between channels, and may be applied to visualize individuals or populations with papilledema throughout treatment.

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.

[CME: Idiopathic Intracranial Hypertension]

CME: Idiopathic Intracranial Hypertension Abstract. Idiopathic intracranial hypertension is a pressure-induced secondary headache disorder and optic neuropathy. It primarily affects obese women of childbearing age and poses an interdisciplinary challenge both diagnostically and therapeutically. The most common symptom of this disorder are headaches frequently accompanied by photo- and/or phonophobia, whose semiology often resembles that of migraine, followed by transient visual obscurations and pulsatile tinnitus. While protection of visual acuity and visual fields are of first therapeutical priority, adequate headache treatment also plays a key role. In the majority of cases, conservative treatment including weight loss and pharmacological therapy is sufficient. In case of a fulminant disease course or loss of visual function, interventional strategies can be applied additionally. Headache treatment is guided by the predominant semiology.

Quality of Life in Patients with Idiopathic Intracranial Hypertension and the Impact of the COVID-19 Pandemic

The COVID-19 pandemic became a challenge to maintain care for patients with idiopathic intracranial hypertension (IIH). We aimed to find out how they were affected during lockdown. Thirty IIH patients admitted to hospital during the COVID-19 pandemic were studied. Their demographic and neuro-ophthalmological findings were evaluated. The World Health Organization - Five Well-Being Index (WHO-5), the EUROHIS Quality of Life (QOL) 8-item index, National Eye Institute Visual Functioning Questionnaire (NEI-VFQ-25), Headache Impact Test (HIT-6), and COVID-19 Fear Scale were used to assess QOL and pandemic-associated fear. Thirty age, sex, and body mass index matched volunteers constituted the control group. Apart from the COVID-19 Fear Scale and colour vision subscale of the NEI-VFQ-25, all scale scores were worse in IIH patients than in healthy control subjects. Patients with severe visual field defects had higher HIT-6 scores (p = .036). Both vision-specific and overall QOL was reduced in patients with IIH. Headache severity and disability were more prominent in patients with severe visual loss. Fear caused by the COVID pandemic was not different in IIH patients than in healthy control subjects.

Experiences of Pain and Quality of Life in Pediatric Intracranial Hypertension

OBJECTIVE

To examine psychosocial correlates, specifically pain intensity, pain interference, and quality of life (QOL), in patients with pediatric intracranial hypertension. We hypothesized that parents and children who report higher levels of pain intensity and interference would be associated with lower QOL.

METHODS

Eighty-three patients and their families seen in the pediatric intracranial hypertension clinic of a large pediatric hospital completed self-report and parent proxy measures on QOL, mood, and other psychosocial correlates. Bivariate correlations were conducted between parent proxy and self-reports and regression analyses between pain and psychosocial correlate variables were examined.

RESULTS

Parent proxy and child reports were highly correlated. Body mass index (BMI) was a significant predictor of parent proxy report of pain intensity with higher BMI associated with higher parent proxy ratings of pain intensity. Parents reported significantly higher levels of pain interference for their children compared to child report. Parent ratings of child depression symptoms, BMI, and age were significant predictors of pain interference. Higher BMI and depression symptoms and younger age were associated with more pain interference. Overall QOL was similar to other headache populations but lower than other chronic illness and healthy populations.

CONCLUSIONS

Pediatric intracranial hypertension is associated with decreased QOL. Body mass index was a significant predictor of pain intensity and interference and should be monitored closely in clinic. Clinical care should include psychosocial screening to identify patients who would benefit from interventions to reduce the impact of this condition.

Pediatric Intracranial Hypertension: A Spotlight on Imaging, the Idiopathic Intracranial Hypertension Treatment Trial, and COVID-19 Associated Cases

Primary intracranial hypertension (PIH) is characterized by clinical signs of increased intracranial pressure, papilledema, elevated opening pressure, and absence of mass lesion, hydrocephalus, or meningeal enhancement on neuroimaging. Visual changes are a common presenting feature and if untreated there is risk of irreversible vision loss. There have been recent proposed changes to the criteria for PIH along with studies looking at the differences in imaging characteristics between adult and pediatric PIH. The presence of transverse sinus stenosis alone was highly sensitive and specific for pediatric PIH. The Idiopathic Intracranial Hypertension Treatment Trial was an adult, multicenter study that examined the use of acetazolamide and weight loss on the course of PIH. The study confirmed many previously held beliefs including the most common presenting symptom in PIH is headache. Most patients present with bilateral papilledema with 58.2% of patients having symmetric Frisen scale grading and within one grade in 92.8%. Although diplopia is a common reported symptom, very few have evidence of cranial nerve palsy. Male gender, high-grade papilledema, and decreased visual acuity at presentation are risk factors for treatment failure. Acetazolamide use is associated with mild metabolic acidosis. During acetazolamide treatment, monitoring for hypokalemia or aplastic anemia is not recommended. Monitoring transaminases in the titration phase of treatment should be considered due to a case of transaminitis and pancreatitis with elevated lipase. Newer case reports have also seen associations of secondary intracranial hypertension with concurrent COVID-19 infection and MIS-C.

The Pre-Lumbar puncture Intracranial Hypertension Scale (PLIHS): A practical scale to identify subjects with normal cerebrospinal fluid pressure in the management of idiopathic intracranial hypertension

BACKGROUND

Idiopathic Intracranial Hypertension (IIH) diagnosis requires lumbar puncture to measure cerebrospinal fluid (CSF) pressure. The Pre-Lumbar puncture Intracranial Hypertension Scale (PLIHS) is aimed to detect cases that will show raised or normal CSF opening pressure.

METHODS

Retrospective analysis of records of patients who underwent lumbar puncture for suspect IIH. The target was CSF opening pressure ≥ 250 mmH2O, whereas a set of known neurological, neuro-ophthalmological and neuro-radiological parameters, plus obesity, were used as predictors in a logistic regression model. The PLIHS was based on significant predictors and a cut-off was validated using chi-squared test around CSF opening pressure ≥ 250 and < 200 mmH2O.

RESULTS

Records of 162 patients were included: CSF opening pressure was <200 mmH2O in 40 and ≥ 250 mmH2O in 95 patients; 85 fulfilled IIH diagnosis. PLIHS is based on Frisén grade 2 or higher papilledema, tinnitus, empty sella, perioptic subarachnoid space distension, and obesity. Score range is 0-7: correlation with CSF opening pressure is 0.508 (p < .001), and PLIHS score is different between subjects not diagnosed with IIH, and those diagnosed with IIH both with and without papilledema (p < .001). PLIHS score ≤ 2 identifies cerebrospinal fluid pressure < 200 mmH2O; PLIHS score ≥ 3 identifies CSF opening pressure ≥ 250 mmH2O, IIH diagnosis, visual acuity ≤0.7, and optic nerve atrophy.

CONCLUSIONS

The PLIHS, can be used to identify patients who will particularly need LP, thus helping with the organization of the diagnostic work-up by optimising healthcare resources and potentially limit the likelihood to incur in LP-related adverse events.

Erenumab for headaches in idiopathic intracranial hypertension: A prospective open-label evaluation

Objective

To determine the effectiveness of erenumab in treating headaches in idiopathic intracranial hypertension (IIH) in whom papilledema had resolved.

Background

Disability in IIH is predominantly driven by debilitating headaches with no evidence for the use of preventative therapies. Headache therapy in IIH is an urgent unmet need.

Methods

A prospective, open‐label study in the United Kingdom was conducted. Adult females with confirmed diagnosis of IIH now in ocular remission (papilledema resolved) with chronic headaches (≥15 days a month) and failure of ≥3 preventative medications received erenumab 4‐weekly (assessments were 3‐monthly). The primary end point was change in monthly moderate/severe headache days (MmsHD) from baseline (30‐day pretreatment period) compared to 12 months.

Results

Fifty‐five patients, mean (SD) age 35.3 (9) years and mean duration of headaches 10.4 (8.4) years with 3.7 (0.9) preventative treatment failures, were enrolled. Mean baseline MmsHD was 16.1 (4.7) and total monthly headache days (MHD) was (29) 2.3. MmsHD reduced substantially at 12 months by mean (SD) [95% CI] 10.8 (4.0) [9.5, 11.9], p < 0.001 and MHD reduced by 13.0 (9.5) [10.2, 15.7], p < 0.001. Crystal clear days (days without any head pain) increased by 13.1 (9.5) [9.6, 15.3], p < 0.001, headache severity (scale 0–10) fell by 1.3 (1.7) [0.9, 1.9], p < 0.001, and monthly analgesic days reduced by 4.3 (9.2) [1.6, 6.9], p = 0.002. All these measures had improved significantly by 3 months, with a consistent significant response to 12 months. Headache impact test‐6 score and quality of life Short Form‐36 Health Survey significantly improved at 12 months. Sensitivity analysis revealed similar results for patients with and without a prior migraine diagnosis (28/55 (52%) patients) or those with or without medication overuse (27/55 (48%) patients).

Conclusions

This study provides evidence for the effectiveness of erenumab to treat headaches in IIH patients with resolution of papilledema. It provides mechanistic insights suggesting that calcitonin gene‐related peptide is likely a modulator driving headache and a useful therapeutic target.

High-Dose Methotrexate-Induced Idiopathic Intracranial Hypertension in Infant Acute Lymphoblastic Leukemia

A 7-month-old baby girl with acute lymphoblastic leukemia (ALL) presented with bulging anterior fontanelle after completing the first and second courses of high-dose methotrexate (HD-MTX) chemotherapy. Between courses, the infant recovered and was discharged. Prior to the third and fourth HD-MTX courses, the baby girl was administered infusions of dexamethasone, which prevented recurrence of neurological side effects observed after the first and second courses of HD-MTX. To our knowledge, this is the first reported case of HD-MTX-induced idiopathic intracranial hypertension in infants, and that prophylactic use of dexamethasone can be applied to prevent acute intracranial hypertension following HD-MTX infusion.

Intraocular and intracranial pressure in glaucoma patients taking acetazolamide

The alternative mechanical theory of glaucoma, in which an increased pressure difference across the lamina cribrosa (difference between intraocular and intracranial pressure; IOP and ICP), rather than solely an elevated IOP, leads to structural and functional vision loss, is still controversial. If the theory is true, a drug that simultaneously lowers both the IOP and ICP may be ineffective. The aim of this study was to determine how acetazolamide (AAZ; a drug prescribed in glaucoma that aims to lower the IOP) affects both IOP and ICP in glaucoma patients and to compare the magnitude and time course of the induced pressure changes with those of healthy subjects not taking AAZ. IOP and noninvasive ICP (measured through emissions from the ear) were measured in 20 glaucoma patients taking 125 mg of AAZ twice daily. Measurements were taken for 30 minutes before taking the drug and for 2 hours post-ingestion. Comparisons were made with 13 age-similar controls. After 12 hours with no anti-glaucoma medication, AAZ did not further reduce IOP in glaucoma patients compared to controls (P = 0.58) but did reduce ICP compared to controls (P = 0.035), by approximately 4 mmHg. Our findings suggest that there are periods during the day when the pressure difference across the lamina cribrosa is larger in case of AAZ use. Future studies should focus on improving the noninvasive ICP testing, different doses and dosing schedules of AAZ, and the time course of IOP in glaucoma patients not taking AAZ.

Genetic Survey of Adult-Onset Idiopathic Intracranial Hypertension

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a condition characterized by increased intracranial pressure of unknown cause. IIH has been shown to be associated with female sex as well as obesity. This genome-wide association study was performed to determine whether genetic variants are associated with this condition.

METHODS

We analyzed the chromosomal DNA of 95 patients with IIH enrolled in the Idiopathic Intracranial Hypertension Treatment Trial and 95 controls matched on sex, body mass index, and self-reported ethnicity. The samples were genotyped using Illumina Infinium HumanCoreExome v1-0 array and analyzed using a generalized linear mixed model that accounted for population stratification using multidimensional scaling.

RESULTS

A total of 301,908 single nucleotide polymorphisms (SNPs) were evaluated. The strongest associations observed were for rs2234671 on chromosome 2 (P = 4.93 × 10), rs79642714 on chromosome 6 (P = 2.12 × 10), and rs200288366 on chromosome 12 (P = 6.23 × 10). In addition, 3 candidate regions marked by multiple associated SNPs were identified on chromosome 5, 13, and 14.

CONCLUSIONS

This is the first study to investigate the genetics of IIH in a rigorously characterized cohort. The study was limited by its modest size and thus would have only been able to demonstrate highly significant association on a genome-wide scale for relatively common alleles exerting large effects. However, several variants and loci were identified that might be strong candidates for follow-up studies in other well-phenotyped cohorts.

The Effect of Acetazolamide and Weight Loss on Intraocular Pressure in Idiopathic Intracranial Hypertension Patients

PURPOSE

Acetazolamide (ACZ) lowers intraocular pressure (IOP), acutely in normal eyes and both acutely and chronically in eyes with glaucoma, and cerebrospinal fluid pressure (CSFp), chronically in patients with idiopathic intracranial hypertension (IIH). We hypothesize chronic daily ACZ would significantly reduce IOP and contribute to a translaminar pressure gradient change reflected by alteration in the CSFp-IOP difference and the deformation of the neural canal in patients with IIH and no glaucoma.

PATIENTS AND METHODS

Before randomization to ACZ or placebo treatment for 6 months, 165 participants in the IIH Treatment Trial had evaluations that included Goldmann applanation, CSFp measurement, and optical coherence tomography determination of the neural canal deformation. These measures were repeated at the 6-month outcome.

RESULTS

The IOP was not significantly decreased from baseline at 1, 3, or 6 months in eyes in both treatment groups. At month 6, the amount of ACZ or weight modification did not correlate with any IOP change. The 6-month mean change in neural canal deformation was 0.96 and -0.04 (P=0.001) and in CSFp was -128 and -38 mm H2O (P=0.001), but CSFp-IOP difference change was not significant, in the ACZ and placebo groups, respectively.

CONCLUSIONS

ACZ does not reduce the IOP in eyes without glaucoma but does decrease the pathologic elevated CSFp, providing evidence that normal systems can compensate for chronic medication effects. The CSFp-IOP is not a direct marker of translaminar pressure gradient and the ACZ normalization of the neural canal deformation appears due to CSFp reduction alone.

11β-Hydroxysteroid dehydrogenase type 1 inhibition in idiopathic intracranial hypertension: a double-blind randomized controlled trial

Treatment options for idiopathic intracranial hypertension are limited. The enzyme 11β-hydroxysteroid dehydrogenase type 1 has been implicated in regulating cerebrospinal fluid secretion, and its activity is associated with alterations in intracranial pressure in idiopathic intracranial hypertension. We assessed therapeutic efficacy, safety and tolerability and investigated indicators of in vivo efficacy of the 11β-hydroxysteroid dehydrogenase type 1 inhibitor AZD4017 compared with placebo in idiopathic intracranial hypertension. A multicenter, UK, 16-week phase II randomized, double-blind, placebo-controlled trial of 12-week treatment with AZD4017 or placebo was conducted. Women aged 18–55 years with active idiopathic intracranial hypertension (>25 cmH₂O lumbar puncture opening pressure and active papilledema) were included. Participants received 400 mg of oral AZD4017 twice daily compared with matching placebo over 12 weeks. The outcome measures were initial efficacy, safety and tolerability. The primary clinical outcome was lumbar puncture opening pressure at 12 weeks analysed by intention-to-treat. Secondary clinical outcomes were symptoms, visual function, papilledema, headache and anthropometric measures. In vivo efficacy was evaluated in the central nervous system and systemically. A total of 31 subjects [mean age 31.2 (SD = 6.9) years and body mass index 39.2 (SD = 12.6) kg/m²] were randomized to AZD4017 (n = 17) or placebo (n = 14). At 12 weeks, lumbar puncture pressure was lower in the AZD4017 group (29.7 cmH₂O) compared with placebo (31.3 cmH₂O), but the difference between groups was not statistically significant (mean difference: −2.8, 95% confidence interval: −7.1 to 1.5; P = 0.2). An exploratory analysis assessing mean change in lumbar puncture pressure within each group found a significant decrease in the AZD4017 group [mean change: −4.3 cmH₂O (SD = 5.7); P = 0.009] but not in the placebo group [mean change: −0.3 cmH₂O (SD = 5.9); P = 0.8]. AZD4017 was safe, with no withdrawals related to adverse effects. Nine transient drug-related adverse events were reported. One serious adverse event occurred in the placebo group (deterioration requiring shunt surgery). In vivo biomarkers of 11β-hydroxysteroid dehydrogenase type 1 activity (urinary glucocorticoid metabolites, hepatic prednisolone generation, serum and cerebrospinal fluid cortisol:cortisone ratios) demonstrated significant enzyme inhibition with the reduction in serum cortisol:cortisone ratio correlating significantly with reduction in lumbar puncture pressure (P = 0.005, R = 0.70). This is the first phase II randomized controlled trial in idiopathic intracranial hypertension evaluating a novel therapeutic target. AZD4017 was safe and well tolerated and inhibited 11β-hydroxysteroid dehydrogenase type 1 activity in vivo. Reduction in serum cortisol:cortisone correlated with decreased intracranial pressure. Possible clinical benefits were noted in this small cohort. A longer, larger study would now be of interest.

Protein aggregate formation permits millennium-old brain preservation

Human proteins have not been reported to survive in free nature, at ambient temperature, for long periods. Particularly, the human brain rapidly dissolves after death due to auto-proteolysis and putrefaction. The here presented discovery of 2600-year-old brain proteins from a radiocarbon dated human brain provides new evidence for extraordinary long-term stability of non-amyloid protein aggregates. Immunoelectron microscopy confirmed the preservation of neurocytoarchitecture in the ancient brain, which appeared shrunken and compact compared to a modern brain. Resolution of intermediate filaments (IFs) from protein aggregates took 2-12 months. Immunoassays on micro-dissected brain tissue homogenates revealed the preservation of the known protein topography for grey and white matter for type III (glial fibrillary acidic protein, GFAP) and IV (neurofilaments, Nfs) IFs. Mass spectrometry data could be matched to a number of peptide sequences, notably for GFAP and Nfs. Preserved immunogenicity of the prehistoric human brain proteins was demonstrated by antibody generation (GFAP, Nfs, myelin basic protein). Unlike brain proteins, DNA was of poor quality preventing reliable sequencing. These long-term data from a unique ancient human brain demonstrate that aggregate formation permits for the preservation of brain proteins for millennia.

Update on the Diagnosis and Treatment of Idiopathic Intracranial Hypertension

Advances in ophthalmic diagnostics and results of interventional clinical trials are shifting diagnosis and management of idiopathic intracranial hypertension (IIH) to be more technology- and evidence-based. In this article, the evidence supporting current diagnostic criteria, evaluation, and medical and surgical management of IIH are reviewed.

Contemporary management of the pseudotumor cerebri syndrome

Introduction: Diagnosis and appropriate management of patients with the pseudotumor cerebri syndrome are imperative to prevent or minimize permanent visual loss and headache-related disability. Areas covered: Steps in management, including making the correct diagnosis, techniques to assess the patient's visual status, medical treatment of intracranial hypertension and the associated headaches, weight management strategies, surgical treatments and stenting are reviewed incorporating the most recent medical evidence. Expert opinion: As the pathogenesis of the pseudotumor cerebri syndrome is still unknown, many of the currently employed management strategies incorporate a 'plumbing approach' to decrease cerebrospinal fluid (CSF) pressure. The Idiopathic Intracranial Hypertension Trial (IIHTT) taught us that the disorder markedly affects visual and overall quality of life, and that reducing pressure alone is not enough to make patients well, even those considered to have 'mild' vision loss. Other than the IIHTT, the evidence supporting the use of various treatments is meager. The course of the disorder can be unpredictable, and the clinician(s) managing these patients are often uncertain about which treatments to employ. Moreover, the desired modalities and specialists are not universally available in all locations. An individualized and detailed approach to the various manifestations and nuances of the disorder is essential.

Role of Resistivity Index Analysis in the Prediction of Hemodynamically Significant Venous Sinus Stenosis in Patient With Idiopathic Intracranial Hypertension

BACKGROUND

The resistivity index (RI) in cerebral venous sinus stenosis (VSS) has not been studied in patients with idiopathic intracranial hypertension (IIH).

OBJECTIVE

To evaluate the role of RI measured by quantitative magnetic resonance venogram (QMRV) as a noninvasive tool in the diagnosis of venous hypertension associated with VSS in IIH.

METHODS

Retrospective evaluation of 13 consecutive IIH patients who underwent venous sinus stenting at our institution between 2013 and 2018.

Patients’ demographics, clinical presentation, cerebral mean venous sinus pressure (MVP), and RI both pre- and poststenting were recorded. The baseline RI was also compared to a control group.

RESULTS

Among 13 patients of IIH, 11 had unilateral VSS in dominant sinus, whereas 2 had bilateral VSS. RI was significantly higher in IIH patients compared to the control group in the superior sagittal (SSS) and transverse sinuses (TS) (0.21 vs 0.11, P = .01 and 0.22 vs 0.13, P = .03, respectively). The MVP (in mm Hg) decreased significantly after venous sinus stenting in the SSS (41.9 to 22.5, P &lt; .001) and TS (39.4 to 19.5, P &lt; .001), which was also associated with a significant reduction of the RI (0.22 vs 0.17, P &lt; .01 in SSS and 0.23 vs 0.17, P = .03 in TS) poststenting.

CONCLUSION

RI calculated using QMRV can serve as a noninvasive tool to aid in the diagnosis of hemodynamically significant VSS. The study had a small sample size, and larger multicenter studies would be required to validate the results further.

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.

The importance of specific rehabilitation for an obese patient with idiopathic intracranial hypertension: a case report

Idiopathic intracranial hypertension (IIH) is associated with obesity, and weight loss is important to reduce intracranial pressure and improve visual function. A 38-year-old woman with IIH followed an extreme diet, which resulted in 30% weight loss (BMI moved from 34.9 to 24.6). Weight loss resulted in a significant reduction of papilloedema, normalization of intracranial pressure and improvement in headache pattern, but also induced a state of initial malnutrition, relevant depression and disability. She was discharged with the indication to start a controlled diet and improve physical activity: clinical situation get back to stability, with the patient loosing further weight (BMI=21.8) through a balanced diet and moderate physical exercise. Obese patients with IIH should be offered a comprehensive treatment approach consisting of diet and nutritional support, psychological counselling, indication to increase physical activity and, when appropriate, a specific rehabilitation programme.

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.

Headache in Idiopathic Intracranial Hypertension: Findings From the Idiopathic Intracranial Hypertension Treatment Trial

OBJECTIVE

To characterize the phenotype, headache-related disability, medical co-morbidities, use of symptomatic headache medications, and headache response to study interventions in the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT).

METHODS

Patients with untreated IIH and mild vision loss enrolled in the IIHTT and randomized to acetazolamide (ACZ) and weight loss or placebo (PLB) and weight loss had prospective assessment of headache disability using the Headache Impact Test-6 (HIT-6) questionnaire. Subjects with headache at the baseline visit were assigned a headache phenotype using the International Classification for Headache Disorders version 3 beta (ICHD-3b). Medication overuse was determined using the participants' reported medication use for the preceding month and ICHD-3b thresholds for diagnosing medication overuse headache. We investigated relationships between headache disability and various other clinical characteristics at baseline and at 6 months.

RESULTS

Headache was present in 139 (84%) of the 165 enrollees at baseline. The most common headache phenotypes were migraine (52%), tension-type headache (22%), probable migraine (16%), and probable tension-type headache (4%). Fifty-one (37%) participants overused symptomatic medications at baseline, most frequently simple analgesics. A similar amount of improvement in the adjusted mean (± standard error) HIT-6 score occurred in the ACZ (-9.56 ± 1.05) and PLB groups (-9.11 ± 1.14) at 6 months (group difference -0.45, 95% CI -3.50 to 2.60, P = .77). Headache disability did not correlate with any of the studies, variables of interest, which included: the lumbar puncture opening pressure at baseline or at 6 months, body mass index, the amount of weight lost, papilledema grade, perimetric mean deviation, or the use of hormonal contraception. Headache disability was significantly associated with patient-reported quality of life in the physical, mental, and visual domains.

CONCLUSIONS

Headache was common, of varied character, disabling, and associated with poorer quality of life in our cohort of patients with mild visual impairment. The lack of correlation between headache disability and cerebrospinal fluid (CSF) pressure at baseline and at the end of the randomized phase of the study implies that headache in IIH may be related to factors other than intracranial hypertension, and that specific headache treatment is needed in addition to therapies directed at lowering CSF pressure.

Peripapillary Retinal Pigment Epithelium Layer Shape Changes From Acetazolamide Treatment in the Idiopathic Intracranial Hypertension Treatment Trial

Purpose

Recent studies indicate that the amount of deformation of the peripapillary retinal pigment epithelium and Bruch's membrane (pRPE/BM) toward or away from the vitreous may reflect acute changes in cerebrospinal fluid pressure. The study purpose is to determine if changes in optic-nerve-head (ONH) shape reflect a treatment effect (acetazolamide/placebo + weight management) using the optical coherence tomography (OCT) substudy of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) at baseline, 3, and 6 months.

Methods

The pRPE/BM shape deformation was quantified and compared with ONH volume, peripapillary retinal nerve fiber layer (pRNFL), and total retinal (pTR) thicknesses in the acetazolamide group (39 subjects) and placebo group (31 subjects) at baseline, 3, and 6 months.

Results

Mean changes of the pRPE/BM shape measure were significant and in the positive direction (away from the vitreous) for the acetazolamide group (P < 0.01), but not for the placebo group. The three OCT measures reflecting the reduction of optic disc swelling were significant in both treatment groups but greater in the acetazolamide group (P < 0.01).

Conclusions

Change in the pRPE/BM shape away from the vitreous reflects the effect of acetazolamide + weight management in reducing the pressure differential between the intraocular and retrobulbar arachnoid space. Weight management alone was also associated with a decrease in optic nerve volume/edema but without a significant change in the pRPE/BM shape, implying an alternative mechanism for improvement in papilledema and axoplasmic flow, independent of a reduction in the pressure differential. (ClinicalTrials.gov number, NCT01003639.)

Update on Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is a disorder of elevated intracranial pressure of unknown cause occurring predominantly in young women of childbearing age. The typical patient symptom profile is the presence of daily headache, pulse synchronous tinnitus, transient visual obscurations, and papilledema with its associated visual loss. Although surgical procedures are performed for those who fail medical therapy, their relative efficacy remains unclear. The main morbidity of IIH is from visual loss. This visual loss is present in most patients and can usually be reversed if recognized early in the patients' course and treated.

The Longitudinal Idiopathic Intracranial Hypertension Trial: Outcomes From Months 6-12

PURPOSE

To determine whether the beneficial effects of acetazolamide (ACZ) in improving vision at 6 months continues to month 12 in participants of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT).

DESIGN

Nonrandomized clinical study.

METHODS

In the IIHTT, subjects were randomly assigned to placebo-plus-diet or maximally tolerated dosage of acetazolamide-plus-diet. At 6 months subjects transitioned from study drug to ACZ. This resulted in the following groups: (1) ACZ to ACZ; n = 34; (2) placebo to ACZ; n = 35; (3) ACZ to no treatment; n = 16; and (4) placebo to no treatment; n = 11. Ninety-six IIHTT subjects had evaluations at 6 and 12 months. Our main outcome measure was change from month 6 to month 12 in visual field mean deviation (MD) with secondary measures being change in papilledema grade, ETDRS scores, and quality-of-life (QoL) measures.

RESULTS

The ACZ to ACZ group improved 0.35 dB, P = .05; placebo subjects with no ACZ improved 0.81 dB MD, P = .07 at 12 months. The other groups improved 0.35-0.46 dB MD. Mean improvements in papilledema grade occurred most markedly in the group that exchanged placebo for ACZ (0.91 units, P < .001). QoL and headache disability scores showed significant improvements in the placebo group with added ACZ.

CONCLUSION

Improvements in MD continued from month 6 to month 12 of the IIHTT in all treatment groups, most marked in the placebo group tapered off study drug. Adding ACZ to the placebo group significantly improved papilledema grade, headache, and QoL measures.

The Effect of Treatment of Idiopathic Intracranial Hypertension on Prevalence of Retinal and Choroidal Folds

PURPOSE

We described 3 types of folds in the retina and a crease in the outer retina associated with papilledema owing to idiopathic intracranial hypertension (IIH) at presentation. We report the change in folds relative to treatment of IIH over the 6 months.

METHODS

In this substudy of a randomized clinical trial, study eyes of subjects assigned to acetazolamide (ACZ, n = 44) or placebo (PLB, n = 43) had spectral-domain optical coherence tomography (SDOCT) images of the optic disc and macula regions at baseline and at 3 and 6 months. Images were evaluated for peripapillary wrinkles (PPW), retinal folds (RF), choroidal folds (CF), and creases using transaxial and en face views. The optic nerve head (ONH) shape, retinal nerve fiber layer (RNFL) thickness, ONH volume, and papilledema grade were measured. Outcome was determination of the presence or absence of PPW, RF, CF, and creases.

RESULTS

At presentation, except for an increase of PPW in ACZ eyes (64% vs 28%), both treatment groups were matched for all OCT features. At 6 months, ACZ-treated, but not PLB-treated, eyes had fewer folds of all types (P < .01), with a 57% reduction in frequency of RF. Creases did not resolve. Resolution of RF, but not of PPW and CF, was associated with significant reduction in RNFL thickness, ONH volume, and papilledema grade.

CONCLUSIONS

The various types of retinal folds associated with papilledema reflect biodynamic processes and show an ACZ treatment effect. Persistence of these folds despite marked improvement in ONH swelling suggests permanent changes in the affected retinal tissues.

Optic disc haemorrhages at baseline as a risk factor for poor outcome in the Idiopathic Intracranial Hypertension Treatment Trial

BACKGROUND

The risk of optic disc haemorrhages on visual outcome in idiopathic intracranial hypertension (IIH) is unknown. We report the type and frequency of optic disc haemorrhages and other funduscopic abnormalities at baseline in the study eye of the 133 subjects enrolled in the Idiopathic Intracranial Hypertension Treatment Trial completing 6 months of follow-up.

METHODS

We reviewed optic disc photographs to tabulate the frequency and type of optic disc haemorrhages, other funduscopic abnormalities and papilloedema grades of the study eye at baseline and analyse if their presence is associated with a poor visual outcome.

RESULTS

27.2% of subjects had nerve fibre layer haemorrhages in at least one eye. Five of seven, 71% of subjects that met criteria for treatment failure, had nerve fibre layer haemorrhages in at least one eye (Fisher's exact test: p=0.02). There was a good correlation between presence of nerve fibre layer haemorrhages and Frisén grade (Spearman's correlation, p=0.002; r=0.271). Subjects with nerve fibre layer haemorrhages had a higher cerebrospinal fluid pressure (40.0 mm water, p=0.04). There was poor correlation between nerve fibre layer haemorrhages at baseline and the perimetric mean deviation change at 6 months. Cotton wool spots were present in 4% of subjects, exudates in 3% and pseudodrusen in 4%.

CONCLUSIONS

Nerve fibre layer haemorrhages are common in patients with IIH with mild visual loss and correlate with the severity of the papilloedema. They occur more frequently in treatment failure subjects and therefore may be associated with poor visual outcomes.

TRIAL REGISTRATION NUMBER

NCT01003639, Post-results.

Role of vitamin A metabolism in IIH: Results from the idiopathic intracranial hypertension treatment trial

INTRODUCTION

Vitamin A and its metabolites (called retinoids) have been thought to play a role in the development of idiopathic intracranial hypertension (IIH). The IIH Treatment Trial (IIHTT) showed the efficacy of acetazolamide (ACZ) in improving visual field function, papilledema grade, quality of life and cerebrospinal fluid (CSF) pressure. We postulated that IIH patients would demonstrate elevated measures of vitamin A metabolites in the serum and CSF.

METHODS

Comprehensive measures of serum vitamin A and its metabolites were obtained from 96 IIHTT subjects, randomly assigned to treatment with ACZ or placebo, and 25 controls with similar gender, age and body mass index (BMI). These included retinol, retinol binding protein, all-trans retinoic acid (ATRA), alpha- and beta-carotenes, and beta-cryptoxanthin. The IIHTT subjects also had CSF and serum vitamin A and metabolite measurements obtained at study entry and at six months.

RESULTS

At study entry, of the vitamin A metabolites only serum ATRA was significantly different in IIHTT subjects (median 4.33nM) and controls (median 5.04nM, p=0.02). The BMI of IIHTT subjects showed mild significant negative correlations with serum ATRA, alpha- and beta-carotene, and beta-cryptoxanthin. In contrast, the control subject BMI correlated only with serum ATRA. At six months, the serum retinol, alpha-carotene, beta-carotene, and CSF retinol were increased from baseline in the ACZ treated group, but only increases in alpha-carotene (p=0.02) and CSF ATRA (p=0.04) were significantly greater in the ACZ group compared with the placebo group. No other vitamin A measures were significantly altered over the six months in either treatment group. Weight loss correlated with only with the change in serum beta-carotene (r=-0.44, p=0.006) and the change in CSF retinol (r=-0.61, p=0.02).

CONCLUSION

Vitamin A toxicity is unlikely a contributory factor in the causation of IIH. Our findings differ from those of prior reports in part because of our use of more accurate quantitative methods and measuring vitamin A metabolites in both serum and CSF. ACZ may alter retinoid metabolism in IIH patients.

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.

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

Purpose

The Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) showed that acetazolamide provided a modest, significant improvement in mean deviation (MD). Here, we further analyze visual field changes over the 6-month study period.

Methods

Of 165 subjects with mild visual loss in the IIHTT, 125 had perimetry at baseline and 6 months. We evaluated pointwise linear regression of visual sensitivity versus time to classify test locations in the worst MD (study) eye as improving or not; pointwise changes from baseline to month 6 in decibels; and clinical consensus of change from baseline to 6 months.

Results

The average study eye had 36 of 52 test locations with improving sensitivity over 6 months using pointwise linear regression, but differences between the acetazolamide and placebo groups were not significant. Pointwise results mostly improved in both treatment groups with the magnitude of the mean change within groups greatest and statistically significant around the blind spot and the nasal area, especially in the acetazolamide group. The consensus classification of visual field change from baseline to 6 months in the study eye yielded percentages (acetazolamide, placebo) of 7.2% and 17.5% worse, 35.1% and 31.7% with no change, and 56.1% and 50.8% improved; group differences were not statistically significant.

Conclusions

In the IIHTT, compared to the placebo group, the acetazolamide group had a significant pointwise improvement in visual field function, particularly in the nasal and pericecal areas; the latter is likely due to reduction in blind spot size related to improvement in papilledema. (ClinicalTrials.gov number, NCT01003639.)

Impact of obesity and binge eating disorder on patients with idiopathic intracranial hypertension

Background Idiopathic intracranial hypertension (IIH) is associated with obesity, and obesity is associated with binge eating disorder (BED). The aim of this paper is to address the presence and impact of BED in patients undergoing an IIH diagnostic protocol. Methods This was a cross-sectional study. Consecutive patients suspected of IIH underwent neurological, neuro-ophthalmologic and psychological examinations, neuroimaging studies and intracranial pressure (ICP) measurements through lumbar puncture in the recumbent position. IIH diagnosis was based on International Classification of Headache Disorders, 2nd Edition criteria; BED diagnosis was based on Diagnostic and Statistical Manual of Mental Disorders, 5th Edition criteria. The presence of oligoclonal bands (OCBs) in the cerebrospinal fluid was also assessed. Results Forty-five patients were enrolled: 33 were diagnosed with IIH and five of them (15%) were obese with BED. Compared to non-obese patients, those who were obese, and particularly those who were obese with BED, were more likely to have an IIH diagnosis (χ²= 14.3; p = 0.001), ICP > 200 mmH₂O (χ²= 12.7; p = 0.002) and history of abuse or neglect (χ²= 11.2; p = 0.004). No association with OCBs was found. Conclusions We reported for the first time the presence of BED among patients with IIH and showed that BED is associated to IIH, ICP and history of abuse or neglect.

Automated Cross-Sectional Measurement Method of Intracranial Dural Venous Sinuses

BACKGROUND AND PURPOSE

MRV is an important blood vessel imaging and diagnostic tool for the evaluation of stenosis, occlusions, or aneurysms. However, an accurate image-processing tool for vessel comparison is unavailable. The purpose of this study was to develop and test an automated technique for vessel cross-sectional analysis.

MATERIALS AND METHODS

An algorithm for vessel cross-sectional analysis was developed that included 7 main steps: 1) image registration, 2) masking, 3) segmentation, 4) skeletonization, 5) cross-sectional planes, 6) clustering, and 7) cross-sectional analysis. Phantom models were used to validate the technique. The method was also tested on a control subject and a patient with idiopathic intracranial hypertension (4 large sinuses tested: right and left transverse sinuses, superior sagittal sinus, and straight sinus). The cross-sectional area and shape measurements were evaluated before and after lumbar puncture in patients with idiopathic intracranial hypertension.

RESULTS

The vessel-analysis algorithm had a high degree of stability with <3% of cross-sections manually corrected. All investigated principal cranial blood sinuses had a significant cross-sectional area increase after lumbar puncture (P ≤ .05). The average triangularity of the transverse sinuses was increased, and the mean circularity of the sinuses was decreased by 6% ± 12% after lumbar puncture. Comparison of phantom and real data showed that all computed errors were <1 voxel unit, which confirmed that the method provided a very accurate solution.

CONCLUSIONS

In this article, we present a novel automated imaging method for cross-sectional vessels analysis. The method can provide an efficient quantitative detection of abnormalities in the dural sinuses.