Brain Imaging in Idiopathic Intracranial Hypertension

The diagnostic value of MRI findings in pediatric idiopathic intracranial hypertension: a case-control study

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a rare medical condition in children. Based on the different radiological findings reported in various studies in pediatric IIH, this study was conducted to determine the diagnostic value of MRI findings in diagnosing IIH in children.

METHODS

In this retrospective study, the medical records of all children aged 1 to 18 years who visited Ghaem Hospital in Mashhad, Iran, between 2012 and 2022 and were diagnosed with IIH were gathered. Forty-nine cases of children with IIH and 48 control cases of children with the first unprovoked seizure with no indications of increased intracranial pressure for comparison were selected. Patient demographic information and MRI findings were extracted. The comparison between different MRI findings in the case and control groups was conducted using statistical tests.

RESULTS

In the case group, the mean diameter of the subarachnoid space expansion around the optic nerve was 5.96 ± 1.21, compared to 4.79 ± 0.33 in the control group, with statistically significant difference (P < 0.001). All the patients with flattening of the posterior globe or transverse sinus stenosis were in the case group, and the frequency of these findings in the case group was significantly higher than in the control group (P < 0.001). The majority of patients (95.5%) classified under category 3 and 4 of empty sella were part of the case group, and the statistical test results indicated a significant difference between the two groups (P < 0.001). The optic nerve sheath diameter cut-off of 5.35 mm, when used for expansion of the subarachnoid space around the optic nerve, with a sensitivity of 82% and a specificity of 100% in diagnosing IIH.

CONCLUSION

The most reliable diagnostic indicators for diagnosing IIH in children are perioptic subarachnoid space expansion with high sensitivity, and posterior globe flattening and transverse sinus stenosis with high specificity.

Applying the 2022 optic neuritis criteria to noninflammatory optic neuropathies with optic nerve T2-hyperintensity: an observational study

INTRODUCTION

Recent diagnostic criteria for optic neuritis include T2-hyperintensity of the optic nerve (ON), even without associated contrast enhancement. However, isolated ON-T2-hyperintensity is a nonspecific finding found in any optic neuropathy or severe retinopathy. We applied the 2022 optic neuritis diagnostic criteria to a cohort of patients with noninflammatory optic neuropathy and ON-T2-hyperintensity in at least one eye, to assess the rate of optic neuritis misdiagnosis using these criteria.

METHODS

Retrospective study of consecutive patients who underwent brain/orbit MRI with/without contrast between 07/01/2019 and 06/30/2022. Patients with ON-T2-hyperintensity in at least one eye were included. The 2022 optic neuritis diagnostic criteria were applied to patients with noninflammatory optic neuropathies who had an ophthalmologic examination available for review.

RESULTS

Of 150 patients included, 85/150 had compressive optic neuropathy; 32/150 had glaucoma; 12/150 had papilledema; 8/150 had hereditary (3), radiation-induced (3), nutritional (1), traumatic (1) optic neuropathies (none fulfilled the criteria); 13/150 had ischemic optic neuropathy and 4 fulfilled the criteria as definite optic neuritis due to contrast enhancement of the ON head. Seven additional patients would have satisfied the diagnostic criteria if red flags for alternative diagnoses had been overlooked.

DISCUSSION

The application of the 2022 optic neuritis diagnostic criteria in patients with noninflammatory optic neuropathy and ON-T2-hyperintensity in at least one ON resulted in misdiagnosis of optic neuritis in only 4 patients because of ON head enhancement, all with nonarteritic anterior ischemic optic neuropathy. Neuro-ophthalmologic evaluation and exclusion of the ON head as a location in the MRI criteria would have prevented optic neuritis misdiagnosis in our study.

Interrelation Between Cerebrospinal Fluid Pressure, Intracranial Morphology and Venous Hemodynamics Studied by 4D Flow MRI

PURPOSE

To quantify the effects of CSF pressure alterations on intracranial venous morphology and hemodynamics in idiopathic intracranial hypertension (IIH) and spontaneous intracranial hypotension (SIH) and assess reversibility when the underlying cause is resolved.

METHODS

We prospectively examined venous volume, intracranial venous blood flow and velocity, including optic nerve sheath diameter (ONSD) as a noninvasive surrogate of CSF pressure changes in 11 patients with IIH, 11 age-matched and sex-matched healthy controls and 9 SIH patients, before and after neurosurgical closure of spinal dural leaks. We applied multiparametric MRI including 4D flow MRI, time-of-flight (TOF) and T2-weighted half-Fourier acquisition single-shot turbo-spin echo (HASTE).

RESULTS

Sinus volume overlapped between groups at baseline but decreased after treatment of intracranial hypotension (p = 0.067) along with a significant increase of ONSD (p = 0.003). Blood flow in the middle and dorsal superior sagittal sinus was remarkably lower in patients with higher CSF pressure (i.e., IIH versus controls and SIH after CSF leak closure) but blood flow velocity was comparable cross-sectionally between groups and longitudinally in SIH.

CONCLUSION

We were able to demonstrate the interaction of CSF pressure, venous volumetry, venous hemodynamics and ONSD using multiparametric brain MRI. Closure of CSF leaks in SIH patients resulted in symptoms suggestive of increased intracranial pressure and caused a subsequent decrease of intracranial venous volume and of blood flow within the superior sagittal sinus while ONSD increased. In contrast, blood flow parameters from 4D flow MRI did not discriminate IIH, SIH and controls as hemodynamics at baseline overlapped at most vessel cross-sections.

Enhancing Diagnostic Accuracy Through Neuroimaging Revisions in Pediatric Pseudotumor Cerebri Syndrome: A Cross-Sectional Study

BACKGROUND

This cross-sectional study aimed to report all neuroimaging findings suggestive of raised intracranial pressure in children with pseudotumor cerebri syndrome (PTCS), before and after re-review by two neuroradiologists.

METHODS

We included 48 children aged <18 years diagnosed with PTCS between 2016 and 2021. Clinical and radiological data were obtained from their medical files. Two neuroradiologists independently re-reviewed all neuroimages, and the average of their assessments was compared with the initial neuroimaging reports; an additional review was done to analyze inter- and intraclass correlation.

RESULTS

The initial neuroimaging reports showed under-reporting of findings, with only 26 of 48 (54.1%) patients identified with abnormal reports. After revision, the proportion of the reported findings increased to 44 of 48 (91.6%). Distention of the perioptic space was the most commonly reported finding after revision (36.5 of 48; 76%). Flattening of the posterior globe and empty sella were initially under-reported but improved after revision. Moreover, several findings suggestive of increased intracranial pressure not mandated by Friedman criteria were identified, such as narrowing of the Meckel cave, posterior displacement of the pituitary stalk, and narrowing of the cavernous sinus. Analysis of associations between neuroimaging findings and demographic and clinical characteristics yielded no statistically significant results. The inter- and intraclass correlation results demonstrated a significant agreement between raters and within each rater's assessment (P < 0.05).

CONCLUSIONS

This study highlights the impact of image revision in enhancing PTCS diagnosis. Intra- and interclass correlations underscore the reliability of the review process, emphasizing the importance of meticulous image analysis in clinical practice.

Is foramen magnum decompression for acquired Chiari I malformation like putting a finger in the dyke? - A simplistic overview of artificial intelligence in assessing critical upstream and downstream etiologies

Background

Missed diagnosis of evolving or coexisting idiopathic (IIH) and spontaneous intracranial hypotension (SIH) is often the reason for persistent or worsening symptoms after foramen magnum decompression for Chiari malformation (CM) I. We explore the role of artificial intelligence (AI)/convolutional neural networks (CNN) in Chiari I malformation in a combinatorial role for the first time in literature, exploring both upstream and downstream magnetic resonance findings as initial screening profilers in CM-1. We have also put together a review of all existing subtypes of CM and discuss the role of upright (gravity-aided) magnetic resonance imaging (MRI) in evaluating equivocal tonsillar descent on a lying-down MRI. We have formulated a workflow algorithm MaChiP 1.0 (Manjila Chiari Protocol 1.0) using upstream and downstream profilers, that cause de novo or worsening Chiari I malformation, which we plan to implement using AI.

Materials and Methods

The PRISMA guidelines were used for "CM and machine learning and CNN" on PubMed database articles, and four articles specific to the topic were encountered. The radiologic criteria for IIH and SIH were applied from neurosurgical literature, and they were applied between primary and secondary (acquired) Chiari I malformations. An upstream etiology such as IIH or SIH and an isolated downstream etiology in the spine were characterized using the existing body of literature. We propose the utility of using four selected criteria for IIH and SIH each, over MRI T2 images of the brain and spine, predominantly sagittal sequences in upstream etiology in the brain and multiplanar MRI in spinal lesions.

Results

Using MaChiP 1.0 (patent/ copyright pending) concepts, we have proposed the upstream and downstream profilers implicated in progressive Chiari I malformation. The upstream profilers included findings of brain sagging, slope of the third ventricular floor, pontomesencephalic angle, mamillopontine distance, lateral ventricular angle, internal cerebral vein-vein of Galen angle, and displacement of iter, clivus length, tonsillar descent, etc., suggestive of SIH. The IIH features noted in upstream pathologies were posterior flattening of globe of the eye, partial empty sella, optic nerve sheath distortion, and optic nerve tortuosity in MRI. The downstream etiologies involved spinal cerebrospinal fluid (CSF) leak from dural tear, meningeal diverticula, CSF-venous fistulae, etc.

Conclusion

AI would help offer predictive analysis along the spectrum of upstream and downstream etiologies, ensuring safety and efficacy in treating secondary (acquired) Chiari I malformation, especially with coexisting IIH and SIH. The MaChiP 1.0 algorithm can help document worsening of a previously diagnosed CM-1 and find the exact etiology of a secondary CM-I. However, the role of posterior fossa morphometry and cine-flow MRI data for intracranial CSF flow dynamics, along with advanced spinal CSF studies using dynamic myelo-CT scanning in the formation of secondary CM-I is still being evaluated.

The glymphatic system in migraine and other headaches

Glymphatic system is an emerging pathway of removing metabolic waste products and toxic solutes from the brain tissue. It is made of a network of perivascular spaces, filled in cerebrospinal and interstitial fluid, encompassing penetrating and pial vessels and communicating with the subarachnoid space. It is separated from vessels by the blood brain barrier and from brain tissue by the endfeet of the astrocytes rich in aquaporin 4, a membrane protein which controls the water flow along the perivascular space. Animal models and magnetic resonance (MR) studies allowed to characterize the glymphatic system function and determine how its impairment could lead to numerous neurological disorders (e.g. Alzheimer's disease, stroke, sleep disturbances, migraine, idiopathic normal pressure hydrocephalus). This review aims to summarize the role of the glymphatic system in the pathophysiology of migraine in order to provide new ways of approaching to this disease and to its therapy.

Empty Sella in Neuro-Ophthalmology Patients Without Raised Intracranial Pressure

BACKGROUND

Empty sella often supports a diagnosis of raised intracranial pressure (ICP) but is also seen in normal individuals. This study's objective was to determine the prevalence of empty and partially empty sella in neuro-ophthalmology patients undergoing MRI for indications other than papilledema or raised ICP.

METHODS

Consecutive patients without papilledema or suspected raised ICP who underwent brain MRI between August 2017 and May 2021 were included in this study. Sagittal T1 images were evaluated by 2 independent, blinded neuroradiologists who graded the sella using the published criteria (Categories 1-5, with 1 being normal and 5 showing no visible pituitary tissue). Clinical parameters were also collected.

RESULTS

A total of 613 patients (309 men; average age 56.69 ± 18.06 years) were included in this study with optic neuropathy as the most common MRI indication. A total of 176 patients had moderate concavity of the pituitary gland (Category 3), 81 had severe concavity (Category 4), and 26 had no visible pituitary tissue (Category 5). Sella appearance was mentioned in 92 patients' radiology reports (15%). There was a statistically significant difference in age between composite Categories 1 and 2 (mean 52.89 ± 18.91; P < 0.001) and composite Categories 4 and 5 (mean 63.41 ± 15.44), but not the other clinical parameters.

CONCLUSION

Empty sella is common in neuro-ophthalmology patients without raised ICP; 17.4% of patients have severe concavity or no pituitary tissue visible. An isolated finding of empty or partially empty sella on imaging is therefore of questionable clinical value in this patient population.

The Relationship between Lumbar Puncture Opening Pressure and Retinal Nerve Fiber Layer Thickness in the Diagnosis of Idiopathic Intracranial Hypertension: Is a Lumbar Puncture Always Necessary?

OBJECTIVES

Idiopathic intracranial hypertension (IIH), is characterized by elevated intracranial pressure (ICP) without an identified cause. Today, lumbar puncture (LP) is the most common method used for diagnosis by measuring cerebrospinal fluid (CSF) pressure to reflect intracranial pressure. This invasive examination has significant disadvantages, such as complications and negative experiences for patients. Therefore, noninvasive methods for ICP measurement are desired. Optical coherence tomography (OCT) is widely used for the diagnosis and follow-up of IIH patients as it reflects papilledema. The aim of this study is to investigate the relationship between CSF pressure and OCT parameters and the ability of OCT in the diagnostic approach.

METHODS

In our study, patients who were followed up with a diagnosis of IIH with complete neuro-ophthalmological examinations, including visual acuity (VA), visual field, and OCT imaging within 24 hours before lumbar puncture, were retrospectively evaluated. CSF pressure, visual acuity LogMAR, mean deviation of visual fields, retinal nerve fiber layer (RNFL) thickness measured by OCT, and treatment protocols were obtained from our hospital data system.

RESULTS

A total of 42 eyes of 21 patients were enrolled in the study. A statistically significant positive and moderate correlation was found between CSF pressure values and average RNFL thickness ( r =0.507; P =0.001). The same relationship was demonstrated in all 4 quadrants: inferior, superior, nasal, and temporal.

CONCLUSIONS

Increased peripapillary RNFL thickness in optic nerve head OCT may be correlated with increased ICP in IIH patients. A larger number of patients are needed to better understand the correlation between OCT parameters and CSF pressure in patients with IIH.

Assessment of Reversibility of Transverse Venous Sinus Stenosis in Patients With Papilledema

BACKGROUND

Bilateral transverse venous sinus stenosis (TVSS) or stenosis of a dominant venous sinus has been found to be very sensitive radiological findings in patients with intracranial hypertension (IH), yet there is still an ongoing debate whether they constitute reversible or permanent phenomena. Thus, the purpose of this study was to investigate the reversibility of TVSS in patients with IH, including conservatively treated patients with signs of IH as defined by the presence of papilledema.

METHODS

This was a retrospective chart review of all patients diagnosed with IH between 2016 and 2022, assessed from 2 tertiary university-affiliated neuro-ophthalmology practices. Inclusion criteria were the presence of papilledema, as quantified by optical coherence tomography, and bilateral TVSS, which is considered typical of IH on neuroimaging. During follow-up, included patients must have had confirmation of papilledema resolution as well as subsequent neuroimaging after conservative treatment or cerebrospinal fluid flow diversion. Patients with dural sinus vein thrombosis or intrinsic stenosis from sinus trabeculations or significant arachnoid granulations were excluded from the study. Either CT venography or MRI/MR venography was reviewed by a fellowship-trained neuroradiologist, and the degree of stenosis was scored through the combined conduit score (CCS), as described by Farb et al. The primary outcome was to assess TVSS changes after resolution or improvement of papilledema.

RESULTS

From 435 patients, we identified a subset of 10 who satisfied all inclusion criteria. Our cohort comprised entirely women with a median age of 29.5 years and a median BMI of 32.5 kg/m2. Treatment consisted of acetazolamide in 7 patients, of which 1 had additional topiramate and 2 underwent cerebrospinal fluid flow diversion. Furthermore, 6 patients demonstrated significant weight loss during follow-up. For the primary outcome, 5 of 10 patients exhibited no appreciable TVSS change, and 5 patients demonstrated significant improvement in TVSS, of which 4 received conservative treatment only. Papilledema resolution or improvement was statistically significantly associated with increasing average CCS, TVSS diameter, and grade.

CONCLUSIONS

We were able to demonstrate that TVSS can be both irreversible and reversible in patients with resolved papilledema. The finding of TVSS reversibility from conservative treatment alone is novel and has important implications to optimize patient care. Future studies should work to identify factors associated with irreversible TVSS for subsequent targeted intervention and prevention.

MRI signs of intracranial hypertension in morbidly obese and normal-weight individuals

PURPOSE

 Idiopathic intracranial hypertension (IIH) is associated with intracranial abnormalities, although not obligatory, which can be detected with cranial MRI. Obesity is an important risk factor for IIH and a pathogenetic link is suspected but the extent to which these MRI signs are already related to obesity has not yet been examined. We investigated whether IIH-MRI signs are present more often in obese individuals with a BMI > 30 kg/m² than in individuals of normal weight.

MATERIALS AND METHODS

 Brain MRI of 32 obese and 53 normal-weight participants from the Food-Chain-Plus cohort were analyzed for three main signs of IIH: (I) stenosis of the transverse sinus, (II) increased width of the optic nerve sheath, and (III) reduction of pituitary height. In addition, a scoring system for the MRI signs was applied. Furthermore, tortuosity of the optic nerve and flattening of the posterior globe were considered as additional MRI signs.

RESULTS

 Obese participants had a significantly higher MRI score (p < 0.001) than those in the normal-weight cohort, with significant differences in quantitative measurements of cerebral venous sinus stenosis (p < 0.001), widening of the optic nerve sheath (p < 0.05), and flattening of the pituitary gland (p < 0.05) also always being observed more frequently and in a more pronounced manner in the obese group. Furthermore, our findings correlated significantly with BMI and proportionately with hip and waist circumference.

CONCLUSION

 Obese individuals show a significantly higher prevalence of cerebral MRI signs related to IIH. This supports the hypothesis that obesity is a risk factor for possible intracranial hypertension and reinforces the suspicion that obesity is involved in the pathomechanism of IIH.

KEY POINTS

  · Obesity is associated with changes such as those seen in IIH.. · BMI, weight, and body measurements correlate with the expression of MRI signs of IIH.. · To prevent IIH symptoms in obesity, the pathomechanism must be further clarified..

A rare finding of bilateral facial canal meningoceles involving the tympanic segment in suspected idiopathic intracranial hypertension

Meningoceles are a common radiological feature found in cases of idiopathic intracranial hypertension (IIH). Rarely, they can affect the facial canal within the petrous temporal bone, leading to symptoms such as facial nerve palsy, hearing loss or meningitis. This is the first case report that describes bilateral facial canal meningoceles involving the tympanic segment of the canal. Prominent Meckel's caves were also seen on MRI, a feature commonly associated with IIH.

The expanding spectrum of idiopathic intracranial hypertension

Once considered a rare and often difficult diagnosis in the era predating routine MRI, idiopathic intracranial hypertension has become an everyday concern in ophthalmology and neurology clinics where, especially in the latter, essentially every young overweight woman with headaches is initially presumed to have IIH. Has the diagnosis of IIH become too easy, and are we over-diagnosing IIH in this period of an accelerating obesity crisis? Or are we actually missing cases of IIH because they do not fit the classic clinical profile? We think it is both: at the same time IIH is being diagnosed in excess in obese women without papilledema, often resulting in unnecessary procedures, inappropriate treatment and even iatrogenic complications, the spectrum of this disorder is expanding to include a broad array of clinical presentations that involve multiple specialists beyond just the ophthalmologist and neurologist.

Current and emerging diagnostic and management approaches for idiopathic intracranial hypertension

INTRODUCTION

Idiopathic intracranial hypertension is characterized by raised intracranial pressure that triggers disabling headaches and can cause permanent visual loss. There is an increased incidence and prevalence of the condition linked to location-specific obesity rates. There are no licensed treatments for the condition. The majority of approaches to managing the disease prioritize resolution of papilledema. However, evidence is emerging that idiopathic intracranial hypertension is a systemic metabolic disease.

AREAS COVERED

The aim of this review is to present the emerging pathophysiology evidence which is leading to novel targeted therapeutics. The diagnostic pathway is outlined. The current and potential management approaches for idiopathic intracranial hypertension are also discussed.

EXPERT OPINION

Idiopathic intracranial hypertension is a condition with metabolic dysregulation with systemic manifestations that are present over and above what can be expl.ained by obesity alone. While most of the current management of this condition focuses on the eyes, future management needs to address the disabling headaches and the systemic risks of preeclampsia, gestational diabetes, and major cardiovascular events.

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.

Risk factors for the development of secondary intracranial hypertension in acute cerebral venous thrombosis

PURPOSE

Intracranial hypertension (IH) can complicate cerebral venous thrombosis (CVT), potentially causing permanent visual loss. Current knowledge on risk factors for the development of IH following CVT is scarce. We applied a compound classifier (CSF opening pressure > 25 cmH₂O, papilledema, or optic disc protrusion on MRI) as a surrogate for IH and studied the predictive value of thrombus location, the number of thrombosed segments, and thrombus volume.

METHODS

We prospectively included 26 patients with acute CVT and complete MRI data. IH was defined by CSF opening pressure > 25 cmH₂O, papilledema, or optic disc protrusion on MRI. Using high-resolution contrast-enhanced venography, we determined the thrombus location, number of thrombosed segments, and thrombus volume. We analyzed their association with IH by logistic regression, their predictive power by the area under the receiver operating characteristic curve, and their association with CSF opening pressure by linear regression.

RESULTS

IH occurred in 46% of CVT patients and was associated with higher thrombus volume (AUC 0.759, p = 0.025) and superior sagittal sinus thrombosis both alone (OR 2.086, p = 0.049) and combined with transverse sinus thrombosis (OR 2.014, p = 0.028). Effects in patients presenting CSF opening pressure > 25 cm H₂O and the compound classifier were consistent. Thrombus volume > 4 ml was the single most important predictor of higher CSF opening pressure (ß = 0.566, p = 0.035), increasing IH risk.

CONCLUSION

Larger thrombus volume, dominant transverse sinus occlusion, and extensive superior sagittal combined with transverse sinus thrombosis were associated with IH. Thrombus volumetry might identify patients at risk for IH and direct further clinical evaluation.

Dural Venous Sinus Thrombosis and Papilledema Related to JAK2 Mutation: A Case Series

BACKGROUND

Dural venous sinus thrombosis (DVST) is an important cause of papilledema. Patients diagnosed with DVST should undergo work-up for underlying hypercoagulable state, including genetic causes. One important prothrombotic mutation is in the JAK2 gene, which is a driver of myeloproliferative neoplasms including polycythemia vera (PV). We aimed to determine the prevalence of JAK2 mutation in patients in presenting to neuro-ophthalmology clinic with DVST and papilledema.

METHODS

Retrospective case series of patients seen in a tertiary neuro-ophthalmology practice who presented with papilledema due to DVST and were investigated for presence of JAK2 mutation.

RESULTS

Four out of 15 patients with DVST (26%) were found to have JAK2 V617F mutation which led to subsequent diagnosis of PV in 2. One additional patient had a known diagnosis of essential thrombocytosis. We describe the clinical presentation of these four patients with papilledema and JAK2 mutation.

CONCLUSIONS

A significant proportion of patients with papilledema secondary to DVST will harbor mutations in the JAK2 gene. Clinicians should be aware of this mutation as early testing will facilitate timely diagnosis and treatment of myeloproliferative disease to improve prognosis and reduce risk of recurrent thrombotic events.

Presumptive Idiopathic Intracranial Hypertension Based on Neuroimaging Findings: A Referral Pattern Study

BACKGROUND

Radiologic findings of intracranial hypertension (RAD-IH) are common in idiopathic intracranial hypertension (IIH) patients. Paralleling the increasing rates of obesity, the burden of IIH is growing. Urgent neuro-ophthalmology consultations for possible IIH in patients with incidentally detected RAD-IH are increasing, with many patients receiving unnecessary lumbar punctures (LPs) and treatments. This retrospective observational study aimed to determine the prevalence of neuro-ophthalmology consultations for RAD-IH, rate of funduscopic examination by referring providers, prevalence of papilledema, outcomes after neuro-ophthalmic evaluation, and rates of misdiagnosis.

METHODS

Records of 1,262 consecutive new patients seen in one neuro-ophthalmology clinic from January 2019 to January 2020 were reviewed. We identified patients who were: 1) referred with concern for IIH because of findings of RAD-IH; 2) referred for "papilledema"; 3) referred with a diagnosis of IIH; and 4) referred for spontaneous cranial cerebrospinal fluid (CSF) leaks. In addition to basic demographic profiles for all groups, detailed information was collected for patients referred solely for RAD-IH, including referral patterns, prior history of IIH, previous LPs, prior medical or surgical treatment(s), risk factors for increased intracranial pressure (ICP), presenting symptoms, radiologic features observed on neuroimaging, and final disposition. When available, the neuroimaging was reviewed by an expert neuroradiologist.

RESULTS

Of 1,262 consecutive new patients, 66 (5%) were referred specifically for RAD-IH; most referrals came from neurologists (58%); 8/66 (12%) patients had papilledema; 16/66 (24%) patients had prior LP and 13/66 (20%) were already treated based on MRI findings; and 22/66 (33%) patients had ≤2 RAD-IH. Only 34/66 (52%) of patients referred for RAD-IH had prior funduscopic examinations. We confirmed papilledema in 26/82 (32%) patients referred for "papilledema." Only 29/83 (35%) patients referred with a diagnosis of IIH had active papilledema, and 3/16 (19%) patients with spontaneous CSF leaks had papilledema. In total, 247/1,262 (20%) new patients were referred to our clinic over 1 year with concern for IIH, among whom only 66 (27%) were confirmed to have active IIH with papilledema.

CONCLUSIONS

One in 5 new patient referrals seen in our neuro-ophthalmology clinic were referred because of concern for increased ICP, but only 1/4 had active papilledema. Most patients referred for isolated RAD-IH do not have papilledema, many having undergone unnecessary LPs and treatments. The burden of these "rule-out IIH" consultations is overwhelming and will only continue to increase with the concurrent rise of obesity and IIH, straining the already limited neuro-ophthalmologic resources available in the US.

Pituitary enlargement in patients with cerebrospinal fluid drainage due to ventricular shunt insertion: know the condition and do not mistake for adenoma

OBJECTIVE

Childhood hydrocephalus patients treated by ventriculo-peritoneal (v.-p.) shunting are sometimes referred years after this therapy for evaluation of suspicious pituitary enlargement. Since pituitary size has been shown to depend on cerebrospinal fluid (CSF) pressure, we assume this phenomenon to be caused by shunt overdrainage. Therefore, we studied pituitary size and morphology in shunted hydrocephalus patients with radiological signs of high CSF drainage.

PATIENTS AND METHODS

Retrospective study of pituitary size and morphology in 15 shunted patients with non-tumoral hydrocephalus and 7 shunted hydrocephalus patients due to childhood brain tumor compared to a population mean. In five brain tumor patients also pre- and postsurgical comparisons were performed.

RESULTS

Pituitary mid-sagittal size and pituitary volume were significantly higher in both hydrocephalus groups, compared to the population mean (midsagittal size t = 5.91; p < 0.001; pituitary volume, t = 3.03; p = 0.006). In patients available for pre- and postoperative comparison, there was also a significant increase in pituitary size and volume postoperatively (mean preoperative midsagittal height 2.54 ± 1.0 mm vs. 6.6 ± 0.7 mm post-surgery; mean pre-operative pituitary volume 120.5 ± 69.2 mm³ vs. 368.9 ± 57.9 mm³ post-surgery).

CONCLUSION

Our results confirmed a significant increase in pituitary size and volume, mimicking pituitary pathology, after v.-p. shunt insertion. This phenomenon can be explained by the Monro-Kellie doctrine, stating that intracranial depletion of CSF-as caused by v.p. shunting-leads to compensatory intracranial hyperemia, especially in the venous system, with the consequence of engorged venous sinuses, most likely responsible for enlargement of the pituitary gland.

Expanding the clinical spectrum of idiopathic intracranial hypertension

PURPOSE OF REVIEW

Idiopathic intracranial hypertension (IIH) is a disorder of raised intracranial pressure (ICP). Although the majority of patients with IIH present classically with headache and papilledema, some patients may have unusual presentations or manifestations. Recent advancements in neuroimaging have facilitated the identification of other presentations associated with IIH. This review provides an overview of the expanding clinical spectrum of IIH.

RECENT FINDINGS

Presentations of IIH that are considered unusual include highly asymmetric or unilateral papilledema, IIH without papilledema, and IIH associated with cranial nerve involvement. These presentations likely reflect differences in the way cerebrospinal fluid (CSF) pressure is transmitted intracranially. Radiological signs of intracranial hypertension are increasingly recognized in patients with IIH and provide further insights into the effects of raised ICP on intracranial structures. Osseous changes in the skull base leading to formation of meningoceles and encephaloceles have been identified in patients with IIH, spontaneous skull base CSF leak, and drug-resistant temporal lobe epilepsy, suggesting a possible association.

SUMMARY

Clinicians should be familiar with the expanding clinical spectrum of IIH and the implications for the management of these presentations.

Idiopathic intracranial hypertension in patients with cerebral small vessel disease: A case report

INTRODUCTION

Idiopathic intracranial hypertension (IIH) is a clinical syndrome characterized by increased intracranial pressure (ICP) without any identifiable cause. However, restrictions of cerebrospinal fluid absorption from the cerebral venous system, the glymphatic system overflow, and the cerebrospinal fluid's lymphatic pathways may be involved in the pathophysiology of IIH. Furthermore, an impaired glymphatic system is also implicated in the initiation and progression of cerebral small vessel disease (CSVD). Here, we reported a case of CSVD with concomitant IIH, possibly associated with the brain's glymphatic and lymphatic system dysfunction.

CASE CONCERN

A 39-year-old male presented with worsening headaches over the bilateral parietal areas during the past year and nausea for 2 days. Fundus examination revealed bilateral papilledema and lumbar puncture suggestive of elevated ICP, laboratory results showed hyperhomocysteinemia and mutation of methylenetetrahydrofolate reductase C677T. On magnetic resonance imaging, subcortical small infarct, white matter lesions, lacunes, enlarged perivascular spaces and dilatation of the optic nerve sheaths was detected, and right transverse sinus stenosis and a hypoplastic left sinus were showed on contrast-enhanced magnetic resonance venography.

DIAGNOSIS

The diagnoses of IIH, CSVD, transverse sinus stenosis, and hyperhomocysteinemia were performed.

INTERVISION AND OUTCOMES

The patient received antihypertensive, antiplatelet, anti-atherosclerotic, and homocysteine-lowering therapies. Finally, the patient's symptoms remised, and the increased ICP returned to normal; however, the bilateral TSS persisted after 3 months of follow-up.

CONCLUSIONS

In this case, we speculate that the normal glymphatic outflow pathway may serve as a compensatory mechanism for regulating increased ICP in patients with bilateral venous sinus obstruction, indicating impaired venous outflow pathway, possibly associated with dysfunction of the glymphatic and lymphatic systems in patients with CSVD.

Intracranial computed tomography histogram analysis detects changes in the setting of elevated intracranial pressure and normal imaging

BACKGROUND

Patients with idiopathic intracranial hypertension (IIH) have elevated intracranial pressure (ICP) of unclear etiology. This study evaluated the ability of quantitative intracranial Hounsfield unit (HU) histogram analysis to detect pathophysiological changes from elevated ICP in the setting of a normal head CT.

METHODS

Retrospective analysis of non-contrast-enhanced head CT images of IIH patients and matched controls. Following skull stripping, total intracranial CT voxels within the range of 0-70 HU were divided into seven 10 HU bins. A measurement of total intracranial HU was also calculated for each patient. Imaging studies for IIH patients were reviewed for features of IIH including transverse sinus stenosis (TSS). Histogram measures were compared between IIH and control groups and correlated with imaging and clinical data.

RESULTS

Fourteen IIH patients with CSF opening pressure ≥25 cm water, and 31 age-, sex-, and ethnicity-matched controls were included. Compared to controls, IIH patients had a significantly greater proportion of voxels in the 40-50, 50-60, and 60-70 HU bins (p = 0.003, 0.001, and 0.003, respectively) but similar proportion in the 0-10 HU range. Severity of TSS significantly correlated with total intracranial HU measures. 50-60 HU and 60-70 HU bins demonstrated high AUCs of 0.81 and 0.80, respectively, in differentiating IIH from normal status.

CONCLUSION

Idiopathic intracranial hypertension patients have a greater proportion of high intracranial HU voxels representing blood volume, which may be explained by TSS causing venous congestion. The pattern provides further insights into the pathophysiology of IIH and may be useful for detecting elevated ICP in the setting of normal head CT imaging.

Secondary Headache Disorders: Approach, Workup, and Special Considerations for Select Populations

Headache is one of the most common diagnoses in neurology. A thorough understanding of the clinical presentation of secondary headache, which can be life-threatening, is critical. This review provides an overview of the diagnostic approach to a patient with headache, including discussion of "red," "orange," and "green" flags. We emphasize particular scenarios to help tailor the clinical workup to individual circumstances such as in pregnant women, when particular attention must be paid to the effects of blood pressure and hypercoagulability, as well as in older adults, where there is a need for higher suspicion for an intracranial mass lesion or giant cell arteritis. Patients with risk factors for headache secondary to alterations in intracranial pressure, whether elevated (e.g., idiopathic intracranial hypertension) or decreased (e.g., cerebrospinal fluid leak), may require more specific diagnostic testing and treatment. Finally, headache in patients with COVID-19 or long COVID-19 is increasingly recognized and may have multiple etiologies.

CT Cisternogram Findings in Idiopathic Cerebrospinal Fluid Leaks with Emphasis on Long Term Management

To study the various computed tomography (CT) cisternogram findings in idiopathic cerebrospinal fluid (CSF) leaks and the long term treatment modalities after surgical repair of idiopathic CSF leaks. This was a descriptive study conducted among 25 patients in MCV memorial ENT trust hospital, Pollachi between May 2014 and May 2020 amongst patients who underwent CT cisternogram for unilateral or bilateral spontaneous rhinorrhea with or without associated headache, visual disturbances and papilloedema diagnosed to be idiopathic CSF leak by investigations. These patients then underwent CSF leak repair and postoperatively were managed with weight reduction, low salt diet and diuretic therapy. Post surgery these patients were followed up for a period of 12 months and were evaluated on the basis of presence or absence of headache, rhinorrhea and papilloedema at the end of 1st month, 3rd month, 6th month and 1 year and data was collected. CT cisternogram findings were evaluated by proportion method and evaluation of long term management was done using proportion and repeated measures ANOVA for all patients. Evidence of the presence of previously mentioned CT cisternogram or contrast MRI findings at the end of 1 year of post-surgical treatment was recorded where patients were willing for the same. CT Cisternography was done for all patients and 72% patients had empty sella appearance while 28% had partially empty sella. Other findings included perioptic filling, optic blunting and arachnoid pits which were found in 11(44%), 8(32%) and 12(48%) of patients respectively. Only 3(12%) out of 25 patients had an encephalocoele. The commonest site of leak in CT cisternography was the cribriform plate (52%) followed by lateral recess of sphenoid (48%). None of the patients had multiple sites of leak in CT cisternography. On follow up post surgery maximum resolution of symptoms was found at the end of 12 months where 23 out of 25 patients improved. In our study, out of 25 only 5 patients agreed to undergo post diuretic therapy MRI scan out of which 2 patients had partially empty sella and 3 had normal sella indicating resolution of BIH. CT cisternography is an important investigation which aids in the diagnosis of CSF rhinorrhea due to idiopathic intracranial hypertension (IIH). The medical management of IIH post surgery such as weight reduction, salt restriction and diuretic therapy is also crucial to prevent recurrence of symptoms.

The Reliability of Venous Sinus Stenosis Using Non Contrast 3D MRV in Prediction of the Diagnosis of Idiopathic Intracranial Hypertension, A Case Control Study

Idiopathic intracranial hypertension, or shorty IIH, refers to a clinical syndrome in which there is elevated CSF pressure and papilledema in the lack of any focal neurological signs. It is largely a diagnosis of exclusion, but imaging workup is undertaken routinely in order to rule out other pathologies. In this study we tried to evaluate the prevalence of venous sinus abnormalities using the simpler and less invasive non contrast enhanced 3D TOF MRV in group of patients with IIH, using the combined stenosis score, and compare this score with a group of controls, to assess the accuracy of MRV alone as an individual test in predicting the diagnosis of IIH.

The study sample included 44 patients and 25 control subjects, following MRV analysis it was found that a combined severity score of cut of value of 4.5 for the combined conduit score (CCS) was associated with 79% sensitivity and 88.6 specificity for the diagnosis of IIH, and a cut off value of 5.5 for the adjusted score method gives a 83% sensitivity and 88.6 % specificity for the diagnosis.

MRV is a valuable in the diagnosis of IIH; non contrast 3D MRV is an efficient test and gives valuable diagnostic information.

[Idiopathic intracranial hypertension: From physiopathological mechanisms to therapeutic decision]

Clinical features include visual disturbances, headaches, and pulsatile tinnitus that can be associated with reduced quality of life, and a risk of irreversible visual impairment in some cases. Obese women of childbearing age represent the main at-risk population, and the incidence of the disease is increasing because of rising prevalence of obesity worldwide. In addition, an imbalance in sex hormones is reported as a contributing risk factor. The pathophysiology of idiopathic intracranial hypertension involves a disturbance of the evacuation pathway of intracranial fluids caused by the increase in intracranial venous pressure. Brain imaging is useful for diagnosis with several signs including bilateral stenosis of the transverse sinuses that plays a major role in the pathogenesis of the disease by creating a positive feedback loop that increases intracranial venous hypertension and contributes to clinical manifestations. Treatment aims to relieve symptoms and prevent permanent visual impairment. Drug therapies including acetazolamide and topiramate have moderate effectiveness. Among invasive treatments, transverse sinus stenting seems to be the most interesting option to consider in drug-resistant patients. Weight loss remains essential to achieve a sustainable improvement by reducing central venous pressure. Future randomized trials are expected to reach a consensus on this treatment.

Venous Sinus Thrombosis in the Hypoglossal Canal Mimics a Neurogenic Tumor in a Patient with Presumed Idiopathic Intracranial Hypertension: A Case Report

Presumed idiopathic intracranial hypertension (IIH) is a disorder of elevated intracranial pressure with unknown etiology, and 10% of cases occur secondarily to cerebral venous sinus thrombosis (CVST). CVST may be underestimated when findings of IIH are missed in a normal-weight patient without risk factors of coagulopathy. Here, we present a case of CVST that mimics a neurogenic tumor in the hypoglossal canal in a normal-weight patient without risk factors of coagulopathy.

Accuracy and reliability of magnetic resonance imaging in the diagnosis of idiopathic intracranial hypertension

PURPOSE

To determine the diagnostic utility of brain magnetic resonance imaging (MRI) findings in patients with idiopathic intracranial hypertension (IIH) and to investigate the significance of evaluating radiological findings together with neurological and ophthalmological data in the diagnosis of IIH.

MATERIALS AND METHODS

All consecutive patients diagnosed with IIH in our tertiary neuro-ophthalmology center between January 1, 2018 and March 15, 2020, were included in the study. The clinical, radiological, and ophthalmological findings of IIH patients were compared with the control group with similar demographic characteristics.

RESULTS

A total of 98 patients, 49 cases and 49 controls, were included in the study. Lateral ventricular index had the highest area under the curve (AUC) value (0.945) for prediction of disease group followed by sella height category (AUC = 0.915) and optic nerve tortuosity (AUC = 0.855) According to the multivariate model we developed, caudate index (OR = 0.572, 95% CI 0.329-0.996), lateral ventricle index (OR = 3.969, 95% CI 1.851-8.509) and bilateral optic nerve tortuosity (OR = 22,784, 95% CI 2.432-213.450) were significant predictors for disease group.

CONCLUSION

Tortuosity in the optic nerve, lateral ventricular index and caudate index can be used as MRI parameters supporting the diagnosis of IIH in clinically suspicious cases. A holistic approach to the clinical and radiological findings of the cases in the diagnosis of IIH can prevent overdiagnosis and enable early correct diagnosis.

Idiopathic intracranial hypertension imaging approaches and the implications in patient management

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

Expansion of the Foramen Ovale in Patients With Cerebrospinal Fluid Leak or Encephalocele

OBJECTIVE

Spontaneous cerebrospinal fluid (CSF) leaks are associated with elevated intracranial pressure and idiopathic intracranial hypertension (IIH). Skull base erosion and widening of the foramen ovale have been reported in patients with IIH. This study sought to investigate changes in the size of the foramen ovale and foramen spinosum in patients with IIH, spontaneous CSF leak, and encephalocele.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary care academic medical center.

PATIENTS

Adult patients treated from 2014 to 2018 with computed tomographic imaging of the head and who were diagnosed with IIH, encephalocele, or CSF leak.

INTERVENTION

Two blinded observers measured the long and short axes of the foramen ovale and foramen spinosum on axial computed tomographic images. Measurements were used to calculate the approximate elliptical cross-sectional area of the foramina.

MAIN OUTCOME MEASURES

Length, width, and area of the foramen ovale and foramen spinosum.

RESULTS

A total of 264 patients were identified meeting the inclusion criteria and were placed into three groups. There were 170 patients with IIH, 48 with spontaneous CSF leak or encephalocele (CSF/E group), and 46 with traumatic or iatrogenic CSF leak (control group). Mean foramen ovale short axis (4.85 ± 1.00 mm) and cross-sectional area (30.17 ± 9.25 mm2) in the CSF/E group were significantly increased compared with measurements in patients with IIH or the control groups. Foramen ovale size was positively correlated with age in the CSF/E group. No significant difference in foramen spinosum size was found.

CONCLUSION

Skull base defect resulting in spontaneous CSF leak or encephalocele is associated with enlargement of the foramen ovale on axial computed tomography.

Noticable Findings in Cranial MRI of the Patients with Idiopathic Intracranial Hypertension

OBJECTIVES

Idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure. We investigated the optic nerve, Meckel's cavity, internal carotid artery (ICA) and pituitary findings of IIH by Cranial Magnetic Resonance Imaging (MRI).

METHODS

Cranial MRI images of 35 adult patients with IIH and 35 adult subjects with normal cranial MRI results (control) were evaluated. Optic nerve diameter (OND), optic nerve sheat diameter (ONSD), OND/ONSD ratio, ON tortuosity, ON protrusion, posterior scleral flattening, ICA transverse diameter, CSF distance in Meckel's cavity and ICA transverse diameter/CSF distance in Meckel's cavity ratio, and pituitary gland measurements (height and transverse dimension; and Optic chiasm- pituitary gland distance) were measured.

RESULTS

OND and ONSD of the IIH group were significantly higher than those of the control groups at anterior and posterior measurements (p < 0.05). OND/ONSD ratio of the IIH group was lower at anterior measurement; and higher at the posterior measurement than the control group (p < 0.05). Right ICA transverse diameter and bilateral CSF distance in Meckel's cavity of the IIH group were higher than those of the control. Optic chiasm- pituitary gland distance of the IIH group was significantly higher than that of the control group (p < 0.05).

CONCLUSION

OND/ONSD ratio is different in anterior and posterior measurements. So we recommend measuring OND and ONSD separately in IIH patients to use in the clinical practice. Similarly, optic chiasm-pituitary gland distance is also another point to note for IIH patients on MRI. Our paper adds new approach to IIH in terms of OND/ONSD ratio.

Cerebral Venous Outflow Implications in Idiopathic Intracranial Hypertension-From Physiopathology to Treatment

In this review, we provide an update on the pathogenesis, diagnosis, and management of adults with idiopathic intracranial hypertension (IIH) and implications of the cerebral venous system, highlighting the progress made during the past decade with regard to mechanisms of the venous outflow pathway and its connection with the cerebral glymphatic and lymphatic network in genesis of IIH. Early diagnosis and treatment are crucial for favorable visual outcomes and to avoid vision loss, but there is also a risk of overdiagnosis and misdiagnosis in many patients with IIH. We also present details about treatment of intracranial hypertension, which is possible in most cases with a combination of weight loss and drug treatments, but also in selected cases with surgical interventions such as optic nerve sheath fenestration, cerebral spinal fluid (CSF) diversion, or dural venous sinus stenting for some patients with cerebral venous sinus stenosis, after careful analysis of mechanisms of intracranial hypertension, patient clinical profile, and method risks.

Optic Disc Edema and Elevated Intracranial Pressure (ICP): A Comprehensive Review of Papilledema

Papilledema is a swelling of the optic disc secondary to elevated intracranial pressure (ICP). We analyzed 79 peer-review journal articles and provided a concise summary of the etiology, epidemiology, pathophysiology, clinical presentation, evaluation, natural history, differential diagnosis, treatment, and prognosis of papilledema. Only studies written in English with the full text available were included. Although many etiologies of papilledema exist, idiopathic intracranial hypertension is the most common and, thus, a large focus of this review.

Utility of Neuroimaging in the Management of Chronic and Acute Headache

Imaging plays an important role in identifying the cause of the much less common secondary headaches. Such headaches may be caused by a variety of pathologic conditions which can be categorized as intracranial and extracranial. Idiopathic intracranial hypertension imaging findings include "empty sella," orbital changes, and dural venous sinus narrowing. Intracranial hypotension (ICH) is frequently caused by CSF leaks. Imaging findings include loss of the CSF spaces, downward displacement of the brain, as well as dural thickening and enhancement. Severe cases of ICH may result in subdural hematomas. A variety of intracranial and skull base tumors may cause headaches due to dural involvement. Extracranial tumors and lesions that frequently present with headaches include a variety of sinonasal tumors as well as mucoceles. Neurovascular compression disorders causing headaches include trigeminal and glossopharyngeal neuralgia. Imaging findings include displacement and atrophy of the cranial nerve caused by an adjacent arterial or venous structure.

Population-Based Evaluation of Indirect Signs of Increased Intracranial Pressure

BACKGROUND

The Mayo Clinic Study of Aging (MCSA) is a unique prospective study that systematically evaluates the normal aging population and includes many participants undergoing both MRI and lumbar puncture (LP). Using MCSA date, we aimed to determine the prevalence of indirect signs of raised intracranial pressure (ICP) on MRI and whether these correlate with LP opening pressure (OP). This is a large-scale study that evaluates how often indirect signs of increased ICP occur in a normal population.

METHODS

MCSA participants who had an MRI within 3 months of an LP with recorded OP were included in the study. MRIs were reviewed for indirect signs of raised ICP, including pituitary to sella (P/S) ratio, cerebellar tonsillar ectopia, and optic nerve sheath diameter (ONSD). These signs were evaluated for correlations with OP and influences from body mass index (BMI) and obstructive sleep apnea (OSA).

RESULTS

Five hundred ninety-seven MCSA patients were identified who underwent both LP and MRI. Two hundred sixty (43.6%) were women. The median age was 70.7 years (range 32.6-92.7). Median OP was 152 mm H2O (range 60-314 mm H2O), with 91 (15.2%) participants having an OP ≥ 200 mm H2O. Empty or partially empty sella was seen in 81 (12.8%) of the cohort. The P/S ratio decreased with increasing OP (r = -0.3, P < 0.001). There was a weak correlation between OP and average ONSD (r = 0.184, P = 0.01), which was no longer significant when accounting for age, gender, and BMI (partial r2 = 0.014, P = 0.097). There was no correlation between OP and cerebellar tonsillar ectopia. OSA was associated with increased ONSD (P = 0.004), but this did not remain statistically significant after accounting for age, gender, and BMI (P = 0.085).

CONCLUSION

Smaller pituitary gland size correlated with increasing OP. This suggests that ICP is a continuum with some normal individuals demonstrating asymptomatic radiologic signs of raised ICP.

Pseudotumor Cerebri Syndrome Without Headache in an Obese Male With Eight Restricted Cerebrospinal Fluid (CSF) Oligoclonal Bands: A Case Report

Pseudotumor cerebri syndrome (PTCS) is a condition caused by an abnormal elevation of intracranial pressure (ICH), which may be primary (idiopathic intracranial hypertension) or because of an identifiable secondary cause. We present a rare case of an obese male who complained of gradual bilateral vision loss for one year without headaches and tinnitus. On fundoscopy, he had high-grade bilateral papilledema and, on lumbar puncture, he had an elevated intracranial pressure of 260 mmH2O. Cerebrospinal fluid (CSF) was unique for eight restricted oligoclonal bands while extensive other demyelinating workup was negative. He was started on acetazolamide initially and subsequently proceeded with bilateral optic nerve sheath fenestration (ONSF) with mild improvement in the right eye and no improvement in the left eye. Although the causative mechanism of PTCS is a matter of debate, immune-mediated processes are one of the proposed mechanisms that may play a role in the pathophysiology of PTCS, evidenced by the presence of oligoclonal bands (OCBs) and pro-inflammatory markers in CSF. PTCS diagnosed in men and patients with OCBs poses an increased risk of vision loss as this case and literature documented. Therefore, prompt treatment through therapeutic lumbar punctures, acetazolamide therapy concurrently with weight loss, and surgical intervention in severe or refractory cases are necessary.

Diagnostic performance of neuroimaging in suspected idiopathic intracranial hypertension

The diagnostic utility of neuroradiologic signs associated with idiopathic intracranial hypertension (IIH) for the evaluation of patients presenting with papilloedema remains yet to be elucidated. This multicentre retrospective cohort study assessed consecutive patients presenting with suspected papilloedema to Auckland District Health Board (NZ) and Stanford University Medical Centre (US), between 2005 and 2019, undergoing magnetic resonance imaging and venography (MRI/MRV) or computed tomography and venography (CT/CTV) prior to lumbar puncture assessment for diagnostic suspicion of IIH. Data were collected regarding demographic, clinical, radiologic, and lumbar puncture parameters, and the diagnosis of IIH was determined according to the Friedman criteria for primary pseudotumor cerebri syndrome. A total of 204 participants (174 females; mean ± SD age 29.9 ± 12.2 years) were included, and 156 (76.5%) participants fulfilled the diagnostic criteria for IIH. The presence of any IIH-associated radiologic sign on MRI/MRV demonstrated a sensitivity (95% CI) of 74.8% (65.8%-82.0%) and specificity (95% CI) of 94.7% (82.7%-98.5%), while radiologic signs on CT/CTV exhibited a sensitivity (95% CI) of 61.0% (49.9%-71.2%) and specificity (95% CI) of 100.0% (83.2%-100.0%). In summary, the modest sensitivities of radiologic signs of IIH would support the routine use of lumbar puncture assessment following neuroimaging to secure the diagnosis. However, the high specificities might lend limited support for the judicious deferment of lumbar puncture assessment among typical IIH demographic patients who consent to the inherent small risk of missed pathology, which has been proposed by some clinicians.

Seizure as the presenting sign of idiopathic intracranial hypertension

A 38-year-old man presented to the emergency room with a new generalised tonic-clonic seizure. He also complained of headaches, and brain MRI/magnetic resonance venography (MRV) showed an anterior left temporal encephalocoele with gliosis and brain parenchyma herniating into the left foramen ovale. Ophthalmic examination revealed bilateral optic disc oedema and his lumbar puncture confirmed an elevated opening pressure of 48 cm of water. He was diagnosed with idiopathic intracranial hypertension (IIH) and his papilloedema resolved with weight loss and acetazolamide. Raised intracranial pressure (ICP) can be associated with encephalocoeles and lead to seizures. It is important to screen for papilloedema in these patients as they are at risk for permanent vision loss. This was a unique case in which IIH was diagnosed only after a seizure due to an encephalocoele, which was likely related to chronically undetected raised ICP.

[Papilledema as a sign of intracranial hypertension]

Papilledema (choked disk) is a sign of intracranial hypertension (ICH) - condition that presents danger not only for patient's vision, but also for their life. Despite the fact that ICH is usually a neurosurgical pathology, sometimes an ophthalmologist is the first doctor such patients visit, most often in a primary healthcare clinic. At the same time, as practice shows, not all ophthalmologists are well aware about in this pathology; difficulties occur in differential diagnosis of papilledema against similar changes of the optic nerve head seen during ophthalmoscopic examination. This article reviews scientific literature on ICH, including benign ICH, diagnosis and differential diagnosis of papilledema. The authors also share their decades-long experience of working in a neurosurgical facility.

Posterior fossa volume in idiopathic intracranial hypertension: a magnetic resonance imaging-based study

BACKGROUND

The etiology of idiopathic intracranial hypertension (IIH) is uncertain. Studies suggest the fundamental cause of the Chiari 1 malformation, a congenitally hypoplastic posterior fossa, may explain the genesis of IIH in some patients.

PURPOSE

To assess the hypothesis that linear and volumetric measurements of the posterior fossa (PF) can be used as predictors of IIH.

MATERIAL AND METHODS

A retrospective analysis of magnetic resonance imaging (MRI) studies on 27 patients with IIH and 14 matched controls was performed. A volumetric sagittal magnetization prepared rapid acquisition gradient echo sequence was used to derive 10 linear cephalometric measurements. Total intracranial and bony posterior fossa volumes (PFVs) were derived by manual segmentation. The ratio of PFV to total intracranial volume was calculated.

RESULTS

In total, 41 participants were included, all women. Participants with IIH had higher median body mass index (BMI). No significant differences in linear cephalometric measurements, total intracranial volumes, and PFVs between the groups were identified. Linear measurements were not predictive of volumetric measurements. However, on multivariate logistic regression analysis, the likelihood of IIH decreased significantly per unit increase in relative PFV (odds ratio [OR]=3.66 × 10^-50; 95% confidence interval [CI]=1.39 × 10^-108 to 1.22 × 10^-5; P = 0.04). Conversely, the likelihood of IIH increased per unit BMI increase (OR=1.19; 95% CI=1.04-1.47; P = 0.02).

CONCLUSION

MRI-based volumetric measurements imply that PF alterations may be partly responsible for the development of IIH and Chiari 1 malformations. Symptoms of IIH may arise due to an interplay between these and metabolic, hormonal, or other factors.

Optic Nerve Angle in Idiopathic Intracranial Hypertension

BACKGROUND

The tortuosity of the optic nerve can be quantified radiologically by measuring the angle of optic nerve deformation (the "optic nerve angle" [ONA]). In patients with idiopathic intracranial hypertension (IIH), lowering the intracranial pressure (ICP) to a normal range by lumbar puncture leads to straightening of the optic nerve and an increase in the measured sagittal ONA on MRI. It is uncertain whether there is any correlation between ONA and cerebrospinal fluid (CSF) opening pressure or visual function.

METHODS

Retrospective study of patients with and without IIH who had MRI of the brain followed by lumbar puncture with CSF opening pressure within 24 hours of MRI. Before LP and within 24 hours of MRI of the brain, all patients with IIH had neuro-ophthalmologic assessment including visual acuity, Humphrey Visual Field (HVF), and fundus photography. Sagittal ONA was measured on multiplanar T2-SPACE images on a DICOM viewer. Papilledema on the fundus photographs was graded using the Frisén scale.

RESULTS

Fifty-four patients with IIH and 30 unmatched controls were included. The IIH group was 6.3 years younger (95% CI 2.4-10.3, P = 0.002), had 8.7 kg/m2 higher body mass index (4.9-12.5, P < 0.001), and 26.3% more women (P = 0.011) compared with controls. In both eyes, the ONA was significantly smaller in patients with IIH by 12° compared with controls (7°-17°, P < 0.00001). In the IIH group, no correlation between ONA and the CSF opening pressure was present in either eye (right eye r = 0.19, P = 0.15; left eye r = 0.18, P = 0.19) The ONA did not correlate with logarithm of the minimum angle of resolution visual acuity (right eye r = 0.26, P = 0.063; left eye r = 0.15, P = 0.27), HVF mean deviation (right eye r = 0.0059, P = 0.97; left eye r = -0.069, P = 0.63), or Frisén grade (Spearman's rho right eye 0.058, P = 0.67; left eye 0.14, P = 0.30).

CONCLUSIONS

The ONA is significantly smaller in patients with IIH compared to controls, but does not correlate with CSF opening pressure, severity of papilledema, or visual function. The ONA may be useful in identifying patients with raised ICP, but not necessarily those with a poor visual prognosis.

Evidence of air-conduction transmission pathway and strategized transtemporal operative techniques for venous pulsatile tinnitus: Combining water occlusion test and operative sensing applications

OBJECTIVES

(1) To establish evidence of the transmission pathway of venous pulsatile tinnitus (PT) associated with sigmoid sinus wall anomalies (SSWAs) and (2) quantify the efficacy of transtemporal surgery.

METHODS

This retrospective study included 33 surgical cases of PT associated with SSWAs and 15 controls with venous PT without SSWAs. Quantitative water occlusion test (q-WOT) and imaging data were acquired for preoperative evaluation prior to strategized transtemporal osteovascular reconstruction surgery. A condenser microphone and hydrophone were intraoperatively deployed to assess and monitor in vivo amplitude variations of the PT in eight participants.

RESULTS

A total of 23 (69.6%) participants with SSWA responded to the q-WOT with a median solution volume of 1.3 (1.1/1.6), which significantly differed from that observed in controls (p < 0.01). The change in the operative peak amplitude of the acoustic data was statistically significant (p < 0.01), from a median of 57.6 (55.5/57.9) dB SPL to 34.3 (33.4/38.8) dB SPL.

CONCLUSION

Intraoperative application of acoustic sensors revealed that PT associated with SSWAs is predominantly transmitted via the air-conduction pathway. If objective findings such as q-WOT and sensing applications suggest that the transmission of venous PT is involved in middle ear air conduction, the reconstruction technique should be prioritized; if less involvement of middle ear air-conduction is indicated, addressing flow pathologies may be imperative for resolving venous PT.

LEVEL OF EVIDENCE

4.

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.

Unilateral Isolated Paucisymptomatic Optic Disc Edema

BACKGROUND

Unilateral isolated optic disc edema (UIODE) represents a challenging clinical presentation that frequently precipitates an extensive diagnostic work-up. Patients without an apparent diagnosis despite appropriate investigations are often categorized as having "papillophlebitis," an entity that is poorly defined in the existing literature. Our aim was to describe the characteristics of a series of patients with paucisymptomatic UIODE, determine the optimal diagnostic approach to such cases, and clarify the clinical features of presumed papillophlebitis.

METHODS

We retrospectively identified 29 patients with UIODE who were seen by neuro-ophthalmologists at a single center between 2005 and 2019. Each patient presented with isolated, unilateral disc edema that was either entirely asymptomatic or associated with minimal visual symptoms. Patients underwent a comprehensive neuro-ophthalmic evaluation and several ophthalmic and systemic investigations. Data from the initial visit and all subsequent clinical visits were collected, including patient demographics, examination findings, and details of the diagnostic work-up.

RESULTS

Our 29 patients with UIODE were found to have a variety of underlying diagnoses including unilateral papilledema due to idiopathic intracranial hypertension (10 patients), optic nerve sheath meningioma (5), incipient nonarteritic anterior ischemic neuropathy (4), vitreopapillary traction (3), orbital masses (2), a peripapillary choroidal neovascular membrane (1), and presumed papillophlebitis (4). The duration of disc edema varied considerably based on the etiology, but most patients had favorable visual outcomes.

CONCLUSIONS

A systematic approach to the evaluation of UIODE, combined with long-term follow-up, led to a definite diagnosis in a majority of patients, with only 4 patients presumed to have papillophlebitis, a diagnosis the actual existence of which remains controversial.

Clinical features and the role of magnetic resonance imaging in pediatric patients with intracranial hypertension

Increased intracranial hypertension (IIH) is a defined clinical condition; however, an unsolved pathophysiologic background usually creates problems in its diagnosis and proper approach. The aim of this study was to emphasize the clinical conditions and brain magnetic resonce imaging (MRI) clues of pediatric patients, especially this clinical entity with high morbidity. Here, we review the etiology, clinical presentation, brain MRI findings, and prognosis of IIH in children. The symptoms' onset age ranged from 9 months to 16 years. Headache (81%), vomiting (37%), and diplopia (33.3%) were the most frequent symptoms. The most common etiologic factors were found to be obesity and dural venous sinus thrombosis. Cerebrospinal fluid (CSF) opening pressure had mean a mean value of 615.2 ± 248 mm H₂O. A significant relationship was found between visual field impairment and height of CSF pressure (p < 0.001). Optic nerve sheath enlargement (88.8%) and optic nerve tortuosity (85.1%) were found as the most common brain MRI findings. Slit-like ventricle (37%), venous sinus thrombosis (29.6%), posterior globe sclera flattening (29.6%), empty sella (25.9%), and intraocular protrusion of the optic nerve (14.8%) were the other findings. A significant relationship was found between CSF opening pressure and the presence of optic nerve tortuosity (p = 0.002), and distension of the optic nerve sheath (p = 0.006). All patients received acetazolamide, only one patient underwent lumboperitoneal shunt, and only one received steroids. In children, IIH can present with different etiologies and symptoms. Brain MRI provides crucial clues in diagnosis. Urgent diagnosis and treatment planning are required to protect vision functions.

Prediction of Postoperative Risk of Raised Intracranial Pressure After Spontaneous Skull Base Cerebrospinal Fluid Leak Repair

BACKGROUND

A relationship between idiopathic intracranial hypertension and spontaneous skull base cerebrospinal fluid (CSF) leaks has been proposed, by which CSF leak decreases intracranial pressure (ICP) and masks the symptoms and signs of elevated ICP. These patients are at risk of developing papilledema, symptoms of elevated ICP, or a recurrent CSF leak after CSF leak repair. The objective of this study was to assess whether radiographic signs of raised ICP on preoperative magnetic resonance or computed venography (MRI or CTV) are predictors of postoperative papilledema, recurrence of CSF leak, or need for CSF shunt surgery.

METHODS

We performed a retrospective review of systematically collected demographics, fundus examination, and presurgical brain MRI and magnetic resonance venography/computed tomography venography (MRV/CTV) in patients seen at 1 institution between 2013 and 2019 with spontaneous skull base CSF leak repair. Patients were divided into 2 groups depending on whether they developed papilledema, recurrent CSF leak, or required CSF shunting (Group 1) or not (Group 2).

RESULTS

Fifty-seven patients were included, among whom 19 were in Group 1. There was no difference in demographic characteristics or clinical features between patients in Group 1 and Group 2. Controlling for other imaging features, bilateral transverse venous sinus stenosis (TVSS) on preoperative imaging increased the odds of being in Group 1 by 4.2 times (95% confidence interval [CI], 1.04-21.2, P = 0.04), optic nerve tortuosity decreased the odds of being in Group 1 by 8.3 times (95% CI: 1.4-74.6, P = 0.02).

CONCLUSION

Imaging of the intracranial venous system with MRV or CTV is warranted before repair of spontaneous CSF leak, as bilateral TVSS is an independent risk factor for postoperative papilledema, CSF leak recurrence, or need for a CSF shunting procedure.

Papilledema: A review of etiology, pathophysiology, diagnosis, and management

Papilledema is optic nerve head edema secondary to raised intracranial pressure (ICP). It is distinct from other causes of optic disk edema in that visual function is usually normal in the acute phase. Papilledema is caused by transmission of elevated ICP to the subarachnoid space surrounding the optic nerve that hinders axoplasmic transport within ganglion cell axons. There is ongoing controversy as to whether axoplasmic flow stasis is produced by physical compression of axons or microvascular ischemia. The most common cause of papilledema, especially in patients under the age of 50, is idiopathic intracranial hypertension (IIH); however, conditions that decrease cerebrospinal fluid (CSF) outflow by either causing CSF derangements or mechanically blocking CSF outflow channels, and rarely conditions that increase CSF production, can be the culprit. When papilledema is suspected clinically, blood pressure should be measured, and pseudopapilledema should be ruled out. Magnetic resonance imaging of the brain and orbits with venography sequences is the preferred neuroimaging modality that should be performed next to look for indirect imaging signs of increased ICP and to rule out nonidiopathic causes. Lumbar puncture with measurement of opening pressure and evaluation of CSF composition should then be performed. In patients not in a typical demographic group for IIH, further investigations should be conducted to assess for underlying causes of increased ICP. Magnetic resonance imaging of the neck and spine, magnetic resonance angiography of the brain, computed tomography of the chest, complete blood count, and creatinine testing should be able to identify most secondary causes of intracranial hypertension. Treatment for patients with papilledema should be targeted toward the underlying etiology. Most patients with IIH respond to weight loss and oral acetazolamide. For patients with decreased central acuity and constricted visual fields at presentation, as well as patients who do not respond to treatment with acetazolamide, surgical treatments should be considered, with ventriculoperitoneal shunting being the typical procedure of choice.

Non-invasive intracranial pressure monitoring in idiopathic intracranial hypertension and lumbar puncture in pediatric patient: Case report

Background

Intracranial pressure (ICP) monitoring has been variously explored as a diagnostic and therapeutic modality in many pathological conditions leading neurological injury. This monitoring standardly depends on an invasive procedure such as cranial or lumbar catheterization. The gold standard for ICP monitoring is through an intraventricular catheter, but this invasive technique is associated with certain risks such as haemorrhage and infection. (1) Also, it is a high-cost procedure and consequently not available in a variety of underprivileged places and clinical situations in which intracranial hypertension is prevalent (3). An accurate non-invasive and low-priced method to measure elevated ICP would therefore be desirable. Under these circumstances, Brazilian scientists developed a non-invasive method for intracranial pressure monitoring (ICP-NI), which uses an electric resistance extensometer that measures micro deformations of the skull and transforms it into an electrical signal. In this case report, the authors describe a pediatrician patient with the diagnosis of idiopathic intracranial hypertension who was successfully submitted to a lumbar puncture under monitorization with this device.

Case description

7 year old girl with progressive symptoms that lead to the diagnosis of idiopathic intracranial hypertension. The patient was submitted to a lumbar punction with continuous non-invasive ICP monitoring.

Conclusion

Estimating ICP (non-invasive) from LP monitoring (invasive) often reflect inaccurate ICP results, and affects negatively on IIH diagnosis and a non-invasive diagnostic method could reduce the requirement for invasive approaches, improving patient health outcomes.

Evaluation of 2D FLAIR hyperintensity of the optic nerve and optic nerve head and visual parameters in idiopathic intracranial hypertension

BACKGROUND AND PURPOSE

T2/FLAIR hyperintensity of the optic nerve/optic nerve head has been described as a sensitive finding in idiopathic intracranial hypertension using post-contrast 3D-T2/FLAIR imaging. The purpose of this study is to assess whether hyperintensity on non-enhanced 2D-T2/FLAIR imaging occurs more likely in diseased patients than controls and to evaluate the relationship between FLAIR signal and visual parameters MATERIALS AND METHODS: A retrospective case-control study was performed of patients with idiopathic intracranial hypertension and controls who underwent orbital MRI. Three neuroradiologists reviewed the FLAIR images, subjectively evaluating for hyperintense signal within the optic nerves/optic nerve heads using a 5-point Likert Scale. Quantitative assessment of optic nerve signal using regions of interests was performed. Clinical parameters were extracted. The diagnostic performance was evaluated, and Spearman correlation calculated to assess the relationship between FLAIR signal and visual outcomes.

RESULTS

The sensitivity of abnormal FLAIR signal within the optic nerves and optic nerve heads in patients with idiopathic intracranial hypertension ranged from 25-54% and 4-29%, respectively, with specificities ranging from 67-92% and 83-100%. Quantitative assessment revealed a significant difference in CNR between cases and controls in the left posterior optic nerve (p=.002). A positive linear relationship existed between abnormal optic nerve head signal and papilledema grade (OD: p=.02, OS: p=.008) but not with other visual parameters.

CONCLUSION

T2/FLAIR hyperintensity in the optic nerve/optic nerve head may support the diagnosis of idiopathic intracranial hypertension but its absence should not dissuade it. If present, abnormal signal in the optic nerve head correlates with papilledema.