Idiopathic Intracranial Hypertension as a Differential Diagnosis in Persistent Idiopathic Facial Pain: A Case Report.

Persistent idiopathic facial pain (PIFP), previously known as atypical facial pain (ATFP), is a chronic pain disorder with the characteristic of persistent, undulating pain in the face or the teeth without a known cause or any structural correlation. Women are more commonly affected than men. We report a case of a 38-year-old married female patient with a history of Crohn's disease who presented to the oral and maxillofacial surgery (OMFS) clinic with chronic dull bilateral facial pain and headache mainly affecting the right side of the face and neck without a known cause. She was initially diagnosed with PIFP due to a badly decayed right wisdom tooth. Wisdom teeth were extracted secondary to vague complaints of discomfort due to wisdom teeth; however, no significant improvement was noticed. Further investigations were carried out with new CT scans and magnetic resonance venography (MRV), which revealed evidence of having idiopathic intracranial hypertension (IIH), described as increased intracranial pressure with facial pain, headache, tinnitus, and papilledema. The patient was referred to neurology and received appropriate treatment. She began her treatment with topiramate, then transitioned to acetazolamide, underwent bilateral botulinum toxin (botox) injections into the temporal region, and underwent regular follow-up. The patient was significantly improved. Idiopathic intracranial hypertension must be ruled out in cases of PIFP that do not respond to ordinary treatment measures.

Transorbital B-mode ultrasound for the assessment of posterior globe flattening in idiopathic intracranial hypertension: a pilot study.

BACKGROUND: Posterior globe flattening (PGF) is a specific neuroimaging sign in patients with idiopathic intracranial hypertension (IIH), but its detection is based on subjective qualitative neuroradiological assessment. This study sought to evaluate the utility of transorbital ultrasound to detect and quantify PGF in IIH patients using the Posterior Globe Angle (PGA). METHODS: Consecutive IIH patients and healthy controls were enrolled in a prospective case-control study. Transorbital ultrasound was performed to assess the presence of PGF. For quantification of PGF, an angular measurement (PGA) was performed with the vertex centering the optic nerve at a predefined distance from the lamina cribrosa and angle legs tangentially aligned to the borders of the vitreous body. PGA measurements were compared between IIH patients and healthy controls. Additionally, the diagnostic accuracy of PGA measurements in detecting PGF was evaluated using ROC analysis. RESULTS: Thirty-one IIH patients (37.3 ± 12.3 years, 29 female) and 28 controls (33.3 ± 11.8 years, 21 female) were compared. PGF was present in 39% of IIH patients and absent in the control group. PGA3mm measurements significantly differed between IIH and controls (116.5° ± 5.5 vs. 111.7° ± 2.9; p < 0.001). A PGA3mm cutoff of ≥ 118.5° distinguished IIH patients from controls with 100% specificity, while retaining a sensitivity of 37.5%. CONCLUSIONS: Transorbital ultrasound may be applied to detect and quantify PGF in IIH patients. Prospective, multicenter studies with extended cohorts and blinded design are needed to validate these preliminary findings and confirm the diagnostic utility of transorbital ultrasound for the assessment of PGF in IIH.

Efficacy and Side Effects of Topiramate in Treatment of Children With Pseudotumor Cerebri Syndrome.

BACKGROUND: Topiramate is often considered as a second-line medication for the treatment of pseudotumor cerebri syndrome (PTCS), but limited studies exist that evaluate its efficacy in children. METHODS: Retrospective study of patients aged <21 years with PTCS who were treated with topiramate alone or in combination with acetazolamide was performed. Data regarding clinical courses and visual outcomes were recorded. RESULTS: A total of 46 patients were identified. Three (6.5%) patients were treated with topiramate alone, 31 (67.4%) transitioned to topiramate from acetazolamide, and 12 (26.1%) took both topiramate and acetazolamide concurrently. The median time to resolution of papilledema on topiramate was 0.57 years (interquartile range 0.32 to 0.84). Among eyes with papilledema graded on the Frisen scale at topiramate initiation, 40 of 57 (70.2%) were grade 1, nine of 57 (15.8%) were grade 2, and eight of 57 (14.0%) were grade 3. Twenty-seven of 46 (58.7%) reported headache improvement after starting topiramate. The mean dose of topiramate was 1.3 ± 0.8 mg/kg/day. The most common side effect was patient report of cognitive slowing (10 of 46 [21.7%]). All patients on topiramate monotherapy who were compliant with treatment and follow-up had resolution of papilledema with no evidence of visual function loss. CONCLUSIONS: Topiramate can effectively treat PTCS in children with mild to moderate papilledema or in those unable to tolerate acetazolamide. More research is needed to assess the efficacy of topiramate for higher grade papilledema.

Progress and recognition of idiopathic intracranial hypertension: A narrative review.

BACKGROUND: Idiopathic intracranial hypertension (IIH) mainly affects obese young women, causing elevated intracranial pressure, headaches, and papilledema, risking vision loss and severe headaches. Despite weight loss as the primary treatment, the underlying mechanisms remain unclear. Recent research explores novel therapeutic targets. AIMS: This review aimed to provide a comprehensive understanding of IIH's pathophysiology and clinical features to inform pathogenesis and improve treatment strategies. METHODS: Recent publications on IIH were searched and summarized using PubMed, Web of Science, and MEDLINE. RESULTS: The review highlights potential pathomechanisms and therapeutic advances in IIH. CONCLUSION: IIH incidence is rising, with growing evidence linking it to metabolic and hormonal disturbances. Early diagnosis and treatment remain challenging.

Outcomes of Pulsatile Tinnitus after Cerebral Venous Sinus Stenting: Systematic Review and Pooled Analysis of 616 Patients.

BACKGROUND: Pulsatile tinnitus (PT) is a debilitating condition with substantial morbidity related to quality of life. Cerebral venous sinus stenosis has recently emerged as a non-infrequent cause of PT, either in the setting of concurrent idiopathic intracranial hypertension (IIH) or due to primary venous stenosis. Venous sinus stenting (VSS) is an endovascular technique that can be used to treat venous stenosis. However, it is unclear if outcomes are different between patients with primary venogenic PT and IIH associated PT. METHODS: A systematic literature review and pooled analysis was completed to evaluate the clinical outcomes of PT in patients undergoing cerebral VSS. Outcome measures included: Improved PT, complete resolution of PT, PT recurrence at follow up. Subgroup analysis between patients with IIH and primary PT was completed. RESULTS: In total, 28 studies were identified with 616 patients. The proportion of improved PT symptoms after VSS had an overall pooled rate of 91.7% (CI:88.1%-95.2%; I2=65%) and no difference between subgroups (P=0.12). Complete resolution after VSS had an overall pooled rate of 88.6% (CI:84.0%-93.3%; I2=68%) and no significant difference between subgroups (P=0.35). Recurrent PT after stenting occurred in 6.5% of cases (CI:1.7%-11.3%; I2=62%). Furthermore, subgroup analysis demonstrated that IIH patients had a significantly higher recurrence rate (10.6%; CI:5.2%-16.1%; I2=26%) compared to patients treated with venous stenting for PT as the primary indication (2.0%; CI:0.8%-4.7%; I2=0%) (P<0.0001). CONCLUSION: Venous stenting in patients with pulsatile tinnitus results in a substantial decrease and often complete resolution of symptoms. PT is more likely to recur in patients with IIH-associated PT.

An interdisciplinary integrated specialized one-stop outpatient clinic for idiopathic intracranial hypertension-a comprehensive assessment of clinical outcome.

BACKGROUND AND PURPOSE: Management of idiopathic intracranial hypertension (IIH) is complex requiring multiple specialized disciplines. In practice, this creates considerable organizational and communicational challenges for healthcare professionals and patients. Thus, an interdisciplinary integrated outpatient clinic for IIH (comprising neurology, neuroophthalmology, neuroradiology, neurosurgery and endocrinology) was established with central coordination and a one-stop concept. Here, the aim was to evaluate the effects of this one-stop concept on objective clinical outcome. METHODS: In a retrospective cohort study, the one-stop era with integrated care (IC) (1 July 2021 to 31 December 2022) was compared to a reference group receiving standard care (SC) (1 July 2018 to 31 December 2019) regarding visual impairment/worsening and headache improvement/freedom 6 months after diagnosis. Multivariate binary logistic regression models were used to adjust for confounders. RESULTS: Baseline characteristics of the IC group (n = 85) and SC group (n = 81) were comparable (female 90.6% vs. 90.1%; mean age 33.6 vs. 32.8 years; median body mass index 31.8 vs. 33.0; median cerebrospinal fluid opening pressure 32 vs. 34 cmH2O; at diagnosis, visual impairment was present in 71.8% vs. 69.1% and chronic headache in 55.3% vs. 56.8% in IC vs. SC). IC was associated with a higher likelihood of achieving both headache improvement (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.52-4.33, p < 0.001) and headache freedom (OR 1.75, 95% CI 1.11-3.09, p = 0.031). Regarding the risk of visual impairment and visual worsening IC was superior numerically but not statistically significantly (OR 0.87, 95% CI 0.69-1.16, p = 0.231, and OR 0.67, 95% CI 0.41-1.25, p = 0.354). CONCLUSIONS: Interdisciplinary integrated care of IIH is favourably associated with headache outcomes and potentially also visual outcomes.

Isolated Intracranial Hypertensions as Onset of Myelin Oligodendrocyte Glycoprotein Antibody Disease.

Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) is characterized by multiple phenotypic conditions such as acute disseminated encephalomyelitis, optic neuritis, and myelitis. MOGAD's spectrum is expanding, with potential symptoms of increased intracranial pressure that are similar to idiopathic intracranial hypertension (IIH). We report a boy with new-onset continuous headache and a brain MRI at onset suggesting idiopathic intracranial hypertension (IIH). The patient showed resistance to treatment with acetazolamide and, after one month, developed optic neuritis in the left eye. Laboratory tests documented positive MOG antibodies (anti-MOG) in the serum. The final diagnosis was MOGAD, with the initial symptoms resembling IIH.

Idiopathic intracranial hypertension pathogenesis: The jugular hypothesis.

In spite of expanding research, idiopathic intracranial hypertension (IIH) and its spectrum conditions remain challenging to treat. The failure to develop effective treatment strategies is largely due to poor agreement on a coherent disease pathogenesis model. Herein we provide a hypothesis of a unifying model centered around the internal jugular veins (IJV) to explain the development of IIH, which contends the following: (1) the IJV are prone to both physiological and pathological compression throughout their course, including compression near C1 and the styloid process, dynamic muscular/carotid compression from C3 to C6, and lymphatic compression; (2) severe dynamic IJV stenosis with developments of large cervical gradients is common in IIH-spectrum patients and significantly impacts intracranial venous and cerebrospinal fluid (CSF) pressures; (3) pre-existing IJV stenosis may be exacerbated by infectious/inflammatory etiologies that induce retromandibular cervical lymphatic hypertrophy; (4) extra-jugular venous collaterals dilate with chronic use but are insufficient resulting in impaired aggregate cerebral venous outflow; (5) poor IJV outflow initiates, or in conjunction with other factors, contributes to intracranial venous hypertension and congestion leading to higher CSF pressures and intracranial pressure (ICP); (6) glymphatic congestion occurs but is insufficient to compensate and this pathway becomes overwhelmed; and (7) elevated intracranial CSF pressures triggers extramural venous sinus stenosis in susceptible individuals that amplifies ICP elevation producing severe clinical manifestations. Future studies must focus on establishing norms for dynamic cerebral venous outflow and IJV physiology in the absence of disease so that we may better understand and define the diseased state.

Radiological signs supporting idiopathic intracranial hypertension in symptomatic patients with lumbar puncture opening pressure < 250 mm.

Lumbar puncture opening pressure (LPOP) exceeding 250mmH2O is key in diagnosing idiopathic intracranial hypertension (IIH), per revised Friedman's criteria. Some patients do not meet LPOP criteria (with or without papilledema), despite having IIH-related symptoms and neuroimaging findings. This study aimed to investigate the radiological findings and clinical symptoms in patients suspected of having IIH without meeting the LPOP criteria. We retrospectively evaluated cerebral venous sinus stenosis using the conduit Farb score (CFS) and other radiological findings suggestive of IIH by computed tomography venography and magnetic resonance venography in females ≥ 18 years-old with chronic headaches, suspected IIH, and LPOP < 250 mm. Eighty-eight women (56 with LPOP < 200 mm H2O and 32 with LPOP ranging between 200 and 250mmH2O) were included. Among patients with LPOP 200-250mmH2O, 40% (12) exhibited three or more radiological findings supporting IIH, compared to 17% (8) in the LPOP < 200 mmH2O group (p = 0.048). Cerebral venous stenosis (CFS ≤ 5) was observed in 80% (24) of those with LPOP 200-250 mmH2O, contrasting with 40% (19) of those with LPOP < 200 mmH2O (p < 0.001). Cerebral venous stenosis was significantly more common in patients with LPOP 200-250 mmH2O than < 200 mmH2O, suggesting that they may benefit from IIH treatment.

An interdisciplinary integrated specialized one-stop outpatient clinic for idiopathic intracranial hypertension - a comprehensive assessment of patient satisfaction.

BACKGROUND: Management of idiopathic intracranial hypertension (IIH) is complex requiring contributions from multiple specialized disciplines. In practice, this creates considerable organizational and communicational challenges. To meet those challenges, we established an interdisciplinary integrated outpatient clinic for IIH with a central coordination and a one-stop concept. Here, we aimed to evaluate effects of this one-stop concept on subjective patient satisfaction and economic outcome in patients with IIH. METHODS: In a retrospective cohort study, we compared the one-stop era with integrated care (IC, 1-JUL-2021 to 31-DEC-2022) to a reference group receiving standard care (SC, 1-JUL-2018 to 31-DEC-2019) regarding subjective patient satisfaction (assessed by the Vienna Patient Inventory). Multivariable binary linear regression models were used to adjust for confounders. RESULTS: Baseline characteristics of the IC group (n = 85) and SC group (n = 81) were comparable (female: 90.6% vs. 90.1%; mean age: 33.6 vs. 32.8 years, educational level: ≥9 years of education 60.0% vs. 59.3%; located in Vienna 75.3% vs. 76.5%). Compared to SC, management within IC concept was associated with statistically significantly higher subjective patient satisfaction (beta = 0.93; p < 0.001) with the strongest effects observed in satisfaction with treatment accessibility and availability (beta = 2.05; p < 0.001). Subgroup analyses of patients with migration background and language barrier consistently indicated stronger effects of IC in these groups. CONCLUSIONS: Interdisciplinary integrated management of IIH statistically significantly and clinically meaningfully improves patient satisfaction - particularly in socioeconomically underprivileged patient groups. Providing structured central coordination to facilitate and improve access to interdisciplinary management provides means to further improve outcome.

Non-invasive estimation of cerebrospinal fluid pressure in idiopathic intracranial hypertension: magnetic resonance imaging analysis of optic nerve and eyeball.

PURPOSE: Invasive methods such as lumbar puncture and intraventricular catheters are commonly used to measure intracranial pressure (ICP). This study aims to develop quantitative and non-invasive techniques to measure ICP in patients with Idiopathic Intracranial Hypertension (IIH) using magnetic resonance imaging (MRI) findings. METHODS: MRI data obtained from 50 patients with IIH and 30 age- and sex- matched controls were analyzed and optic nerve sheath diameter (ONSD), eyeball transverse diameter (ETD) and optic nerve diameter (OND) were measured. ONSD, ONSD/ETD and OND/ONSD indexes were calculated according to different ONSD measurement distances. Correlations of MRI findings with ICP were calculated. Sensitivity and specificity of all methods were analyzed. RESULTS: ONSD and ONSD/ETD index at 3 mm and 10 mm behind the eyeball were significantly higher (p < 0.001) and OND/ONSD index at 3 mm behind the eyeball was significantly lower (p < 0.001) in the IIH group. The ONSD/ETD index at 3 mm had the highest area under the curve (AUC) value (0.898) with a cut-off of 0.27 mm (82% sensitivity and 91.67% specificity) for predicting high cerebrospinal fluid (CSF) pressure, followed by ONSD measurements at 3 mm (AUC = 0.886) with a cut-off of 6.17 mm (83% sensitivity and 86.67% specificity). The OND/ONSD index at 3 mm posterior to the eyeball decreased significantly as ICP increased, and the strength of the relationship was moderate (p < 0.001; r = -0.358). CONCLUSIONS: ONSD and ONSD/ETD index measured on MRI sequences are potentially useful in detecting elevated ICP. The OND/ONSD index correlates with CSF pressure and these techniques may be helpful in diagnosing IIH.

Paediatric idiopathic intracranial hypertension: Epidemiology, clinical features and treatment outcomes in a tertiary care centre in Western Australia.

AIM: This retrospective study aims to analyse the epidemiology, clinical and neuroimaging features, treatment modalities, and outcomes of paediatric idiopathic intracranial hypertension (IIH) in a tertiary care centre in Australia. METHODS: Using the International Classification of Diseases Diagnostic Criteria for IIH, we identified and analysed a cohort of children diagnosed with IIH over a 5-year period (2017-2022). Data on patient demographics, symptomatology, examination findings, investigative results, treatments and outcomes were collected from medical records and electronic health records. RESULTS: A total of 45 cases were analysed. The pre-pubertal group saw a male predominance and the post-pubertal a female one. Increased body mass index was an associated comorbidity in majority of patients. Headaches (89%) and visual symptoms (56%) were the most common symptoms, with tinnitus also seen in 20% of patients. Papilledema was detected in 91% of the cases examined. The commonest neuroimaging features were optic nerve sheath distention (78%) and empty sella (49%). Acetazolamide was the primary treatment, with most patients responding well. Only a minority required surgical intervention. Long-term resolution of headaches was achieved in 89% of patients. CONCLUSIONS: The incidence of paediatric IIH in the West Australian population appears relatively high. It presents with subtle symptoms, emphasising the need for increased awareness among health-care providers. Younger children may represent a distinct subgroup with unique clinical features. Timely diagnosis and aggressive medical management lead to favourable outcomes. However, weight loss interventions showed limited effectiveness. This study underscores the importance of early recognition and management of paediatric IIH to optimise patient outcomes.

Comparing open and closed cell stents in idiopathic intracranial hypertension: A comprehensive meta-analysis of clinical outcomes.

Background: Open cell stents (OC) and closed cell stents (CC) each offer unique advantages and potential drawbacks in the context of idiopathic intracranial hypertension (IIH) treatment. We aim to investigate the safety and efficacy of using OC and CC for IIH.Methods: We conducted a systematic review in PubMed, Embase, and Cochrane Library databases following the PRISMA guidelines. Eligible studies included ≥4 patients with IIH treated by OC or CC. Primary outcomes were headache, visual acuity, and papilledema status before and after the procedure. Additionally, failure rate, minor complications, major complications, and total complications were assessed. Pooled analysis of the OC group and CC group were done separately and then compared.Results: Twenty-four studies were included. Of these, 20 reported on OC and 6 reported on CC. Pooled analysis of failure rate was 8% (4%-12%) in OC and 5% (0%-11%) in CC. For headache improvement rate: 78% (70%-86%) in OC and 81% (66%-69%) in CC. For visual acuity improvement: 78% (65%-92%) in OC and 76% (29%-100%) in CC. For papilledema improvement: 88% (77%-98%) in OC and 82% (67%-98%) in CC. For minor complications: 0% (0%-1%) in OC and 0% (0%-2%) in CC. For major complications: 0% (0%-1%) in OC and 2% (0%-6%) in CC. Total complications: 0% (0%-1%) in OC and 2% (0%-6%) in CC.Conclusion: Low failure and complication rates were found in both OC and CC, with no significant difference between them in effectiveness. The CC showed a slight but significant increase in major and total complications compared to the OC. Additionally, a subtle yet significantly lower failure rate was identified in the CC.

A Case Report of Idiopathic Intracranial Hypertension With Left-Sided Facial Spasm.

Idiopathic intracranial hypertension (IIH) typically presents with increased intracranial pressure of an unknown origin. Facial spasms are an uncommon manifestation of IIH. We report a 56-year-old female patient displaying atypical IIH symptoms of left-sided facial spasm. Clinical examination and imaging confirmed the diagnosis of IIH, and the patient received treatment with acetazolamide. This case highlights the importance of considering IIH as a potential diagnosis in patients with facial spasms, especially when accompanied by other neurological symptoms. Early recognition, a high level of suspicion, and appropriate management are crucial for optimizing outcomes in IIH cases. Furthermore, collaboration among neurologists, neurosurgeons, radiologists, and ophthalmologists is essential for the comprehensive evaluation and management of IIH patients.

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

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

Predictors of Headaches and Quality of Life in Women with Ophthalmologically Resolved Idiopathic Intracranial Hypertension.

Background/objectives: The aim of this study was to evaluate the long-term outcomes of a cohort of ophthalmologically resolved female idiopathic intracranial hypertension (IIH) patients. Methods: Our cross-sectional study included adult females with at least 6 months of ophthalmologically resolved IIH. Patients with papilledema or who underwent IIH-targeted surgical intervention were excluded. Participants completed a questionnaire consisting of medical information, the Migraine Disability Assessment Scale (MIDAS) and the Headache Impact Test (HIT-6). Electronic medical records and the results of imaging upon diagnosis were retrospectively reviewed. Results: One-hundred-and-four participants (mean age 35.5 ± 11.9 years) were included (7.85 ± 7 years post-IIH diagnosis). Patients with moderate-severe disability according to the MIDAS scale (n = 68, 65.4%) were younger (32.4 ± 8.9 vs. 41.5 ± 14.4 year-old, p < 0.001), had a shorter time interval from IIH diagnosis (5.9 ± 5.3 vs. 11.7 ± 8.5 years, p < 0.001), and had lower FARB scores (indicating a more narrowed transverse-sigmoid junction; 1.28 ± 1.82 vs. 2.47 ± 2.3, p = 0.02) in comparison to patients with low-mild disability scores. In multivariate analysis, a lower FARB score (OR 1.28, 95% CI 0.89-1.75, p = 0.12) and younger age (OR 1.09, 95% CI 0.98-1.19, p = 0.13) showed a trend toward an association with a moderate-severe MIDAS score. Moreover, in the sub-analysis of patients with a moderate-severe MIDAS scale score, the 10 patients with the highest MIDAS scores had a low FARB score (1.6 ± 1.1 vs. 2.7 ± 2.4, p = 0.041). Conclusions: High numbers of patients with ophthalmologically resolved IIH continue to suffer from related symptoms. Symptoms may be associated with the length of time from the diagnosis of IIH and a lower FARB score.

Regulation of brain fluid volumes and pressures: basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus.

The principles of cerebrospinal fluid (CSF) production, circulation and outflow and regulation of fluid volumes and pressures in the normal brain are summarised. Abnormalities in these aspects in intracranial hypertension, ventriculomegaly and hydrocephalus are discussed. The brain parenchyma has a cellular framework with interstitial fluid (ISF) in the intervening spaces. Framework stress and interstitial fluid pressure (ISFP) combined provide the total stress which, after allowing for gravity, normally equals intracerebral pressure (ICP) with gradients of total stress too small to measure. Fluid pressure may differ from ICP in the parenchyma and collapsed subarachnoid spaces when the parenchyma presses against the meninges. Fluid pressure gradients determine fluid movements. In adults, restricting CSF outflow from subarachnoid spaces produces intracranial hypertension which, when CSF volumes change very little, is called idiopathic intracranial hypertension (iIH). Raised ICP in iIH is accompanied by increased venous sinus pressure, though which is cause and which effect is unclear. In infants with growing skulls, restriction in outflow leads to increased head and CSF volumes. In adults, ventriculomegaly can arise due to cerebral atrophy or, in hydrocephalus, to obstructions to intracranial CSF flow. In non-communicating hydrocephalus, flow through or out of the ventricles is somehow obstructed, whereas in communicating hydrocephalus, the obstruction is somewhere between the cisterna magna and cranial sites of outflow. When normal outflow routes are obstructed, continued CSF production in the ventricles may be partially balanced by outflow through the parenchyma via an oedematous periventricular layer and perivascular spaces. In adults, secondary hydrocephalus with raised ICP results from obvious obstructions to flow. By contrast, with the more subtly obstructed flow seen in normal pressure hydrocephalus (NPH), fluid pressure must be reduced elsewhere, e.g. in some subarachnoid spaces. In idiopathic NPH, where ventriculomegaly is accompanied by gait disturbance, dementia and/or urinary incontinence, the functional deficits can sometimes be reversed by shunting or third ventriculostomy. Parenchymal shrinkage is irreversible in late stage hydrocephalus with cellular framework loss but may not occur in early stages, whether by exclusion of fluid or otherwise. Further studies that are needed to explain the development of hydrocephalus are outlined.

Is There Evidence for the (Sole) Use of Third Ventriculostomy in the Treatment of Idiopathic Intracranial Hypertension: A Literature Review.

BACKGROUND: Idiopathic intracranial hypertension (IIH) remains a poorly understood condition with no standardized treatment. Treatment is therefore generally individualized. Recent isolated reports have begun to describe the use of third ventriculostomy (open or closed) for the treatment of IIH. This review aims to communicate the current evidence for the use of third ventriculostomy in IIH. METHODS: A systemic review, using PubMed, was performed of studies describing the use of third ventriculostomy, either open or closed, for the treatment of idiopathic intracranial hypertension. RESULTS: Only 3 studies for a total of 3 patients were found in which a third ventriculostomy was performed for the treatment of IIH. CONCLUSION: Despite very plausible proposed mechanisms of action, there is currently a paucity of both studies and, therefore, evidence for the use of either endoscopic or open third ventriculostomy for the treatment of IIH. The studies done to date do strongly suggest that further consideration is warranted.

Application of novel non-invasive ophthalmic imaging to visualize peripapillary wrinkles, retinal folds and peripapillary hyperreflective ovoid mass-like structures associated with elevated intracranial pressure.

Background: Elevated intracranial pressure (ICP) is a serious and potentially life-threatening condition, for which clinically useful non-invasive measures have been elusive, in some cases due to their inadequate sensitivity and specificity. Our aim was to evaluate novel non-invasive ophthalmic imaging of selected pathological features seen in elevated ICP, namely peripapillary hyperreflective ovoid mass-like structures (PHOMS), peripapillary wrinkles (PPW) and retinal folds (RF) as potential biomarkers of elevated ICP. Methods: This single-center pilot study included subjects with untreated or incompletely treated high ICP. The retinas of these subjects were evaluated with averaged en-face optical coherence tomography (OCT), OCT retinal cross-sections (OCT B-scans), adaptive optics scanning light ophthalmoscopy (AOSLO), and fundus photos. Results: Seven subjects were included in the study. 6 subjects with high ICP (5 idiopathic intracranial hypertension, 1 medication induced, 30.8 ± 8.6 years, 75% female, 5 with papilledema) and 1 control (20-25 years) were included. PHOMS, PPW and RF were present in all subjects with papilledema, but neither in the high ICP subject without papilledema nor in the control subject. Averaged en-face OCT scans and AOSLO were more sensitive for PPW and RF than OCT B-scans and commercial fundus photos. Conclusion: PPW, RF and PHOMS volume have potential as non-invasive biomarkers of ICP. Novel imaging modalities may improve sensitivity. However, lack of automated image acquisition and processing limits current widespread adoption in clinical settings. Further research is needed to validate these structures as biomarkers for elevated ICP and improve clinical utility.

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.