Neurofilament light chain is elevated in patients with newly diagnosed idiopathic intracranial hypertension: A prospective study.

BACKGROUND: Idiopathic intracranial hypertension is a secondary headache disorder potentially causing visual loss. Neurofilament light chain is a candidate, prognostic biomarker, but further studies of neuronal biomarkers are needed. Our objective was to investigate neurofilament light chain in cerebrospinal fluid (cNfL) and plasma (pNfL), amyloid-beta 42 (Aß-42), total-tau and phosphorylated-tau in cerebrospinal fluid in new-onset idiopathic intracranial hypertension. METHODS: Prospective case-control study including new-onset idiopathic intracranial hypertension and age, sex and BMI matched controls. Biomarkers were compared between patients and controls and related to papilledema, visual fields and opening pressure. RESULTS: We included 37 patients and 35 controls. Patients had higher age-adjusted cNfL (1.4 vs. 0.6 pg/mL, p-adjusted < 0.001), pNfL (0.5 vs. 0.3 pg/mL, p-adjusted < 0.001) and total-tau/Aß-42 (0.12 vs. 0.11, p-adjusted = 0.039). Significant, positive linear correlations were found between cNfL, pNfL, total-tau/Aß-42 and opening pressure. Patients with severe papilledema had elevated cNfL compared to mild-moderate papilledema (median cNfL: 4.3 pg/mL (3.7) versus 1.0 pg/mL (1.4), p-adjusted = 0.009). cNFL was inversely associated with perimetric mean deviation (r = -0.47, p-adjusted < 0.001). CONCLUSIONS: cNfL, pNfL and total-tau/Aß-42 were elevated in new-onset idiopathic intracranial hypertension. cNfL was associated with severity of papilledema and visual field defects at diagnosis. This indicates early axonal damage. Neurofilament light chain is a candidate biomarker for disease severity.

Are the ICHD-3 criteria for headache attributed to idiopathic intracranial hypertension valid? Headache phenotyping and field-testing in newly diagnosed idiopathic intracranial hypertension.

BACKGROUND: Headache burden is substantial in idiopathic intracranial hypertension. The classification of idiopathic intracranial hypertension headache by the International Classification of Headache Disorders (ICHD) is an important tool for research and clinical purposes. METHODS: We phenotyped headaches and tested sensitivity and specificity of the ICHD-3 criteria for idiopathic intracranial hypertension headache in a prospective cohort of patients suspected of idiopathic intracranial hypertension at two tertiary headache centers. RESULTS: Sensitivity was 93% and specificity was 100% of ICHD-3 criteria for idiopathic intracranial hypertension-related headache validated in idiopathic intracranial hypertension (n = 140) and patients in whom idiopathic intracranial hypertension was suspected but disproven (n = 103). The phenotype of new/worsened headaches related to idiopathic intracranial hypertension suspicion was equally migraine-like (p = 0.76) and tension-type-like (p = 0.08). Lumbar puncture opening pressure was higher (p < 0.0001) and pulsatile tinnitus more frequent (p < 0.0001) in idiopathic intracranial hypertension patients, but neither improved the applicability of the headache criteria, nor did papilledema. CONCLUSION: Headache phenotype is not distinct in idiopathic intracranial hypertension. ICHD-3 criteria for idiopathic intracranial hypertension headache are sensitive and specific, but simplicity can be improved without compromising accuracy. We propose that a new or worsened headache temporally related to active idiopathic intracranial hypertension is a sufficient criterion for idiopathic intracranial hypertension headache regardless of headache phenotype or accompanying symptoms, and that elements of idiopathic intracranial hypertension diagnostics (papilledema and opening pressure) be segregated from headache criteria.Trial Registration: ClinicalTrials.gov Identifier: NCT04032379.

Fundus imaging and perimetry in patients with idiopathic intracranial hypertension-an intermethod and interrater validity study.

BACKGROUND AND PURPOSE: There is a need to improve the diagnostic process of patients suspected of papilledema. In patients with known or suspected idiopathic intracranial hypertension a fundus imaging and perimetric visual field assessment system (COMPASS) performed at a headache center was validated in comparison to an assessment (Topcon plus OCTOPUS) at a neuroophthalmological clinic. METHODS: For intermethod assessment, blinded fundus images and perimetry from COMPASS versus Topcon plus OCTOPUS were assessed by a neuroophthalmologist. For interrater assessment, fundus images and perimetry obtained by the COMPASS system were assessed by an untrained medical doctor, a trained neurologist and a trained medical student and compared to the neuroophthalmologist's assessments. RESULTS: For the intermethod variation of the presence of papilledema on fundus images, a kappa value of 0.60, sensitivity of 87% and specificity of 73% were found. The interrater variation of the presence of papilledema on fundus images showed kappa values ranging from 0.43 to 0.74, sensitivity values ranging from 70% to 96% and specificity values ranging from 46% to 93% when comparing the assessments made by the headache center staff with neuroophthalmologist's assessments. The COMPASS showed a 59% sensitivity and moderate agreement in detecting visual field defects compared with OCTOPUS. The visual field assessment showed only slight to fair agreement from 0.19 to 0.31 between assessments made by the headache center staff and the neuroophthalmologist. CONCLUSION: The COMPASS system can be used with reasonable sensitivity in the assessment of papilledema in patients suspected of idiopathic intracranial hypertension at a tertiary headache center.

Diagnosis of idiopathic intracranial hypertension: A proposal for evidence-based diagnostic criteria.

BACKGROUND: Based on expert opinion, abducens nerve palsy and a neuroimaging criterion (≥3 neuroimaging signs suggestive of elevated intracranial pressure) were added to the diagnostic criteria for idiopathic intracranial hypertension. Our objective was to validate this. METHODS: This prospective study included patients with new-onset idiopathic intracranial hypertension for a standardized work-up: interview, neuro-ophthalmological exam, lumbar puncture, neuroimaging. Neuroimaging was evaluated by a blinded neuroradiologist. RESULTS: We included 157 patients classified as idiopathic intracranial hypertension (56.7%), probable idiopathic intracranial hypertension (1.9%), idiopathic intracranial hypertension without papilledema (idiopathic intracranial hypertension-without papill edema; 0%), suggested idiopathic intracranial hypertension-without papill edema (4.5%), or non-idiopathic intracranial hypertension (36.9%). Moderate suprasellar herniation was more common in idiopathic intracranial hypertension than non-idiopathic intracranial hypertension (71.4% versus 47.4%, p < 0.01), as was perioptic nerve sheath distension (69.8% versus 29.3%, p < 0.001), flattening of the globe (67.1% versus 11.1%, p < 0.001) and transverse sinus stenosis (60.2% versus 18.9%, p < 0.001). Abducens nerve palsy was of no diagnostic significance. Sensitivity of ≥3 neuroimaging signs was 59.5% and specificity was 93.5%. CONCLUSION: Moderate suprasellar herniation, distension of the perioptic nerve sheath, flattening of the globe and transverse sinus stenosis were associated with idiopathic intracranial hypertension. We propose that idiopathic intracranial hypertension can be defined by two out of three objective findings (papilledema, opening pressure ≥25 cm cerebrospinal fluid and ≥3 neuroimaging signs).

Retinal vessel dynamics analysis as a surrogate marker for raised intracranial pressure in patients with suspected idiopathic intracranial hypertension.

INTRODUCTION: Retinal vessel dynamics analysis has proven to be a viable, non-invasive surrogate marker for increased intracranial pressure. We aimed to test this method in patients with suspected idiopathic intracranial hypertension. METHODS: Patients with suspected idiopathic intracranial hypertension were prospectively enrolled for hand-held fundus-videography during diagnostic lumbar puncture. After extracting optic disc images, peripapillary arteriole-to-venule-ratios were measured using machine-learning algorithms with manual identification control. A general linear model was applied to arteriole-to-venule-ratios and corresponding lumbar opening pressures to estimate cerebrospinal fluid pressure. RESULTS: Twenty-five patients were included with a significant difference in arteriole-to-venule-ratio between patients with (n = 17) and without (n = 8) idiopathic intracranial hypertension (0.78 ± 0.10 vs 0.90 ± 0.08, p = 0.006). Arteriole-to-venule-ratio correlated inversely with lumbar opening pressure (slope regression estimate -0.0043 (95% CI -0.0073 to -0.0023), p = 0.002) and the association was stronger when lumbar opening pressure exceeded 15 mm Hg (20 cm H2O) (slope regression estimate -0.0080 (95% CI -0.0123 to -0.0039), p < 0.001). Estimated cerebrospinal fluid pressure predicted increased lumbar opening pressure >20 mm Hg (27 cm H2O) with 78% sensitivity and 92% specificity (AUC 0.81, p = 0.02). A stand-alone arteriole-to-venule-ratio measurement predicting lumbar opening pressure >20 mm Hg (27 cm H2O) was inferior with a 48% sensitivity and 92% specificity (AUC 0.73, p = 0.002). CONCLUSION: Retinal vessel dynamics analysis with the described model for estimating cerebrospinal fluid pressure is a promising non-invasive method with a high sensitivity and specificity for detecting elevated intracranial pressure at follow-up assessments of patients with confirmed idiopathic intracranial hypertension if initial lumbar opening pressure and arteriole-to-venule-ratio data are available.

Phenotyping non-idiopathic pseudotumor cerebri syndrome - A prospective cohort study.

OBJECTIVE: To identify the most frequent causes of secondary pseudotumor cerebri syndrome and compare phenotype, clinical presentation, and symptoms of secondary pseudotumor cerebri syndrome to the primary form of pseudotumor cerebri syndrome, idiopathic intracranial hypertension. METHODS: The study was a prospective cohort study including patients with new-onset pseudotumor cerebri syndrome. Diagnostic work up was standardized. Patients were diagnosed with secondary pseudotumor cerebri syndrome or idiopathic intracranial hypertension according to the revised Friedman criteria. Secondary pseudotumor cerebri syndrome patients were categorized into five causes: medication, systemic causes, sleep apnea, cerebrovascular causes, and several competing causes. Phenotype, clinical presentation, symptoms and neuroimaging were compared between groups. RESULTS: Out of 278 cases, 28 secondary pseudotumor cerebri syndrome and 120 idiopathic intracranial hypertension patients were included. The most frequent causes of secondary pseudotumor cerebri syndrome were medication (n = 8, 28.6%) and systemic causes (n = 8, 28.6%), followed by sleep apnea (n = 5, 17.9%), cerebrovascular causes (n = 4, 14.3%) and several competing causes (n = 3, 10.7%). Secondary pseudotumor cerebri syndrome and idiopathic intracranial hypertension patients were phenotypically alike and predominately female, premenopausal, and obese. Symptoms and objective findings at disease onset were similar between groups. CONCLUSION: Secondary pseudotumor cerebri syndrome should be considered in all patients with suspected pseudotumor cerebri syndrome as secondary pseudotumor cerebri syndrome and idiopathic intracranial hypertension patients are phenotypically and clinically alike. A thorough diagnostic workup is needed as treatment of idiopathic intracranial hypertension and secondary pseudotumor cerebri syndrome is markedly different.

Transorbital sonography: A non-invasive bedside screening tool for detection of pseudotumor cerebri syndrome.

BACKGROUND: Our objective was to assess optic nerve sheath diameter (a marker of elevated intracranial pressure) and optic disc elevation (a marker of papilledema) in pseudotumor cerebri syndrome using transorbital sonography. METHODS: The study was a prospective case-control study. We included patients with new-onset pseudotumor cerebri syndrome and matched healthy controls. All had fundoscopy, lumbar puncture with opening pressure and transorbital sonography. Sonography was assessed by a blinded observer. RESULTS: We evaluated 45 patients and included 23 cases. We recruited 35 controls. Optic nerve sheath diameter was larger in pseudotumor cerebri syndrome compared to controls (6.3 ± 0.9 mm versus 5.0 ± 0.5 mm, p < 0.001) and so was optic disc elevation (0.9 ± 0.4 mm versus 0.4 ± 0.1 mm, p < 0.001). The optimal cut-off point for optic nerve sheath diameter was 6 mm with a sensitivity of 74% for prediction of pseudotumor cerebri syndrome and 68% for prediction of elevated opening pressure. Specificity was 94%. The optimal cut-off point for optic disc elevation was 0.6 mm. Sensitivity was 100% and specificity 83% for prediction of pseudotumor cerebri syndrome. CONCLUSION: Optic disc elevation and optic nerve sheath diameter are increased in new-onset pseudotumor cerebri syndrome. Optic disc elevation achieved high specificity and excellent sensitivity for diagnosis of pseudotumor cerebri syndrome. Transorbital sonography (TOS) is a potential, non-invasive screening tool for pseudotumor cerebri syndrome in headache clinics.

Psychiatric Comorbidities in Patients With Idiopathic Intracranial Hypertension: A Prospective Cohort Study.

BACKGROUND AND OBJECTIVES: Psychiatric disease is a frequent co-morbidity in idiopathic intracranial hypertension (IIH) and has been associated with a poor subjective outcome. No prospective studies have investigated psychiatric co-morbidities in new-onset IIH. Our primary aim was to investigate disease severity in IIH depending on co-morbid psychiatric disease. Important secondary outcomes were disease severity after 6-months and prevalence of psychiatric diseases in IIH. METHODS: This prospective, observational cohort study consecutively included patients with clinically suspected, new-onset IIH from two headache centers. A standardized diagnostic work-up was completed to confirm or exclude IIH according to the revised Friedman criteria: semi-structured interview, neurological and neuro-ophthalmological exam, lumbar puncture with opening pressure, neuroimaging. Exclusion criteria were known IIH, secondary intracranial hypertension, missing data, pregnancy. Disease severity was evaluated based on papilledema, visual fields, opening pressure and headache in IIH patients without psychiatric disease (IIH-P) compared to IIH patients with psychiatric disease (IIH+P). A blinded neuro-ophthalmologist assessed visual outcomes. Age- and sex matched prevalence rates of psychiatric diseases in the general population were found in national reports. RESULTS: 258 patients were screened, 69 were excluded. 189 patients with clinically suspected IIH were then evaluated with the diagnostic work-up, and IIH was confirmed in 111 patients (58.7%). 45% of IIH patients had a psychiatric co-morbidity. Visual fields were worse in patients with IIH+P at baseline (-8.0 versus -6.0 dB, p = 0.04) and after 6 months (-5.5 versus -4.0 dB, p < 0.01) compared to IIH-P. Highly prevalent psychiatric disorders were major depressive disorder (24.3%, n = 27), anxiety or stress-related disorders (24.3%, n=27) and emotionally unstable personality disorder (6.3%, n=7). Substance abuse (1.8%), schizophrenia (0.9%) and bipolar disorder (0.9%) were rare. In the general population prevalence estimates of major depressive disorder and emotionally unstable personality disorder were 1.8-3.3% and 2% respectively. DISCUSSION: Visual fields were significantly worse at baseline and 6 months in IIH+P compared to IIH-P. Psychiatric co-morbidities, particularly depression and emotionally unstable personality disorder, were highly prevalent in IIH. Increased awareness of psychiatric disease as a marker for worse visual status may improve patient care.

Diagnosis of idiopathic intracranial hypertension - the importance of excluding secondary causes: A systematic review.

BACKGROUND: Idiopathic intracranial hypertension is characterized by increased intracranial pressure without any pathological findings on neuroimaging, except for signs of high intracranial pressure. Before diagnosing idiopathic intracranial hypertension secondary causes of increased intracranial pressure should be excluded. OBJECTIVE: to characterize the phenotype of patients with secondary intracranial hypertension and to identify possible risk factors for secondary intracranial hypertension. METHODS: We have systematically searched the PubMed database. The publications were analyzed according to the patient phenotype, age, gender, comorbidities, body mass index/weight status, and additional medication. The results are summarized in four categories: medication, infection, hormonal induced intracranial hypertension and miscellaneous groups of diseases related to sIH. RESULTS: We identified 105 eligible papers which included 272 cases. There were 49.6% pediatric cases. Among the adult group,70.9% were women. A total of 40.4% of all cases were obese or overweight, 27% among adults and 13.4% among pediatric cases. Increased BMI and recent weight gain, anemia, renal diseases and hypertension were the most frequent comorbidities related to sIH. CONCLUSION: Among sIH patients, 40.4% were obese or overweight; two thirds were women. We recommend that even patients with a typical IIH phenotype should be screened for secondary causes.

Awareness, Diagnosis and Management of Idiopathic Intracranial Hypertension.

The diagnosis and management of idiopathic intracranial hypertension (IIH) can be difficult and multiple medical subspecialities are often involved. Several national and international guidelines regarding the investigations and management of IIH have been published in recent years but still there is no consensus about the optimal organization of IIH-care. The objective of this review was to propose and describe a referral pathway and an organization scheme for diagnosis and management of IIH. An extensive search of existing literature was conducted and summarized. In total, 237 IIH-articles were identified and hereof 43 included. The clinical practice in our specialized IIH-clinic is characterized and described. We conclude that an educational campaign involving medical care providers and patients with chronic headaches is necessary. A detailed organizational proposal for a referral pathway and management of IIH patients based on the literature search and our clinical experience from a highly specialized IIH outpatient clinic is suggested and discussed.

[Idiopathic intracranial hypertension].

Idiopathic intracranial hypertension (IIH) is a challenging disease characterized by an increase in intracranial pressure which occurs without any known cause. The disease is mainly seen in obese females of child-bearing age. While originally described as rare, the incidence is increasing in parallel with pandemic obesity, and clinicians in all fields are increasingly likely to meet patients with IIH. The condition causes major morbidity due to chronic headache and visual loss if untreated. In the past ten years new diagnostic criteria and guidelines for management have been published.

Neurofilament light chain as biomarker in idiopathic intracranial hypertension.

BACKGROUND: Damage of the optic nerve is the major complication of idiopathic intracranial hypertension. A biomarker indicative for optic nerve damage would help identifying high-risk patients requiring surgical procedures. Here, we studied the potential of cerebrospinal fluid neurofilament to predict idiopathic intracranial hypertension-induced optic nerve damage. METHODS: In two centers, serum and cerebrospinal fluid of 61 patients with clinically suspected idiopathic intracranial hypertension were prospectively collected. Neurofilament concentrations were measured and related to ophthalmological assessment. RESULTS: The average cerebrospinal fluid neurofilament concentration in patients with moderate and severe papilledema was increased compared to patients with minor and no papilledema (1755 ± 3507 pg/ml vs. 244 ± 102 pg/ml; p < 0.001). Cerebrospinal fluid neurofilament concentrations correlated with the maximal lumbar puncture opening pressure (r = 0.67, p < 0.001). In patients fulfilling the Friedman criteria for idiopathic intracranial hypertension with or without papilledema (n = 35), development of bilateral visual field defects and bilateral atrophy of the optic nerve were associated with increased average age-adjusted cerebrospinal fluid neurofilament concentrations. At last follow-up (n = 30), 8/13 of patients with increased, but only 3/17 with normal, cerebrospinal fluid neurofilament had developed bilateral visual field defects and/or bilateral optic nerve atrophy resulting in a sensitivity of 72.7% and a specificity of 73.7% of cerebrospinal fluid neurofilament to detect permanent optic nerve damage. CONCLUSIONS: Cerebrospinal fluid neurofilament is a putative biomarker for optical nerve damage in idiopathic intracranial hypertension.