A retrospective longitudinal analysis of risk factors, treatment outcomes and imaging parameters of ventricular collapse in idiopathic intracranial hypertension.

Pseudotumor Cerebri (Benign Intracranial Hypertension): Etiopathogenesis, Diagnosis, And Management

The purpose of this study was to analyse less known clinical scenarios associated with idiopathic intracranial hypertension. The study involved analysis of magnetic resonance imaging signs of idiopathic intracranial hypertension in patients with spontaneous rhinoliquorrhoea (n = 7), in patients with temporal lobe epilepsy and surgically treated antero-inferior temporal lobe meningo-encephaloceles (n = 15), and in patients who developed clinical signs of idiopathic intracranial hypertension following the treatment of spontaneous intracranial hypotension (n = 7). Three of six patients with spontaneous rhinoliquorrhoea and six of 15 operated patients with temporal lobe epilepsy due to temporal lobe meningo-encephaloceles showed magnetic resonance imaging signs of idiopathic intracranial hypertension and had a body mass index >30 kg/m2. Rebound high pressure headaches and sings of idiopathic intracranial hypertension occurred in seven of 44 surgically treated spontaneous intracranial hypotension patients. Magnetic resonance imaging findings should guide the clinician to consider (idiopathic) intracranial hypertension when patients develop spontaneous rhinoliquorrhoea, temporal lobe epilepsy secondary to temporal lobe meningoencephaloceles or high pressure headaches in spontaneous intracranial hypotension. Whether idiopathic intracranial hypertension must be regarded as a differential diagnosis or as a cause, or whether there are common pathophysiological pathways that lead to signs of idiopathic intracranial hypertension in this wider spectrum of disease is the focus of further study.

Venous sinus stenosis, typically at the junction of the transverse and sigmoid sinus, is increasingly recognized as a contributor to the pathophysiology of idiopathic intracranial hypertension (IIH), whether it be the intrinsic type that does not reverse with normalization of intracranial pressure or the extrinsic type, which does. Efforts to treat the stenosis and reduce the associated transstenotic gradient through placement of a stent at the site of stenosis have been studied over the past 2 decades, primarily through retrospective studies, with variable emphasis on formal visual testing and direct assessment of poststent opening pressure. Most studies have presented evidence for utilization of stenting as an alternative to cerebrospinal fluid shunting or optic nerve sheath fenestration in patients with IIH who harbor the stenosis and are refractory to or intolerant of intracranial pressure-lowering medications, but an assessment of the current data is needed to better understand the role of stenting for this patient population. A search in PubMed was made for "IIH," "papilledema," and "venous stenting." Data pre and post stenting, including symptoms attributable to IIH, intracranial pressure, papilledema, retinal nerve fiber layer thickening on optical coherence tomography, and visual field assessment (mean deviation), were collected. Need for retreatment and complications were assessed among all studies. Studies using stenting for special circumstances, such as cerebrospinal leaks or for stenosis along anomalous vessels, were reviewed. In total, 49 studies (45 retrospective and 4 prospective) and 18 case reports (with 3 or less patients) were found and included in the analysis, for a total of 1,626 patients. In 250 patients in whom poststent intracranial pressure was measured, the mean value was 19.7 cm H 2 O, reduced from a mean of 33 cm H 2 O. Transient visual obscurations resolved in 79.6% of 201 patients who complained of it, pulsatile tinnitus resolved in 84.7% of 515, diplopia resolved in 93% of 86 patients, and nonspecific visual symptoms such as "blurry vision" improved in 76.2% of 537 patients. Headaches resolved in 36% and improved in a further 40.7% of 1,105 patients in whom they were documented before stenting. Of 1,116 with papilledema, 40.8% demonstrated resolution and 38.2% improvement. The mean retinal nerve fiber layer thickness improved from 170.2 µm to 89.2 µm among 402 eyes in which optical coherence tomography was used to measure it. Among 135 eyes in which formal visual fields were performed pre and post stenting, the prestent average mean deviation of -7.35 dB improved to -4.72 dB after stenting. Complications associated with stenting included in-stent stenosis or thrombosis, subdural hematoma, intracerebral hematoma, cerebral edema, stent migration, and death. A recurrence of symptoms requiring a follow-up surgical intervention occurred in 9%. A growing body of evidence supports the use of venous sinus stenting as a viable option for medically refractory IIH, especially when papilledema threatens visual function. Complication and failure rates seem to be similar to alternative surgical approaches, although serious neurological sequalae can rarely occur. Emerging studies evaluating stent type, including novel stents designed for use in the venous system, may help improve ease of the procedure and long-term success rates. Prospective head-to-head studies are needed to better understand the performance of stenting compared with other interventions.

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Pseudo-Foster Kennedy syndrome due to idiopathic intracranial hypertension

The role of aquaporin-1 in idiopathic and drug-induced intracranial hypertension

BackgroundElevated intracranial pressure (ICP) is observed in association with a range of brain disorders. One of these challenging disorders is idiopathic intracranial hypertension (IIH), characterized by raised ICP of unknown cause with significant morbidity and limited therapeutic options. In this review, special focus is put on the preclinical research performed in order to understand the pathophysiology behind ICP regulation and IIH. This includes cerebrospinal fluid dynamics, molecular mechanisms underlying disturbances in brain fluids leading to elevated ICP, role of obesity in IIH, development of an IIH model and ICP measurements in rodents. The review also discusses existing and new drug targets for IIH that have been evaluated in vivo.ConclusionsICP monitoring in rodents is challenging and different methods have been applied. Some of these methods are invasive, depend on use of anesthesia and only allow short-term monitoring. Long-term ICP recordings are needed to study IIH but existing methods are hampered by several limitations. As obesity is one of the most common risk factors for IIH, a rodent obese model has been developed that mimics some key aspects of IIH. The most commonly used drugs for IIH have been evaluated in vivo for their efficacy at lowering ICP in the existing animal models. These studies suggest these drugs, including acetazolamide, might have limited or no reducing effect on ICP. Two drug targets that can impact ICP in healthy rodents are topiramate and a glucagon-like peptide-1 receptor (GLP-1R) agonist. However, it remains to evaluate their effect in an IIH model with more precise and valid ICP monitoring system. Therefore, continued evaluation in the preclinical research with refined tools is of great importance to further understand the pathophysiology behind disorders with raised ICP and to explore new drug targets.

Psychiatric disease is a frequent comorbidity in idiopathic intracranial hypertension (IIH) and has been associated with a poor subjective outcome. No prospective studies have investigated psychiatric comorbidities in new-onset IIH. Our primary aim was to investigate disease severity in IIH depending on comorbid psychiatric disease. Important secondary outcomes were disease severity after 6 months and prevalence of psychiatric diseases in IIH. This prospective, observational cohort study consecutively included patients with clinically suspected, new-onset IIH from 2 headache centers. A standardized diagnostic workup was completed to confirm or exclude IIH according to the revised Friedman criteria: semi-structured interview, neurologic and neuro-ophthalmologic examination, lumbar puncture with opening pressure (OP), and neuroimaging. Exclusion criteria were known IIH, secondary intracranial hypertension, missing data, and pregnancy. Disease severity was evaluated based on papilledema, visual fields, OP, and headache in patients with IIH without psychiatric disease (IIH-P) compared with patients with IIH 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. A total of 258 patients were screened; 69 were excluded. A total of 189 patients with clinically suspected IIH were then evaluated with the diagnostic workup and IIH was confirmed in 111 patients (58.7%). A total of 45% of patients with IIH had a psychiatric comorbidity. Visual fields were worse in patients with IIH+P at baseline (-8.0 vs -6.0 dB; p = 0.04) and after 6 months (-5.5 vs -4.0 dB; p < 0.01) compared with 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. Visual fields were significantly worse at baseline and 6 months in IIH+P compared with IIH-P. Psychiatric comorbidities, 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.

A 6-year-old girl complained of diplopia and headache over a 2-week period after sustaining a minor head injury. Her neurological examinations were normal, but visual examination identified bilateral papilledema. Magnetic resonance imaging of the brain revealed a protruding nodular lesion causing compression within the anterior superior sagittal sinus in the midline, showing high signal intensity on T2-weighted imaging (T2WI) and low signal intensity on T1WI, similar to that of cerebrospinal fluid. Enhanced T1WI showed irregular narrowing of the anterior superior sagittal sinus adjacent to this lesion. The cortical vein drained to the frontal pole of the arachnoid granulation lesion and into the superior sagittal sinus. No other parenchymal abnormality was noted. A lumbar puncture showed increased opening pressure (30mmHg), and the laboratory findings were normal. Based on the imaging and clinical findings, benign intracranial venous hypertension with giant arachnoid granulation was diagnosed. The patient's symptoms were reduced satisfactorily following daily treatment with 750mg acetazolamide. We report a case of giant arachnoid granulation involving the anterior superior sagittal sinus in a 6-year-old girl who presented with benign intracranial hypertension. Clinicians should be aware of this rare anatomic variant to avoid unnecessary invasive procedures or examinations in children with benign intracranial hypertension.

Idiopathic intracranial hypertension (IIH) mainly occurs in women of a reproductive age who are overweight or obese. As pregnancy occurs in this age group, it is important to understand whether there are associations between IIH and pregnancy. The purpose of this study was to determine the incidence of IIH development during a pregnancy and whether IIH is associated with hypertensive disorders of pregnancy (HDP). In this retrospective cohort analysis, electronic health records from a tertiary care center were used to identify patients with IIH. Patients who had a diagnostic code for IIH or papilledema and were seen between June 1, 2012, and September 1, 2023, were included. After meeting the revised Dandy diagnostic criteria, patients were evaluated for a history of pregnancy before, during, or after their IIH diagnosis and hypertensive disorders including preeclampsia/eclampsia, HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome, and hypertension. Incidence and risk ratios (RR) were calculated comparing patients with IIH with controls without IIH. To corroborate these results while controlling for obesity and migraine, the TriNetX platform housing more than 100 million patients was used to design a case-control analysis evaluating the odds of an IIH patient having an HDP. Two hundred ninety-two IIH patients with a prior pregnancy were identified of which 7% developed new onset IIH during pregnancy. Patients had increased risks of all HDP including eclampsia (RR: 12.92, 95% CI: 5.35, 31.22), preeclampsia (2.39, CI 1.84, 3.10), and HELLP syndrome (6.72, CI 2.16, 20.90) compared with controls. Patients with IIH also had higher risks of ectopic pregnancies and miscarriages ( P < 0.05). When controlling for obesity and migraine, patients continued to have increased odds of all HDP and eclampsia ( P < 0.05). Patients with IIH had an increased risk of having an HDP, especially eclampsia and HELLP syndrome highlighting a need for increased clinical monitoring of these patients during pregnancy.

Idiopathic intracranial hypertension (IIH) is a neurological disease characterized by symptoms and signs of increased intracranial pressure (ICP) of unknown cause. Most attention has been given to the role of cerebrospinal fluid (CSF) disturbance and intracranial venous hypertension caused by sinus vein stenosis. We previously proposed that key pathophysiological processes take place within the brain at the glia-neuro-vascular interface. However, the relative importance of the proposed mechanisms in IIH disease remains unknown. Modern treatment regimens aim to reduce intracranial CSF and venous pressures, but a substantial proportion of patients experience lasting complaints. In 2010, the first author established a database for the prospective collection of information from individuals being assessed for IIH. The database incorporates clinical, imaging, physiological, and biological data, and information about treatment/outcome. This study retrieved information from the database, asking the following research questions: In IIH subjects responding to shunt surgery, what is the occurrence of signs of CSF disturbance, sinus vein stenosis, intracranial hypertension, and microscopic evidence of structural abnormalities at the glia-neuro-vascular interface? Secondarily, do semi-quantitative measures of abnormal ultrastructure at the glia-neurovascular differ between subjects with definite IIH and non-IIH (reference) subjects? The study included 13 patients with IIH who fulfilled the diagnostic criteria and who improved following shunt surgery, i.e., patients with definite IIH. Comparisons were done regarding magnetic resonance imaging (MRI) findings, pulsatile and static ICP scores, and immune-histochemistry microscopy. Among these 13 IIH subjects, 6/13 (46%) of patients presented with magnetic resonance imaging (MRI) signs of CSF disturbance (empty sella and/or distended perioptic subarachnoid spaces), 0/13 (0%) of patients with IIH had MRI signs of sinus vein stenosis, 13/13 (100%) of patients with IIH presented with abnormal preoperative pulsatile ICP [overnight mean ICP wave amplitude (MWA) above thresholds], 3/13 (23%) patients showed abnormal static ICP (overnight mean ICP above threshold), and 12/13 (92%) of patients with IIH showed abnormal structural changes at the glia-neuro-vascular interface. Comparisons of semi-quantitative structural variables between IIH and aged- and gender-matched reference (REF) subjects showed IIH abnormalities in glial cells, neurons, and capillaries. The present data suggest a key role of disease processes affecting the glia-neuro-vascular interface.

Idiopathic intracranial hypertension, polycystic-ovary syndrome, and thrombophilia

We reviewed the medical case report literature to determine the proportion of cases of idiopathic intracranial hypertension (IIH) that were either inappropriately labelled as IIH or prematurely given this diagnosis. We searched OVID MEDLINE from 2012 to 2022 to identify case reports that diagnosed patients with IIH. Case reports were assessed for diagnostic accuracy using Friedman et al.'s revised diagnostic criteria for primary pseudotumor cerebri syndrome. Our primary outcome was the crude prevalence of inappropriate or premature IIH diagnoses. Our secondary outcome was determining if inaccurate IIH diagnoses were associated with variables such as journal subscription model and impact factor, author affiliation, country of origin, and year of publication. A total of 33/185 case reports (17.8%) either incorrectly labelled a patient as having IIH or did not perform all of the investigations necessary to make a diagnosis of IIH. Some of these studies (4.8%) were believed to still represent 'probable' IIH given the clinical presentation, whereas 13.0% of studies were determined to have mislabelled their patients as having IIH. The most common reason that case reports did not meet diagnostic criteria included: a lack of MRV in atypical patient cases (42.4%, n = 14), no papilledema in addition to a lack of characteristic neuroimaging features (33.3%, n = 11), intracranial hypertension being secondary to another documented cause (12.1%, n = 4), normal LP opening pressure in addition to other factors (12.1%,n = 4), no description of neuroimaging (6.1%, n = 2), and abnormal CSF composition (6.1%, n = 2). Case reports that used the term 'IIH' incorrectly had a significantly lower journal impact factor (2.0 vs. 2.6, p = 0.01). There is a high prevalence of premature or inappropriate diagnoses of IIH in the peer-reviewed case report literature. Adherence to published diagnostic criteria is needed when publishing IIH case reports, and authors are expected to report all relevant data in their report to ensure that an accurate diagnosis is made.

Idiopathic intracranial hypertension (IIH) is a pathological state defined as an increase of intracranial pressure in the absence of a causative pathological process. The aim of this study was to evaluate the clinical features of the patients with IIH diagnosed in our Headache Center according to the current knowledge of this disorder. In the retrospective and cross-sectional analysis of 3395 patients we present 12 newly diagnosed IIH patients, ten women and two men, aged from 19 to 51, with obtained values of cerebrospinal fluid pressure between 250 and 680 mm of water. The symptoms of IIH clinical presentation have been headache, reported by 92% of patients; papilledema, noted in 67%; and cranial nerve impairment (25%). The results obtained from presented patients confirmed the presence of headache features that are included in criteria for headache attributed with IIH in majority of them: progressive, daily, diffuse, non-pulsatile headache with aggravation by coughing or straining. Decrease of pain intensity after lumbar puncture was noted in all patients. We notice the relatively small proportion of patients with headache attributed to IIH among the patients treated in our Headache Center. The prevalence of IIH is not low and headache is the most frequent presenting symptom; therefore, we could only conclude that some chronic headache patients refractory for treatment are patients with IIH.

OBJECTIVE Several lines of evidence suggest common pathophysiological mechanisms in Chiari malformation Type I (CMI) and idiopathic intracranial hypertension (IIH). It has been hypothesized that tonsillar ectopy, a typical finding in CMI, is the result of elevated intracranial pressure (ICP) combined with a developmentally small posterior cranial fossa (PCF). To explore this hypothesis, the authors specifically investigated whether ICP is comparable in CMI and IIH and whether intracranial volumes (ICVs) are different in patients with CMI and IIH, which could explain the tonsillar ectopy in CMI. The authors also examined whether the symptom profile is comparable in these 2 patient groups. METHODS The authors identified all CMI and IIH patients who had undergone overnight diagnostic ICP monitoring during the period from 2002 to 2014 and reviewed their clinical records and radiological examinations. Ventricular CSF volume (VV), PCF volume (PCFV), and total ICV were calculated from initial MRI studies by using volumetric software. The static and pulsatile ICP scores during overnight monitoring were analyzed. Furthermore, the authors included a reference (REF) group consisting of patients who had undergone ICP monitoring due to suspected idiopathic normal-pressure hydrocephalus or chronic daily headache and showed normal pressure values. RESULTS Sixty-six patients with CMI and 41 with IIH were identified, with comparable demographics noted in both groups. The occurrence of some symptoms (headache, nausea, and/or vomiting) was comparable between the cohorts. Dizziness and gait ataxia were significantly more common in patients with CMI, whereas visual symptoms, diplopia, and tinnitus were significantly more frequent in patients with IIH. The cranial volume measurements (VV, PCFV, and ICV) of the CMI and IIH patients were similar. Notably, 7.3% of the IIH patients had tonsillar descent qualifying for diagnosis of CMI (that is, > 5 mm). The extent of tonsillar ectopy was significantly different between the CMI and IIH cohorts (p < 0.001) but also between these 2 cohorts and the REF group. Pulsatile ICP was elevated in both cohorts without any significant between-group differences; however, static ICP was significantly higher (p < 0.001) in the IIH group. CONCLUSIONS This study showed comparable and elevated pulsatile ICP, indicative of impaired intracranial compliance, in both CMI and IIH cohorts, while static ICP was higher in the IIH cohort. The data did not support the hypothesis that reduced PCFV combined with increased ICP causes tonsillar ectopy in CMI. Even though impaired intracranial compliance seems to be a common pathophysiological mechanism behind both conditions, the mechanisms explaining the different clinical and radiological presentations of CMI and IIH remain undefined.