Epidemiology and risk factors for idiopathic intracranial hypertension

[CME: Idiopathic Intracranial Hypertension]

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

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.

Thinning of the Skull Base and Calvarial Thickness in Patients With Idiopathic Intracranial Hypertension

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a disorder characterized by elevated intracranial pressure without secondary causes on neuroimaging. IIH typically occurs in young, obese female patients and, when severe, can cause permanent and irreversible vision loss. The association between skull base thinning in patients with intracranial hypertension and obesity has been previously reported; however, no study has reported these findings in IIH. The goal of our study is to determine whether IIH is independently associated with skull base and calvarial thinning.

METHODS

A retrospective, matched case-control study was performed. Each patient diagnosed with IIH (case) was matched with a patient diagnosed with headache (control) by age, gender, and race. Patients were included if they underwent computed tomographic imaging of the head, maxillofacial, or orbits within 3 months of their diagnosis. Exclusion criteria were history of skull base or frontal bone pathology because of surgery or skull trauma, central nervous system infections, or incomplete radiologic data. Patient demographics, medical history, clinical examination, and skull base, calvarial, and zygoma thickness were recorded. Skull base thickness was measured by the height of the auditory canal in the coronal plane. Calvarial thickness was measured just anterior to the foramen rotundum in the coronal plane. Extracranial zygoma thickness was measured and used as an internal imaging control because the zygoma is not subject to intracranial forces.

RESULTS

One hundred twenty-six patients were included in the study, 63 cases and 63 controls. Each group comprised 61 female patients (97%), 24 (38%) Caucasian, 23 (37%) black, 1 (2%) Asian, and 15 (24%) others. The average age was 31.5 ± 8.7 years. Patients with IIH were more likely to be obese (n = 60, 95%) compared with the control patients (n = 23, 37%, P < 0.001). All patients with IIH underwent lumbar puncture (LP) with an average opening pressure (OP) of 40.5 ± 15.6 cm H2O, whereas only 13 (20%) controls underwent an LP with a mean OP of 19.5 ± 8.5 cm H2O. There was no statistical difference in mean visual acuity between the IIH and control groups (logMar 0.22 [20/30] ± 0.45 vs logMar 0.09 [20/25] ± 0.30, P = 0.093, respectively). Compared with the controls, patients with IIH were more likely to have headache (97% vs 74%, P = 0.001), pulsatile tinnitus (48% vs 7%, P < 0.001), horizontal binocular diplopia (24% vs 4%, P = 0.006), confrontational visual field deficit (23% vs 2%, P = 0.003), and papilledema (74% vs 0%, P < 0.001). Patients with IIH had thinner skull base and calvarium width compared with the controls (mean skull base thickness 4.17 ± 0.94 mm vs 5.05 ± 1.12 mm, P < 0.001 and mean calvarial width 1.50 ± 0.50 mm vs 1.71 ± 0.61 mm, P = 0.024). Zygoma thickness was similar in both groups (mean zygoma thickness 1.18 ± 0.30 mm in the IIH group vs 1.26 ± 0.35 mm in the control group, P = 0.105). In a subgroup analysis controlling for obesity (body mass index >30 kg/m2), there was no statistically significant difference in skull base, calvarial, or zygoma thickness between obese and nonobese patients.

CONCLUSIONS

Patients with IIH have thinner mean skull base and calvarial thickness compared with the controls. There was no difference in the mean extracranial zygoma thickness, which was the internal imaging control. Contrary to previous reports, we did not find an association between obesity and skull base or calvarial thinning. These findings suggest that IIH is associated with skull base and calvarial thinning.

Idiopathic Intracranial Hypertension: An Unusual Cause of Headache in a Patient With Sickle Cell Disease

Idiopathic intracranial hypertension (IIH) is a rare cause of headache and visual disturbance with no known association with sickle cell disease (SCD). We present a patient with SCD with gradual onset of a severe headache and visual changes. Brain magnetic resonance imaging, angiography, and venography were nondiagnostic. Lumbar puncture established a diagnosis of IIH, and the patient had rapid improvement with large-volume lumbar puncture and acetazolamide. To our knowledge, this is the first case of IIH in a nonobese adult with SCD taking hydroxyurea, suggesting an association between SCD or hydroxyurea use and IIH. Furthermore, her clinical course demonstrates the complexities of treating IIH in patients with SCD.

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.

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.

Sensorineural Hearing Loss and Tinnitus Characteristics in Patients With Idiopathic Intracranial Hypertension

OBJECTIVES

To characterize patterns of sensorineural hearing loss (SNHL) and tinnitus in patients with idiopathic intracranial hypertension (IIH).

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS

Adult patients diagnosed with IIH via lumbar puncture (LP) between 2010 and 2020 who had available audiograms. The study included a total of 40 patients; 33 women, and 7 men with a median age of 43.

INTERVENTIONS

Diagnostic LP and audiogram.

MAIN OUTCOME MEASURES

Otologic symptoms, ophthalmologic signs, hearing thresholds, cerebrospinal fluid opening pressures.

RESULTS

The most commonly reported symptoms were tinnitus in 28 (70%, 23 pulsatile and 5 tonal), aural fullness in 11 (28%), and vertigo in 10 (25%). Twenty-nine patients had ophthalmologic examinations and 18 had evidence of papilledema. Twenty-five (63%) patients had hearing loss in at least one ear at one frequency range. Patients presented with both unilateral and bilateral hearing loss across low, middle, and high frequency ranges. No significant association was observed between hearing loss threshold and LP opening pressure except for 250 Hz in the left ear. After stratification by tinnitus group (pulsatile, tonal, and no tinnitus), no significant difference was found between mean hearing loss threshold at different frequencies. In addition, no significant mean age difference was identified in patients within each tinnitus group.

CONCLUSIONS

There was no classic pattern or presentation for hearing loss in our IIH patients. They developed sudden, unilateral, or bilateral SNHL in low, middle, or high frequency range. The degree of hearing loss did not correlate with CSF opening pressure.

Characterizing idiopathic intracranial hypertension socioeconomic disparities and clinical risk factors: A retrospective case-control study

INTRODUCTION

Against the backdrop of the diverse minority-majority state of Hawaii, this study seeks to better characterize associations between idiopathic intracranial hypertension (IIH) with sociodemographic variables and medical comorbidities.

METHODS

A retrospective case-control study was conducted by utilizing 54 IIH patients and 216 age-, sex-, and race-matched controls, 216 unmatched controls, and 63 age-, sex-, and race-matched migraine patients.

RESULTS

Relative to controls, IIH were 25 years younger (p < 0.0001) and 10.18 kg/m² heavier (p < 0.0001), as well as exhibited greater odds of the following variables (p < 0.05): female (odds ratio [OR]: 8.87), the lowest income quartile (OR: 2.33), Native Hawaiian or other Pacific Islander (NHPI; OR: 2.23), Native American or Alaskan Native (OR: 16.50), obesity class 2 (35.0-39.9 kg/m²; OR: 4.10), obesity class 3 (>40 kg/m²; OR: 6.10), recent weight gain (OR: 11.66), current smoker (OR: 2.48), hypertensive (OR: 3.08), and peripheral vascular disease (OR: 16.42). Odds of IIH were reduced (p < 0.05) for patients who were Asian (OR: 0.27) or students (OR: 0.30;). Unique from Whites, NHPI IIH patients exhibited greater odds (p < 0.05) for being from lower socioeconomic status and currently smoking, as well as potential association with seizures (p = 0.08). Compared to migraines, IIH headaches were at increased odds of occurring (p < 0.05) occipitally, for greater than 15 days per month, aggravated by postural changes, and comorbid with dizziness and tinnitus.

CONCLUSIONS

These results not only better characterize IIH, but also highlight socioeconomic and racial disparities in diagnosis.

Idiopathic intracranial hypertension: Do we diagnose and manage it appropriately in the light of current data?

BACKGROUND AND OBJECTIVE

Idiopathic intracranial hypertension (IIH) is an increase of intracranial pressure without a known cause, which usually presented with headache. This study aimed to evaluate the changing diagnosis and management approaches of neurologists for IIH in light of recent data.

METHODS

An online questionnaire about IIH was developed covering 28 questions, and five sections: demographic data, diagnosis, examination, treatment, and follow-up. We compared the approach of neurologists with 1-9 years of experience (group-A) with that of neurologists with more than 10 years' experience (group-B).

RESULTS

A total of 517 neurologists (group A: n = 252, group B: n = 265) participated in the study. Responder rate of questionarre is 18.3%. The approach to IIH in diagnosis, examination, treatment, and follow-up processes was similar in both groups. The younger group (group A) recognized all neuro-radiologic findings, especially flattening of the posterior aspect of the globe (p = 0.001) and tortuosity of the optic nerve (p < 0.001) at higher rates compared with group B. The most commonly used medical treatment was acetazolamide (99%); corticosteroids were used more frequently by group B (p < 0.001). Optic nerve sheath fenestration (88.3%) was the first-line and ventriculo-peritoneal shunt (70.5%) was the second preferred surgical approach. It was observed that serial lumbar puncture applications (57.0%) were preferred more frequently than venous sinus stenting (19.0%) and bariatric surgery (10.0%).

CONCLUSIONS

The changing information in the last decade about IIH was more closely followed by younger neurologists despite their lesser experience, but classic methods were preferred in surgical approaches in both groups. Our findings indicated that post-graduate education and guidelines should be disseminated for IIH.

A national Swedish case-control study investigating incidence and factors associated with idiopathic intracranial hypertension

OBJECTIVE

To study the incidence of idiopathic intracranial hypertension in Sweden and to explore whether previously proposed risk factors are associated with idiopathic intracranial hypertension by investigating the odds of exposure one year prior to diagnosis in patients compared to controls.

METHODS

Using Swedish health care registers and validated diagnostic algorithms, idiopathic intracranial hypertension patients diagnosed between 2000-2016 were compared with randomly selected matched controls, five from the general population and five with obesity.

RESULTS

We identified 902 idiopathic intracranial hypertension patients and 4510 matched individuals in each control group. Mean incidence among inhabitants ≥18 years of age was 0.71 per 100,000; rising from 0.53 in 2000-2005 to 0.95 in 2012-2016. There were increased odds for idiopathic intracranial hypertension patients compared to general population for exposure to: kidney failure (odds ratio =13.2 (4.1-42.0)), arterial hypertension (odds ratio =17.5 (10.5-29.3)), systemic lupus erythematosus (odds ratio =13.8 (4.3-44.7)), tetracyclines, sulphonamides, lithium, and corticosteroids. In obese controls, odds ratios were also significantly increased for these exposures. Hormonal contraceptive use and exposure to pregnancy did not appear to be associated factors for idiopathic intracranial hypertension development.

CONCLUSIONS

The incidence of idiopathic intracranial hypertension in Sweden is lower relative to reports from other countries but is on the rise. This case-control study confirms several previously reported risk factors associated with idiopathic intracranial hypertension.

Self-Reported Weight and Height Among Idiopathic Intracranial Hypertension Patients

BACKGROUND

Idiopathic intracranial hypertension (IIH) mostly affects overweight and obese women. Severe obesity is associated with poorer visual outcomes in IIH, and weight gain can precipitate IIH and increase the risk of recurrence. Conversely, weight loss can decrease intracranial pressure and is an effective IIH treatment. Therefore, accurate monitoring of weight and body mass index (BMI) is important to help guide the management of IIH patients. Our goal was to compare estimated and measured BMI among patients with presumed IIH and non-IIH controls to determine whether these vital signs should be systematically measured when evaluating patients for IIH.

METHODS

A retrospective chart review was performed of consecutive patients with reported and measured weight and height seen in one ophthalmology-based neuro-ophthalmology clinic for IIH between January 2, 2018 and September 10, 2018. Patients with IIH or presumed IIH were compared to non-IIH controls, matched according to age (±5 years), BMI (±5 kg/m unless ≥40 kg/m), sex, and race. Patients with confirmed IIH were asked to self-report their weight when seen in follow-up and they were weighed to compare their self-reported vs measured percent weight change.

RESULTS

We included 379 subjects (140 patients; 239 controls) among whom 75 of the IIH patients were matched to non-IIH controls. Patients with presumed or definite IIH accurately estimated their height and generally underestimated their weight by a median of 1.8 kg (4 lb), resulting in a median BMI underestimate of 0.9 kg/m. There was no difference in BMI underestimation when comparing presumed or definite IIH patients to matched non-IIH controls while controlling for insurance status, smoking, diabetes, and vascular disease (P = 0.66). As BMI increased, all subjects underestimated their BMI more (by 0.9% per 10 measured BMI unit increase), when controlling for age, sex, and race (P < 0.003). Sixteen confirmed IIH patients were seen in follow-up. At initial neuro-ophthalmology consultation, these subjects underestimated their weight by a mean of 3.2%. At last follow-up they underestimated their weight by only 1.2% (P = 0.03).

CONCLUSIONS

There was no evidence that IIH or presumed IIH patients had a different perception of their weight than non-IIH controls at initial neuro-ophthalmology consultation. Both patients and matched controls tended to underestimate their weight by the same amount, resulting in an overall BMI underestimation of approximately 1% per 10 measured BMI unit increase. Heavier subjects tended to underestimate their body weight and resultant BMI more, and IIH patients tended to estimate their weight more accurately at follow-up. Our results emphasize the need to systematically objectively measure the weight of presumed IIH patients seen in an ophthalmology clinic.

Incidence of idiopathic intracranial hypertension in Southern Tasmania, Australia

Introduction

Anecdotally, the incidence of idiopathic intracranial hypertension (IIH) is increasing, linked to an increase in the obesity rate in Australian society. However, formal incidence and prevalence studies are rare. We therefore sought to determine the incidence and clinical features of IIH in Southern Tasmania, Australia.

Method

Neurology discharge summaries and lumbar puncture referrals from the single tertiary referral centre in this region were screened for an IIH diagnosis. All regional neurologists were surveyed to capture patients diagnosed through private neurology clinics. A retrospective review of medical records was conducted to confirm the diagnosis and determine whether patients met the Modified Dandy Criteria (MDC). Patients were included if they were above the age of 18 years and received a new diagnosis of IIH between June 2016 and June 2018. Population statistics were obtained from the Australian Bureau of Statistics.

Results

IIH incidence was 5.4/100 000. All patients were females, aged between 18 and 45 years. Headache was the most commonly reported symptom, with high rates of pre-existing or concurrent migraine diagnoses. Weight loss and commencement of oral acetazolamide were the most common treatment approaches. Four patients were medically refractory and required surgical intervention.

Conclusion

The incidence of IIH in Southern Tasmania is comparable with the incidence reported in subgroups of females of childbearing age in recent prior studies. The demographic, diagnostic and therapeutic data presented can inform future local health service provision and serve as a baseline for ongoing assessment of change in incidence and treatment of IIH at a community level.

Dural venous sinus stenting in the treatment of idiopathic intracranial hypertension: A systematic review and critique of literature

Idiopathic intracranial hypertension (IIH) is increased intracranial pressure without a known cause. Dural venous sinus stenting (DVSS) is a relatively new intervention for treatment of IIH refractory to medical therapy and lifestyle modifications. In this review, we outline various hypotheses of IIH pathogenesis and describe the role of venous sinus stenosis and the technical details of DVSS. We also present a summary and critique of the available evidence describing the outcomes of DVSS in IIH and review the evidence-based guidelines for this procedure. We conclude that, although many studies have shown generally favorable outcomes of DVSS in patients with IIH, most have serious limitations, the most common one being paucity of pre- and postprocedure ophthalmological data. Thus, there is not enough available evidence to conclude whether DVSS is an effective procedure for treatment of IIH. We also present the most commonly used indications for DVSS as described in the literature and stress the importance of neuro-ophthalmological assessment before and after the procedure to monitor response and potential complications.

Radiologically-proven New Development of Superior Semicircular Canal Dehiscence Associated With Development of Superior Semicircular Canal Dehiscence Syndrome

OBJECTIVE

This report describes a case of development of radiologic superior semicircular canal dehiscence and reviews the literature for pertinent clinical and radiologic findings in patients with superior semicircular canal dehiscence syndrome (SCDS).

PATIENT

A 28-year-old man presented with auditory and vestibular symptoms of SCDS and underwent a high-resolution temporal bone computed tomography scan that showed frank dehiscence of the right superior semicircular canal. Diagnosis of SCDS was further verified with audiometric and cervical vestibular-evoked myogenic potential (cVEMP) thresholds. The patient had previously undergone a computed tomography scan 12 years prior for work-up of sudden sensorineural hearing loss that showed no evidence of superior semicircular canal dehiscence bilaterally.

INTERVENTIONS

A combination of diagnostic and therapeutic interventions was conducted consisting of preoperative audiometric and cVEMP thresholds, followed by middle fossa craniotomy for surgical repair of the dehiscence.

MAIN OUTCOME MEASURE

Postoperative audiometric and cVEMP thresholds and symptomatic improvement of SCDS after surgical repair of the dehiscence.

RESULTS

The patient reported resolution of his clinical symptoms after surgical repair of the dehiscence. Postoperative cVEMP thresholds improved to the normal range and the mild low-frequency conductive hearing loss resolved.

CONCLUSIONS

To our knowledge, this case report is the first description of radiologically proven new development of superior canal dehiscence. Further prospective studies that include serial imaging examinations may help with visualizing and understanding the temporal evolution of superior canal dehiscence, and better elucidate the relationship between development/ progression of superior canal dehiscence and onset of clinical symptoms.

Head-Down Tilt Bed Rest Studies as a Terrestrial Analog for Spaceflight Associated Neuro-Ocular Syndrome

Astronauts who undergo prolonged periods of spaceflight may develop a unique constellation of neuro-ocular findings termed Spaceflight Associated Neuro-Ocular Syndrome (SANS). SANS is a disorder that is unique to spaceflight and has no terrestrial equivalent. The prevalence of SANS increases with increasing spaceflight duration and although there have been residual, structural, ocular changes noted, no irreversible or permanent visual loss has occurred after SANS, with the longest spaceflight to date being 14 months. These microgravity-induced findings are being actively investigated by the United States' National Aeronautics Space Administration (NASA) and SANS is a potential obstacle to future longer duration, manned, deep space flight missions. The pathophysiology of SANS remains incompletely understood but continues to be a subject of intense study by NASA and others. The study of SANS is of course partially limited by the small sample size of humans undergoing spaceflight. Therefore, identifying a terrestrial experimental model of SANS is imperative to facilitate its study and for testing of preventative measures and treatments. Head-down tilt bed rest (HDTBR) on Earth has emerged as one promising possibility. In this paper, we review the HDTBR as an analog for SANS pathogenesis; the clinical and imaging overlap between SANS and HDTBR studies; and potential SANS countermeasures that have been or could be tested with HDTBR.

Pseudotumor cerebri syndrome in a child with Alagille syndrome: intracranial pressure dynamics and treatment outcome after ventriculoperitoneal shunting

Alagille syndrome (AS) is a rare multisystem disease of the liver, heart, eyes, face, skeleton, kidneys, and vascular system. The occurrence of pseudotumor cerebri syndrome (PTCS) in patients with AS has been reported only exceptionally. Owning to its rarity and a mostly atypical presentation, the diagnosis and natural history of affected patients remain uncertain. We report an atypical case of PTCS in a 4-year-old boy with a known history of AS who presented with bilateral papilledema (PE) on a routine ophthalmological examination. Visual findings deteriorated after treatment with acetazolamide. Continuous intracranial pressure (ICP) monitoring was then utilized to investigate ICP dynamics. Successful treatment with resolution of PE was achieved after ventriculoperitoneal shunting but relapsed due to growth-related dislocation of the ventricular catheter. This report brings new insights into the ICP dynamics and the resulting treatment in this possibly underdiagnosed subgroup of PTCS patients. It also demonstrates that ventriculoperitoneal shunting can provide long-term improvement of symptoms for more than 10 years.

Familial Idiopathic Intracranial Hypertension in Two Non-obese Chinese Sisters

Background: Familial idiopathic intracranial hypertension (FIIH) is a rare condition, the etiology of which is unclear.

Aims: To describe two non-obese Chinese sisters who met the criteria of FIIH and to analyze the clinical features and prognosis of FIIH.

Methods: The clinical course, treatment, and prognosis of these two patients were analyzed retrospectively. Meanwhile, all the literature of familial IIH (FIIH) was reviewed.

Results: These two sisters presented with headaches and visual impairment in their mid-thirties. Magnetic resonance imaging (MRI) of the brain was unremarkable except for partial empty sella. No comorbidities or defined causes were detected. Headaches were partially relieved by dehydrated medicine, whereas the visual impairment persisted.

Conclusion: In cases where patients present with headaches, empty sella are found on an MRI, and there is visual impairment with or without papilla edema, intracranial hypertension should be excluded. Furthermore, we should pay more attention to the relatives of those patients with increased intracranial hypertension.

Retinal Manifestations of Idiopathic Intracranial Hypertension

TOPIC

This review presents a case series and systematic review to understand retinal changes in patients with idiopathic intracranial hypertension (IIH) using fundus photography and OCT.

CLINICAL RELEVANCE

IIH is a condition of raised intracranial pressure of unknown cause, usually observed in young, obese women. Ophthalmologic manifestations of IIH such as papilledema and abducens nerve palsy are well recognized, but less common retinal manifestations may occur.

METHODS

A retrospective institutional chart review (July 2018-March 2020) was performed on consecutive IIH patients. Fundus photographs were obtained followed by neuro-ophthalmology assessment to elicit clinical characteristics and for diagnosis. Patients who met the modified Dandy criteria were included. A systematic review of observational studies was conducted using Ovid MEDLINE and EMBASE to November 17, 2019, to supplement the case series data.

RESULTS

Of 144 consecutive IIH clinical patients reviewed, 10 (6.9%) and over 182 patients from the literature showed retinal findings (% in case series, % in literature, respectively): subretinal fluid (SRF; 30,9), chorioretinal folds (30,68), macular exudate (ME; 20,5), choroidal neovascular membrane (CNVM; 10,15), venous stasis retinopathy (VSR; 10,2), choroidal infarction (0,1), and branch retinal artery occlusion (BRAO; 0,1). Eight clinical patients were women (80%), average age was 32.00 ± 13.99 years, body mass index was 40.63 ± 7.43 kg/m², baseline visual acuity (VA) was 0.79 ± 0.30 in both eyes, and visual field (VF) results were -9.89 ± 11.52 dB in both eyes. Among clinical patients, 2 (1 with SRF, 1 with CNVM) had distinctive retina-related VF defects at presentation. Outer retinal abnormalities persisted on OCT in patients after resolution of SRF and papilledema. Surgical treatment (peritoneal shunt) was required for 2 patients (1 with VSR, 1 with SRF); others were treated with weight loss and acetazolamide alone. The patient with significant ME had hypertension that was treated.

DISCUSSION

Significant retinal manifestations associated with IIH include CNVM, ME, SRF, VSR, chorioretinal folds, choroidal infarction, and BRAO. These may reduce VA or cause VF defects unrelated to papilledema, emphasizing the importance of a detailed dilated fundus examination. Consultation with a retina specialist is advised in patients with peripapillary CNVM.

Demographics, Clinical Characteristics, and Management of Idiopathic Intracranial Hypertension in Kuwait: A Single-Center Experience

Background: Idiopathic intracranial hypertension (IIH) affects predominantly obese females during their reproductive age period. The demographics of this condition has not been studied in Kuwait before. Objectives: To determine the demographics, clinical features, risk factors, and treatment modalities of IIH in the main neurology tertiary referral hospital in Kuwait and to compare our data with literature. Methods: A retrospective study was conducted to identify cases of IIH seen between January 1, 2018, and December 31, 2018. Patients were diagnosed in and referred from the neurology and neuro-ophthalmology clinics. Results: Our cohort consisted of 139 patients. We estimated a crude annual incidence rate of IIH of 3.28 per 100,000 population. Female-to-male ratio was 9.6:1. Mean age was 32.1 ± 10.8 years. Mean age of males was 31.46 ± 12.63 and that of females was 32.11 ± 10.67. The median of the duration from the first symptoms till diagnosis was 6 weeks (2-10 weeks). Headache was the most common symptom in 134 (96.4%) patients, followed by visual disturbances in 85 (61.2%) patients, transient visual obscurations (TVOs) in 84 (60.4%) patients, pulsatile tinnitus in 72 (51.8%) patients, diplopia in 22 (15.8%) patients, other symptoms (e.g., nausea, vomiting, radicular neck, and back pain) in 19 (13.7%) patients, and 1 (0.7%) patient had facial weakness. High body mass index (BMI) was seen in 89.9% of patients, either overweight or obese, and it was the most common risk factors in both males (46.2%) and females (61.1%). Anemia was found in 38.1%; 21.6% of patients used OCPs and 7.9% used vitamin A. Bilateral transverse sinus stenosis (BTSS) was detected in 47 (33.8%) patients. Only 2 (1.4%) patients developed "fulminant IIH" characterized by rapidly progressive disease. All the patients received medical treatment and only 12 (8.6%) needed surgical management. Conclusion: Incidence of IIH in Kuwait is similar to other regional studies but higher than Western studies. Demographics and clinical features of IIH in our study are comparable to international and regional figures. Most of our patients had a benign course. IIH is more prevalent in females and strongly associated with obesity.

Guide to preclinical models used to study the pathophysiology of idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is characterised by raised intracranial pressure (ICP) and papilloedema in the absence of an identifiable secondary cause typically occurring in young women with obesity. The impact is considerable with the potential for blindness, chronic disabling headaches, future risk of cardiovascular disease and marked healthcare utilisation. There have been marked advances in our understanding the pathophysiology of IIH including the role of androgen excess. Insight into pathophysiological underpinnings has arisen from astute clinical observations, studies, and an array of preclinical models. This article summarises the current literature pertaining to the pathophysiology of IIH. The current preclinical models relevant to gaining mechanistic insights into IIH are then discussed. In vitro and in vivo models which study CSF secretion and the effect of potentially pathogenic molecules have started to glean important mechanistic insights. These models are also useful to evaluate novel therapeutic targets to abrogate CSF secretion. Importantly, in vitro CSF secretion assays translate into relevant changes in ICP in vivo. Models of CSF absorption pertinent to IIH, are less well established but highly relevant and of future interest. There is no fully developed in vivo model of IIH but this remains an area of importance. Progress is being made to improve our understanding of the underlying aetiology in IIH including the characterisation of disease biomarkers and their mechanistic role in driving disease pathology. Preclinical models, used to evaluate IIH mechanisms are yielding important mechanistic insights. Further work to refine these techniques will provide translatable insights into disease aetiology.

Dural venous sinus stenting for treatment of pediatric idiopathic intracranial hypertension

BACKGROUND

Dural venous sinus stenting (VSS) is an effective treatment for idiopathic intracranial hypertension (IIH) in adult patients. There are no published series to date evaluating safety and efficacy of VSS in pediatric patients.

OBJECTIVE

To report on procedural device selection and technique as well as safety and efficacy of VSS for pediatric patients with medically refractory IIH due to underlying venous sinus stenosis.

METHODS

A multi-institutional retrospective case series identified patients with medically refractory IIH aged less than 18 years who underwent VSS.

RESULTS

14 patients were identified at four participating centers. Patient ages ranged from 10 to 17 years, and 10 patients (71.4%) were female. Mean body mass index was 25.7 kg/m² (range 15.8-34.6 kg/m²). Stenting was performed under general endotracheal anesthesia in all except two patients. The average trans-stenotic gradient during diagnostic venography was 10.6 mm Hg. Patients had stents placed in the superior sagittal sinus, transverse sinus, sigmoid sinus, occipital sinus, and a combination. Average follow-up was 1.7 years after stenting. Six patients out of 10 (60%) had reduced medication dosing, 12 of 14 patients (85.7%) had improvements in headaches, two patients (100%) with pre-stent tinnitus had resolution of symptoms, and four (80%) of five patients with papilledema had improvement on follow-up ophthalmological examinations. Two patients (14.3%) developed postprocedural groin hematomas, one patient (7.1%) developed a groin pseudoaneurysm, and one patient (7.1%) had postprocedural groin bleeding. No other procedural complications occurred. Four patients (28.6%) required further surgical treatment (cerebrospinal shunting and/or stenting) after their first stenting procedure.

CONCLUSIONS

This series suggests that VSS is feasible in a pediatric population with IIH and has a low complication rate and good clinical outcomes.

An update on idiopathic intracranial hypertension in adults: a look at pathophysiology, diagnostic approach and management

Idiopathic intracranial hypertension is a neurological syndrome determined by a rise in intracranial pressure without a detectable cause. Course and prognosis may be changeable, requiring a multidisciplinary approach for its diagnosis and management. Although its precise pathogenesis is still unknown, many studies have been carried out to define the possible causal and associated factors, such as retinoids, steroid hormones, body mass index and recent weight gains, cytokines and adipokines levels. The clinical presentation can be variable including chronic headache, disturbance of vision, diplopia and tinnitus. Even if papilloedema is considered the most specific sign, it could not be observed in more than 5% of patients during the evaluation of the fundus oculi. Neuroradiological signs acquire greater importance in patients who do not present papilloedema and may suggest the diagnosis of idiopathic intracranial hypertension. Other assessments can be useful in the diagnostic process, such as optical coherence tomography, visual evoked potentials, ocular ultrasonography and fundus fluorescein angiography and autofluorescence. Nonetheless, cerebrospinal fluid pressure measurement is required to establish a definite diagnosis. Management may be different, since surgical procedures or lumbar punctures are often required when symptoms develop rapidly leading to a loss of visual function. Apart from these cases, patients can be treated with a pharmacological approach and low-calorie diet, but they also need to be monitored over time since relapses years later are not uncommon.

Infectious and inflammatory disorders might increase the risk of developing idiopathic intracranial hypertension - a national case-control study

Objective

To investigate whether conditions causing inflammatory activation are associated with increased risk of idiopathic intracranial hypertension.

Methods

All newly diagnosed idiopathic intracranial hypertension patients (cases) in Sweden between 2000–2016 were identified using pre-determined algorithms (n = 902) and matched with five controls from the general population and five individuals with an obesity diagnosis (n = 4510) for age, sex, region, and vital status. National health registers provided information on infections, inflammatory disorders and dispensed medications. Conditional logistic regression was used to estimate odds ratios and 95% confidence intervals.

Results

Compared to general population controls, the cases had fourfold increased odds of having an infection (odds ratio = 4.3, 95% confidence interval 3.3–5.6), and threefold increased odds of an inflammatory disorder the year prior to idiopathic intracranial hypertension diagnosis (odds ratio = 3.2, 95% confidence interval 2.4–4.3). Organ specific analyses showed that odds were increased for the study diseases in the respiratory organ, kidney organ and gastrointestinal tract, but not for female genital infections. Similar results were found when comparing idiopathic intracranial hypertension with obese controls though the odds ratios were of lower magnitude. Sub-analyses on exposure to anti-infectious and anti-inflammatory drugs confirmed the increased odds ratios for idiopathic intracranial hypertension patients.

Conclusions

These findings suggest that major inflammatory activation may be a risk factor in idiopathic intracranial hypertension development.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

Eye Conditions in Women

Changes in vision can have significant impact on health and quality of life. Differences between women and men have been identified in the incidence of several eye conditions. Some of these differences are a result of the greater longevity of women. However, the eye, like other organs, is susceptible to the impacts of inflammation and sex steroids. Conditions, such as thyroid eye disease, optic neuritis, and dry eye disease are related to autoimmune or inflammatory conditions and are, thus, more common among women. Idiopathic intracranial hypertension occurs disproportionately in women of childbearing age; the etiology of this condition appears to be related to both inflammatory and sex hormone fluctuations.

Idiopathic Intracranial Hypertension: The Monster Within

Idiopathic intracranial hypertension (IIH) is defined as a syndrome of raised intracranial pressure with normal imaging of the brain and cerebrospinal fluid (CSF) composition. There are many controversies and myths that surround IIH. Although patients of IIH may present “typical” symptoms and signs of raised intracranial pressure, clinical scenarios often vary. A typical clinical and radiological finding poses significant problems in diagnosis and management of patients with IIH. We have tried to resolve these controversies and provide a comprehensive update on different aspects of IIH. In this article, we review the common problems encountered while dealing with patients of IIH.

An Ultrasound Vibro-Elastography Technique for Assessing Papilledema

Papilledemais optic nerve swelling caused by increased intracranial hypertension, which has the potential to cause significant vision loss. Papilledema from idiopathic intracranial hypertension (IIH) is typically bilateral and symmetric, but can be asymmetric and even unilateral. The purpose of this study was to develop ultrasound vibro-elastography (UVE) for non-invasive measurement of ocular tissue wave speed for patients with papilledema. A total of 9 patients with papilledema from IIH and 9 age-matched healthy control patients were enrolled in this study. A local, gentle, 0.1-s harmonic vibration was applied on the eyelid to generate wave propagation in the ocular tissue. We used 3 excitation frequencies of 100, 150 and 200 Hz to measure the wave speeds. A 6.4-MHz ultrasound probe was used to non-invasively measure wave propagation in the ocular structures. Wave speeds were analyzed in the posterior sclera of the maculae of the eyes. The magnitudes of wave speed at each frequency of the IIH patients' posterior sclera were significantly higher than those of healthy patients. It was found that the magnitudes of wave speed at each frequency were statistically higher in the eyes with papilledema than in the contralateral eyes without papilledema for the patients with unilateral papilledema. UVE provides a non-invasive technique to measure the wave speed of posterior sclera, which may be useful for assessing patients with papilledema.

Dural sinus collapsibility, idiopathic intracranial hypertension, and the pathogenesis of chronic migraine

Available evidences suggest that a number of known assumption on idiopathic intracranial hypertension (IIH) with or without papilledema might be discussed. These include (1) the primary pathogenetic role of an excessive dural sinus collapsibility in IIH, allowing a new relatively stable intracranial fluids pressure balance at higher values; (2) the non-mandatory role of papilledema for a definite diagnosis; (3) the possibly much higher prevalence of IIH without papilledema than currently considered; (4) the crucial role of the cerebral compliance exhaustion that precede the raise in intracranial pressure and that may already be pathologic in cases showing a moderately elevated opening pressure; (5) the role as "intracranial pressure sensor" played by the trigeminovascular innervation of dural sinuses and cortical bridge veins, which could represent a major source of CGRP and may explain the high comorbidity and the emerging causative link between IIHWOP and chronic migraine (CM). Accordingly, the control of intracranial pressure is to be considered a promising new therapeutic target in CM.

Differing presenting features of idiopathic intracranial hypertension in the UK and US

AIM

Demographic factors potentially influencing the presentation and severity of idiopathic intracranial hypertension (IIH) in the US vs. UK populations include obesity and ethnicity. We aimed to compare the presenting features of IIH between populations in the UK and US tertiary referral centres, to assess what population differences exist and whether these cause different presentations and impact on visual function.

METHODS

Clinical data were collected on 243 consecutive UK IIH patients and 469 consecutive US IIH patients seen after 2012 in two tertiary centres. Visual function was defined as severe visual loss when Humphrey visual field mean deviation was <-15 dB, when Goldmann visual fields showed constriction or when visual acuity was <20/200.

RESULTS

US patients were more commonly of self-reported black race (58.9% vs. 7.1%) than UK patients, but had a similar mean body mass index (38.3 ± 0.63kg/m² UK vs. 37.7 ± 0.42kg/m² US; p = 0.626). The UK cohort had lower presenting Frisén grade (median 1 vs. 2; p < 0.001) and severe visual loss less frequently (15.4% vs. 5%; p = 0.014), but there was no difference in mean cerebrospinal fluid-opening pressure (CSF-OP) (35.8 ± 0.88cmH₂O UK vs. 36.3 ± 0.52cmH₂O US; p = 0.582). African Americans had poorer visual outcomes compared with US whites (19.4% vs. 10% severe visual loss; p = 0.011). Visual function was weakly associated with CSF-OP (R² = 0.059; p = 0.001), which was similar between UK and US patients.

CONCLUSIONS

The UK and the US cohorts had a similar average presenting BMI. However, the worse presenting visual function in the US IIH cohort was partially attributable to differences in the black populations in the two countries.

Ventriculo-peritoneal shunting is a safe and effective treatment for idiopathic intracranial hypertension

PURPOSE

To determine the outcome of ventriculo-peritoneal shunts as a treatment for idiopathic intracranial hypertension (IIH) Materials and Methods: Retrospective case series of 28 patients with IIH and evidence of raised intracranial pressure (ICP) who underwent shunt insertion. Patients were identified from a prospectively updated operative database. A case-notes review was performed and data on type of shunt, pre- and post-operative symptoms, ophthalmological findings and post-operative complications were recorded.

RESULTS

All patients had symptoms of IIH that had failed medical management. Twelve patients had previous lumbo-peritoneal shunts and 2 patients had previous venous sinus stents. All patients had evidence of raised ICP as papilloedema and raised CSF pressure on lumbar puncture. Twenty-seven patients received a ventriculo-peritoneal shunt and 1 patient a ventriculo-atrial shunt. Twenty-six patients received Orbis Sigma Valves and 2 patients Strata valves. At follow-up all patients (100%) had improvement/resolution of papilloedema, 93% had improved visual acuity and 84% had improved headaches. Mean time to last follow-up was 15 (range 4-96) months. Complications occurred in 3 patients (11%): 2 patients required revision of their peritoneal catheters and 1 patient had an anti-siphon device inserted.

CONCLUSIONS

Previous literature reported a ventricular shunt revision rate of 22-42% in the management of IIH. We demonstrate ventriculo-peritoneal shunts to be an effective treatment with a revision rate of 11% compared to the previously reported 22-42%.

A Population-Based, Case-Control Evaluation of the Association Between Hormonal Contraceptives and Idiopathic Intracranial Hypertension

PURPOSE

To determine if the use of oral contraceptive pills (OCP) and other hormonal contraceptives are associated with a higher incidence of idiopathic intracranial hypertension (IIH).

DESIGN

Retrospective, population-based, case-control study.

METHODS

Setting: Female IIH patients evaluated between January 1, 1990, and December 31, 2016 were identified using the Rochester Epidemiology Project (REP), a record-linkage system of medical records for all patient-physician encounters among Olmsted County, Minnesota, residents.

STUDY POPULATION

Fifty-three female residents of Olmsted County diagnosed with IIH between 15 and 45 years of age. The use of OCPs and other hormonal contraceptives was compared to controls matched for age, sex, and body mass index. Interventions/Exposures: Hormonal contraceptives.

MAIN OUTCOME MEASURE

Odds of developing IIH.

RESULTS

Of the 53 women diagnosed with IIH between 15 and 45 years of age, 11 (20.8%) had used hormonal contraceptives within ≤30 days of the date of IIH diagnosis, in contrast to 30 (31.3%) among the control patients. The odds ratio of hormonal contraceptive use and IIH was 0.55 (95% conficence interval [CI]: 0.24-1.23, P = .146). The odds ratio of OCP use was 0.52 (95% CI: 0.20-1.34, P = .174).

CONCLUSIONS

OCP and other hormonal contraceptives were not significantly associated with a higher incidence of IIH, arguing against the need for women with IIH to discontinue their use.

Pattern of Idiopathic Intracranial Hypertension in Indian Population

Objective

To evaluate the clinical and demographic profile, laboratory parameters and outcomes of Idiopathic Intracranial hypertension (IIH) patients from Indian subpopulation.

Materials and method

We did a prospective study on patients who fulfilled the revised diagnostic criteria for Primary pseudotumor cerebri syndrome in adults and children, proposed by Friedman et al in 2013. All patients were examined for BMI, papilloedema, extraocular muscle movement, opening CSF pressure and underwent MRI, MR venography of brain and perimetry. Patients were followed up for a minimum period of 6 months, upto 2 years, with the outcomes monitored being visual acuity, visual field, headache, diplopia and optic disc changes.

Results

We evaluated 33 patients (31 female and 2 male). 25 patients had BMI less than 25. Commonest clinical presentation was headache. 7 patients showed normal CSF opening pressure. The most common MRI finding was flattening of posterior aspect of globe and was found in 90.90% (30). 25 patients showed either unilateral or bilateral transverse sinus stenosis. Most common finding in perimetry was enlarged blind spot. 4 patients recovered spontaneously and rests were treated with acetazolamide (1gm/day). All showed favorable outcome when followed up.

Conclusion

Obesity may not be a dominant risk factor for development of IIH in the Indian subcontinent. Non obese IIH have better prognosis and tend to have a good response to medical management alone.

Incidence of idiopathic intracranial hypertension in Fife

BACKGROUND AND AIMS

Idiopathic intracranial hypertension is a clinical syndrome of intracranial hypertension with normal cerebrospinal fluid in the absence of a mass lesion or hydrocephalus on brain imaging. Headache is the most common symptom of idiopathic intracranial hypertension, and about 10-15% of patients suffer from irreversible visual impairment. Previous estimates of the annual incidence of idiopathic intracranial hypertension vary worldwide from 0.03 to 2.2 per 100,000. The major risk factor implicated in idiopathic intracranial hypertension is body mass. Scotland has one of the worst records for obesity in the developed world, and the prevalence of obesity in Fife is higher than the Scottish average. Our aim was to record the incidence of idiopathic intracranial hypertension in NHS Fife over a one-year period.

METHODS AND RESULTS

Prospective study including every patient who was seen in the ophthalmology department in NHS Fife with a new diagnosis of idiopathic intracranial hypertension over a one-year period. Thirteen patients were seen with a new diagnosis of idiopathic intracranial hypertension from August 2013 to July 2014 giving an incidence of 3.56 per 100,000. Headache was the most common presenting symptom. Three patients were asymptomatic but were noted to have swollen optic discs during a routine sight test. One patient complained of visual symptoms. All patients were overweight. The mean BMI was 36 (range: 28-49).

CONCLUSION

The incidence of idiopathic intracranial hypertension in NHS Fife was significantly higher than previous estimates in the literature. This is probably due to a high level of obesity in Fife. Scotland is in the midst of an obesity epidemic and if this continues we may see increasing levels of idiopathic intracranial hypertension nationally with associated increasing incidence of visual impairment in young adults.

Meta-analysis and systematic review of population-based epidemiological studies in idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is positively associated with obesity, mostly in young women. The global increase in obesity may influence the burden of IIH. Using the PubMed, Embase, MEDLINE and Web of Science databases, a meta-analysis and systematic review of epidemiological studies of IIH were performed up to June 2017. Temporal changes in IIH incidence were measured, and incidence rates of IIH were correlated with country-specific World Health Organization obesity rates. Prevalence data and shunting rates of IIH were recorded. The quality of epidemiological studies was assessed using the Standards of Reporting of Neurological Disorders (STROND) criteria. In 15 identified studies, there were 889 patients (87% women), mean age 29.8 years. The incidence of IIH ranged from 0.03 to 2.36 per 100 000 per year. The pooled incidence of IIH was 1.20 per 100 000 per year although there was very high heterogeneity (I² 98%). The incidence rates of IIH were correlated with country-specific prevalence of obesity (Spearman's correlation 0.82, P < 0.01). The prevalence of IIH was rarely recorded. A shunting procedure was reported in 8% of patients. STROND criteria were variably reported, median of 26.5 of 43 (range 16-35). IIH is a public health concern as increased obesity prevalence is associated with increased incidence of IIH. A better quality of epidemiological studies is required to improve understanding of IIH and inform health policy for IIH management.

The Role of Optical Coherence Tomography in Differentiating Optic Disc Drusen from Optic Disc Edema

An elevated optic nerve head can be an ominous sign, sometimes signifying an underlying basis for raised intracranial pressure. Alternatively, patients may harbor a different mechanism for this optic nerve head appearance, including optic disc drusen (ODD), which does not confer any life-threatening implications. It is important to refine the approach to distinguishing ODD from papilledema because this is a relatively common, and important, conundrum encountered in clinical practice. Optical coherence tomography (OCT) is a noninvasive, readily accessible, and cost-effective ocular imaging technique that can improve the diagnostic accuracy for detecting ODD; or, instead, increase the index of suspicion for papilledema, thus prompting additional investigations needed to identify (or exclude) potential causes of raised intracranial pressure. In this review, we will discuss the value of OCT in the diagnostic approach to cases of mild optic disc elevation, with acknowledgment of the potential pearls and pitfalls of this imaging technology. In particular, we will emphasize the helpful role OCT can play in differentiating cases of ODD from mild papilledema in the context of idiopathic intracranial hypertension (IIH).

Pseudotumor Cerebri Syndrome with Resolution After Discontinuing High Vitamin A Containing Dietary Supplement: Case Report and Review

A 24-year-old non-obese, but slightly overweight, female presented with a two-week history of progressive severe headache associated with two days of blurry vision. Clinical exam was significant for bilateral papilledema and an enlarged blind spot on visual field testing. Contrast enhanced MRI head revealed no space occupying lesion. A lumbar puncture revealed an elevated opening pressure of 38 cm H₂O with normal cerebrospinal fluid composition leading to a diagnosis of pseudotumor cerebri syndrome (PTCS). The patient lacked the typical risk factors of high body mass index or obvious antecedent medications; however, on subsequent questioning, she was chronically ingesting a high vitamin A containing weight loss dietary supplement (Thrive W® - Table 1), which we believe had caused intracranial hypertension. Discontinuation of the diet pill and treatment with acetazolamide led to marked improvement of her PTCS. This case highlights the fact that non-traditional products or medications with high vitamin A may cause pseudotumor cerebri, which treating physicians should assess for while dealing with non-obese PTCS patients.

Improving identification of idiopathic intracranial hypertension patients in Swedish patient register

OBJECTIVE

Idiopathic intracranial hypertension (IIH) is often misdiagnosed. This can cause problems if conducting register-based studies. The study purpose was to produce algorithms that better identify patients with correct diagnosis of IIH in the Swedish National Patient Register (NPR).

METHODS

Patients with ICD-10 code G93.2 for IIH registered in the NPR (2006-2013, Stockholm County) were included and diagnosis validated by medical record reviews. Patients were randomized into two groups: one used to produce the algorithm (n = 105) and one for validation (n = 102). We tested variables possible to extract from registries and used forward stepwise logistic regression which provided a predicted probability of correct diagnosis for each patient.

RESULTS

We included 207 patients of which 135 had confirmed IIH. This gave a positive predictive value of 65.2% (CI: 58.4-71.4). The algorithm produced with variables extracted from registries, that is, age, number of times with diagnosis code G93.2 recorded (>2 times), and acetazolamide treatment, predicted the diagnosis correctly 88.2% (CI: 80.3-93.3) of the time. Excluding treatment data from the algorithm did not change the prediction notably, 86.3% (CI: 78.1-91.7).

CONCLUSION

We produced two algorithms that with improved accuracy predict whether an IIH diagnosis in the NPR is correct. This can be a useful tool when performing register-based studies.

Approach to Chronic Secondary Headache: A Case Report on Unusual Drug Side Effects

In this article, we present the case of a 12-year-old female child who complained of bilateral temporal and frontal headache for 2 to 3 months with nausea and vomiting. Physical examination revealed right-sided sixth cranial nerve palsy and papilledema in ophthalmoscopy. To find the cause of increased intracranial pressure, the patient underwent brain imaging and brain MRI showed no abnormality. Ultimately, lumbar puncture (LP) was performed and cerebrospinal fluid (CSF) pressure was 280 mmH₂O with normal chemistry. We considered pseudotumor cerebri as the first diagnosis. LP was carried out three times and 30cc of CSF was tapped each time. Finally, patient's headache and papilledema improved and physical examination after 6 months showed no sign of raised intracranial pressure (rICP). The most prominent point in her past medical history was the use of growth hormone (GH) for 2 years. No sign of symptom relapse has been seen after 6 months of drug discontinuation. We must consider the hazard of growth hormone as a potential cause of increased intracranial pressure. When the use of GH is justified, the follow-up must include an ophthalmoscopy examination in each session.

Population-based incidence and clinical characteristics of idiopathic intracranial hypertension

OBJECTIVE

To validate the diagnosis of idiopathic intracranial hypertension (IIH) from the Swedish National Patient Register (NPR) and investigate the incidence of IIH, as well as co-morbidities and medication use in a large Swedish population-based sample.

METHODS

We searched the NPR to find all patients ≥18 years old with the ICD-10 diagnosis code (G93.2) for IIH in Stockholm County from Jan 1, 2006, to Dec 31, 2013. All medical records were reviewed to validate the diagnosis and to collect additional information.

RESULTS

We included 207 patients with an IIH diagnosis, of which 135 (65%) were correctly diagnosed when validated by charts review. Eighty-three patients had disease onset during the study period. This gave a yearly incidence of 0.65/100 000. Female-to-male ratio was 6.1:1. Females, mean age 31.0 (CI 28.8-33.1), were younger at time of diagnosis compared to males, mean age 42.9 (CI 36.4-49.5), P<.001. The most common co-morbidities were obesity (92%), hormonal conditions (21%) and recent infections preceding the diagnosis (21%). Prior treatment with tetracycline derivatives were seen in 9%.

CONCLUSION

The incidence of IIH in Stockholm is in the lower range of previously reported rates, possibly due to a lower prevalence of obesity. A substantial proportion of patients (35%) did not fulfill diagnostic criteria. Disease onset occurs at younger age in females. Co-morbidities were mainly associated with diseases affecting hormonal balance or causing inflammatory activation. These findings raise new hypothetical theories regarding mechanisms involved in IIH pathogenesis.

Safety of antimalarial medications for use while scuba diving in malaria Endemic Regions

Background

Recreational diving occurs annually in areas of the world where malaria is endemic. The safety and efficacy of antimalarials for travelers in a hyperbaric environment is unknown. Of particular concern would be medications with adverse effects that could either mimic diving related illnesses such as barotrauma, decompression sickness (DCS) and gas toxicities, or increase the risk for such illnesses.

Methods

We conducted a review of PubMed and Cochrane databases to determine rates of neurologic adverse effects or other effects from antimalarials that may be a problem in the diving environment.

Results

One case report was found on diving and mefloquine. Multiple case reports and clinical trials were found describing neurologic adverse effects of the major chemoprophylactic medications atovaquone/proguanil, chloroquine, doxycycline, mefloquine, and primaquine.

Conclusions

Of the available literature, atovaquone/proguanil and doxycycline are most likely the safest agents and should be preferred; atovaquone/proguanil is superior due to reduced rates of sunburn in the marine environment. Primaquine also appears to be safe, but has reduced efficacy against P. falciparum; mefloquine possesses the highest rate of neurologic side effects and therefore these agents should be limited to extreme cases of patients intolerant to other agents. Chloroquine appears unsafe in the hyperbaric environment and should be avoided. More studies are required to include database reviews of returned divers traveling to malaria endemic areas and randomized controlled trials in the hyperbaric environments.