The syndrome of pseudotumour cerebri and idiopathic intracranial hypertension

Utility of Neuroimaging in the Management of Chronic and Acute Headache

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

Weight Loss in Idiopathic Intracranial Hypertension: A Retrospective Review of Outcomes in the Clinical Setting

BACKGROUND

Weight loss is important in the management of idiopathic intracranial hypertension (IIH); however, extremely caloric restrictive diets have been used in published studies, which may not be practical for all patients. We aim to review the weight loss outcomes of IIH patients and weight loss methods used by patients who achieve clinical remission (CR) in a standard clinical setting.

METHODS

The medical records of IIH patients were retrospectively reviewed. Measures evaluated included: reported symptoms, visual acuity, retinal nerve fiber layer analysis, automated visual fields, optic disc appearance, and cessation of medications. Patients were divided into different outcome groups and weight changes were compared. Patients who achieved CR were contacted to assess weight loss methods used.

RESULTS

Of the 39 patients included in the analysis, 28 patients (71.8%) achieved CR with concomitant weight loss, 6 patients (15.4%) improved clinically with concomitant weight loss but did not achieve CR. Among the patients with CR, 10 patients (35.7%) were successfully weaned off their medications completely, whereas another 10 patients (35.7%) are in the process of this. Median weight loss from baseline to lowest weight for this group was 10.5 kg (11.5%) achieved using self-directed methods.

CONCLUSION

This study demonstrated that a large proportion of IIH patients were able to achieve CR or improvement with self-directed weight loss regimens, reinforcing the evidence and the practicality of weight loss in the management of IIH in the clinical setting.

Management of the regression of papilledema with regional axon loss in idiopathic intracranial hypertension patients

PURPOSE

To use optic coherence tomography (OCT) to evaluate idiopathic intracranial hypertension (IIH) patients with subclinical segmental optic atrophy despite being under apparently effective treatment.

METHODS

IIH patients underwent an OCT examination including the peripapillary retina never fiber layer (RNFL) thickness, ganglion cell complex (GCC) thickness, focal loss volume (FLV) and global loss volume (GLV) of the GCC, and total macular thickness measurements at presentation and at 3, 6, 9, and 12 months after the diagnosis. The obtained data were compared with healthy subjects. Subjects with and without subclinical segmental atrophy at the 12th month were compared according to the demographics, clinical findings, and the OCT parameters recorded at the beginning of the disease.

RESULTS

Both eyes of 56 patients with papilledema due to IIH and 50 age- and sex-matched control subjects were included in this prospective case-control study. Regression of papilledema with regional axon loss on the peripapillary RNFL thickness map was found in 37 (33%) eyes in the IIH group. IIH patients with segmental atrophy had the following characteristics when compared to those without segmental atrophy at the beginning of the disease: higher CSF opening pressure, higher grade of papilledema, thicker mean peripapillary RNFL thickness, thinner GCC layer, greater FLV and GLV loss, and severe visual field loss.

CONCLUSIONS

Axonal loss occurred in the patients despite apparent treatment. It would be appropriate to follow-up with aggressive medical treatment those patients who present with the following characteristics: higher CSF opening pressure, higher grade of papilledema, thicker mean peripapillary RNFL thickness, and thinner GCC.

Evaluation of optic nerve head changes with optic coherence tomography in patients with idiopathic intracranial hypertension

In the case of mild papilledema, fundoscopy findings may sometimes be insufficient, leading to false and misleading indices in the diagnosis of early-stage idiopathic intracranial hypertension (IIH). This study aims to evaluate these patients through optic coherence tomography (OCT). The study included 54 individuals diagnosed with IIH and 48 healthy individuals in the control group. All patients underwent neurological and ophthalmologic examinations. Opening pressure values of patients' cerebrospinal fluid (CSF) were recorded. We measured the thickness of the retinal nerve fiber layer (RNFL) and the ganglion cell complex, cup volume, and the optical disc area, as well as the neuroretinal rim in both groups. A total of 108 eyes from the patient group and 96 eyes from the control group were evaluated. It was found that the mean value of the RNFL thickness of the IIH patients was greater than the control group in the following eight segments: superior nasal, superior temporal, inferior nasal, inferior temporal, nasal superior, nasal inferior, temporal superior, and temporal inferior (p < 0.01 for all). In contrast to the control group, the disc and rim area values of the patient group were higher (p < 0.01), while the cup volume was smaller (p < 0.01) than in the control group. In the patient group, a positive correlation was observed between the papilledema grade and the RNFL thickness (r = 0.64, p < 0.01), CSF opening pressure (r = 0.59, p < 0.01), disc area (r = 0.68, p < 0.01), and rim area (r = 0.70, p < 0.01). Furthermore, RNFL thickness, CSF opening pressure (r = 0.61, p < 0.01), disc area (r = 0.71, p < 0.01), and rim area (r = 0.71, p < 0.01) values were determined to be positively correlated to each other. OCT is believed to contribute to the diagnosis of IIH, by providing reliable data on optical cup volume, optical disc and rim area, and a greater RNFL thickness.

Bariatric Surgery or Non-surgical Weight Loss for Idiopathic Intracranial Hypertension? A Systematic Review and Comparison of Meta-analyses

Background

Idiopathic intracranial hypertension (IIH) is associated with obesity and weight loss by any means is considered beneficial in this condition.

Objectives

This study aims to appraise bariatric surgery vs. non-surgical weight-loss (medical, behavioural and lifestyle) interventions in IIH management.

Methods

A systematic review and meta-analyses of surgical and non-surgical studies.

Results

Bariatric surgery achieved 100% papilloedema resolution and a reduction in headache symptoms in 90.2%. Non-surgical methods offered improvement in papilloedema in 66.7%, visual field defects in 75.4% and headache symptoms in 23.2%. Surgical BMI decrease was 17.5 vs. 4.2 for non-surgical methods.

Conclusions

Whilst both bariatric surgery and non-surgical weight loss offer significant beneficial effects on IIH symptomatology, future studies should address the lack of prospective and randomised trials to establish the optimal role for these interventions.

Electronic supplementary material

The online version of this article (doi:10.1007/s11695-016-2467-7) contains supplementary material, which is available to authorized users.

The diagnostic challenge of evaluating papilledema in the pediatric patient

Pseudopapilledema is a fairly common finding in ophthalmic practice, and in many cases, the diagnosis is straightforward. However, an accurate diagnosis can challenge the most seasoned clinicians, and missing true papilledema can result in life-threatening or vision-threatening consequences. In this review, we describe the clinical findings and a diagnostic algorithm to distinguish pseudopapilledema and papilledema in the pediatric patients. We also describe the clinical evaluation once a diagnosis of papilledema has been established.

Controversies: Optic nerve sheath fenestration versus shunt placement for the treatment of idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension (IIH) has been increasing in prevalence in the past decade, following the obesity epidemic. When medical treatment fails, surgical treatment options must be considered. However, controversy remains as to which surgical procedure is the preferred surgical option - optic nerve sheath fenestration (ONSF) or cerebrospinal fluid (CSF) shunting - for the long-term treatment of this syndrome.

PURPOSE

To provide a clinical update of the pros and cons of ONSF versus shunt placement for the treatment of IIH.

DESIGN

This was a retrospective review of the current literature in the English language indexed in PubMed.

METHODS

The authors conducted a PubMed search using the following terms: Idiopathic IIH, pseudotumor cerebri, ONSF, CSF shunts, vetriculo-peritoneal shunting, and lumbo-peritoneal shunting. The authors included pertinent and significant original articles, review articles, and case reports, which revealed the new aspects and updates in these topics.

RESULTS

The treatment of IIH remains controversial and lacks randomized controlled clinical trial data. Treatment of IIH rests with the determination of the severity of IIH-related visual loss and headache.

CONCLUSION

The decision for ONSF versus shunting is somewhat institution and surgeon dependent. ONSF is preferred for patients with visual symptoms whereas shunting is reserved for patients with headache. There are positive and negative aspects of both procedures, and a prospective, randomized, controlled trial is needed (currently underway). This article will hopefully be helpful in allowing the reader to make a more informed decision until that time.

Surgically managed idiopathic intracranial hypertension in adults: a single centre experience

INTRODUCTION

Idiopathic intracranial hypertension (IIH) is a rare condition that is often managed conservatively. In patients with aggressive progression of the disease surgical options are considered. There are few data on the outcomes of these patients when surgically managed. We describe our experience of surgically managed IIH and the outcomes of these patients, in particular the surgical revision rate and interventions required for resolution of symptoms.

METHODS

A retrospective review of all patient files coded with benign intracranial hypertension, idiopathic intracranial hypertension or pseudotumour cerebri was undertaken. Files were searched with the date of diagnosis and the date these patients were referred for surgical intervention. The surgical interventions and complications were then documented and note was made of the number of inpatient admissions and days spent in hospital.

RESULTS

From 2000-2013, 79 patients were identified as patients with IIH that had required surgical intervention; 52 % required further surgical intervention. The average number of surgical interventions was 5.6. For patients requiring further intervention the average number of surgical interventions was 8.6. On average patients with IIH also spent 42 inpatient days in neurosurgical beds, whilst those patients who required further intervention spent 63 days on average in neurosurgical beds. The length of the average individual admission was longer for patients requiring repeated surgical interventions.

CONCLUSION

Based on our experience, patients that require surgical management of IIH frequently require further surgical interventions to control symptoms and manage complications of CSF diversion surgery. Those that require such further intervention on average will have six further operations and spend significantly longer in hospital. Lumboperitoneal (LP) shunting is an effective first line surgical intervention for 52 % of our patient cohort. This sub-group of patients therefore requires specialist neurosurgical input for this long-term and challenging pathological process.

Correlation between papilledema grade and diffusion-weighted magnetic resonance imaging in idiopathic intracranial hypertension

BACKGROUND

To explore the relationship between diffusion-weighted magnetic resonance imaging (DWI) hyperintensity of the optic nerve head (ONH) and papilledema grade in patients with idiopathic intracranial hypertension (IIH).

METHODS

A retrospective chart review was conducted of patients with definitively diagnosed IIH by clinical examination and visual field (VF) analysis who underwent orbital magnetic resonance imaging (MRI) within 4 weeks of diagnosis. A neuroradiologist masked to the diagnosis assessed the results of DWI for each eye independently and graded the signal intensity of the ONH into none, mild, and prominent categories. DWI grading was compared with papilledema grade and visual field mean deviation (VFMD) by Spearman rank correlation analysis and t-tests.

RESULTS

Forty-two patients were included in the study. A statistically significant difference (P = 0.0195) was found between papilledema grade and patients with prominent DWI findings (n = 16; mean papilledema grade 3.75 ± 1.25) vs mild or no ONH hyperintensity (n = 26; mean papilledema grade 2.79 ± 1.24) at the time of initial diagnosis. DWI hyperintensity of the ONH at diagnosis was also found to be significantly correlated with the degree of papilledema at follow-up (ρ = 0.39, P = 0.0183) but not with VFMD.

CONCLUSIONS

We found a significant correlation between the severity of papilledema and ONH hyperintensity on DWI in patients with IIH but not with VF loss or other visual parameters. These findings may offer insight into the pathophysiology of papilledema in IIH and provide a surrogate marker for the presence and severity of papilledema.

Management of idiopathic intracranial hypertension with a programmable lumboperitoneal shunt: Early experience

OBJECTIVE

To evaluate the clinical outcomes and complications rate among idiopathic intracranial hypertension (IIH) patients who underwent lumboperitoneal (LP) shunt insertion with a programmable Strata valve.

METHODS

We retrospectively evaluated patients who underwent LP shunt with a programmable Strata valve insertion at the University of Ottawa Civic Hospital from November 2012 to June 2013. The demographic data, clinical symptoms, opening pressure, pre-operative and post-operative visual fields, neuroimaging, visual acuity, disc status, and complications were recorded and analyzed.

RESULTS

Seven female patients with IIH underwent insertion of an LP shunt with a programmable Strata valve. The mean opening pressure was 35.8 cm H2O. The initial valve setting was 1.5, and four patients required post-operative valve pressure adjustment. All patients showed significant improvement in objective visual testing at follow-up as well as less frequent headaches. None of the patients developed intra- or post-operative complications.

CONCLUSION

LP shunts with programmable Strata valve systems are a potential alternative to conventional LP and programmable ventriculoperitoneal shunt systems as well as optic nerve sheath fenestration, due to their potential in avoiding brain injury, lower failure and complication rates, lower intracranial hypotension incidence, and flexibility in adjusting valve pressure settings post-operatively evading under- and overdrainage complications. They should be considered for the management of IIH instead of early design LP systems and VP shunts. A randomized multi-center trial should be conducted to compare the efficacy of these surgical techniques.

A novel method to study cerebrospinal fluid dynamics in rats

BACKGROUND

Cerebrospinal fluid (CSF) flow dynamics play critical roles in both the immature and adult brain, with implications for neurodevelopment and disease processes such as hydrocephalus and neurodegeneration. Remarkably, the only reported method to date for measuring CSF formation in laboratory rats is the indirect tracer dilution method (a.k.a., ventriculocisternal perfusion), which has limitations.

NEW METHOD

Anesthetized rats were mounted in a stereotaxic apparatus, both lateral ventricles were cannulated, and the Sylvian aqueduct was occluded. Fluid exited one ventricle at a rate equal to the rate of CSF formation plus the rate of infusion (if any) into the contralateral ventricle. Pharmacological agents infused at a constant known rate into the contralateral ventricle were tested for their effect on CSF formation in real-time.

RESULTS

The measured rate of CSF formation was increased by blockade of the Sylvian aqueduct but was not changed by increasing the outflow pressure (0-3cm of H2O). In male Wistar rats, CSF formation was age-dependent: 0.39±0.06, 0.74±0.05, 1.02±0.04 and 1.40±0.06μL/min at 8, 9, 10 and 12 weeks, respectively. CSF formation was reduced 57% by intraventricular infusion of the carbonic anhydrase inhibitor, acetazolamide.

COMPARISON WITH EXISTING METHODS

Tracer dilution methods do not permit ongoing real-time determination of the rate of CSF formation, are not readily amenable to pharmacological manipulations, and require critical assumptions. Direct measurement of CSF formation overcomes these limitations.

CONCLUSIONS

Direct measurement of CSF formation in rats is feasible. Our method should prove useful for studying CSF dynamics in normal physiology and disease models.

Has rising pediatric obesity increased the incidence of idiopathic intracranial hypertension in children?

OBJECTIVE

Idiopathic intracranial hypertension (IIH) in children is an uncommon but significant cause of morbidity, including permanent visual loss. It is important to understand if, like obesity, IIH in children is on the rise and is related to that increase. The aim of this study is to compare the recent incidence rate of pediatric IIH in a tertiary care hospital with earlier data published from that same hospital.

DESIGN

Retrospective chart review.

PARTICIPANTS

All children aged 2 to 16 years diagnosed with IIH at the IWK Health Centre in Halifax between 1997 and 2007.

METHODS

Charts of eligible patients were reviewed to ensure all diagnostic criteria for IIH were met. Incidence and obesity rates were calculated based on data from Statistics Canada.

RESULTS

Twelve cases (5 males, 7 females) fulfilling the diagnostic criteria for IIH were identified, for an annual incidence of 0.6 cases per 100,000 children with no sex predilection (p = 0.51). Obesity was noted in 75% of patients examined (9/12). Children older than 12 years were more likely to be obese (6/6, 100%) compared with those younger than 12 years (3/6, 50%).

CONCLUSIONS

The calculated incidence is lower than that found in an earlier study for the same geographic region (0.9 cases per 100,000 children) despite increasing obesity rates. This decrease may be a reflection of improved diagnostic techniques or may indicate that factors other than obesity govern IIH predilection in younger children.

The Pseudotumor Cerebri Syndrome: A Unifying Pathophysiological Concept for Patients with Isolated Intracranial Hypertension with Neither Mass Lesion Nor Ventriculomegaly

In 1991 we proposed that while the syndrome of isolated intracranial hypertension might have many definite and probable causes, it has nonetheless a single unifying pathophysiological mechanism: namely, impairment of cerebrospinal fluid (CSF) reabsorption. For that reason, we also proposed then that it is best described by a single, unifying, inclusive term, namely, pseudotumor cerebri syndrome. Although it appears that there is, as far as nomenclature is concerned, now international agreement, there is as yet no agreement on pathophysiology and classification. Herein we outline our views on these matters and give our reasons.

Intracranial idiopathic hypertension: 1-year follow-up study

Standard guidelines for ongoing management, as well as definitive data about the long-term course of idiopathic intracranial hypertension (IIH) are not available. The aim of this study was to compare several clinical and instrumental variables as assessed at the time of diagnosis and then after 1 year in a sample of IIH patients. A total of 21 patients were studied. Our results confirmed that headache and TVO are the most frequent symptoms in IIH patients, and that overweight is a very common feature. A trend towards a favorable outcome in patients followed for 1 year and treated by usual medical therapy was found: intracranial pressure was lower at follow-up; improvement of headache and transient visual obscurations, as well as of papilledema, was reported in most patients. On the other hand, neuroradiological findings (such as empty sella, perioptic subarachnoid space distension, narrowing of the transverse sinuses) were substantially stable at follow. These findings may be relevant for future research as far as understanding the role of different clinical and instrumental findings as diagnostic items as well as predictors of outcome in IIH.

Macular thickness measurements with frequency domain-OCT for quantification of axonal loss in chronic papilledema from pseudotumor cerebri syndrome

PURPOSE

To evaluate the ability of frequency domain-optical coherence tomography (FD-OCT)-measured macular thickness parameters to differentiate between eyes with resolved chronic papilledema and healthy eyes and to evaluate the correlation between FD-OCT measures and visual field (VF) loss on standard automated perimetry (SAP).

METHODS

Fifty-two eyes from 29 patients suffering from pseudotumor cerebri syndrome (PTC) and 62 eyes from 31 normal controls underwent FD-OCT scanning and ophthalmic evaluation including VF with SAP. All patients had previously been submitted to treatment of PTC and had clinically resolved papilledema and stable VF for at least 6 months before the study. Macular and peripapillary retinal nerve fiber layer (RNFL) thickness measurements were determined for both groups. Comparisons were made using Generalized Estimated Equations. Correlations between FD-OCT and VF measurements were verified.

RESULTS

In eyes with resolved papilledema, the macular thickness parameters corresponding to the inner and outer superior, temporal, inferior and nasal segments, average macular thickness and most RNFL thickness measurements were significantly reduced when compared with controls. The discrimination ability was similar for macular thickness measurements and RNFL thickness measurements. Both sets of OCT measurements correlated well with VF sensitivity loss.

CONCLUSIONS

Eyes with resolved chronic papilledema show a significant reduction in macular thickness, which is well correlated with the severity of VF loss. Macular thickness measurements can potentially be used to estimate and monitor the amount of ganglion cell loss in eyes with papilledema from patients with PTC.

Updated physiology and pathophysiology of CSF circulation--the pulsatile vector theory

INTRODUCTION

Hydrocephalus is still a not well-understood diagnostic and a therapeutic dilemma because of the lack of sufficient and comprehensive model of cerebrospinal fluid circulation and pathological alterations.

CONCLUSIONS

Based on current studies, reviews, and knowledge of cerebrospinal fluid dynamics, brain water dynamics, intracranial pressure, and cerebral perfusion physiology, a new concept is deducted that can describe normal and pathological changes of cerebrospinal fluid circulation and pathophysiology of idiopathic intracranial hypertension.

Reevaluation of presentation and course of idiopathic intracranial hypertension--a large cohort comprehensive study

OBJECTIVES

We analyzed the clinical and ophthalmological findings in a large group of patients with idiopathic intracranial hypertension (IIH) trying to find factors that might influence the course of the disease.

MATERIALS AND METHODS

Medical records of patients with IIH were retrospectively reviewed. The patients included were women after menarche and men older than 18 years of age who were followed up for at least 1 year.

RESULTS

Eighty-two patients (89% women) with a mean age of 30.2 ± 12.0 years were included. The prevailing complaint was headache and transient visual obscurations followed by tinnitus and double vision. Eighty-two percent of patients were overweight at the time of diagnosis. Overweight patients had higher opening cerebrospinal fluid (CSF) pressure than patients with normal weight did. The grade of papilledema correlated with the CSF opening pressure. Inverse correlation was found between the depression of the visual field sensitivity and the grade of papilledema. The mean follow-up time was 61.3 ± 62.3 months. Eighty-four percent of the patients have improved while in 22% CSF diversion procedures or optic nerve decompression was required. The mean body mass index (BMI) at the end of follow-up decreased significantly. Sixty-seven percent of the patients suffered a recurrence of IIH. The number of recurrences inversely correlated with weight loss. Visual field defects on presentation were encountered more frequently in patients with recurrence. Women with recurrence had a history of more pregnancies.

CONCLUSIONS

Our results confirm the strong association between overweight and IIH. The recurrence rate seemed to be influenced by the obstetrical history and the severity of visual field defects at presentation. In contrast to some previous studies, we have found an interrelation between the CSF opening pressure, grade of papilledema and depression of the visual field sensitivity.

The role of venous sinus outflow obstruction in pediatric idiopathic intracranial hypertension

OBJECT

The authors examined the role of venous sinus obstruction in the etiology of idiopathic intracranial hypertension (IIH) by reviewing more than 200 MR venograms performed in suspected cases of IIH.

METHODS

Individual MR venograms performed in cases of suspected IIH at the Children's Hospital at Westmead in Sydney, Australia, were reviewed. The authors excluded cases in which an intervention was performed before the scan or a structural cause for venous obstruction was identified. Cases with confirmed hydrocephalus were also excluded. For each of the 145 remaining scans, the authors completed a detailed review on a slice-by-slice basis of the 2D source images used to compile the rendered 3D MR venogram. The anatomical configuration of the dural venous sinuses and any areas of decreased flow in circulation were then noted. Where possible, they correlated their radiological findings with evidence of raised intracranial pressure based on LP opening pressures. They also reviewed a control group of 50 MR venograms.

RESULTS

Seventy-six (52%) of 145 scans showed evidence of venous obstruction in the dominant-side circulation. Substantial nonphysiological collateral circulation was seen in 68% of cases with dominant-sided obstruction, suggesting a process of recanalization. In contrast, in the absence of dominant-sided obstruction, collateral circulation was uncommon. In 27 cases, CSF opening pressure measurements were available. In 20 cases the opening pressures were in excess of 20 cm H(2)O. Of those, 17 demonstrated evidence of dominant-sided venous outflow obstruction. Among those cases, the median opening pressure was 34 cm H(2)O. Dominant-sided venous outflow obstruction was seen in only 2 of 50 MR venograms in the control group. Furthermore, evidence of collateral circulation was also uncommon in the control group. There was a highly statistically significant difference between rates of dominant-sided venous obstruction in the suspected IIH and control groups (p ≤ 0.001).

CONCLUSIONS

A majority of patients presenting for investigation of suspected IIH demonstrated evidence of dominant-sided venous obstruction on MR venogram. In addition there was a high correlation between elevated CSF opening pressures and dominant-sided venous sinus obstruction. This correlation was further supported by evidence of collateral recanalization in patients with elevated CSF pressures and dominant-sided venous obstruction. A control group of 50 MR venograms indicated that dominant-sided venous outflow obstruction is an unlikely incidental finding, and a highly statistically significant difference was found between rates of obstruction in the suspected IIH and control groups.

Orbital and intracranial effects of microgravity: findings at 3-T MR imaging

PURPOSE

To identify intraorbital and intracranial abnormalities in astronauts previously exposed to microgravity by using quantitative and qualitative magnetic resonance (MR) techniques.

MATERIALS AND METHODS

The institutional review board approved this HIPAA-compliant, retrospective review and waived the requirement for informed consent. Twenty-seven astronauts (mean age ± standard deviation, 48 years ± 4.5) underwent 3-T MR imaging with use of thin-section, three-dimensional, axial T2-weighted orbital and conventional brain sequences. Eight astronauts underwent repeat imaging after an additional mission in space. Optic nerve sheath diameter (ONSD) and optic nerve diameter (OND) were quantified in the retrolaminar optic nerve. OND and central optic nerve T2 hyperintensity were quantified at mid orbit. Qualitative analysis of the optic nerve sheath, optic disc, posterior globe, and pituitary gland morphology was performed and correlated for association with intracranial evidence of hydrocephalus, vasogenic edema, central venous thrombosis, and/or mass lesion. Statistical analyses included the paired t test, Mann-Whitney nonparametric test for group comparisons, Cronbach α coefficient for reproducibility, and Pearson correlation coefficient.

RESULTS

All astronauts had previous exposure to microgravity and, thus, control data were not available for comparison. The ONSD and OND ranged from 4.7 to 10.8 mm (mean, 6.2 mm ± 1.1) and from 2.4 to 4.5 mm (mean, 3.0 mm ± 0.5), respectively. Posterior globe flattening was seen in seven of the 27 astronauts (26%), optic nerve protrusion in four (15%), and moderate concavity of the pituitary dome with posterior stalk deviation in three (11%) without additional intracranial abnormalities. Retrolaminar OND increased linearly relative to ONSD (r = 0.797, Pearson correlation). A central area of T2 hyperintensity was identifiable in 26 of the 27 astronauts (96%) and increased in diameter in association with kinking of the optic nerve sheath.

CONCLUSION

Exposure to microgravity can result in a spectrum of intraorbital and intracranial findings similar to those in idiopathic intracranial hypertension.

Undiagnosed papilledema in a morbidly obese patient population: a prospective study

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a rare condition that can lead to significant morbidity from visual loss. The cause of IIH is unknown, but IIH is known to be associated with obesity. Obese patients may be at particularly high risk for suffering vision loss from IIH. The purpose of the present study is to determine the prevalence of undiagnosed or asymptomatic papilledema in a population of morbidly obese individuals and to determine if these patients should undergo routine screening for papilledema.

METHODS

Patients presenting to the UC Davis Bariatric Surgery Clinic between February 2008 and January 2011 who met the National Institutes of Health criteria for bariatric surgery were invited to participate in the study. Those patients who met the inclusion criteria and consented to the study were included. Participants were screened for IIH by nonmydriatic fundus photographs and by concerning symptoms prompting direct referral for neuro-ophthalmologic evaluation. Images were reviewed by a neuro-ophthalmologist, and patients with suspicious optic discs underwent neuro-ophthalmologic evaluation. Patients with findings consistent with IIH were sent for neurological evaluation.

RESULTS

A total of 606 patients with an average body mass index of 47 kg/m2 were included in the study. Seventeen of these patients had photographic optic disc findings or symptoms suspicious for IIH. Seven of these patients did not have disc edema on clinical examination. Six patients were not evaluated in the clinic. Four of the 17 patients had subtle optic disc edema confirmed by clinical evaluation and were referred for full neurological workup. These 4 patients had normal neuroimaging, 3 of whom underwent lumbar punctures with borderline high opening pressures. All 4 patients had unremarkable visual field examinations. Fundus abnormalities other than optic disc edema were discovered in 33 patients.

CONCLUSION

Our study suggests that in a morbidly obese patient population, papilledema with significant visual loss is rare. Routine screening with fundus photography of morbidly obese patients likely is not warranted.

Idiopathic intracranial hypertension following spinal deformity surgery in children

Idiopathic intracranial hypertension (IIH) after pediatric spinal deformity surgery has not been previously reported. The authors conducted a retrospective analysis of more than 1500 pediatric spinal surgeries performed between 1992 and 2011. From their analysis, they report on 3 adolescent patients who underwent uncomplicated segmental spinal instrumentation for pediatric spinal deformity correction and subsequently developed features of IIH. The common variables in these 3 patients were adolescent age, spinal deformity, being overweight, symptom onset within 2 weeks postoperatively, significant estimated blood loss, and intraoperative use of ε-aminocaproic acid (antifibrinolytic) injection. The authors postulate that the development of IIH could be the result of venous outflow obstruction due to derangement of the epidural venous plexus during surgery. The use of ε-aminocaproic acid could potentially have the risk of causing IIH, probably mediated through hyperfibrinogenemia, although there have not been published cases in the neurosurgical, orthopedic, cardiac, or general surgical literature. Idiopathic intracranial hypertension after spinal deformity correction is a condition that should be recognized by neurosurgeons and orthopedic surgeons, because appropriate intervention with early medical therapy can lead to a satisfactory clinical outcome.

The economic costs of obesity and the impact of bariatric surgery

The obesity epidemic has far-reaching implications for the economic and health care future in the United States. Treatments that show reduction in health care costs over time should be approved and made available to as many patients as possible. It is our opinion that bariatric surgery meets this criterion. However, bariatric surgery cannot provide the impact necessary for reduction in health care and economic costs on a national scale. The obesity epidemic must be addressed by policy efforts at the local, state, and national levels. As experts on obesity, bariatric surgeons must be prepared to guide and inform these efforts.