Asymmetric papilledema in idiopathic intracranial hypertension

Contemporary management of the pseudotumor cerebri syndrome

Introduction: Diagnosis and appropriate management of patients with the pseudotumor cerebri syndrome are imperative to prevent or minimize permanent visual loss and headache-related disability. Areas covered: Steps in management, including making the correct diagnosis, techniques to assess the patient's visual status, medical treatment of intracranial hypertension and the associated headaches, weight management strategies, surgical treatments and stenting are reviewed incorporating the most recent medical evidence. Expert opinion: As the pathogenesis of the pseudotumor cerebri syndrome is still unknown, many of the currently employed management strategies incorporate a 'plumbing approach' to decrease cerebrospinal fluid (CSF) pressure. The Idiopathic Intracranial Hypertension Trial (IIHTT) taught us that the disorder markedly affects visual and overall quality of life, and that reducing pressure alone is not enough to make patients well, even those considered to have 'mild' vision loss. Other than the IIHTT, the evidence supporting the use of various treatments is meager. The course of the disorder can be unpredictable, and the clinician(s) managing these patients are often uncertain about which treatments to employ. Moreover, the desired modalities and specialists are not universally available in all locations. An individualized and detailed approach to the various manifestations and nuances of the disorder is essential.

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.

The swollen optic nerve: an approach to diagnosis and management

The differential diagnosis of swollen optic nerves differs according to whether the swelling is unilateral or bilateral, or whether visual function is normal or affected. Patients with a unilaterally swollen optic nerve and normal visual function most likely have optic nerve head drusen. Patients with abnormal visual function most likely have demyelinating optic neuritis or non-arteritic anterior ischaemic optic neuropathy. Patients with bilaterally swollen optic nerve heads and normal visual function most likely have papilloedema, and require neuroimaging followed by lumbar puncture. However, if their visual function is affected, the most likely causes are bilateral demyelinating optic neuritis, neuromyelitis optica spectrum disorder and anti-myelin oligodendrocyte glycoprotein optic neuritis: these patients require investigating with contrast-enhanced MRI of the orbits.

Evaluation of optic canal anatomy and symmetry using CT

Objective

We aim to describe the anatomy and symmetry patterns of the optic canal in patients having undergone maxillofacial CT imaging.

Methods

In this retrospective chart review, we included all patients who received sinus and maxillofacial CT at the University of North Carolina hospitals between 2008 and 2016, without facial or cranial fractures or other medical conditions that would affect optic canal size. We measured the length of ≥75% enclosed canal, minimum cross-sectional area and minimum diameter bilaterally using iNtuition TeraRecon (Durham, North Carolina) and compared bilateral symmetry using a 20 % difference threshold. Each parameter above was compared among white, black, non-white and non-black patients.

Results

Of 335 patients, the mean canal length was 5.61±2.22 mm. The mean minimum area was 11.84±3.11 mm². The mean minimum diameter was 3.28±0.55 mm. A total of 39.4% (132/335) of patients had asymmetric canal lengths, 18.8% (63/335) had asymmetric minimum areas, and 12.5% (42/335) had asymmetric minimum diameters. No differences were found between racial groups. The right optic canal was larger than the left (right: 12.12 mm vs left: 11.55 mm, p<0.0001).

Conclusion

Optic canal asymmetry is not uncommon. It may affect risk of papilloedema severity, explain cases of unilateral or asymmetric papilloedema and possibly asymmetric glaucoma.

Optic canal size in idiopathic intracranial hypertension and asymmetric papilledema

OBJECTIVE

Asymmetric papilledema (AP) is a rare condition in idiopathic intracranial hypertension (IIH). As the pathophysiology of papilledema developement in IIH remains unclear, the study of AP could clarify some etiologic aspects. We aimed to evaluate bony optic canal size in IIH patients with AP.

PATIENTS AND METHODS

All IIH patients based on modified Dandy criteria in our referral tertiary eye hospital underwent neuro-opthalmologic exams and grading of papilledema according to modified Frisén scale. Very asymmetric papilledema (VAP) defined as a ≥2 grade difference between the two eyes. Clinical features, cerebrospinal fluid opening pressure (CSF OP), best corrected visual acuity, Humphery visual field, and brain magnetic resonance imaging (MRI) and MR venography was performed for all patients. Spiral orbital computed tomography (CT) scan which is the choice method for details of bony structures with axial, coronal and sagittal planes was done in patients with VAP.

RESULT

59 patients with IIH were diagnosed that 18.6% of them (n = 11) had VAP. There was no IIH patient with strictly unilateral Papilledema. Presenting symptoms and CSF OP was not significantly different between patients with symmetric and asymmetric papilledema. In patients with VAP, bony optic canal size was not statistically significant different in axial, coronal and sagittal plane when comparing the eye with higher grade edema to the fellow eye.

CONCLUSION

Our study showed that bony optic canal size evaluated by orbital CT scan was not different in VAP in IIH patients. Finding the exact pathophysiology of AP need further studies.

Detection of Papilloedema Study (DOPS): rates of false positive papilloedema in the community

BACKGROUND

Overdiagnosis of papilloedema is common and carries significant potential for morbidity from over-investigation and over-treatment. We aimed to determine the community prevalence of false positive diagnosis of papilloedema (FPE) on fundus imaging.

METHODS

We evaluated fundus images from a community cross-section of 198 12-14-year-olds from the Avon Longitudinal Study of Parents and Children (ALSPAC) longitudinal cohort study database and patient images from our hospital departmental database with and without papilloedema. We asked clinicians, in isolation, to rate the subjects as a forced choice task to "papilloedema" or "not papilloedema" based on the fundus images alone. Raters comprised (i) four neuro-ophthalmologists, (ii) four ophthalmologists, (iii) four neurologists and (iv) four emergency medicine physicians.

RESULTS

The prevalence of FPE in the ALSPAC population, defined as images mistaken as papilloedema by χ% of raters (P_χ) varied from P₁₀₀ = 0% to P₅₀ = 21.3 ± 3.9%. In the hospital population, there was a lower rate of FPE, P₅₀ = 7.1 ± 10.8%. Sensitivity for papilloedema detection approached 100%, though three raters incorrectly labelled the same patient with unilateral disc swelling as normal, all other cases were detected by all raters.

CONCLUSIONS

Fundus photography assessment in isolation is highly sensitive but poorly specific for papilloedema detection. Using this method to screen the general population has significant potential for harm as overdiagnosis occurs, even in the hands of experienced clinicians.

Idiopathic Intracranial Hypertension in a Mother and Pre-pubertal Twins

Idiopathic intracranial hypertension is a syndrome of elevated intracranial pressure without an identifiable cause. The majority of cases appear to be sporadic, and incidence is highest in obese women of childbearing age. The role of genetics in the pathophysiology of the disease is unclear, and familial cases are rare. We report a familial occurrence in a mother and her twin, 5-year-old sons.

Predictive role of presenting symptoms and clinical findings in idiopathic intracranial hypertension

BACKGROUND

The aim of the study was to evaluate the presenting symptoms and signs of idiopathic intracranial hypertension (IIH) in a large cohort of patients and to estimate their possible role in establishing the diagnosis of IIH.

METHODS

This prospective cohort study in two tertiary centers, the Danish Headache Center in Rigshospitalet-Glostrup and the Neurology Clinic of the Clinical Center of Serbia, included 286 patients referred by attending specialists for possible IIH evaluation. Patients were divided into two groups: one with confirmed IIH diagnosis and one with rejected IIH diagnosis.

RESULTS

The diagnosis of IIH was confirmed in 219 (76.6%) patients. It was more often confirmed if the patient was referred by an ophthalmologist than if the referral was from a neurologist (83.6% vs. 69.8%, p = .029) and in patients with higher body mass index (BMI) (p = .032). Transient visual obscurations (p = .006), double vision (p = .033), neck pain (p = .025), and tinnitus (p = .013) were presenting symptoms more frequently reported by patients with IIH diagnosis. In the same group of patients, papilledema (p < .001) and sixth nerve palsy (p = .010) were noted significantly more often. Papilledema was extracted by multivariate analysis as an independent predictor of IIH diagnosis (p < .001).

CONCLUSION

Although studies investigating IIH report an abundance of presenting symptoms, our results indicate that these symptoms are not diagnostic for IIH. Papilledema is the most reliable clinical sign predicting the correct IIH diagnosis in patients with suspected IIH.

European headache federation guideline on idiopathic intracranial hypertension

Background

Idiopathic Intracranial Hypertension (IIH) is characterized by an elevation of intracranial pressure (ICP no identifiable cause. The aetiology remains largely unknown, however observations made in a number of recent clinical studies are increasing the understanding of the disease and now provide the basis for evidence-based treatment strategies.

Methods

The Embase, CDSR, CENTRAL, DARE and MEDLINE databases were searched up to 1st June 2018. We analyzed randomized controlled trials and systematic reviews that investigate IIH.

Results

Diagnostic uncertainty, headache morbidity and visual loss are among the highest concerns of clinicians and patients in this disease area. Research in this field is infrequent due to the rarity of the disease and the lack of understanding of the underlying pathology.

Conclusions

This European Headache Federation consensus paper provides evidence-based recommendations and practical advice on the investigation and management of IIH.

Electronic supplementary material

The online version of this article (10.1186/s10194-018-0919-2) contains supplementary material, which is available to authorized users.

Perioptic Cerebrospinal Fluid Dynamics in Idiopathic Intracranial Hypertension

Purpose: To examine the cerebrospinal fluid (CSF) dynamics along the entire optic nerve in patients with idiopathic intracranial hypertension (IIH) and papilledema by computed tomographic (CT) cisternography. Methods: Retrospective analysis of CT cisternographies in 16 patients with a history of IIH and papilledema (14 females and 2 males, mean age: 49 ± 16 years). Contrast loaded CSF (CLCSF) was measured in Hounsfield Units (HU) at three defined regions of interest (ROI) along the optic nerve (orbital optic nerve portion: bulbar and mid-orbital segment, intracranial optic nerve portion) and additionally in the basal cistern. The density measurements in ROI 1, ROI 2, and ROI 3 consist of measurements of the optic nerve complex: optic nerve sheath, CLCSF filled SAS and optic nerve tissue. As controls served a group of patients (mean age: 60 ± 19 years) without elevated intracranial pressure and without papilledema. Results: In IIH patients the mean CLCSF density in the bulbar segment measured 65 ± 53 HU on the right and 63 ± 35 HU on the left side, in the mid-orbital segment 68 ± 37 HU right and 60 ± 21 HU left. In the intracranial optic nerve portion 303 ± 137 HU right and 323 ± 169 HU left and in the basal cistern 623 ± 188 HU. Within the optic nerve the difference of CLCSF density showed a highly statistical difference (p < 0.001) between the intracranial optic nerve portion and the mid-orbital segment. CLCSF density was statistically significantly (p < 0.001) reduced in both intraorbital optic nerve segments in patients with IIH compared to controls. Conclusions: The current study demonstrates reduced CLCSF density within the orbital optic nerve segments in patients with IIH and papilledema compared to 12 controls without elevated intracranial pressure and without papilledema. Impaired CSF dynamics could be involved in the pathophysiology of optic nerve damage in PE in IIH.

Do Optic Canal Dimensions Measured on CT Influence the Degree of Papilloedema and Visual Dysfunction in Idiopathic Intracranial Hypertension?

A recent study found that increased optic canal area on magnetic resonance imaging was associated with worse papilloedema in idiopathic intracranial hypertension (IIH). We repeated this study using more accurate computerized tomography derived measurements. Optic canal dimensions were measured from 42 IIH patients and 24 controls.  These were compared with papilloedema grade.  There was no correlation between any of the optic canal measurements and papilloedema grade and no significant difference in optic canal measurements between patients and controls. Our results cast doubt on the existing literature regarding the association between optic canal size and the degree of papilloedema in IIH. CT delineates bony anatomy more accurately than MRI and our CT-derived optic canal measurements cast doubt on the existing literature regarding the association between optic canal size and the degree of Papilloedema in IIH.

Update on Idiopathic Intracranial Hypertension

PURPOSE OF REVIEW

This review presents a critical appraisal of current therapeutic strategies for patients with idiopathic intracranial hypertension (IIH). We present the reader with the most recent evidence to support medical and surgical interventions in patients with IIH and provide recommendations about treatment initiation and escalation. We also indicate areas where knowledge gaps exist regarding therapeutic efficacy and superiority of one intervention over another.

RECENT FINDINGS

A double-masked, randomized prospective study of medical management of patients with mild IIH (Idiopathic Intracranial Hypertension Treatment Trial-IIHTT) has established that acetazolamide therapy has additional efficacy when compared to weight loss alone. Furthermore, management of IIH-related headache, even in patients with papilledema, may require treatment other than ICP lowering for patients to experience symptomatic relief. Finally, a number of uncontrolled interventional studies have shown transverse sinus stenting to be a potentially effective treatment for medically refractory IIH. Medical therapy with acetazolamide should be considered in addition to structured weight loss in patients with mild IIH. Surgical treatment for patients with vision-threatening disease IIH can be performed by either optic nerve sheath fenestration or cerebrospinal fluid diversion, with venous sinus stenting emerging as an alternate therapy. Headache relief from ICP lowering therapy is variable and often not sustained.

Optic nerve head edema among patients presenting to the emergency department

OBJECTIVE

To determine the frequency of and predictive factors for optic nerve head edema (ONHE) among patients with headache, neurologic deficit, visual loss, or elevated blood pressure in the emergency department (ED).

METHODS

Cross-sectional analysis was done of patients with ONHE in the prospective Fundus Photography vs Ophthalmoscopy Trial Outcomes in the Emergency Department (FOTO-ED) study. Demographics, neuroimaging results, management, and patient disposition were collected. Patients in the ONHE and non-ONHE groups were compared with bivariate and logistic regression analyses.

RESULTS

Of 1,408 patients included, 37 (2.6%, 95% confidence interval 1.9-3.6) had ONHE (median age 31 [interquartile range 26-40] years, women 27 [73%], black 28 [76%]). ONHE was bilateral in 27 of 37 (73%). Presenting complaints were headache (18 of 37), visual loss (10 of 37), acute neurologic deficit (4 of 37), elevated blood pressure (2 of 37), and multiple (3 of 37). The most common final diagnoses were idiopathic intracranial hypertension (19 of 37), CSF shunt malfunction/infection (3 of 37), and optic neuritis (3 of 37). Multivariable logistic regression found that body mass index ≥35 kg/m² (odds ratio [OR] 1.9, p = 0.0002), younger age (OR 0.5 per 10-year increase, p < 0.0001), and visual loss (OR 5, p = 0.0002) were associated with ONHE. Patients with ONHE were more likely to be admitted (62% vs 19%), to be referred to other specialists (100% vs 54%), and to receive neuroimaging (89% vs 63%) than patients without ONHE (p < 0.001). Fundus photographs in the ED allowed initial diagnosis of ONHE for 21 of 37 (57%) patients. Detection of ONHE on ED fundus photography changed the final diagnosis for 10 patients.

CONCLUSIONS

One in 38 patients (2.6%) presenting to the ED with a chief complaint of headache, neurologic deficit, visual loss, or elevated blood pressure had ONHE. Identification of ONHE altered patient disposition and contributed to the final diagnosis, confirming the importance of funduscopic examination in the ED.

The Optic Canal Size Is Associated With the Severity of Papilledema and Poor Visual Function in Idiopathic Intracranial Hypertension

BACKGROUND

To determine whether the size of the bony optic canal is associated with the severity of papilledema and poor visual function in idiopathic intracranial hypertension (IIH).

METHODS

We performed a retrospective review of definite patients with IIH with requisite brain magnetic resonance imaging allowing for optic canal measurement. Clinical characteristics and automated (Humphrey) visual field results were reviewed; papilledema was graded according to the modified Frisén scale. Cross-sectional area of the optic canals was measured independently by 2 readers and averaged for each canal. Logistic regression modeling was applied.

RESULTS

Sixty-nine patients with IIH were included (mean age: 33; 91% women; 65% black). Controlling for age, sex, body mass index, race, and cerebrospinal fluid (CSF) opening pressure, each mm increase in canal size was associated with a 0.50 dB reduction in Humphrey visual field mean deviation (P = 0.006); this was likely mediated by the increased odds of Grade 4-5 papilledema or optic atrophy in patients with larger canals (odds ratio: 1.30 [95% CI: 1.10-1.55; P = 0.003] for Grade 4-5 papilledema or atrophy vs grade <4 papilledema per mm increase in canal size).

CONCLUSIONS

Poor visual function and severe papilledema or optic atrophy were associated with a larger optic canal. Potential mechanisms include alteration of local CSF flow or bony remodeling at the optic canals.

Lower body negative pressure reduces optic nerve sheath diameter during head-down tilt

The microgravity ocular syndrome (MOS) results in significant structural and functional ophthalmic changes during 6-mo spaceflight missions consistent with an increase in cerebrospinal fluid (CSF) pressure compared with the preflight upright position. A ground-based study was performed to assess two of the major hypothesized contributors to MOS, headward fluid shifting and increased ambient CO₂, on intracranial and periorbital CSF. In addition, lower body negative pressure (LBNP) was assessed as a countermeasure to headward fluid shifting. Nine healthy male subjects participated in a crossover design study with five head-down tilt (HDT) conditions: -6, -12, and -18° HDT, -12° HDT with -20 mmHg LBNP, and -12° HDT with a 1% CO₂ environment, each for 5 h total. A three-dimensional volumetric scan of the cranium and transverse slices of the orbita were collected with MRI, and intracranial CSF volume and optic nerve sheath diameter (ONSD) were measured after 4.5 h HDT. ONSD increased during -6° (P < 0.001), -12° (P < 0.001), and -18° HDT (P < 0.001) and intracranial CSF increased during -12° HDT (P = 0.01) compared with supine baseline. Notably, LBNP was able to reduce the increases in ONSD and intracranial CSF during HDT. The addition of 1% CO₂ during HDT, however, had no further effect on ONSD, but rather ONSD increased from baseline in a similar magnitude to -12° HDT with ambient air (P = 0.001). These findings demonstrate the ability of LBNP, a technique that targets fluid distribution in the lower limbs, to directly influence CSF and may be a promising countermeasure to help reduce increases in CSF.NEW & NOTEWORTHY This is the first study to demonstrate the ability of lower body negative pressure to directly influence cerebrospinal fluid surrounding the optic nerve, indicating potential use as a countermeasure for increased cerebrospinal fluid on Earth or in space.

Efficacy and safety of optic nerve sheath fenestration in patients with raised intracranial pressure

Objective:

To evaluate the efficacy and safety of Optic Nerve Sheath Fenestration (ONSF) in patients with raised intracranial pressure (ICP).

Methods:

This Quasi Experimental Study was conducted at Armed Forces Institute of Ophthalmology, Rawalpindi from July 2013 to July 2015. Thirty one eyes of 18 patients who underwent ONSF for raised ICP were followed up for one year to ascertain efficacy and safety of ONSF procedure.

Results:

Thirteen (72.22%) patients underwent ONSF bilaterally, while five (27.78%) underwent unilateral ONSF. Best corrected visual acuity (BCVA) improved in 24 (77.4%), remained stable in four (12.9%) and deteriorated in three (9.7%) patients. Papilledema improved in 27 (87.1%) while remained stable in four (12.9%) according to Frisénscale of Papilledema. Change in BCVA and papilledema from pre-operative values was statistically significant (p<0.001). There was significant negative correlation (r= -0.434, p=.017) between duration of symptoms before presentation and improvement in BCVA. Common complications were a tonic pupil, subconjunctival haemorrhage, chemosis, weakness of recti and diplopia.

Conclusion:

ONSF is an effective procedure with statistically significant improvement in BCVA and reduction in severity of papilledema.

Intracanalicular Optic Nerve Swelling and Signal Change in Fulminant Untreated Idiopathic Intracranial Hypertension

The role of the optic canal in the pathogenesis of papilloedema has been under scrutiny recently. Whether a larger canal precedes more severe papilloedema or is the result of bone remodelling from chronically raised pressure across a pressure gradient is not clear. The authors present the magnetic resonance imaging findings of a 29-year-old female with fulminant and untreated idiopathic intracranial hypertension. Imaging showed focal expansion and intrinsic signal changes of the intracanalicular optic nerve. The authors discuss the possibility of either fluid accumulation within the optic nerves from a water hammer effect across blocked optic canals resulting from the steep pressure gradient or opticomalacia (optic nerve softening) from chronic ischaemia.

The Optic Canal: A Bottleneck for Cerebrospinal Fluid Dynamics in Normal-Tension Glaucoma?

Purpose

To report on the optic canal cross-sectional area (OCA) in Caucasian patients with normal-tension glaucoma (NTG) compared with Caucasian control subjects without known optic nerve (ON) diseases.

Methods

Retrospective analysis of computed tomographic images of the cranium and orbits in 56 NTG patients (30 females and 26 males; 99 of 112 eyes; mean age 67.7 ± 11.1 years). Fifty-six age- and gender-matched subjects (mean age: 68.0 ± 11.2 years) without known ON diseases served as controls. The OCA at the orbital opening was measured in square millimeters by using the tool “freehand.” Statistical analysis was performed by using the independent two-tailed t-test.

Results

The mean orbital opening OCA in NTGs measured 14.5 ± 3.5 mm² (right OCA: 14.4 ± 3.6 mm², left OCA: 14.5 ± 3.4 mm²) and in controls measured 18.3 ± 2.6 mm² (right OCA: 18.5 ± 2.7 mm², left OCA: 18.1 ± 2.5 mm²). The difference between NTG and controls was statistically significant (p < 0.000 for the right OCA, p < 0.000 for the left OCA).

Conclusion

This study demonstrates narrower OCAs in Caucasian NTG patients compared with Caucasian control subjects without known ON diseases. Narrower OCAs might contribute to a discontinuity of the cerebrospinal fluid flow between the intracranial and orbital subarachnoid space in NTG patients. This might have an influence onto the pathophysiology in NTG.

Asymmetrical Intraocular Pressures and Asymmetrical Papilloedema in Pseudotumor Cerebri Syndrome

This report is of two cases of asymmetrical papilloedema in patients with asymmetrical intraocular pressures (IOPs). The first patient presented with headaches, transient visual obscurations (TVOs), and elevated IOPs, and was found to have increased intracranial pressure caused by a torcula meningioma. He developed papilloedema after his IOPs were pharmacologically lowered; the papilloedema resolved after the IOP became elevated again after stopping his glaucoma drops, and then again returned as the IOP reduced when the drops were restarted. The second patient with a history of Sturge-Weber syndrome requiring previous left trabeculectomy, presented with left-sided TVOs, photopsia, and pulsatile tinnitus caused by idiopathic intracranial hypertension. Asymmetrical papilloedema was observed, worse in the eye with the lower IOP following trabeculectomy. These cases suggest that asymmetric IOP may be one factor that can influence the development of asymmetric papilloedema. Ophthalmologists finding disc swelling at low normal pressures should ask about symptoms of raised ICP, and neuro-ophthalmologists confronted with asymmetrical disc swelling should routinely measure IOP.

Brain Imaging in Idiopathic Intracranial Hypertension

BACKGROUND

The primary role of brain imaging in idiopathic intracranial hypertension (IIH) is to exclude other pathologies causing intracranial hypertension. However, subtle radiologic findings suggestive of IIH have emerged with modern neuroimaging. This review provides a detailed description of the imaging findings reported in IIH and discusses their possible roles in the pathophysiology and the diagnosis of IIH.

EVIDENCE ACQUISITION

References were identified by searches of PubMed from 1955 to January 2015, with the terms "idiopathic intracranial hypertension," "pseudotumor cerebri," "intracranial hypertension," "benign intracranial hypertension," "magnetic resonance imaging," "magnetic resonance venography," "computed tomography (CT)," "CT venography," "imaging," and "cerebrospinal fluid (CSF) leak." Additional references were identified by hand search of relevant articles. When possible, we extracted the number of patients and control subjects from each study for each radiological finding. When at least 2 studies used the same criteria to define a radiological finding, all patients from these studies were pooled to obtain a mean sensitivity and specificity with 95% confidence interval.

RESULTS

Specific neuroimaging findings may suggest long-standing IIH, including empty sella, flattening of the posterior globes, optic nerve head protrusion, distention of the optic nerve sheaths, tortuosity of the optic nerve, cerebellar tonsillar herniation, meningoceles, CSF leaks, and transverse venous sinus stenosis.

CONCLUSION

Although IIH remains a diagnosis of exclusion, the most recently proposed diagnostic criteria have included neuroimaging findings to suggest IIH when major diagnostic criteria are not fulfilled. However, these findings are not diagnostic of IIH, and their presence is not required for the diagnosis of definite IIH. Their incidental discovery on brain imaging should not prompt invasive procedures, unless other signs of IIH, such as papilledema, are present.

Idiopathic intracranial hypertension: ongoing clinical challenges and future prospects

Idiopathic intracranial hypertension (IIH) is an uncommon disorder characterized by increased intracranial pressure without radiological or laboratory evidence of intracranial pathology except empty sella turcica, optic nerve sheath with filled out cerebrospinal fluid spaces, and smooth-walled nonflow-related venous sinus stenosis or collapse. This condition typically affects obese women. The incidence of IIH is increasing with the rising prevalence of obesity. Persistent headache is the most common symptom. Visual impairment is a serious complication that may not be recognized by the patients. This paper reviews clinical manifestations, diagnostic challenges, and current treatments of IIH in adults. Various imaging modalities have been studied on their validity for detection of IIH and papilledema. This review also includes new studies on medical, surgical, and interventional management of this condition. Acetazolamide and topiramate are the only two medications that have been studied in randomized controlled trials about their efficacy in treatment of IIH. In patients who have severe visual impairment or progressive visual deterioration despite medical management, surgical or interventional treatment may be considered. The efficacy and complications of cerebrospinal fluid diversion, optic nerve sheath fenestration, and endovascular venous stenting reported in the last 3 decades have been summarized in this review. Finally, the prospective aspects of biomarkers and treatments are proposed for future research.

Understanding idiopathic intracranial hypertension: mechanisms, management, and future directions

Idiopathic intracranial hypertension is a disorder characterised by raised intracranial pressure that predominantly affects young, obese women. Pathogenesis has not been fully elucidated, but several causal factors have been proposed. Symptoms can include headaches, visual loss, pulsatile tinnitus, and back and neck pain, but the clinical presentation is highly variable. Although few studies have been done to support evidence-based management, several recent advances have the potential to enhance understanding of the causes of the disease and to guide treatment decisions. Investigators of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT) reported beneficial effects of acetazolamide in patients with mild visual loss. Studies have also established weight loss as an effective disease-modifying treatment, and further clinical trials to investigate new treatments are underway. The incidence of idiopathic intracranial hypertension is expected to increase as rates of obesity increase; efforts to reduce diagnostic delays and identify new, effective approaches to treatment will be key to meeting the needs of a growing number of patients.

Sonographic assessment of the optic nerve sheath diameter in the diagnosis of idiopathic intracranial hypertension

OBJECTIVE

Sonographic assessment of the optic nerve sheath diameter (ONSD) is a useful technique in detecting raised intracranial pressure (ICP) in neurocritical care patients. Its utility in idiopathic intracranial hypertension (IIH) is less known. The aim of this study was to evaluate the diagnostic accuracy of ONSD for detecting IIH.

MATERIAL AND METHODS

Ultrasound measurement of ONSD was performed in 19 patients with IIH and in 11 patients with different neurological diseases without raised ICP that required undergoing a lumbar puncture. The validity of this technique for diagnosing IIH was established with cerebrospinal fluid manometry values.

RESULTS

Patients with IIH showed significantly enlarged ONSD than those without IIH. The best cut-off point for detecting raised ICP was 6.3 mms, with a sensitivity, specificity and positive likelihood ratio of 94.7%, 90.9% and 10.4, respectively. After a therapeutic lumbar puncture an 87% of cases had a partial reduction of ONSD values.

CONCLUSION

Sonographic assessment of ONSD seems to be a useful and reliable technique for detecting raised ICP. While the spinal manometry is not replaced in usual clinical settings, transorbital sonography alternatively allows a suitable and harmless screening of patients with suspected IIH. It would be desirable to perform an internal validation of the technique in each hospital in order to get the optimal cut-off point.