Functional Visual Loss in Idiopathic Intracranial Hypertension

The Pseudotumor Cerebri Syndrome

Pseudotumor cerebri syndrome is a syndrome of increased cerebrospinal fluid pressure without ventriculomegaly, mass lesion, or meningeal abnormality. It is either primary (idiopathic intracranial hypertension, IIH) or secondary. A secondary cause is unlikely when adhering to the diagnostic criteria. Permanent visual loss occurs if undetected or untreated, and the associated headaches may be debilitating. Fulminant disease may result in blindness despite aggressive treatment. This study addresses the diagnosis and management of IIH including new insights into the pathobiology of IIH, updates in therapeutics and causes of overdiagnosis.

Observational cohort study of 100 patients presenting with functional visual loss: clinical characteristics and comparison with other functional neurologic disorders

OBJECTIVE

Recent research has helped to develop a more detailed understanding of many functional neurologic disorders. The aim of this study was to increase our knowledge of functional visual loss and to compare the findings with those of other functional syndromes.

DESIGN

Prospective and retrospective observational cohort study.

METHODS

This study took place at neuro-ophthalmology clinics at 3 major hospitals in London, United Kingdom, over a 12-month period. The study population consisted of 157 participants, 100 with functional visual loss, 21 pathologic control subjects with organic visual loss, and 36 healthy nonpathologic control subjects. All participants had their diagnosis confirmed with a full neuro-ophthalmic examination, neuroimaging, and visual electrophysiology. A full assessment of all participants' medical history was obtained from their general practitioner, and all participants completed a series of questionnaires assessing relevant associations.

RESULTS

Data were obtained on 157 participants, 100 with functional visual loss, 21 pathologic control subjects with organic visual loss, and 36 healthy nonpathologic control subjects. Participants with functional visual loss were typically female (74%) with a mean age at vision loss of 40.0 ± 16 years. Sixty-four percent of participants had bilateral vision loss; the remainder, unilateral loss. Twenty-six percent of the total cohort had organic visual loss with functional overlay. Fifty percent of participants with functional visual loss had a preexisting psychiatric diagnosis, the most common being a depressive disorder. Sixty-two percent of participants had an ocular history, and 87% had a previously diagnosed medical illness, most commonly neurologic (45%). Thirty-five percent of participants self-reported at least 1 additional functional symptom.

CONCLUSIONS

Our population of functional visual loss subjects shares many similarities with the majority of patients with other functional neurologic disorders. They are generally young and female and have a greater than expected rate of psychiatric, medical, and coexisting ocular conditions. We found increased rates of precipitating stressors, clinical depression, and organic eye problems in subjects with functional visual loss.

Functional vision disorder: a review of diagnosis, management and costs

Functional vision disorder (FVD) is a relatively common diagnosis in ophthalmic practice which can be difficult to make because of clinician's apprehension to miss organic pathology. We review the diagnostic approach to patients with FVD, organic mimics of FVD, its diagnostic and management strategies and associated cost burden. Patients with FVD typically present with visual acuity and/or field loss. Diagnostic work-up should include patient observation, detailed history, pupillary examination, dilated ophthalmoscopy, visual field testing and ganglion cell analysis of the macular complex. Most common organic mimickers of FVD are amblyopia, cortical blindness, retrobulbar optic neuritis, cone dystrophy and chiasmal tumours; however, all could be ruled out by structured diagnostic approach. For patients with unilateral visual loss, bottom-up refraction, fogging of the well-seeing eye in the phoropter, convex lens and base-down prism tests could aid in diagnosis. For patients claiming binocular vision loss, checking for eye movement during the mirror test or nystagmus elicited by an optokinetic drum can be helpful. Effective management of FVD involves reassurance, stress reduction and, if agreed on, management of comorbid anxiety and/or depression. The social cost of FVD is predominately economic as patients typically meet several healthcare providers over multiple visits and often undergo several neuroimaging studies before neuro-ophthalmology referral. Further, inappropriate granting of disability benefits confers additional stigma to patients with organic vision loss.

Characteristics of 110 Patients With Functional Visual Loss

PURPOSE

Functional visual loss (FVL) is characterized by complaints of visual impairment without evidence of an organic cause. Physicians are often reluctant to diagnose FVL; thus, little is known about health care utilization in patients with FVL.

DESIGN

Retrospective case series.

METHODS

A total of 110 patients seen at 2 university-affiliated neuro-ophthalmology practices who were diagnosed with FVL were included. Medical records were evaluated, and data were collected on demographics, clinical presentation, ophthalmologic examination, neuroimaging, ancillary tests, and other health care provider visits and treatments.

RESULTS

More than 70% of patients with FVL were women with a mean age of 37 ± 15 years. The presenting complaint in 71.8% (79/110) of participants was decreased vision, which was bilateral in >50% of cases. Close to half (53/110) endorsed at least 1 coexisting psychiatric or neurologic diagnosis. The mean number of different medical specialists seen before neuro-ophthalmic consultation was 3.7 ± 2.6, and the average number of health care visits was 4.6 ± 4.4. Each patient had 2.2 ± 1.8 neuroimaging studies performed. Fifteen percent of patients underwent unnecessary treatments, including receiving steroids, visual therapy, and prisms.

CONCLUSIONS

Patients with FVL typically see at least 3 different health care providers across 4 different visits and undergo at least 2 neuroimaging studies before having neuro-ophthalmic consultation. To avoid this undue burden on patients and the health care system, clinicians should refer patients with suspected FVL to a neuro-ophthalmologist to confirm the diagnosis of FVL and appropriately counsel the patient.

Management of Functional Vision Disorders

PURPOSE OF REVIEW

The purpose of this review is to summarize current approaches to management of functional vision disorder (FVD).

RECENT FINDINGS

Several retrospective studies of FVD in both adults and children have shed light on the range of outcomes and the prevalence of psychosocial stressors among FVD patients. While the first line of treatment for FVD is reassurance and education, recent case reports highlight the use of additional treatment modalities including psychotherapy, hypnosis, and transcranial magnetic stimulation in specific cases. Although the epidemiology and diagnosis of functional vision disorder are well described, there is limited evidence supporting treatment modalities. Nevertheless, the majority of patients improve with conservative management including reassurance, education, and appropriate follow-up. Additional approaches such as mental health care referral can be considered in refractory cases.

Idiopathic intracranial hypertension: Pathophysiology, diagnosis and management

Idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure, manifested by papilledema and radiological findings, in the absence of an identifiable casual factor. The primary symptoms include headache, vision loss, and pulsatile tinnitus, and are recognized to have profound impacts on quality of life and visual function. IIH demonstrates a strong predilection towards obese women of reproductive age, and the population incidence is rising with the growing prevalence of obesity worldwide. The pathophysiology involves dysregulation of cerebrospinal fluid (CSF) dynamics and venous sinus pressure, and recent studies highlighting the pathogenic role of metabolic and hormonal factors have led to the identification of several pharmacological targets and development of novel therapeutic agents. The overarching treatment goals include symptomatic alleviation and prevention of permanent vision loss. The Idiopathic Intracranial Hypertension Treatment Trial, the first of its kind randomized controlled trial on IIH, provides class I evidence for treatment with weight loss and acetazolamide. In medically refractive or fulminant cases, optic nerve sheath fenestration, CSF diversion, and venous sinus stenting, have been successfully implemented. However, there are few high-quality prospective studies investigating the treatment and natural history of IIH, highlighting the compelling need for further research to determine the optimal treatment regimen.

Functional Visual Loss in a Young Patient With Systemic Lupus Erythematosus

We describe a rare case of a patient with systemic lupus erythematosus (SLE) with functional visual loss (FVL). A 30-year-old female had blindness in the left eye due to multiple episodes of optic neuritis with underlying SLE. She presented with blurred vision in the right eye after an upper respiratory tract infection. The visual acuity in the right eye was 6/24, while the left eye had no light perception. The right eye optic nerve function tests were within normal limits. There was a positive relative afferent pupillary defect in the left eye. Fundoscopy showed left optic atrophy, while the right fundus was normal. The patient was treated according to a diagnosis of right retrobulbar optic neuritis. However, despite a course of intravenous methylprednisolone, her right visual acuity deteriorated to light perception. A magnetic resonance imaging (MRI) scan of the brain and orbit was normal. The visual evoked potential (VEP) in the right eye was also normal. The patient was suspected of having FVL and was referred to a psychiatrist. She was diagnosed with major depressive disorder after a full psychiatric assessment.

How do ophthalmologists manage functional visual symptoms? A UK survey of ophthalmologists' experience

BACKGROUND/AIMS

Functional visual symptoms are relatively common symptoms seen by ophthalmologists. However, there are no consensus guidelines on ophthalmological management of this condition, and there is a paucity of knowledge about the collective challenges experienced in treating patients with functional visual symptoms. In order to establish an ophthalmological perspective on this condition, we undertook the first national survey of experience, knowledge and management of functional visual symptoms amongst ophthalmologists.

METHODS

An online survey was disseminated to ophthalmologists in the UK via all Royal College of Ophthalmology college tutors.

RESULTS

One hundred nineteen ophthalmologists completed the survey. Functional visual symptoms accounted for 3% of all new referrals. Forty per cent of respondents felt they had a good understanding of functional visual symptoms. Two-thirds reported a need for further training in this area. Respondents estimated two-thirds of patients' symptoms improved, but a third experienced severe or extreme disability. Following diagnosis, a minority of patients were referred to mental health or neurology services. The majority of respondents described difficulty discussing psychological factors, with a lack of time or space in a clinic preventing a holistic approach. Free text comments highlighted a lack of access to dedicated psychological support for patients.

CONCLUSION

Functional visual symptoms are disabling and are seen relatively frequently by ophthalmologists. This preliminary survey suggests that care pathways for patients with functional visual symptoms could be optimised. Fostering links between ophthalmology and existing services with expertise in functional disorders could improve patient care and clinician education and ultimately encourage research in this area.

Outcomes measures in idiopathic intracranial hypertension

Introduction: Idiopathic intracranial hypertension is a condition characterized by raised intracranial pressure, papilledema, and normal neuroimaging (aside from radiological signs of raised intracranial pressure). Symptoms of idiopathic intracranial hypertension include chronic headaches and for some, visual loss. New treatments are unmet clinical needs.Areas covered: The aim of this review is to present the evidence base and considered opinion on outcome measures to determine successful management of idiopathic intracranial hypertension.Expert opinion: Less invasive measures of disease activity such as optical coherence tomography will continue to grow in this field, both as a measure of papilledema, and potentially as a surrogate for intracranial pressure and visual function. As a highly disabling aspect of the disease is headache, treatment outcomes for headache morbidity need to be appropriately chosen and standardized to allow comparison between trials.

Outcome of idiopathic intracranial hypertension after laparoscopic sleeve gastrectomy

BACKGROUND

Idiopathic intracranial hypertension (IIH) predominantly affects young, obese women and presents with signs and symptoms of increased intracranial pressure, such as headaches and visual impairment.

OBJECTIVE

We aim to present our experience in the management of IIH.

SETTING

University Hospital.

METHODS

Obese IIH patients who had a laparoscopic sleeve gastrectomy during the study period (2 years) were included. Data were retrieved from prospectively collected database. Headaches, visual alterations, and medications or interventions used to treat are discussed.

RESULTS

The study included 16 obese women with IIH. Mean age was 31 ± 2 years (range, 25-44 yr) and mean body mass index was 46 ± 4 kg/m² (range, 42-53 kg/m²). Main symptoms and signs were chronic headaches (14), impaired vision (15), vision loss (1), papilledema (6), and field defects in 4 patients. Symptoms were present for a mean of 5 years (4-11). History of medical treatment with carbonic anhydrase inhibitor (acetazolamide) and thecoperitoneal shunting was present in 12 and 9 patients, respectively. Mean lumbar puncture opening pressure was 41.2 ± 21- (range, 30-64) cm water. At 12 months after laparoscopic sleeve gastrectomy, body mass index and percentage excess weight loss were 27.8 ± 1 kg/m² and 75.2 ± 2%, respectively. Symptoms gradually improved with complete resolution in all but 2 patients (87.5%).

CONCLUSION

The present work emphasizes the role of bariatric surgery in the management of obese patients with IIH. Larger, prospective, controlled studies are needed.

Idiopathic Intracranial Hypertension

PURPOSE OF REVIEW

Idiopathic intracranial hypertension is a syndrome of increased intracranial pressure of unclear etiology that most often occurs in obese women of childbearing age but can also occur in men, children, and older adults. This article reviews the diagnostic criteria, clinical features, neuroimaging findings, differential diagnosis, and management options for this condition.

RECENT FINDINGS

Recent population studies have found that the annual incidence of idiopathic intracranial hypertension is increasing in association with obesity rates, whereas recent scientific studies indicate a possible role for androgen sex hormones and adipose tissue in the pathogenesis of the disease. Prospective clinical trials have demonstrated a role for weight loss, acetazolamide, and topiramate in the management of mild disease. A recently begun randomized multicenter trial of surgical interventions will provide insight into the indications for surgical intervention, optimal timing and choice of intervention, and long-term outcomes.

SUMMARY

Idiopathic intracranial hypertension is a disorder producing symptoms and signs of increased intracranial pressure in the absence of an alternative cause. The main goals of treatment are to preserve visual function and alleviate symptoms, which can usually be achieved with a combination of weight loss, medical therapies, and surgical interventions depending on the severity of symptoms and vision loss, response to treatment, and subsequent clinical course.

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.

Headaches Due to Low and High Intracranial Pressure

PURPOSE OF REVIEW

Headache disorders attributed to low and high intracranial pressure are commonly encountered in specialty headache practices and may occur more frequently than realized. While the headaches resulting from intracranial pressure disorders have what are conventionally thought of as defining characteristics, a substantial minority of patients do not manifest the "typical" features. Moreover, patients with intracranial pressure disorders may also have a preexisting primary headache disorder. Heightening the complexity of the presentation, the headaches of intracranial pressure disorders can resemble the phenotype of a primary disorder. Lastly, patients with so-called intracranial "hypotension" often have normal CSF pressure and neuroimaging studies. Thus, a high index of suspicion is needed. The published literature has inherent bias as many types of specialists evaluate and treat these conditions. This article reviews the key points to emphasize the history, examination, and laboratory evaluation of patients with intracranial pressure disorders from a neurologist's perspective.

RECENT FINDINGS

Lumbar puncture opening pressure in patients with spontaneous intracranial hypotension was low enough to meet diagnostic criteria (≤60 mm CSF) in only 34% of patients in one study. Most patients had an opening pressure in the low normal to normal range, and 5% had an opening pressure of 200 mm CSF or more. Diskogenic microspurs are a common cause of this syndrome. The Idiopathic Intracranial Hypertension Treatment Trial found that most participants had a headache phenotype resembling migraine or tension-type headache. No "typical" or characteristic headache phenotype was found, and headache-related disability was severe at baseline. Headache disability did not correlate with the lumbar puncture opening pressure at baseline or at the 6-month primary outcome period. Although participants who were randomly assigned to acetazolamide had a lower mean CSF opening pressure at 6 months, headache disability in that group was similar to the group who received placebo.

SUMMARY

Significant overlap is seen in the symptoms of high and low CSF pressure disorders and in those of primary headache disorders. Neurologists are frequently challenged by patients with headaches who lack the typical clinical signs or imaging features of the pseudotumor cerebri syndrome or spontaneous intracranial hypotension. Even when characteristic symptoms and signs are initially present, the typical features of both syndromes tend to lessen or resolve over time; consider these diagnoses in patients with long-standing "chronic migraine" who do not improve with conventional headache treatment. While the diagnostic criteria for pseudotumor cerebri syndrome accurately identify most patients with the disorder, at least 25% of patients with spontaneous intracranial hypotension have normal imaging and over half have a normal lumbar puncture opening pressure. Detailed history taking will often give clues that suggest a CSF pressure disorder. That said, misdiagnosis can lead to significant patient morbidity and inappropriate therapy.

Ganglion Cell Complex Analysis as a Potential Indicator of Early Neuronal Loss in Idiopathic Intracranial Hypertension

Reliable visual field testing is the gold standard in identifying future vision loss in patients with Idiopathic Intracranial hypertension (IIH). However, when field performance is unreliable, GCC analysis may be useful. We evaluated IIH patients over three visits: initial visit, follow-up visit and a third visit, almost 1 year later. We evaluated mean deviation (MD), GCC and RNFL at presentation and the second visit and compared it to the mean deviation (MD) on fields at the third visit. As early as the second visit, GCC loss correlated with visual field results seen at the third visit.

Papilloedema and Autoimmune Retinopathy from Systemic Lupus Erythematosus

A 33-year-old female presented with bilateral papilloedema and constricted visual fields from autoimmune retinopathy. She then developed a painful peripheral neuropathy that led to further work-up and the diagnosis of systemic lupus erythematosus. Papilloedema and autoimmune retinopathy from systemic lupus erythematosus is a unique presentation.

Outcomes of endoscopic optic nerve decompression in patients with idiopathic intracranial hypertension

BACKGROUND

The conventional treatment for idiopathic intracranial hypertension involves weight loss, steroids, diuretics, and/or serial lumbar punctures; however, if the symptoms persist or worsen, surgical intervention is recommended. Surgical options include cerebrospinal fluid diversion procedures, such as ventriculoperitoneal and lumboperitoneal shunts, and optic nerve decompression with nerve sheath fenestration. The latter can be carried out using an endoscopic approach, but the outcomes of this technique have not been firmly established.

METHODS

This systematic review examined the outcomes of performing endoscopic optic nerve decompression (EOND) in patients with idiopathic intracranial hypertension (IIH). Six studies were included for a total of 34 patients.

RESULTS

The patients presented with visual field disturbances (32 of 32 [100%]), visual acuity disruptions (33 of 34 [97.1%]), papilledema (26 of 34 [76.5%]), and persistent headache (30 of 33 [90.1%]). The mean duration of symptoms ranged from 7 to 32 months. Overall, the patients showed post-EOND improvement in signs and symptoms associated with IIH, specifically visual field deficits (93.8%), visual acuity (85.3%), papilledema (81.4%), and headaches (81.8%). Interestingly, 11 cases showed postoperative improvement in their symptoms with bony decompression of the optic canal alone, without nerve sheath fenestration. There were no major adverse events or complications reported with this approach.

CONCLUSION

EOND appears to be a promising and safe surgical alternative for patients with IIH who fail to respond to medical treatment. Further studies are needed before we can attest to the clinical validity of this procedure.

Papilledema and idiopathic intracranial hypertension

PURPOSE OF REVIEW

Papilledema is one of the most concerning physical examination findings in neurology: it has a broad differential diagnosis of intracranial (and occasionally spinal) pathology associated with increased intracranial pressure. Papilledema impairs axoplasmic flow within the optic nerves and compresses the optic nerves externally; it may lead to profound visual loss. Thus, detection of papilledema and assessment of visual function are essential to patient management. This article reviews the treatment of papilledema-related visual loss in pseudotumor cerebri syndrome, one of the most common causes of papilledema encountered by neurologists.

RECENT FINDINGS

Results from the Idiopathic Intracranial Hypertension Trial (IIHTT), the first randomized, double-masked, placebo-controlled trial for the treatment of patients with mild visual loss from idiopathic intracranial hypertension, were published in April 2014. The IIHTT provides the first evidence-based treatment recommendations, showing the benefit of acetazolamide and weight loss for improving visual status in patients with mild visual field loss from idiopathic intracranial hypertension.

SUMMARY

A detailed ophthalmic examination, including perimetry, is critical to the evaluation, treatment, and assessment of treatment response in patients with papilledema.

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.

The Incidence of Blindness Due to Idiopathic Intracranial Hypertension in the UK

PURPOSE

To determine the incidence of blindness secondary to idiopathic intracranial hypertension (IIH) in the United Kingdom.

METHODS

New cases of blindness occurring secondary to IIH were identified prospectively through the British Ophthalmological Surveillance Unit (BOSU) from October 2005 to November 2006. Only idiopathic cases of intracranial hypertension and those meeting the World Health Organisation`s definition of blindness were included. Cases that were already blind or had already been blind registered before the study period were excluded.

RESULTS

There were 24 new cases of registerable blindness secondary to IIH reported during the 12 month period. Questionnaires were completed for 19 cases. Of these 19 cases, 3 were not truly idiopathic and 3 cases did not fulfil the strict criteria for blindness. One case was a duplicate report. There were 12 definite cases of blindness secondary to IIH giving a UK incidence of blindness secondary to IIH of 0.6-2% (assuming a UK population of 63.2 million and an incidence of IIH of 1-3/100,000). If the 5 cases reported as blind but without a completed questionnaire are assumed to be true cases then the incidence of blindness would be 1-3%.

CONCLUSIONS

The results of this study suggest that approximately 1-2% of new cases of IIH are likely to become blind in a given year. This contrasts with rates of between 4-10% reported previously in hospital-based studies, but may be a more accurate figure for the population as a whole. Under-ascertainment and improving standards of care may also have contributed to the lower figure than previously reported.

The twists and turns of optic disk swelling in a teenager

A 17-year-old girl developed headaches, transient visual obscuration, pulsatile tinnitus, and hearing loss during an episode of pneumonia. Neuro-ophthalmologic examination disclosed severe bilateral optic disk swelling and macular exudate in the right eye. Lumbar puncture showed an opening pressure of 55 cm H2O without neurochemical abnormalities. Subsequent magnetic resonance imaging showed no mass lesion or signs of venous sinus thrombosis, confirming the diagnosis of idiopathic intracranial hypertension. Following the lumbar puncture, the papilledema resolved but visual acuity decreased to 20/40 in the right eye despite normal color vision. Perimetric signs of psychogenic visual loss developed. This case underscores that hyperacute papilledema can simulate bilateral optic neuritis and illustrates the importance of color vision testing in distinguishing macular visual loss from optic neuropathy. It also illustrates the confounding effect of psychogenic visual loss in judging the clinical course of idiopathic intracranial hypertension.

Update on idiopathic intracranial hypertension

PURPOSE

To provide an update on various features of idiopathic intracranial hypertension.

DESIGN

Perspective.

METHODS

Selected articles on the epidemiology, clinical and imaging features, natural history, pathophysiology, and treatment of idiopathic intracranial hypertension were reviewed and interpreted in the context of the authors' clinical and research experience.

RESULTS

Idiopathic intracranial hypertension primarily is a disease of obese women of childbearing age, but it can affect patients of any weight, sex, and age. Although a relatively rare disorder, idiopathic intracranial hypertension's associated costs in the United States entail hundreds of millions of dollars. Even after treatment, headaches frequently are persistent and may require the continued involvement of a neurologist. Quality-of-life reductions and depression are common among idiopathic intracranial hypertension patients. However, visual dysfunction, especially visual field abnormalities, represents the major morbidity of this disorder, and serial automated perimetry remains the primary method of patient monitoring. Patients who are men, black, very obese, or anemic are at higher risk of visual loss. Vitamin A metabolism, adipose tissue as an actively secreting endocrine tissue, and cerebral venous abnormalities are areas of active study regarding the pathophysiology of idiopathic intracranial hypertension. Treatment studies show that lumbar puncture is a valuable treatment (in addition to its crucial diagnostic role), and that weight management is critical. However, open questions remain regarding the efficacy of acetazolamide, cerebrospinal fluid diversion procedures, and cerebral venous stenting.

CONCLUSIONS

Many questions remain unanswered about idiopathic intracranial hypertension. Ongoing studies, especially an ongoing National Institutes of Health-funded clinical trial of acetazolamide, should provide more insight into this important, yet poorly understood, syndrome of isolated intracranial hypertension.

The syndrome of pseudotumour cerebri and idiopathic intracranial hypertension

PURPOSE OF REVIEW

Idiopathic intracranial hypertension (IIH) is a condition in which raised intracranial pressure is associated with a high body mass index, and in those societies in which the prevalence of obesity is increasing the disorder is of increasing importance. It is one cause of the syndrome of pseudotumour cerebri but the cause and the link with a rise in body weight are not understood. Furthermore the treatment of the more severe, sight-threatening cases is controversial.

RECENT FINDINGS

A major theme in recent years has been an attempt to identify the underlying mechanism of IIH. Some theories - such as the dural sinus stenosis theory - seem to ignore the relationship with weight gain; others have proposed a direct link between obesity and raised intracranial pressure through a specific fat distribution in the body; others through the production of lipokines; and yet others have suggested a converse causation with raised intracranial pressure giving rise to obesity. Uncontrolled case series continue to demonstrate the success of interventions such as cerebrospinal fluid diversion procedures, venous sinus stenting and bariatric surgery but there are no level 1 clinical trials.

SUMMARY

Interest in IIH is increasing and currently generating numerous studies but there is no consensus view on either cause or management.

Use of optical coherence tomography to evaluate papilledema and pseudopapilledema

Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, describes a condition of elevated intracranial pressure (ICP) that typically presents in obese women of childbearing age with symptoms and signs of posture-dependent headaches, pulsatile tinnitus, visual changes, and papilledema. Optical coherence tomography (OCT) has begun to be utilized as an adjunctive, quantitative tool in the evaluation of patients with IIH to help distinguish between true optic nerve head edema and pseudopapilledema, and to contribute to our understanding of the consequences of prolonged optic nerve edema. Although few longitudinal studies of patients with IIH have been published to date, it appears that there may be a correlation between retinal nerve fiber layer (RNFL) thickness and visual function. With the new spectral domain OCT, additional parameters of the optic nerve imaging, including volume and height measurements, might provide greater sensitivity of the response to treatment and the long-term visual outcome in patients with IIH.

Functional visual loss

Neurologists frequently evaluate patients complaining of vision loss, especially when the patient has been examined by an ophthalmologist who has found no ocular disease. A significant proportion of patients presenting to the neurologist with visual complaints have nonorganic or functional visual loss. Although there are examination techniques that can aid in the detection and diagnosis of functional visual loss, the frequency with which functional visual loss occurs concomitantly with organic disease warrants substantial caution on the part of the clinician. Furthermore, purely functional visual loss is never a diagnosis of exclusion and must be supported by positive findings on examinations that demonstrate normal visual function. The relationship of true psychological disease and functional visual loss is unclear, and most patients respond well to simple reassurance.

Endoscopic orbital roof fenestration as an alternative treatment option for idiopathic intracranial hypertension: a cadaveric anatomical study

BACKGROUND

We investigated a new minimally invasive surgical technique for the treatment of idiopathic intracranial hypertension in a cadaveric model. This technique aims at establishing a communication between the intraorbital and intracranial compartments by creating a bone, dural, and periorbital window in the anterior cranial fossa. This procedure is predicated on intraorbital absorptive capability that has been demonstrated in animals and discussed in humans.

METHODS

Three fresh cadaver heads were fixed in a head holder so as to mimic the hyperextended supine position. The procedure was conducted bilaterally in each specimen. Our technique is as follows: 1) An incision is made in the eyebrow medial to the supraorbital notch; 2) using an endoscope and a periosteal elevator, the intraorbital surface of the orbital roof is separated from the periorbita in an anteroposterior direction for a length of 1.5-2.5 cm; 3) a 1 cm of the exposed orbital roof is removed, and the dura and arachnoid are opened; and 4) slits are made in the exposed periorbita.

RESULTS

We were able to create a communication between the intracranial and the intraorbital compartments in all specimens.

CONCLUSION

Our technique is new and does not require any foreign body implantation. Its applicability in humans needs to be evaluated in a clinical context.