The pseudotumor syndrome. Disorders of cerebrospinal fluid circulation causing intracranial hypertension without ventriculomegaly

Regulation of brain fluid volumes and pressures: basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus

The principles of cerebrospinal fluid (CSF) production, circulation and outflow and regulation of fluid volumes and pressures in the normal brain are summarised. Abnormalities in these aspects in intracranial hypertension, ventriculomegaly and hydrocephalus are discussed. The brain parenchyma has a cellular framework with interstitial fluid (ISF) in the intervening spaces. Framework stress and interstitial fluid pressure (ISFP) combined provide the total stress which, after allowing for gravity, normally equals intracerebral pressure (ICP) with gradients of total stress too small to measure. Fluid pressure may differ from ICP in the parenchyma and collapsed subarachnoid spaces when the parenchyma presses against the meninges. Fluid pressure gradients determine fluid movements. In adults, restricting CSF outflow from subarachnoid spaces produces intracranial hypertension which, when CSF volumes change very little, is called idiopathic intracranial hypertension (iIH). Raised ICP in iIH is accompanied by increased venous sinus pressure, though which is cause and which effect is unclear. In infants with growing skulls, restriction in outflow leads to increased head and CSF volumes. In adults, ventriculomegaly can arise due to cerebral atrophy or, in hydrocephalus, to obstructions to intracranial CSF flow. In non-communicating hydrocephalus, flow through or out of the ventricles is somehow obstructed, whereas in communicating hydrocephalus, the obstruction is somewhere between the cisterna magna and cranial sites of outflow. When normal outflow routes are obstructed, continued CSF production in the ventricles may be partially balanced by outflow through the parenchyma via an oedematous periventricular layer and perivascular spaces. In adults, secondary hydrocephalus with raised ICP results from obvious obstructions to flow. By contrast, with the more subtly obstructed flow seen in normal pressure hydrocephalus (NPH), fluid pressure must be reduced elsewhere, e.g. in some subarachnoid spaces. In idiopathic NPH, where ventriculomegaly is accompanied by gait disturbance, dementia and/or urinary incontinence, the functional deficits can sometimes be reversed by shunting or third ventriculostomy. Parenchymal shrinkage is irreversible in late stage hydrocephalus with cellular framework loss but may not occur in early stages, whether by exclusion of fluid or otherwise. Further studies that are needed to explain the development of hydrocephalus are outlined.

Effectiveness and Safety of Ventriculoperitoneal Shunt Versus Lumboperitoneal Shunt for Idiopathic Intracranial Hypertension: A Systematic Review and Comparative Meta-Analysis

INTRODUCTION

Idiopathic Intracranial Hypertension (IIH) is a condition characterized by elevated intracranial pressure. Although several mechanisms have been proposed as underlying causes of IIH, no identifiable causative factor has been determined for this condition. Initial treatments focus on weight or CSF reduction, but severe cases may require surgery. This study compares outcomes in IIH patients treated with lumboperitoneal shunts (LPSs) versus ventriculoperitoneal shunts (VPSs).

METHODS

This systematic-review and meta-analysis follows Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines and includes studies about VPS and LPS patients, reporting one of the outcomes of interest. We conducted searches on PubMed, Embase, Web of Science, and Cochrane Library.

RESULTS

Our analysis involved twelve studies, comprising 5990 patients. The estimated odds ratio (OR) for visual improvement was 0.97 (95% CI 0.26-3.62; I2 = 0%) and for headache improvement was 0.40 (95% CI 0.20-0.81; I2 = 0%), favoring LPS over VPS. Shunt revision analysis revealed an OR of 1.53 (95% CI 0.97-2.41; I2 = 77%). The shunt complications showed an OR of 0.91 (95% CI 0.68-1.22; I2 = 0%). The sub-analyses for shunt failure uncovered an OR of 1.41 (95% CI 0.92-2.18; I2 = 25%) and for shunt infection events an OR of 0.94 (95% CI 0.50-1.75; I2 = 0%).

CONCLUSIONS

The interventions showed general equivalence in complications, shunt failure, and other outcomes, but LPS seems to hold an advantage in improving headaches. Substantial heterogeneity highlights the need for more conclusive evidence, emphasizing the crucial role for further studies. The findings underscore the importance of considering a tailored decision between VPS and LPS for the management of IIH patients.

A scoping review of the discrepancies in the measurement of cerebral blood flow in idiopathic intracranial hypertension: oligemia, euvolemia or hyperemia?

BACKGROUND

The literature regarding the global cerebral blood flow (CBF) in idiopathic intracranial hypertension (IIH) is divergent leading to skepticism about the significance of blood flow to the disease's underlying pathophysiology.

METHODS

The purpose of the current paper is to perform a PRISMA scoping review of the literature describing the CBF in IIH. The review investigated the PUBMED and Scopus data bases looking at case mix, technique and the methodologies employed by the studies selected.

DISCUSSION

Many studies indicate that the flow in IIH is normal but others show the flow to be altered. These later studies show a range of flows from a reduction of 20% to an increase of 50% compared to control values. Obesity is a common finding in IIH and is known to reduce CBF, anemia occurs in approximately 20% of IIH patients and is a potent cause of an increased CBF. Thus, variations in case mix may have a significant effect on the final outcome in those studies which are underpowered. The varying techniques which have been used to estimate CBF have differing strengths and weaknesses which may also have a bearing on the outcome. Some papers have significant confounding methodological issues.

CONCLUSIONS

This review suggests each of the variables investigated are responsible for the divergent CBF findings in IIH.

Cerebellar Tonsillar Descent Mimicking Chiari Malformation

Chiari I malformation has been defined as cerebellar tonsillar descent greater than 5 mm below the foramen magnum. Suboccipital decompression remains the mainstay of treatment for symptomatic patients. Other conditions sometimes have imaging features that mimic Chiari I malformation. These patients are at risk of misdiagnosis and mismanagement, including surgery that may be unnecessary or may even worsen the underlying condition. The aim of this study was to analyse a series of Chiari I malformation mimics and identify differentiating imaging features. The mimics are categorised as post-traumatic cranio-cervical junction arachnoiditis, dural band, spontaneous intracranial hypotension, idiopathic intracranial hypertension, and cysts. Better understanding of these conditions will assist with diagnosis and optimal management, including avoiding unnecessary surgery.

Telltale Signs of Idiopathic Intracranial Hypertension With Normal Opening Cerebrospinal Fluid Pressure

Introduction

Idiopathic Intracranial Hypertension (IIH) with normal opening cerebrospinal fluid (CSF) pressure comprises a rare IIH variant.

Case Report

We report the case of a non-obese Caucasian woman, who presented with asymmetrical papilledema, typical IIH-findings on optic nerve sonography and brain magnetic resonance imaging (MRI), and was diagnosed with IIH despite normal opening CSF pressure. Following treatment with acetazolamide, a complete remission of her symptoms was achieved, accompanied by significant improvement of the fundoscopy findings.

Conclusion

Although normal opening CSF pressure in IIH patients is rare, clinicians should be aware of this IIH variant and promptly indicate IIH treatment in patients presenting with typical clinical symptoms and neuroimaging findings suggestive of IIH.

A Systematic Review on Whether an Association Exists Between Adolescent Obesity and Idiopathic Intracranial Hypertension

Pseudotumor cerebri syndrome (PTCS)/idiopathic intracranial hypertension (IIH) is a clinical presentation appertaining to signs/symptoms of raised intracranial pressure, like headache and papilledema. It is an uncommon but clinically significant cause of morbidity such as permanent vision loss. It is crucial to understand if idiopathic intracranial hypertension (IIH) is on the rise in adolescents, it is probably due to the rising prevalence of obesity worldwide. Our study aimed to find an association between obesity and IIH in adolescents. We utilized Preferred Reporting Items for Systematic Review and Meta-Analysis 2020 (PRISMA) guidelines to run this systematic review. Many publications related to the topic in the discussion were scrutinized through a comprehensive database search. We filtered them down to a final count of 10 articles after utilizing our inclusion/exclusion criteria and assessing the quality of work. In these final papers, we identified several possibilities to explain the link between obesity and IIH in adolescents. Overweight and obese adolescents were found to have a significantly increased risk of IIH development, with a more severe clinical picture seen in morbidly obese female patients.

Optic nerve sheath decompression saves sight in severe papilloedema: results from 81 eyes in 56 patients with pseudotumor cerebri

PURPOSE

To report the outcome of optic nerve sheath decompression (ONSD) for papilloedema in a teaching hospital in western Turkey.

METHODS

The charts of 56 patients who had ONSD surgery between April 2007 and September 2019 were collated; and a total of 81 operated and 31 fellow eyes were included. Pre- and postoperative ophthalmologic examination including best-corrected visual acuity (BCVA), colour vision (CV), visual field (VF) analysis, fundoscopic examination and demographic and medical characteristics of the patients were noted and outcomes after surgery were investigated.

RESULTS

Of all study eyes, 49 (43.7%) eyes had BCVA 0.2 or less and 62 (55.3%) eyes had mean deviation (MD) below - 20.0 dB. 62 (55.3%) eyes had Frisen grade 4 or 5 papilloedema. Almost half of the eyes had severe vision loss. After ONSD, BCVA, CV and MD in both operated and fellow non-operated eyes improved significantly (p < 0.001, p = 0.009 and p < 0.001 for operated, p < 0.001, p = 0.007 and p < 0.001 for fellow eyes, respectively). Earlier surgery and higher cerebrospinal fluid opening pressure were related to better outcomes. None of the patients had major operative complications.

CONCLUSION

Optic nerve sheath decompression can safely improve vision not only of the operated but also of the non-operated eye, even in cases with severe vision loss from severe bilateral papilloedema. Regardless of initial VA and VF, patients may benefit from ONSD; the earlier it is done the more likely the better outcome.

Chiari I malformation and altered cerebrospinal fluid dynamics-the highs and the lows

PURPOSE

This paper reviews the altered cerebrospinal fluid dynamics that can be associated with paediatric Chiari I malformation and we present our own institutional experience.

METHODS

We conducted a thorough review of the literature and retrospectively analyzed all cases of operatively managed paediatric Chiari 1 malformation at our institution between February 2006 and February 2019.

RESULTS

Acquired Chiari malformation (ACM) can radiologically mimic Chiari I and has been associated with both intracranial hypotension (either secondary to lumboperitoneal shunting or spontaneous CSF hypotension) and idiopathic intracranial hypertension (IIH). At our institution, 61 paediatric cases (range, 2-15 years) underwent foramen magnum decompression (FMD) for Chiari I malformation. Whilst 80% (50/61) of cases underwent FMD with no preceding or post-operative problems of CSF dynamics, 8% (5/61) of cases had hydrocephalus at initial presentation requiring CSF diversion followed by FMD for persistent Chiari, and 10% (6/61) developed hydrocephalus following FMD and required long-term CSF diversion.

CONCLUSIONS

In paediatric ACM, the management of intracranial hypotension involves thorough radiological assessment and inclusion/adjustment of a valve in the case of lumboperitoneal shunting or epidural blood patch or interventional techniques in the case of spontaneous CSF leak. Thereby, unwarranted posterior fossa decompression surgery is avoided. In the case of IIH and Chiari I malformation, children who have recurrent symptoms despite adequate posterior fossa decompression surgery (failed Chiari), there is a strong role for intracranial pressure monitoring as raised intracranial pressure may indicate long-term CSF diversion.

Intracranial Hypertension Secondary to Cervical Dural Arteriovenous Fistula

Idiopathic intracranial hypertension (IIH) is a disease of mainly unknown etiology. Latest theories as to the pathogenesis have postulated a final common pathway of cerebral venous hypertension secondary to venous outflow impairment leading to decreased cerebrospinal fluid absorption. We present the case of a 42-year-old female who was treated for several years for headache and for approximately 12 months for IIH until appropriate imaging showed a right-sided cervical dural arteriovenous fistula (AVF) at the level of C4. The patient's IIH symptoms resolved following surgical excision of the fistula. We suggest that the cranial venous outflow impairment secondary to the cervical AVF was responsible for intracranial hypertension and that complete investigation of IIH patients should include imaging of the neck vasculature.

Chiari I malformation with underlying pseudotumor cerebri: Poor symptom relief following posterior decompression surgery

INTRODUCTION


 Pseudotumor cerebri (PTC) patients exhibit clear clinical signs and symptoms of higher intracranial pressure (ICP) without ventricular enlargement or mass lesions. The clinical picture of patients with PTC can sometimes be similar to that of Chiari Malformation type I (CMI). There is some evidence that Chiari I malformation and PTC may coexist, which raises the question of whether PTC is an idiopathic disease or a complication of posterior decompression surgery-treatment of choice for Chiari I malformation.

PRESENTATION OF CASES

A retrospective review of electronic medical records of patients diagnosed with PTC at the University of Toledo Medical Center (UTMC) was performed. The objective was to determine whether PTC patients had a concurrent diagnosis of Chiari I malformation and whether the diagnosis of PTC occurred before or after posterior decompression surgery. Out of the 8 eligible patient medical records reviewed, 5 patients diagnosed with PTC had undergone posterior decompression surgery for Chiari I malformation at anywhere from several days to three years prior to being diagnosed with PTC. The diagnosis of PTC was based on temporary symptomatic relief following lumbar puncture which also showed elevated CSF opening pressures. Finally, a VP shunt was placed in each of the 5 patients to relieve the elevated intracranial pressure which resulted in the complete resolution of the patients' symptoms.

DISCUSSION

Our study focuses on patients who were diagnosed with and treated for CMI then reported back to the clinic within several days to three years complaining of symptoms of headache. Upon re-presenting to the clinic, a CSF flow study was performed which showed normal flow of CSF. Then, these patients underwent a lumbar puncture which demonstrated an elevated opening pressure (and ICP) and a temporary relief of the headache with lumbar drainage. A VP shunt was placed for each patient to treat for PTC, and the patients' headaches were relieved.

CONCLUSION

This study suggests that the presence of Chiari I malformation in a patient conceals the symptoms of PTC which may become apparent following posterior decompression surgery. Other possibilities could be that the patients are misdiagnosed for Chiari I malformation when they are in fact suffering from PTC, or that PTC is a complication of surgery.

Case of Primary Leptomeningeal Lymphoma Presenting with Papilloedema and Characteristics of Pseudotumor Syndrome

The authors describe an immunocompetent, 50-year-old man who complained of a daily transient blurring of his vision with bilateral papilloedema. His visual acuity was 20/20 OU, and the blind spot was enlarged bilaterally. There was intracranial hypertension, but imaging for systemic and brain tumours were negative. These findings suggested a diagnosis of the pseudotumor syndrome. However, MRI showed leptomeningeal enhancement, and acetazolamide successfully resolved his visual symptoms and papilloedema. Cytology and flow cytometry of the CSF led to the final diagnosis of primary leptomeningeal lymphoma (PLML). Clinicians need to be aware that a case of PLML may be misdiagnosed as peudotumor cerebri.

Pediatric Intracranial Hypertension

Primary (idiopathic) intracranial hypertension has been considered to be a rare entity, but with no precise estimates of the pediatric incidence in the United States. There have been attempts to revise the criteria over the years and adapt the adult criteria for use in pediatrics. The clinical presentation varies with age, and symptoms tending to be less obvious in younger individuals. In the prepubertal population, incidentally discovered optic disc edema is relatively common. By far the most consistent symptom is headache; other symptoms include nausea, vomiting tinnitus, and diplopia. Treatment mainstays include weight loss when appropriate and acetazolamide. Furosemide may exhibit a synergistic benefit when used in conjunction with acetazolamide. Surgical interventions are required relatively infrequently, but include optic nerve sheath fenestration and cerebrospinal fluid shunting. Pain and permanent vision loss are the two major complications of this disorder and these manifestations justify aggressive treatment. Once intracranial hypertension has resolved, up to two thirds of patients develop a new or chronic headache type that is different from their initial presenting headache.

The relationship between obesity and symptomatic Chiari I malformation in the pediatric population

BACKGROUND

Concomitant with the rise in childhood obesity in the United States is an increase in the diagnosis of Chiari I malformation (CM1).

OBJECTIVE

To discern a correlation between obesity and CM1, defined as >5 mm of cerebellar tonsillar descent on sagittal magnetic resonance imaging.

METHODS

Charts of CM1 patients aged 2-20 years were retrospectively reviewed. Chiari size, age, body mass index (BMI), and CM1 signs/symptoms were recorded. Patients were stratified by age: 2-9, 10-14, and 15-20 years. Mixed-effect linear models and linear regression analysis were applied to investigate the relationship between BMI-for-age percentiles and CM1 signs/symptoms.

RESULTS

One hundred sixty-seven patients were included (mean age 14.5 ± 2.97 years, BMI 22.98 ± 6.5, and Chiari size 12.27 mm ± 5.91). When adjusted for age, 42% were overweight or obese-higher than normative BMI for children in the studied area (29.6%). When stratified by age, patients between 2 and 9 years were most commonly obese and presented the highest mean BMI (25.66), largest Chiari size (13.58), and highest incidence of headache (75%) and syringomyelia (66.67%). Patients between 15 and 20 years were most commonly overweight and presented the smallest Chiari size (11.76 mm), but the highest incidence of cerebellar (50%) and brainstem (8.55%) compression symptoms. A significant positive correlation existed between BMI and headache in the first two age groups: (R (2): 0.36, P = 0.03; R (2): 0.39, P = 0.01, respectively). Obese patients had higher incidence of headache in the 10-14 group (R (2): 0.37, P = 0.02) and the largest Chiari size in the 15-20 group (R (2): 0.40, P = 0.03).

CONCLUSIONS

The pediatric CM1 population is more likely to be overweight or obese. Younger obese patients presented the highest incidence of Chiari-related headache symptoms, and older obese patients, the highest incidence of findings other than headache. Thus, body weight and age should be considered when evaluating children with CM1.

Pseudotumor-like syndrome and cerebrospinal fluid leak in meningiomas involving the posterior third of the superior sagittal sinus: report of 4 cases

Meningiomas that partially or completely occlude the superior sagittal sinus may create a pseudotumor-like syndrome in certain patients. These patients may have impaired CSF absorption as a result of higher proximal venous pressure. Higher pressures after resection may encumber adequate wound healing and worsen symptoms. Here, the authors present a small series of patients with meningiomas involving the posterior third of the superior sagittal sinus, with documented high intracranial pressure prior to surgery. This paper aims to address the proposed etiology of high intracranial pressure in these patients and its associated complications, including CSF leak, wound dehiscence, pressure-related headaches, and visual complaints. In this paper, the authors propose a management plan to avoid wound complications and pseudotumor-related complications. When considering surgical intervention for patients with compromise of the posterior third of the superior sagittal sinus, careful attention must be paid to addressing potentially elevated intracranial pressure perioperatively.

Porohyperelastic anatomical models for hydrocephalus and idiopathic intracranial hypertension

OBJECT

Brain deformation can be seen in hydrocephalus and idiopathic intracranial hypertension (IIH) via medical images. The phenomenology of local effects, brain shift, and raised intracranial pressure and herniation are textbook concepts. However, there are still uncertainties regarding the specific processes that occur when brain tissue is subject to the mechanical stress of different temporal and spatial profiles of the 2 neurological disorders. Moreover, recent studies suggest that IIH and hydrocephalus may be diseases with opposite pathogenesis. Nevertheless, the similarities and differences between the 2 subjects have not been thoroughly investigated.

METHODS

An anatomical porohyperelastic finite element model was used to assess the brain tissue responses associated with hydrocephalus and IIH. The same set of boundary conditions, with the exception of brain loading for development of the transmantle pressure gradient, was applied for the 2 models. The distribution of stress and strain during tissue distortion is described by the mechanical parameters.

RESULTS

The results of both the hydrocephalus and IIH models correlated with pathological characteristics. For the hydrocephalus model, periventricular edema was associated with the presence of positive volumetric strain and void ratio in the lateral ventricle horns. By contrast, the IIH model revealed edema across the cerebral mantle, including the centrum semiovale, with a positive void ratio and volumetric strain.

CONCLUSIONS

The model simulates all the clinical features in correlation with the MR images obtained in patients with hydrocephalus and IIH, thus providing support for the role of the transmantle pressure gradient and capillary CSF absorption in CSF-related brain deformation. The finite element methods can be used for a better understanding of the pathophysiological mechanisms of neurological disorders associated with parenchymal volumetric fluctuation.

IIH with normal CSF pressures?

Idiopathic intracranial hypertension (IIH) is a condition of raised intracranial pressure (ICP) in the absence of space occupying lesions. ICP is usually measured by lumbar puncture and a cerebrospinal fluid (CSF) pressure above 250 mm H₂O is one of the diagnostic criteria of IIH. Recently, we have encountered two patients who complained of headaches and exhibited disc swelling without an increased ICP. We prescribed acetazolamide and followed both patients frequently; because of the definite disc swelling with IIH related symptoms. Symptoms and signs resolved in both patients after they started taking acetazolamide. It is generally known that an elevated ICP, as measured by lumbar puncture, is the most important diagnostic sign of IIH. However, these cases caution even when CSF pressure is within the normal range, that suspicion should be raised when a patient has papilledema with related symptoms, since untreated papilledema may cause progressive and irreversible visual loss.

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.

Spinal leptomeningeal lymphoma presenting as pseudotumor syndrome

We describe 2 patients with inexorably progressive pseudotumor syndrome (intracranial hypertension without mass lesion or ventriculomegaly) both initially misdiagnosed as having idiopathic intracranial hypertension and who were eventually found to have spinal leptomeningeal lymphoma. Neither had, at any time, any clinical signs of a spinal cord or root lesion. We discuss the possible implications of these observations regarding the diagnosis and mechanism of the pseudotumor syndrome.

Clinical spectrum of the pseudotumor cerebri in children: etiological, clinical features, treatment and prognosis

OBJECTIVE

Pseudotumor cerebri (PTC) is a clinical condition characterized by signs and symptoms of increased intracranial pressure, such as headache and papilledema. Our aim was to investigate the etiological and clinical features of pseudotumor cerebri (PTC) in children.

MATERIALS AND METHOD

We performed a comprehensive analysis of epidemiology, diagnostic work-up, therapy, and clinical follow-up in 42 consecutive patients.

RESULTS

Totally 42 patients diagnosed with PTC [27 (64.3%) females and 15 (35.7%) males] were included in the study. The average age of the symptoms onset was 10.79±3.43 years (range from 12 months to 17 years). Obesity was found in eleven (26.2%) of them. Two of the patients had familial mediterranean fever, two of them had posttraumatic PTC. The following diseases were one patient, respectively; mycophenolate mofetil-induced PTC, hypervitaminosis A induced PTC, corticosteroid induced withdrawal due to nephritic syndrome, use of oral contraceptives, Guillain-Barre syndrome, urinary tract infection, varicella-zoster virus infection and dural venous sinus thrombosis associated with otitis media. The most common symptom was headache, recorded in 76.2% of the patients. All patients were treated medically. Three patients in our group also required a ventriculoperitoneal shunt.

CONCLUSION

Pseudotumor cerebri is an avoidable cause of visual loss, both in adults and children. Pre-pubertal obese girls are more common. Medical therapy appeared to be successful in treating pediatric PTC in most patients. Nevertheless, despite adequate treatment, children can rarely experience loss of visual field and acuity; thus, prompt diagnosis and management are important.

Malignant meningitis presenting as pseudotumor cerebri

Malignant leptomeningitis can present as the clinical syndrome of pseudotumor cerebri due to infiltration of arachnoid villi in the superior sagittal sinus. We show that malignant pachymeningitis can also present with pseudotumor cerebri, likely due to cerebral venous hypertension from transverse sinus compression. We present 3 cases of pseudotumor cerebri due to pachymeningeal or leptomeningeal metastases and discuss the mechanism of intracranial hypertension in such cases, its diagnosis and treatment.

Pediatric pseudotumor cerebri

Although PTC most frequently occurs in obese females of childbearing age, the syndrome occurs in children as well.(3),(5) Prepubertal children with PTC have a lower incidence of obesity compared with adults and there is no sex predilection. The onset of puberty is best defined by the onset of secondary sexual characteristics such has menarche, pubic hair, and breast development. Children with PTC have a higher incidence of associated conditions and cranial nerve deficits compared with adults. Similar to adult patients, children are at risk for the development of permanent visual loss. In rare instances, children initially diagnosed with PTC will be found to harbor an intracranial neoplasm such as gliomatosis cerebri. An intracranial pressure of 28 cm H2O has recently been established as the upper limit of normal in children.31 Treatment is indicated for the symptomatic management of headaches and to preserve vision. Most children respond to medications such as acetazolamide, furosemide, or topiramate. Surgical treatment such as ONSF and shunting procedures are indicated for children with severe headaches, visual loss, or both despite maximal tolerated medical treatment.

Pseudotumour cerebri in children: etiological, clinical features and treatment modalities

To investigate the etiological and clinical features of pseudotumour cerebri (PTC) in children, features of 12 children with PTC were documented. The etiology could be clarified in 6 patients. The other 6 patients were accepted as idiopathic intracranial hypertension (primary PTC). Acetazolamide was used as the first drug and was effective in only 4 patients who had no underlying cause. Repeated lumbar punctures (LP) were performed in 6 patients and 5 of them were unresponsive. Prednisone was used in 3 patients and was effective in only one patient. The CSF pressure continued to be high in five patients and could be normalized only by withdrawing of the precipitating drug in three patients and by ventricular-peritoneal shunting in two patients with cerebral venous thrombosis. Although, medical treatment and repeated LP are usually effective in children with PTC, clarifying and solving the underlying cause can be crucial.

Incidence of cerebellar tonsillar ectopia in idiopathic intracranial hypertension: a mimic of the Chiari I malformation

BACKGROUND AND PURPOSE

IIH is a syndrome of elevated intracranial pressure without hydrocephalus, mass, or identifiable cause. Diagnosis is made by clinical presentation, intracranial pressure measurement, and supportive imaging findings. A subset of patients with IIH may have tonsillar ectopia, meeting the criteria for Chiari malformation type I but not responding to surgical decompression for Chiari I. The purpose of this study was to determine the incidence and morphology of cerebellar tonsillar ectopia in patients with IIH.

MATERIALS AND METHODS

Forty-three patients with clinically confirmed IIH and 44 age-matched controls were included. Two neuroradiologists with CAQs reviewed sagittal T1-weighted MRI in a blinded fashion and measured cerebellar tonsil and obex positions relative to the foramen magnum and prepontine cistern width at the level of the midpons.

RESULTS

Nine of 43 patients with IIH and 1/44 controls had cerebellar tonsillar ectopia of ≥5 mm. Five of 9 of patients with IIH with ectopia of ≥5 mm also had a "peglike" tonsil configuration. Patients with IIH had a significantly lower tonsillar position (2.1 ± 2.8 mm) than age-matched controls (0.7 ±1.9 mm, P < .05). The obex position was significantly lower in patients with IIH versus controls (-7.9 mm [above the FM] versus -9.4 mm [above the FM], P < .05). The prepontine width was not significantly different between the groups.

CONCLUSIONS

Cerebellar tonsil position in patients with IIH was significantly lower than that in age-matched controls, often times peglike, mimicking Chiari I. A significantly lower obex position suggests an inferiorly displaced brain stem and cerebellum. When tonsillar ectopia of >5 mm is identified, imaging and clinical consideration of IIH are warranted to avoid misdiagnosis as Chiari I.

Case report: atypical presentation of jugular foramen mass

INTRODUCTION

Jugular foramen lesions are often associated with pathology of adjacent structures due to either compression or direct invasion. Common presenting symptoms include pulsatile tinnitus, a neck mass, hearing loss, and cranial nerve palsies, leading to changes in taste, vocal cord paralysis, dysphagia, and sternocleidomastoid/trapezius weakness (A. Hakuba, K. Hashi, K. Fujitani, et al., Jugular foramen neurinomas. Surg Neurol 1979; 11:83-94). This patient was found to have a jugular foramen mass after presenting with the unusual constellation of visual changes and headache.

CASE PRESENTATION

A jugular foramen mass in a young woman was discovered after presenting with visual changes and headache; the patient was found to have papilledema on initial examination. Otologic and head and neck examination were normal. Subsequent imaging demonstrated a mass at the right jugular foramen with compression of this structure; a contralateral transverse sinus stenosis was also seen. This latter abnormality (along with obstruction of the jugular foramen) impeded venous drainage leading to papilledema and visual changes.

DISCUSSION

In a patient presenting with papilledema and severe headache with an associated jugular foramen mass, a multidisciplinary approach benefits the patient with input from interventional neuroradiology, neurosurgery, and neuro-ophthalmology. Venous outflow was compromised through the left stenotic transverse sinus, and the normal outflow on the right side through the jugular bulb was impeded by the tumor; obstructions of both led to symptomatic impeded venous outflow. This compromise in venous outflow led to an increase in superior sagittal sinus pressure, with subsequent increase in intracranial pressure and resultant papilledema. In an attempt to increase blood flow, an angioplasty was performed on the patient's affected transverse sinus. In addition, symptomatology consistent with pseudotumor cerebri prompted the use of acetazolamide for medical management. After both therapies, the patient's symptoms dramatically improved and were stable. The tumor has also remained stable, with no immediate need for surgical resection, stereotactic radiation, or consideration of an intraluminal transverse sinus stent placement or shunting.

CONCLUSION

The unique presentation of a jugular foramen mass in a young woman leading to papilledema highlights the need for high clinical suspicion of potential etiologies necessary for diagnosis. Despite the benign nature of her disease process, an unusual constellation of anatomical factors lead to the need for acute intervention.

Dynamics of intracranial venous flow patterns in patients with idiopathic intracranial hypertension

OBJECTIVE

To examine the dynamics of intracranial venous flow patterns in patients with idiopathic intracranial hypertension (IIH).

METHODS

Nonrandomized controlled trial analyzing the difference in cerebral perfusion in 13 IIH patients and 12 healthy controls using contrast-enhanced duplex sonography. In patients, an additional 3D gradient echo magnetic resonance venography (MRV) using a new technique was performed to quantify stenosis of the cerebral sinus. The cerebral perfusion parameters, including cerebral transit time (CTT) and time to peak (TTP), were analyzed.

RESULTS

IIH patients had a higher BMI (29.3 [95% CI 26.4, 32.2] vs. 23.3 [95% CI 20.7, 25.9], p = 0.003) and an increased prevalence of headache, but all other clinical characteristics were comparable. The CTT did not differ significantly. The TTP was significantly longer in IIH patients compared to controls (8.5 [95% CI 7.6, 9.4] vs. 7.3 s [95% CI 6.3, 8.1], p = 0.04). Twelve of 13 (92%) IIH patients showed stenosis of the cerebral sinus.

CONCLUSIONS

Our study is the first to report an altered cerebral venous flow in IIH patients compared to controls using a dynamic ultrasonographic technique. A simplified MRV technique confirms the high prevalence and reliable detection of venous stenosis in IIH patients.

Refractory cerebrospinal fluid rhinorrhea secondary to occult superior vena cava syndrome and benign intracranial hypertension: diagnosis and management

OBJECTIVE

This study is designed to describe the association between benign intracranial hypertension (BIH) and spontaneous cerebrospinal fluid (CSF) rhinorrhea and address the effect of extracranial venous flow dynamics on intracranial pressure (ICP).

METHODS

We present a 58-year-old woman with refractory spontaneous CSF rhinorrhea who was later found to have superior vena cava syndrome. The patient had undergone two prior transnasal endoscopic repair attempts. In retrospect, a preoperative magnetic resonance venogram (MRV) suggested very prolonged cerebral transit time, despite otherwise normal intracranial venous anatomy.

RESULTS

The CSF leak was repaired through a bifrontal craniotomy. The intraoperative and postoperative course was complicated due to the patient's significant comorbidities. She ultimately made a good recovery and has not had any further CSF rhinorrhea in more than 2 years of follow-up.

CONCLUSIONS

Refractory, spontaneous CSF leak must prompt aggressive investigation for multiple causes of elevated ICP. A cerebral transit time can be obtained from scout imaging when a magnetic resonance angiogram or MRV is performed, and this may disclose elevated ICP if it is prolonged. If endoscopic transnasal repair fails, craniotomy and direct suture repair and autologous tissue reinforcement of the skull base may prove successful and durable, even if BIH persists.

Pseudotumor cerebri

INTRODUCTION

Pseudotumor cerebri is a condition characterized by raised intracranial pressure, normal CSF contents, and normal brain with normal or small ventricles on imaging studies. It affects predominantly obese women of childbearing age; however, its incidence seems to be increasing among adolescent and children. While among older children the clinical picture is similar to that of adults, younger children present demographic and clinical peculiarities. Different diagnostic criteria for adults and pre-pubertal children have been proposed. Etiology and pathogenesis are still unclear, particular concerning the role of obstruction to venous outflow.

METHODS

An extensive literature review concerning all the aspects of pseudotumor cerebri has been performed, both among adults and pre-pubertal children.

CONCLUSION

Pseudotumor cerebri is an avoidable cause of visual loss, both in adults and children. Few diagnostic measures are usually sufficient to determine the correct diagnosis. Since pseudotumor cerebri is a diagnosis of exclusion, the differential diagnosis work out is of special importance. Modern neuroimaging techniques, especially magnetic resonance imaging and magnetic resonance venography may clarify the role of obstruction to venous outflow in each case. Various therapeutic options are available: medical, surgical, and endovascular procedures may be used to prevent irreversible visual loss. Treatment is usually effective, and most patients will experience complete resolution of symptoms without persistent deficits.

Spinal cord syrinx expansion following acquired Chiari malformation decompression: case report

OBJECTIVE

Chiari malformation development after lumboperitoneal (LP) shunting for pseudotumor cerebri is a recognized phenomenon. Treatment options for an acquired Chiari malformation include observation, LP shunt revision or ligation, ventriculoperitoneal (VP) shunt placement, and suboccipital decompression. The authors describe a case of suboccipital decompression of an acquired Chiari malformation that resulted in the development of a spinal cord syrinx.

CLINICAL PRESENTATION

A 24-year-old woman presented with headaches, photophobia, and blurred vision. No ventricular enlargement was seen on a computed tomographic scan of the brain. The patient was diagnosed with pseudotumor cerebri based on the clinical presentation and a lumbar puncture with a high opening pressure. She underwent an LP shunt. At the time of her 10-month follow-up evaluation, she was noted to have a symptomatic acquired Chiari malformation without a spinal cord syrinx.

INTERVENTION

The patient underwent a suboccipital decompression to treat her Chiari malformation. Postoperatively, she developed an enlarging, symptomatic spinal cord syrinx. The patient underwent LP shunt ligation and VP shunt placement and had subsequent resolution of her spinal cord syrinx.

CONCLUSION

An enlarging spinal cord syrinx can occur following the suboccipital decompression of an acquired Chiari malformation in pseudotumor cerebri patients. Careful consideration to VP shunting should be given prior to posterior fossa decompression in such cases in an attempt to avoid syrinx development.

Cerebrospinal fluid dynamics in the human cranial subarachnoid space: an overlooked mediator of cerebral disease. II. In vitro arachnoid outflow model

The arachnoid membrane (AM) and granulations (AGs) are important in cerebrospinal fluid (CSF) homeostasis, regulating intracranial pressure in health and disease. We offer a functional perspective of the human AM's transport mechanism to clarify the role of AM in the movement of CSF and metabolites. Using cultures of human AG cells and a specialized perfusion system, we have shown that this in vitro model mimics the in vivo characteristics of unidirectional fluid transport and we present the first report of serum-free permeability values (92.5 microl min(-1) mm Hg(-1) cm(-2)), which in turn are in agreement with the CSF outflow rates derived from a dynamic, in vivo magnetic resonance imaging-based computational model of the subarachnoid cranial space (130.9 microl min(-1) mm Hg(-1) cm(-2)). Lucifer yellow permeability experiments have verified the maintenance of tight junctions by the arachnoidal cells with a peak occurring around 21 days post-seeding, which is when all perfusion experiments were conducted. Addition of ruthenium red to the perfusate, and subsequent analysis of its distribution post-perfusion, has verified the passage of perfusate via both paracellular and transcellular mechanisms with intracellular vacuoles of approximately 1 microm in diameter being the predominant transport mechanism. The comparison of the computational and in vitro models is the first report to measure human CSF dynamics functionally and structurally, enabling the development of innovative approaches to modify CSF outflow and will change concepts and management of neurodegenerative diseases resulting from CSF stagnation.

Idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a condition which affects predominantly overweight women and is characterized by raised intracranial pressure without any identifiable pathology in the brain and with normal cerebrospinal fluid (CSF) composition. The cause of IIH is unclear and as such it remains a diagnosis of exclusion. Although the pathophysiology of IIH remains elusive, some observations have recently been added to our understanding of this, including the presence of transverse sinus stenosis on many patients and the possible role of leptin and inflammation in the disease pathogenesis. Headache is the most common symptom and papilloedema is the major clinical finding. Choices of medical treatment are limited to the use of diuretics particularly acetazolamide and encouragement of weight loss. Surgical therapies such as CSF diversion procedures and fenestration of the optic nerve may be necessary in some cases with persistent symptoms or progressive visual deterioration. While not life-threatening, IIH has a significant morbidity with up to 25% of patients developing visual impairment from optic atrophy. Visual surveillance is therefore vital. Long-term follow-up is recommended as the disease may worsen after an initial period of stability.

Chiari I malformation without hydrocephalus: acute intracranial hypertension managed with endoscopic third ventriculostomy (ETV)

INTRODUCTION

In a small subset of patients, a Chiari malformation can present with signs of raised intracranial pressure due to obstruction of cerebrospinal fluid flow or with the raised intracranial pressure as the primary pathological driving force resulting in tonsillar herniation.

CASE REPORT

The authors report a unique case in a 14-year-old boy with a Chiari malformation type 1-syringomyelia complex with slit-like ventricles. We have successfully managed the acute presentation of raised intracranial pressure, mimicking idiopathic intracranial hypertension, utilizing a frameless stereotactic image-navigated endoscopic third ventriculostomy alone. We present the preoperative and postoperative radiological and ophthalmological findings and discuss the possible mechanisms related to the pathophysiology and treatment in this case. The patient's symptoms resolved immediately postoperatively with resolution of papilledema. At 18-month follow-up, the patient remains entirely asymptomatic and the need for craniovertebral decompression appears to have been obviated.

CONCLUSION

We advocate that in the Chiari malformation type 1-syringomyelia complex with normal or small ventricles, patients presenting with isolated signs and symptoms of raised intracranial pressure alone can be safely and effectively managed with an electromagnetic-guided stereotactic endoscopic third ventriculostomy as a primary treatment option.

Association of intracranial hypertension without ventriculomegaly and Chiari malformation: a dangerous combination

With the increased use of MRI, tonsillar ectopia, the hallmark of the adult Chiari malformation (ACM) is being more frequently recognized. However, in some cases, the patient's symptoms do not fit with the classical presentation for ACM, but are similar to intracranial hypertension (IH). The latter may be difficult to diagnose in absence of ventricular enlargement. We report a case of ACM and IHWV due to carcinomatous meningitis.

The relationship of transverse sinus stenosis to bony groove dimensions provides an insight into the aetiology of idiopathic intracranial hypertension

INTRODUCTION

Transverse sinus tapered narrowings are frequently identified in patients with idiopathic intracranial hypertension (IIH); however, it remains unclear whether they are primary stenoses or whether they occur secondary to raised cerebrospinal fluid pressure. Computed tomographic venography demonstrates both the morphology of the venous system and the adjacent bony grooves so it may provide an insight into the aetiology of these transverse sinus stenoses.

MATERIALS AND METHODS

Tapered transverse sinus narrowings (>50%) were studied in 19 patients without IIH and 14 patients with IIH. Computed tomography vascular studies were reviewed and the dimensions of the venous sinuses and bony grooves at the sites of maximum and minimum transverse sinus area dimensions were recorded.

RESULTS

There was demonstrated to be a strong correlation of bony groove height with venous sinus height at the largest portions of the transverse sinus in both IIH patients and non-IIH subjects as well as at the transverse sinus narrowing in non-IIH subjects. There was a discordant relationship between bony groove height and venous sinus height at the site of transverse sinus stenoses in IIH patients. In 5/23 IIH transverse sinus stenoses, the bony groove height was proportionate to that seen in non-IIH subjects. There were a further 8/23 cases where the small or absent sinus was associated with an absent bony groove.

CONCLUSION

Transverse sinus tapered narrowings in subjects without IIH and in the majority of patients with IIH were associated with proportionately small or absent grooves, and these are postulated to be primary or fixed. Some patients with IIH demonstrate tapered transverse sinus stenoses with disproportionately large bony grooves, suggesting a secondary or acquired narrowing. This implies a varied aetiology for the transverse sinus stenoses of IIH.

Optic nerve sheath decompression for visual loss in intracranial hypertension: report from a tertiary care center in South India

AIM

Severe visual loss is the only serious complication of intracranial hypertension secondary to idiopathic intracranial hypertension (IIH) and some cases of cerebral venous thrombosis (CVT). Optic nerve sheath decompression (ONSD) has been shown to improve or stabilize visual function in patients with IIH, while its role in CVT is yet to be established. We report our experience with optic nerve sheath decompression for visual loss in IIH and CVT.

MATERIALS AND METHODS

In this prospective noncomparative, interventional study, 41 eyes of 21 patients with IIH and CVT and visual loss underwent ONSD. The main outcome measures included best-corrected visual acuity (BCVA), visual fields, pupillary light reflex, optic nerve sheath diameter on B-scan and resolution of papilledema which were evaluated preoperatively and at follow-up at four days, two weeks, one month, three months and final follow-up. In 7/41 eyes with absent light perception preoperatively, the functional outcome was analyzed separately.

RESULTS

Following ONSD BCVA and visual fields stabilized or improved in 32/34 (94%) eyes. Statistically significant improvement in BCVA, visual fields and pupillary light reflex occurred over the three month follow-up period. Surgical success was indicated by reduction in optic nerve diameter and papilledema resolution occurred in all patients. The outcome in the IIH and CVT groups was comparable. Four eyes with absent light perception showed marginal improvement in visual acuity. Four eyes had transient benign complications.

CONCLUSION

Optic nerve sheath decompression is an effective and safe procedure to improve or stabilize vision in patients with visual loss caused by IIH and CVT.

Mechanisms of visual loss in papilledema

The term "papilledema" indicates swelling of the optic discs secondary to increased intracranial pressure. Papilledema can be caused by an intracranial mass lesion or by other factors. Visual symptoms frequently accompany papilledema, which can lead to permanent visual loss if left untreated. Starting with an illustrative case, the authors review the pathophysiology of the visual signs and symptoms of papilledema. They also briefly review potential treatment options, focusing on the role of the neurosurgeon in the treatment of patients with papilledema.

An unusual parasagittal tumour with acute blindness and response to cerebrospinal fluid shunting

We report a seven-year-old girl who presented with a sudden tumor apoplexy due to a parasagittal hemangiopericytoma. Following tumor excision, the child was noted to have bilateral optic nerve dysfunction and progressive papilledema, despite rapid overall neurological improvement. Based on the clinical features, we feel that this case represents an unusual form of visual deterioration related to impaired CSF absorption somehow precipitated by the acute tumour apoplexy. This unusual case of blindness responded significantly to CSF shunting. Several reports exist describing raised intracranial pressure with papilledema caused by nonthrombotic sinus occlusion due to tumors in proximity to the posterior superior sagittal sinus, torcular herophili and the jugular outlet. Communicating hydrocephalus, pseudotumor syndrome or intracranial venous sinus obstruction should be considered when otherwise inexplicable visual loss coexists with optic nerve dysfunction and papilledema. We emphasize the importance of a thorough search for the cause of visual loss.

Characterization of arachnoidal cells cultured on three-dimensional nonwoven PET matrix

PURPOSE

To culture physiologically functional primary arachnoidal cells on a suitable polymer substrate for an in-vitro model of the cerebrospinal fluid outflow pathway.

METHODS

Primary cultures of arachnoidal cells were prepared within 24 hours post-mortem from brain tissue obtained from human cadavers at autopsy. Arachnoidal cells were characterized using immunocytochemistry and seeded onto needle punched non-woven poly(ethylene terephthalate)(PET) scaffolds. Metabolic rate, cell growth rate in log phase, morphologic assessment, immunocytochemistry, and protein analysis were used to characterize the cultures in both 2-D and 3-D-culture. Functional outflow assessment was performed using the Lucifer Yellow (LY) permeability assay and hydraulic conductivity (Lp) determination.

RESULTS

Cells cultured on PET scaffold grew slightly slower than cells grown in 2-D-culture as measured by metabolic rate and growth rate, however, they often formed sheets that bridged between the adjacent scaffold filaments forming many junctional protein connections. LY permeability coefficients of 2-D cells were compared with cells from scaffolds, and were not significantly different (p > 0.05) for both culture conditions. Average Lp of cells from 2-D-culture and 3-D-scaffolds were compared and shown not to be significantly different.

CONCLUSION

Based on the biochemical and functional analysis, it has been shown that cells cultured on 3D-PET scaffolds retained the same properties as cells from 2D-culture plates.

Identification of venous variants in the pineal region with 3D preoperative computed tomography and magnetic resonance imaging navigation

Object

The purpose of this study was to determine the ability of software-assisted 3D reconstruction performed using a neuronavigation system to delineate the anatomy and variation patterns of the pineal region venous complex, and then to compare these data with previous anatomical findings.

Methods

The authors retrospectively reviewed the neuroimages obtained in 100 patients with intracranial lesions (50 computed tomography [CT] scans obtained with contrast agents and 50 magnetic resonance [MR] images obtained with gadolinium) by using a neuronavigation workstation for 3D reconstruction. Particular attention was given to the internal cerebral vein, basal vein (BV), and the vein of Galen. The various connection patterns between the major vessels were classified and statistically analyzed.

Conclusions

The venous system of the pineal region shows a wide range of sex-related variations. In the female patient the absence of a BV (Type 0) is significantly more frequent than in the male. In this study the authors illustrate the ability to depict the venous drainage patterns in the pineal region for all cases studied by using 3D neuronavigation software without the need for additional examinations. This simple tool provides important information for surgical planning and may be of significant help intraoperatively.

Pseudotumor cerebri in children with Down syndrome

PURPOSE

To report 4 pediatric Down syndrome patients with optic nerve elevation and pseudotumor cerebri.

DESIGN

Retrospective observational case series.

PARTICIPANTS

Four pediatric Down syndrome patients found to have optic nerve elevation on ophthalmologic examination at a single institution.

METHODS

Medical record review of 117 pediatric Down syndrome patients aged 0 to 18 years was performed. All patients were seen at the University of Wisconsin pediatric ophthalmology clinic between 1995 and 2005.

MAIN OUTCOME MEASURES

Visual acuity, optic nerve appearance, and neurologic work-up.

RESULTS

Four (3.4%) of 117 Down syndrome patients seen at the university's pediatric ophthalmology clinic were found to have optic nerve elevation. This included 2 boys and 2 girls, aged 2 to 10 years. None of the patients had a history of headache or transient visual obscuration. One of the patients had high hyperopia at the time of presentation, and all were referred for neurologic evaluation of suspected increased intracranial pressure. Three patients were diagnosed with pseudotumor cerebri (PTC) based on a normal brain magnetic resonance imaging (MRI) scan, an elevated opening cerebrospinal fluid (CSF) pressure on lumbar puncture, and normal CSF analysis results. The fourth patient's elevated optic nerve appearance was likely secondary to PTC after obtaining normal brain MRI results; however, this patient did not undergo a lumbar puncture. One child with PTC demonstrated improvement in visual acuity and optic nerve appearance after acetazolamide and weight loss therapy. The 2 additional patients with PTC were treated with either low-dose acetazolamide or weight loss therapy and experienced optic atrophy. The final patient, who did not undergo lumbar puncture, experienced spontaneous resolution of optic nerve elevation. Mean follow-up duration was 49 months.

CONCLUSIONS

Only 3.4% (4/117) of Down syndrome children were found to have optic nerve elevation in a single institution. Pseudotumor cerebri should be considered in asymptomatic Down syndrome patients with elevated optic nerves. Medical therapy in PTC with acetazolamide can lead to improvement in visual acuity and optic nerve appearance, although optic atrophy also was seen.