Bilateral transverse sinus stenosis and idiopathic intracranial hypertension without papilledema in chronic tension-type headache

Current Perspectives on Idiopathic Intracranial Hypertension without Papilloedema

The pseudotumor cerebri syndrome embraces disorders characterised by raised intracranial pressure, where the commonest symptom is headache (90%). Idiopathic intracranial hypertension without papilloedema (IIHWOP) is increasingly recognised as a source of refractory headache symptoms and resultant neurological disability. Although the majority of patients with IIHWOP are phenotypically similar to those with idiopathic intracranial hypertension (IIH), it remains uncertain as to whether IIHWOP is nosologically distinct from IIH. The incidence, prevalence, and the degree of association with the world-wide obesity epidemic is unknown. Establishing a diagnosis of IIHWOP can be challenging, as often lumbar puncture is not routinely part of the work-up for refractory headaches. There are published diagnostic criteria for IIHWOP; however, some report uncertainty regarding a pathologically acceptable cut off for a raised lumbar puncture opening pressure, which is a key criterion. The literature provides little information to help guide clinicians in managing patients with IIHWOP. Further research is therefore needed to better understand the mechanisms that drive the development of chronic daily headaches and a relationship to intracranial pressure; and indeed, whether such patients would benefit from therapies to lower intracranial pressure. The aim of this narrative review was to perform a detailed search of the scientific literature and provide a summary of historic and current opinion regarding IIHWOP.

Utility of Magnetic Resonance Imaging Features for Improving the Diagnosis of Idiopathic Intracranial Hypertension Without Papilledema

OBJECTIVE

Revised diagnostic criteria for idiopathic intracranial hypertension (IIH) were proposed in part to reduce misdiagnosis of intracranial hypertension without papilledema (WOP) by using 3 or 4 MRI features of intracranial hypertension when a sixth nerve palsy is absent. This study was undertaken to evaluate the sensitivity and specificity of the MRI criteria and to validate their utility for diagnosing IIH in patients with chronic headaches and elevated opening pressure (CH + EOP), but WOP.

METHODS

Brain MRIs from 80 patients with IIH with papilledema (WP), 33 patients with CH + EOP, and 70 control patients with infrequent episodic migraine were assessed in a masked fashion for MRI features of intracranial hypertension.

RESULTS

Reduced pituitary gland height was moderately sensitive for IIH WP (80%) but had low specificity (64%). Increased optic nerve sheath diameter was less sensitive (51%) and only moderately specific (83%). Flattening of the posterior globe was highly specific (97%) but had low sensitivity (57%). Transverse venous sinus stenosis was moderately sensitive for IIH WP (78%) but of undetermined specificity. A combination of any 3 of 4 MRI features was nearly 100% specific, while maintaining a sensitivity of 64%. Of patients with CH + EOP, 30% had 3 or more MRI features, suggesting IIH WOP in those patients.

CONCLUSION

A combination of any 3 of 4 MRI features is highly specific for intracranial hypertension and suggests IIH WOP when present in patients with chronic headache and no papilledema.

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

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

Transverse Sinus Stenosis in Refractory Chronic Headache Patients: An Observational Study

Background: Transverse sinus stenosis is a common brain MRI finding in chronic migraine (CM) and chronic tension-type headache (CTTH) patients in clinical practice; however, its clinical and diagnostic role is unclear. The aim of the study is to determine the frequency of transverse sinus stenosis in these headache patients resistant to preventive treatments and to verify whether this is a useful finding for identifying patients with intracranial hypertension. Methods: This is an observational study. Patients with refractory CM and CTTH underwent a 3T-magnetic resonance venography (MRV) before cerebrospinal fluid (CSF) opening pressure measurement. Transverse sinus stenosis was determined using the combined conduit score. Patients with opening pressure >200 repeated MRV study 1 month after CSF withdrawal to evaluate changes in neuroimaging findings. Results: We analyzed MRV studies of 40 patients (32 F, 8 M; mean age, 49.4 ± 10.8; mean body mass index, 26.7 ± 6.4; 39 CM and 1 CTTH with concomitant episodic migraine). Nineteen cases (47.5%) had evidence of transverse sinus stenosis: bilateral in seven patients (17.5%) and unilateral in 12 cases (30%). No statistically significant differences in transverse sinus stenosis distribution were found between patients with opening pressure <200 mmH₂O and those with opening pressure >200 mmH₂O. On Spearman bivariate test, there was no correlation between opening pressure and combined conduit score. No changes in neuroimaging findings were found 1 month after CSF withdrawal. Conclusion: Transverse sinus stenosis is a frequent radiological finding (47.5%) in CM and CTTH patients refractory to preventive treatments. However, this finding is not suggestive of intracranial hypertension. Whether transverse sinus stenosis may be a possible risk factor for chronic headache or a comorbidity needs to be evaluated in larger epidemiological studies.

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

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

Isolated cerebrospinal fluid hypertension in chronic headache: diagnostic innovations and clinical implications

Isolated cerebrospinal fluid hypertension (ICH) is a condition of increased cerebrospinal fluid (CSF) pressure in the cranial-spinal compartment without an identifiable cause. Isolated headache is the most common symptom of ICH, while missing may be signs such as papilledema or sixth nerve palsy. This fact makes difficult the clinical diagnosis of headache attributable to ICH in headache sufferers. Another source of confusion stems from the CSF pressure measurement. It has been observed that a single-spot CSF opening pressure measurement may be insufficient to identify elevated CSF pressure in headache sufferers. A new method of CSF pressure measurement has been able to identify pressure-related features of isolated CSF hypertension (ICH). In fact, nocturnal or postural headache and abnormal pressure pulsations are the more common pressure-related features of ICH in patients with chronic headache. The compressive action of these abnormal pressure pulsations causes the periventricular white matter microstructure alterations leading to the focal diffusion tensor imaging findings in patients with ICH. Abnormal pressure pulsations are a marker of ICH in chronic headache. The identification of the CSF pressure-related features may be useful for differentiating headache sufferers with ICH from those with primary headache disorder in clinical practice. The therapeutic strategy in these headache sufferers with ICH includes the CSF removal and a medical treatment.

Periventricular white matter changes in idiopathic intracranial hypertension

Objective

To evaluate whether increased cerebrospinal fluid (CSF) pressure causes alteration of periventricular white matter (WM) microstructure in patients with idiopathic intracranial hypertension (IIH).

Methods

In a prospective study, patients with refractory chronic headache with and without IIH performed a neuroimaging study including 3T MRI, 3D Phase Contrast MR venography, and diffusion tensor imaging (DTI) of the brain. Whole‐brain voxel‐wise comparisons of DTI abnormalities of WM were performed using tract‐based spatial statistics. A correlation analysis between DTI indices and CSF opening pressure, highest peak, and mean pressure was also performed in patients with IIH.

Results

We enrolled 62 consecutive patients with refractory chronic headaches. Thirty‐five patients with IIH, and 27 patients without increased intracranial pressure. DTI analysis revealed no fractional anisotropy changes, but decreased mean, axial, and radial diffusivity in body (IIH_MD = 0.80 ± 0.04, non‐IIH_MD = 0.84 ± 0.4, IIH_AD = 1.67 ± 0.07, non‐IIH_AD = 1.74 ± 0.05, IIH_RD = 0.38 ± 0.04, non‐IIH_RD = 0.42 ± 0.05 [mm²/sec × 10⁻³]) of corpus callosum, and in right superior corona radiata (IIH_MD = 0.75 ± 0.04, non‐IIH_MD = 0.79 ± 0.05, IIH_AD = 1.19 ± 0.07, non‐IIH_AD = 1.28 ± 0.09, IIH_RD = 0.59 ± 0.03, non‐IIH_RD = 0.53 ± 0.03 [mm²/sec × 10⁻³]) of 35 patients with IIH compared with 27 patients without increased intracranial pressure. DTI indices were negatively correlated with high CSF pressures (P < 0.05). After medical treatment, eight patients showed incremented MD in anterior corona radiata left and right and superior corona radiata right.

Conclusions

There is significant DTI alteration in periventricular WM microstructure of patients with IIH suggesting tissue compaction correlated with high CSF pressure. This periventricular WM change may be partially reversible after medical treatment.

Cerebrospinal Fluid Pressure-Related Features in Chronic Headache: A Prospective Study and Potential Diagnostic Implications

Objective: To identify the pressure-related features of isolated cerebrospinal fluid hypertension (ICH) in order to differentiate headache sufferers with ICH from those with primary headache disorder. Methods: In this prospective study, patients with refractory chronic headaches and suspected of having cerebrospinal fluid-pressure elevation without papilledema or sixth nerve palsy, together with controls, underwent 1-h lumbar cerebrospinal fluid pressure monitoring via a spinal puncture needle. Results: We recruited 148 consecutive headache patients and 16 controls. Lumbar cerebrospinal fluid pressure monitoring showed high pressure and abnormal pressure pulsations in 93 (63 %) patients with headache: 37 of these patients with the most abnormal pressure parameters (opening pressure above 250 mm H₂O, mean pressure 301 mm H₂O, mean peak pressure 398 mm H₂O, and severe abnormal pressure pulsations) had the most severe headaches and associated symptoms (nocturnal headache, postural headache, transient visual obscuration); 56 patients with the less abnormal pressure parameters (opening pressure between 200 and 250 mm H₂O, mean pressure 228 mm H₂O, mean peak pressure 316 mm H₂O, and abnormal pressure pulsations) had less severe headaches and associated symptoms. Conclusions: Nocturnal and postural headache, and abnormal pressure pulsations are the more common pressure-related features of ICH in patients with chronic headache. Abnormal pressure pulsations may be considered a marker of ICH in chronic headache.

European headache federation guideline on idiopathic intracranial hypertension

Background

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

Methods

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

Results

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

Conclusions

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

Electronic supplementary material

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

Idiopathic Intracranial Hypertension Without Papilledema (IIHWOP) in Chronic Refractory Headache

Background: To determine the prevalence of Idiopathic intracranial hypertension without papilledema (IIHWOP) testing revised diagnostic criteria by Friedman in refractory chronic headache (CH) patients. Methods: This is a prospective observational study. Each patient underwent ophthalmologic evaluation and Optical Coherence Tomography; brain magnetic resonance venography (MRV) and a lumbar puncture (LP) with opening pressure (OP) measurement. CSF withdrawal was performed in patients with CSF OP > 200 mmH20. IIHWOP was defined according Friedman's diagnostic criteria. Effect of CSF withdrawal was evaluated clinically in a 6-month follow-up and with a MRV study at 1 month. Results: Forty-five consecutive patients were enrolled. Five were excluded due to protocol violations. Analyses were conducted in 40 patients (32 F, 8 M; mean age 49.4 ± 10.8). None had papilledema. Nine patients (22.5%) had OP greater than 200 mmH2O, two of them above 250 mmH2O. Two (5%) had neuroimaging findings suggestive of elevated intracranial pressure. One of them (2.5%) met the newly proposed diagnostic criteria by Friedman for IIHWOP. After CSF withdrawal seven (77.8%) of the nine patients improved. No changes in neuroimaging findings were found. Conclusions: We found a low prevalence (2.5%) of IIHWOP in refractory CH patients according to current diagnostic criteria. In agreement with Friedman's criteria, our results confirm that a diagnosis of IIHWOP should be based on CSF OP and the combination of neuroradiological findings. However, where to set the CSF OP upper limit in IIHWOP needs further field testing. Although IIHWOP is a rare clinical condition, it should be considered and treated in refractory CH patients.

Chronic fatigue syndrome and idiopathic intracranial hypertension: Different manifestations of the same disorder of intracranial pressure?

Though not discussed in the medical literature or considered in clinical practice, there are similarities between chronic fatigue syndrome and idiopathic intracranial hypertension (IIH) which ought to encourage exploration of a link between them. The cardinal symptoms of each - fatigue and headache - are common in the other and their multiple other symptoms are frequently seen in both. The single discriminating factor is raised intracranial pressure, evidenced in IIH usually by the sign of papilloedema, regarded as responsible for the visual symptoms which can lead to blindness. Some patients with IIH, however, do not have papilloedema and these patients may be clinically indistinguishable from patients with chronic fatigue syndrome. Yet IIH is rare, IIH without papilloedema (IIHWOP) seems rarer still, while chronic fatigue syndrome is common. So are the clinical parallels spurious or is there a way to reconcile these conflicting observations? We suggest that it is a quirk of clinical measurement that has created this discrepancy. Specifically, that the criteria put in place to define IIH have led to a failure to appreciate the existence, clinical significance or numerical importance of patients with lower level disturbances of intracranial pressure. We argue that this has led to a grossly implausible distortion of the epidemiology of IIH such that the milder form of the illness (IIHWOP) is seen as less common than the more severe and that this would be resolved by recognising a connection with chronic fatigue syndrome. We hypothesise, therefore, that IIH, IIHWOP, lesser forms of IIH and an undetermined proportion of chronic fatigue cases are all manifestations of the same disorder of intracranial pressure across a spectrum of disease severity, in which this subset of chronic fatigue syndrome would represent the most common and least severe and IIH the least common and most extreme.

Brain Imaging in Idiopathic Intracranial Hypertension

BACKGROUND

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

EVIDENCE ACQUISITION

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

RESULTS

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

CONCLUSION

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

Patterns and Rates of Supplementary Venous Drainage to the Internal Jugular Veins

BACKGROUND AND PURPOSE

Several studies have found supplemental venous drainage channels in addition to bilateral internal jugular veins for cerebral venous efflux. We performed this study to characterize the supplemental venous outflow patterns in a consecutive series of patients undergoing detailed cerebral angiography with venous phase imaging.

METHODS

The venographic phase of the arteriogram was reviewed to identify and classify supplemental cerebral venous drainage into anterior (cavernous venous sinus draining into pterygoid plexus and retromandibular vein) and posterior drainage pattern. The posterior drainage pattern was further divided into plexiform pattern (with sigmoid venous sinus draining into the paravertebral venous plexus), and solitary vein pattern (dominant single draining deep cervical vein) drainage. The posterior plexiform pattern was further divided into 2 groups: posterior plexiform with or without prominent solitary vein.

RESULTS

Supplemental venous drainage was seen ipsilateral to internal jugular vein in 76 (43.7%) of 174 venous drainages (87 patients) analyzed. The patterns were anterior (n = 23, 13.2%), posterior plexiform without prominent solitary vein (n = 40, 23%), posterior plexiform with prominent solitary vein (n = 62, 35.6%), and posterior solitary vein alone (n = 3, 1.7%); occipital emissary veins and/or transosseous veins were seen in 1 supplemental venous drainage. Concurrent ipsilateral anterior and posterior supplemental drainage was seen in 6 of 174 venous drainages analyzed.

CONCLUSIONS

We provide an assessment of patterns and rates of supplementary venous drainage to internal jugular veins to improve our understanding of anatomical and physiological aspects of cerebral venous drainage.

Idiopathic intracranial hypertension: ongoing clinical challenges and future prospects

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

The role of intracranial hypertension in the chronification of migraine

Besides a similar clinical presentation, idiopathic intracranial hypertension (IIH) and chronic migraine (CM) also share relevant risk factors, show a higher prevalence of allodynic symptoms and both respond to topiramate. Moreover, sinus stenosis, a radiological marker of IIH, in CM patients is much more prevalent than expected. As a consequence of these striking similarities, IIH without papilledema (IIHWOP) may be easily misdiagnosed as CM. Actually, IIHWOP has been found in up to 14 % of CM clinical series. Considering that, on one hand, an asymptomatic sinus stenosis-associated raised intracranial pressure (ICP) may be highly prevalent in the general population, and on the other, that IIH clinical presentation with chronic headache may require a migraine predisposition, we have proposed that an overlooked IIHWOP could represent a risk factor for migraine progression. This hypothesis prompted us to investigate the prevalence of IIHWOP and its possible role in the process of migraine chronification in a consecutive series of CM patients selected for unresponsiveness to medical treatment and evidence of significant sinus stenosis. The main finding of our study is that the large majority of such patients actually suffer from a chronic headache secondary to IIHWOP. This implies that an IIHWOP mimicking CM is much more prevalent than believed, is commonly misdiagnosed as CM on the basis of ICHD criteria and is strictly predicted by refractoriness to preventive treatments. However, our data fully comply with the alternative hypothesis that an overlooked IIHWOP, although highly prevalent amongst healthy individuals, in migraine-prone subjects is a powerful (and modifiable) risk factor for the progression and the refractoriness of pain. The normalization of ICP by even a single LP with CSF withdrawal may be effective in a significant proportion of patients with a long history of refractory chronic headache, who represent about one-fifth of the patients screened in our study. We suggest that IIHWOP should be considered in all patients with almost daily migraine pain, with evidence of sinus stenosis and unresponsive to medical treatment, referred to specialized headache clinics.

Prevalence of dural venous sinus stenosis and hypoplasia in a generalized population

Background and purpose

While recent literature has described the prevalence of transverse sinus stenosis in patients with idiopathic intracranial hypertension, tinnitus, and refractory headaches, it is unclear what the prevalence is in the general population. This study evaluates the prevalence of venous sinus stenosis and hypoplasia in the general patient population.

Materials and methods

355 of 600 consecutive patients who underwent CT angiography of the head met the inclusion criteria. The diameters of the dural venous sinuses were recorded. Each study was evaluated by a neuroradiologist for the presence of stenoses. Univariate and multivariate statistical analyses were performed by a statistician.

Results

The prevalence of unilateral transverse sinus stenosis or hypoplasia in a sample of patients representing the general population was 33%, the prevalence of bilateral transverse sinus stenosis was 5%, and the prevalence of unilateral stenosis with contralateral hypoplasia was 1%. A multivariate analysis identified arachnoid granulations as a predictor of stenosis (p<0.001). Gender trended toward significance (p=0.094). Race was not a significant predictor of stenosis (p=0.745).

Conclusions

The prevalence of bilateral transverse sinus stenosis in the general population is not trivial. These data may be used as a reference for understanding the mechanistic role of stenoses in idiopathic intracranial hypertension, tinnitus, and refractory headaches.

Update on intracranial hypertension and hypotension

PURPOSE OF REVIEW

The aim of this article is to review recent findings on the pathophysiology of idiopathic changes in intracranial pressure. The review will focus on idiopathic intracranial hypertension (IIH) and spontaneous intracranial hypotension (SIH).

RECENT FINDINGS

Substantial evidence indicates that IIH is associated with delayed absorption of cerebrospinal fluid (CSF). Stenoses of the transverse sinus are common in IIH, but their clinical significance has not been entirely clarified. Despite the observed efficacy of endovascular treatment in some IIH patients, a correlation between the extent of observed stenoses and the clinical course of the disease could not be demonstrated. The underlying cause of SIH is a spontaneous CSF leakage into the epidural space. Conservative treatment and the epidural blood patch remain the treatment of choice for this rare syndrome.

SUMMARY

Recent clinical evidence indicates that IIH is probably a result of CSF outflow abnormality rather than of CSF production. Further research is needed to elucidate the causes of elevated intracranial pressure and the mechanism leading to visual loss. Prospective randomized clinical trials are needed to clarify a possible therapeutic potential of endovascular treatment. Research efforts on SIH should focus further on associated connective tissue disorders predisposing to CSF leaks.

Lumbar puncture, chronic fatigue syndrome and idiopathic intracranial hypertension: a cross-sectional study

OBJECTIVE

Unsuspected idiopathic intracranial hypertension (IIH) is found in a significant minority of patients attending clinics with named headache syndromes, if it is specifically sought out. Chronic fatigue syndrome is frequently associated with headache. Could the same be true of chronic fatigue? Moreover, there are striking similarities between the two conditions. Could they be related? Attempting to answer these questions, we describe the results of a change in clinical practice aimed at capturing patients with chronic fatigue who might have IIH.

DESIGN

Cross-sectional.

SETTING

Hospital outpatient and radiology departments.

PARTICIPANTS

Patients attending a specialist clinic with chronic fatigue syndrome and headache who had lumbar puncture to exclude raised intracranial pressure.

MAIN OUTCOME MEASURES

Intracranial pressure measured at lumbar puncture and the effect on headache of cerebrospinal fluid drainage.

RESULTS

Mean cerebrospinal fluid pressure was 19 cm H2O (range 12-41 cm H2O). Four patients fulfilled the criteria for IIH. Thirteen others did not have pressures high enough to diagnose IIH but still reported an improvement in headache after drainage of cerebrospinal fluid. Some patients also volunteered an improvement in other symptoms, including fatigue. No patient had any clinical signs of raised intracranial pressure.

CONCLUSIONS

An unknown, but possibly substantial, minority of patients with chronic fatigue syndrome may actually have IIH. An unknown, but much larger, proportion of patients with chronic fatigue syndrome do not have IIH by current criteria but respond to lumbar puncture in the same way as patients who do. This suggests that the two conditions may be related.

Venous sinus pulsatility and the potential role of dural incompetence in idiopathic intracranial hypertension

BACKGROUND

Idiopathic intracranial hypertension (IIH) remains a poorly understood and therapeutically challenging disease. Enthusiasm has emerged for endovascular therapy with stent reconstruction of dural sinus narrowing; however, a complete understanding of the hydrodynamic dysequilibrium is lacking.

OBJECTIVE

To review and characterize catheter manometry findings including pulsatility changes within the venous sinuses in IIH.

METHODS

Cases of venous sinus stent implantation for IIH were retrospectively reviewed.

RESULTS

Three cases of venous sinus stent implantation for treatment of IIH are reported. All cases demonstrated severe narrowing (>70%) within the transverse sinus and a high pressure gradient across the lesion (>30 mm Hg). Stent implantation resulted in pulsatility attenuation, correction of pressure gradient, and improvement of flow.

CONCLUSION

We report the finding of high venous sinus pulsatility attenuation after stent implantation for dural sinus narrowing and propose the hypothesis that this finding is a marker of advanced dural sinus incompetence. This characteristic may be useful in identifying patients who would benefit from endovascular stent remodeling.

Idiopathic Intracranial Hypertension. A Systematic Analysis of Transverse Sinus Stenting

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a disorder characterized by signs and symptoms of increased intracranial pressure without structural cause seen on conventional imaging. Hallmark treatment after failed medical management, has been CSF shunting or optic nerve fenestration with the goal of treatment being preservation of vision. Recently, there have been multiple case reports and case series on dural sinus stenting for this disorder.

OBJECTIVE

We aim to review all published cases and case series of dural sinus stenting for IIH, with analysis of patient presenting symptoms, objective findings (CSF pressures, papilledema, pressure gradients across dural sinuses), follow-up of objective findings, and complications.

METHODS

A Medline search was performed to identify studies meeting pre-specified criteria of a case report or case series of patients treated with dural sinus stent placement for IIH. The manuscripts were reviewed and data was extracted.

RESULTS

A total of 22 studies were identified, of which 19 studies representing 207 patients met criteria and were included in the analysis. Only 3 major complications related to procedure were identified. Headaches resolved or improved in 81% of patients. Papilledema improved the (172/189) 90%. Sinus pressure decreased from an average of 30.3 to 15 mm Hg. Sinus pressure gradient decreased from 18.5 (n=185) to 3.2 mm Hg (n=172). Stenting had an overall symptom improvement rate of 87%.

CONCLUSION

Although all published case reports and case series are nonrandomized, the low complication and high symptom improvement rate make dural sinus stenting for IIH a potential alternative surgical treatment. Standardized patient selection and randomization trials or registry are warranted.

Sinus venous stenosis-associated idiopathic intracranial hypertension without papilledema as a powerful risk factor for progression and refractoriness of headache

Data from two recent studies strongly support the hypothesis that idiopathic intracranial hypertension without papilledema (IIHWOP) could represent a powerful risk factor for the progression of pain in primary headache individuals. The first study highlights that an asymptomatic IIHWOP is much more prevalent than believed in the general population and occurs only in central venous stenosis carriers. In the second study, about one half of a large consecutive series of unresponsive primary chronic headache patients shows significant sinus venous stenosis. A continuous or intermittent IIHWOP was detectable in 91% of this subgroup and in no patient with normal venography. Moreover, after the lumbar puncture, a 2- to 4-week improvement in headache frequency was observed in most of the intracranial hypertensive patients. These findings strongly suggest that patients prone to primary headache who carry central venous outflow abnormalities are at high risk of developing a comorbid IIHWOP, which in turn is responsible for the progression and the unresponsiveness of the pain. Based on the available literature data, we propose that central sinus stenosis-related IIHWOP, although highly prevalent among otherwise healthy people, represents an important modifiable risk factor for the progression and refractoriness of pain in patients predisposed to primary headache. The mechanism could refer to up to one half of the primary chronic headache patients with minimal response to treatments referring to specialized headache clinics. Due to the clinical and taxonomic relevance of this hypothesis further studies are urgently needed.

Sinus venous stenosis, intracranial hypertension and progression of primary headaches

The recently advanced hypothesis that idiopathic intracranial hypertension without papilledema (IIHWOP) is a powerful risk factor for the progression of pain in individuals prone to episodic primary headache implies that IIHWOP is much more prevalent than it is believed to be in the general population and that it can run almost asymptomatic in most of the affected individuals. In this review, we discuss the evidence available supporting that: (a) sinus venous stenosis-associated IIHWOP is much more prevalent than believed in the general population and can run without symptoms or signs of raised intracranial pressure in most of individuals affected, (b) sinus venous stenosis is a very sensitive and specific predictor of intermittent or continuous idiopathic intracranial hypertension with or without papilledema, even in asymptomatic individuals, (c) in primary headache prone individuals, a comorbidity with a hidden stenosis-associated IIHWOP represents a very common, although largely underestimated, modifiable risk factor for the progression and refractoriness of headache.

Abnormal pressure waves in headache sufferers with bilateral transverse sinus stenosis

Introduction: Bilateral transverse sinus stenosis (BTSS) has been reported to be associated with idiopathic intracranial hypertension without papilloedema in headache sufferers.

Subjects and methods: To test the accuracy of short-term cerebrospinal fluid (CSF) pressure monitoring through a lumbar needle for detection of elevated intracranial pressure in headache sufferers with BTSS, we prospectively performed lumbar puncture in order to measure lumbar CSF opening pressures and to monitor, for 1 h, the CSF pressure in 48 consecutive headache sufferers with BTSS and in 50 consecutive headache sufferers with normal appearance of transverse sinuses or stenosis of one transverse sinus.

Results: Of the 48 headache sufferers with BTSS, 18 (37.5%) had elevated CSF opening pressure and abnormal pressure waveforms, but short-term CSF pressure monitoring revealed abnormal pressure waves associated with elevated mean CSF pressure also in 26 (86.6%) out of 30 patients who had normal opening pressures. None of the 50 headache sufferers with normal appearance of transverse sinuses or stenosis of one transverse sinus had abnormal pressure waves and elevated CSF pressures.

Conclusions: In this study, short-term CSF pressure monitoring through a lumbar needle revealed abnormal pressure waves and elevated mean CSF pressures in the majority of headache sufferers with BTSS who had normal CSF opening pressures. These findings demonstrate the accuracy of short-term CSF pressure monitoring through a lumbar needle in estimating CSF pressure; they also highlight that a single-spot opening pressure measurement has a low accuracy for recognition of increased intracranial pressure in headache sufferers with BTSS.

Efficacy of endovascular stenting in dural venous sinus stenosis for the treatment of idiopathic intracranial hypertension

Multiple pathophysiological mechanisms have been proposed for the increased intracranial pressure observed in idiopathic intracranial hypertension (IIH). The condition is well characterized, with intractable headaches, visual obscurations, and papilledema as dominant features, mainly affecting obese women. With the advent of MR venography and increased use of cerebral angiography, there has been recent emphasis on the significant number of patients with IIH found to have associated nonthrombotic dural venous sinus stenosis. This has led to a renewed interest in endovascular stenting as a treatment for IIH. However, the assumption that venous stenosis leads to a high pressure gradient that decreases CSF resorption through arachnoid villi requires further evidence. In this paper, the authors analyze the published results to date of dural venous sinus stenting in patients with IIH. They also present a case from their institution for illustration. The pathophysiological mechanism in IIH requires further elucidation, but venous sinus stenosis with subsequent intracranial hypertension appears to be an important mechanism in at least a subgroup of patients with IIH. Among these patients, 78% had complete relief or improvement of their main presenting symptoms after endovascular stenting. Resolution or improvement in papilledema was seen in 85.1% of patients. Endovascular stenting should be considered whenever venous sinus stenosis is diagnosed in patients with IIH.

The upper limit of normal CSF opening pressure is related to bilateral transverse sinus stenosis in headache sufferers

There are limited data on the relationship between normal cerebrospinal fluid (CSF) opening pressure and bilateral transverse sinus stenosis (BTSS); there are also several conflicting reports about the upper limit of normal CSF opening pressure. To evaluate the influence of BTSS on the upper limit of normal CSF opening pressure, we prospectively recorded lumbar CSF opening pressures in 217 adult patients with neurological symptoms who underwent cerebral magnetic resonance venography (MRV). The CSF opening pressures ranged between 65 and 286 mmH2O (mean = 149.3, s.d. = 47.5). The upper limit of opening pressure in patients with both normal appearance of transverse sinuses and unilateral transverse sinus stenosis on MRV ( n = 167) was 195 mmH2O with a range of 65–195 mmH2O. All patients with BTSS were headache sufferers, and the upper limit of opening pressure in patients with BTSS ( n = 50) was 286 mmH2O with a range of 91–286 mmH2O. All patients with opening pressures > 200 mmH2O displayed BTSS, whereas only 13% of patients with a pressure < 200 mmH2O displayed BTSS. Our findings demonstrate that the upper limit of normal CSF opening pressure is related to BTSS, and they also highlight that headache sufferers with opening pressures > 200 mmH2O should be tested for BTSS by MRV.

A comparison of idiopathic intracranial hypertension with and without papilledema

OBJECTIVE

To compare clinical features, visual characteristics, and treatment of idiopathic intracranial hypertension patients with and without papilledema.

BACKGROUND

Idiopathic intracranial hypertension does not often occur without papilledema. This study estimates the prevalence and compares the clinical characteristics of idiopathic intracranial hypertension patients with and without papilledema.

METHODS

We performed a cross-sectional analysis of all idiopathic intracranial hypertension patients diagnosed at the University of Utah Neuro-Ophthalmology Unit between 1990 and 2003. Patient records were reviewed for presence of papilledema and other signs, symptoms, and treatment characteristics. Each patient without papilledema was matched to the patient with papilledema who was closest to his/her age and sex. McNemar's and Wilcoxon-signed rank sum tests were used to compare characteristics between matched pairs.

RESULTS

Among all patients (n = 353), the prevalence of those without papilledema was 5.7% (n = 20). Patients without papilledema reported photopsias (20%), and were found to have spontaneous venous pulsations (75%) and non-physiologic visual field constriction (20%) more often than did those with papilledema. Mean opening pressure, although above normal, was lower in patients without papilledema (mean = 309 mm cerebrospinal fluid) compared with those with papilledema (mean = 373 mm cerebrospinal fluid, P = .031). Idiopathic intracranial hypertension patients without papilledema had more frequent diagnostic lumbar punctures than did patients with papilledema. Visual acuities and treatment were similar between groups.

CONCLUSIONS

The clinical presentation of idiopathic intracranial hypertension without papilledema is only somewhat different from that of idiopathic intracranial hypertension with papilledema. The lower opening pressure in patients without papilledema may explain variations in symptoms and signs between the 2 groups. When there are visual field changes in idiopathic intracranial hypertension without papilledema, non-physiologic visual loss should be considered.