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

Optic Nerve Head and Retinal Changes in Idiopathic Intracranial Hypertension: Correlation with Short-Term Cerebrospinal Fluid Pressure Monitoring

BACKGROUND

We aimed to assess the status of the optic nerve and retina by optical coherence tomography (OCT) in a group of patients with idiopathic intracranial hypertension (IIH) on the basis of dynamic changes in intracranial pressure.

METHODS

This observational and cross-sectional study included patients affected by idiopathic intracranial hypertension with papilledema (IIHWP) and patients with idiopathic intracranial hypertension without papilledema (IIHWOP). All participants underwent an OCT examination of the macula and optic nerve head. Parameters related to intracranial pressure, including cerebrospinal fluid (CSF) opening pressure (oCSFp), CSF mean pressure (mCSFp), and pulse wave amplitude (PWA), were included in the analysis.

RESULTS

Out of the 22 subjects enlisted for the study, a total of 16 patients suggestive of IIH were finally enrolled. Papilledema was detected in nine subjects (56.2%) and seven patients were affected by IIHWOP (43.7%). The OCT examination showed a higher mean RNFL thickness in IIHWP patients in comparison to IIHWOP in both eyes (p < 0.05 and p < 0.01, respectively). Intracranial pressure (ICP) measurements showed that IIHWP had higher values of oCSFp, mCSFp, and PWA compared to IIHWOP (p = 0.0001, p = 0.0001, and p = 0.0001, respectively). In addition, ICP parameters significantly correlated with RNFL.

CONCLUSIONS

Clinical parameters suggestive of idiopathic intracranial hypertension are associated with retina and optic nerve OCT parameters. OCT is a useful tool to detect these alterations in a non-invasive fashion.

Severe bilateral papilledema after sigmoid sinus constriction surgery: a case report

BACKGROUND

Papilledema is a common sign of various diseases in the eye. It could result from any conditions of increased intracranial pressure (ICP). Underlying the etiology of papilledema and appropriate treatment in time is essential.

CASE REPORT

We present a case of severe bilateral papilledema after sigmoid sinus constriction surgery. A 25-year-old female presented with a 1-month history of bilateral blurred vision, headache, and vomiting. The patient had a history of right-side sigmoid sinus constriction surgery for pulsatile tinnitus (PT) one month before in another hospital. Fundus examination showed severe bilateral papilledema. Lumbar puncture showed an elevated cerebrospinal fluid (CSF) opening pressure of 29 cm H2O. Neuroimaging examination demonstrated the right sigmoid sinus filling defect as changes after surgery. We referred the patient to the initial surgeon, who repaired the sigmoid sinus on the right side by removing the implanted gelatin sponge, as diuretic treatment could not be effective. Intracranial hypertension symptoms and signs improved soon after eliminating sigmoid sinus stenosis. Neuroimaging showed resolved right sigmoid sinus stenosis after the second surgery. CSF opening pressure was 14.5 cm H2O at the 1-month follow-up. Fundus examination showed entirely resolved papilledema. Three years of follow-up showed no recurrence.

CONCLUSIONS

This is the first clinical report of intracranial hypertension associated with sigmoid sinus constriction surgery. Although rare, rapid detection and adequate etiology management could lead to a good prognosis. It highlights the need for ophthalmologists to be aware of the diagnostic approach to papilledema and enhance cooperation with multidisciplinary departments. The most likely cause of the intracranial hypertension was dominant sinus surgical constriction by mechanical external compression, as confirmed by the complete clinical remission following the second operation to remove the implanted gelatin sponge. Thus, this case also highlights the importance of selecting the appropriate therapeutic option for PT. Surgical sinus constriction should no longer be considered a viable option for PT treatment.

Recurrent reflex syncope in idiopathic intracranial hypertension patient resolved after lumbar puncture: pathogenetic implications

BACKGROUND

Idiopathic intracranial hypertension is a disease characterized by increased intracranial cerebrospinal fluid volume and pressure without evidence of other intracranial pathology. Dural sinuses are rigid structures representing a privileged low-pressure intracranial compartment. Rigidity of dural sinus ensures that the large physiologic fluctuations of cerebrospinal fluid pressure associated with postural changes or to Valsalva effect cannot be transmitted to the sinus. An abnormal dural sinus collapsibility, especially when associated with various anatomical sinus narrowing, has been proposed as a key factor in the pathogenesis of idiopathic intracranial hypertension. This pathogenetic model is based on an excessive collapsibility of the dural sinuses that leads to the triggering of a self-limiting venous collapse positive feedback-loop between the cerebrospinal fluid pressure, that compresses the sinus, and the increased dural sinus pressure upstream, that reduces the cerebrospinal fluid reabsorption rate, increasing cerebrospinal fluid volume and pressure at the expense of intracranial compliance and promoting further sinus compression. Intracranial compliance is the ability of the craniospinal space to accept small volumetric increases of one of its compartments without appreciable intracranial pressure rise. In idiopathic intracranial hypertension, a condition associated with a reduced rate of CSF reabsorption leading to its volumetric expansion, a pathologically reduced IC precedes and accompanies the rise of ICP. Syncope is defined as a transient loss of consciousness due to a transient cerebral hypoperfusion characterized by rapid onset, short duration, and spontaneous complete recovery. A transient global cerebral hypoperfusion represents the final mechanism of syncope determined by cardiac output and/or total peripheral resistance decrease. There are many causes determining low cardiac output including reflex bradycardia, arrhythmias, cardiac structural disease, inadequate venous return, and chronotropic and inotropic incompetence. Typically, syncopal transient loss of consciousness is mainly referred to an extracranial mechanism triggering a decrease in cardiac output and/or total peripheral resistance. Conversely, the association of syncope with a deranged control of intracranial compliance related to cerebral venous outflow disorders has been only anecdotally reported.

CASE PRESENTATION

We report on a 57-year-old woman with daily recurrent orthostatic hypotension syncope and idiopathic intracranial hypertension-related headaches, which resolved after lumbar puncture with cerebrospinal fluid subtraction.

CONCLUSIONS

A novel mechanism underlying the triggering of orthostatic syncope in the presence of intracranial hypertension-dependent reduced intracranial compliance is discussed.

"Idiopathic" intracranial hypertension: An update from neurointerventional research for clinicians

BACKGROUND

The recognition of venous sinus stenosis as a contributing factor in the majority of patients with idiopathic intracranial hypertension coupled with increasing cerebral venography and venous sinus stenting experience have dramatically improved our understanding of the pathophysiologic mechanisms driving this disease. There is now a dense, growing body of research in the neurointerventional literature detailing anatomical and physiological mechanisms of disease which has not been widely disseminated among clinicians.

METHODS

A literature search was conducted, covering the most recent neurointerventional literature on idiopathic intracranial hypertension, the pathophysiology of idiopathic intracranial hypertension, and management strategies (including venous sinus stenting), and subsequently summarized to provide a comprehensive review of the most recently published studies on idiopathic intracranial hypertension pathophysiology and management.

CONCLUSION

Recent studies in the neurointerventional literature have greatly improved our understanding of the pathophysiologic mechanisms causing idiopathic intracranial hypertension and its associated conditions. The ability to make individualized, patient-specific treatment approaches has been made possible by advances in our understanding of how venous sinus stenosis and cerebral venous hypertension fundamentally contribute to idiopathic intracranial hypertension.

The putative role of trigemino-vascular system in brain perfusion homeostasis and the significance of the migraine attack

Besides representing the place where a migraine attack generates, what is the physiological role of peptidergic control of arteriolar caliber within the trigemino-vascular system? Considering that the shared goal of most human CGRP-based neurosensory systems is the protection from an acute threat, especially if hypoxic, what is the end meaning of a migraine attack? In this paper, we have reviewed available evidence on the possible role of the trigemino-vascular system in maintaining cerebral perfusion pressure homeostasis, despite the large physiological fluctuations in intracranial pressure occurring in daily life activities. In this perspective, the migraine attack is presented as the response to a cerebral hypoxic threat consequent to a deranged intracranial pressure control aimed at generating a temporary withdrawal from the environment with limitation of physical activity, a condition required to promote the restoration of cerebral fluids dynamic balance.

Anatomic Asymmetry of Transverse Sinus May Be Irrelevant to the Prognosis of Intracerebral Hemorrhage

BACKGROUND

We investigate the probable effect of anatomic asymmetry of transverse sinus (TS) on the outcomes of acute intracerebral hemorrhage (ICH), to provide reference for customized treatment.

METHODS

Consecutive patients with imaging-confirmed acute ICH were enrolled from October 2015 through October 2019, and divided into 2 groups: symmetrical and unilateral (left or right) slender TS groups, based on the status of TS in imaging maps. Brain computed tomography (CT) maps of all patients at baseline and half-month post-ICH were obtained, and the volumes of hematoma and the perihematomal edemas (PHE), as well as the modified Rankin Scale (mRS) scores at the month-3 post-ICH between the 2 groups were assessed and analyzed.

RESULTS

A total of 46 eligible patients entered into final analysis, including 18 cases in the slender TS group (14 cases involved the left side while 4 cases involved the right side), and 28 cases in the symmetrical TS group. The mRS scores, hematoma absorption rates, and the residual volumes of PHE of all patients in the 2 groups at half-month post-ICH showed no statistical significance (all P >0.05), and all of the items mentioned above were related to the hematoma volume at baseline (all P <0.001). At the month-3 follow-up post-ICH, the mRS scores between the 2 groups showed no statistical significance as well ( P =0.551).

CONCLUSIONS

Anatomic asymmetry of TS may not affect the prognosis of PHE and clinical outcome after ICH.

Enlarged Vertebral Venous Plexus Alleviated Intracranial Hypertension-Related Symptoms in Patients with Bilateral Transverse Sinus Stenosis

BACKGROUND

Enlarged vertebral venous plexus (EVVP) was often observed in patients with bilateral transverse sinus stenosis (BTSS). The purpose of this study was to investigate the physiological role of EVVP in BTSS patients.

METHODS

Forty-five BTSS patients and 92 normal controls were prospectively recruited from January 2014 to December 2019. The index of transverse sinus stenosis (ITSS) was used for the assessment of BTSS severity. Subjects underwent a standard lumbar puncture to measure the intracranial pressure (ICP). Papilledema and tinnitus were evaluated by using Frisén's grade and questionnaires for Tinnitus Handicap Inventory (THI), respectively. The intensity and impact of headache were assessed by using 10-point Numeric Pain Rating Scale and six-item Headache Impact Test, respectively.

RESULTS

The BTSS group had more subjects with intracranial hypertension (IH) and less subjects with normal ICP than normal controls (p < 0.01; p < 0.01). BTSS patients had higher ICP than normal controls (p < 0.01). ICP was significantly lower in BTSS patients with EVVP than in those without EVVP (p < 0.01). No significant difference in ICP was found between normal controls with EVVP and those without EVVP (p = 0.99). A similar incidence of EVVP in BTSS patients and normal controls was found (p = 0.86). BTSS patients with IH exhibited a lower incidence of EVVP than those with normal ICP and overlapping ICP (p < 0.01; p < 0.01). The incidence of EVVP was not correlated with ITSS (p = 0.81). EVVP, rather than ITSS, correlated with ICP (p = 0.01). Furthermore, EVVP alleviated papilledema evaluated by Frisén's grade and tinnitus evaluated by the THI score in BTSS patients (p = 004; p = 0.02).

CONCLUSIONS

EVVP in normal controls is a congenital phenomenon that exerts no impact on ICP. However, the presence of EVVP reduces ICP and alleviates IH-related papilledema and tinnitus in BTSS patients.

The Pre-Lumbar puncture Intracranial Hypertension Scale (PLIHS): A practical scale to identify subjects with normal cerebrospinal fluid pressure in the management of idiopathic intracranial hypertension

BACKGROUND

Idiopathic Intracranial Hypertension (IIH) diagnosis requires lumbar puncture to measure cerebrospinal fluid (CSF) pressure. The Pre-Lumbar puncture Intracranial Hypertension Scale (PLIHS) is aimed to detect cases that will show raised or normal CSF opening pressure.

METHODS

Retrospective analysis of records of patients who underwent lumbar puncture for suspect IIH. The target was CSF opening pressure ≥ 250 mmH2O, whereas a set of known neurological, neuro-ophthalmological and neuro-radiological parameters, plus obesity, were used as predictors in a logistic regression model. The PLIHS was based on significant predictors and a cut-off was validated using chi-squared test around CSF opening pressure ≥ 250 and < 200 mmH2O.

RESULTS

Records of 162 patients were included: CSF opening pressure was <200 mmH2O in 40 and ≥ 250 mmH2O in 95 patients; 85 fulfilled IIH diagnosis. PLIHS is based on Frisén grade 2 or higher papilledema, tinnitus, empty sella, perioptic subarachnoid space distension, and obesity. Score range is 0-7: correlation with CSF opening pressure is 0.508 (p < .001), and PLIHS score is different between subjects not diagnosed with IIH, and those diagnosed with IIH both with and without papilledema (p < .001). PLIHS score ≤ 2 identifies cerebrospinal fluid pressure < 200 mmH2O; PLIHS score ≥ 3 identifies CSF opening pressure ≥ 250 mmH2O, IIH diagnosis, visual acuity ≤0.7, and optic nerve atrophy.

CONCLUSIONS

The PLIHS, can be used to identify patients who will particularly need LP, thus helping with the organization of the diagnostic work-up by optimising healthcare resources and potentially limit the likelihood to incur in LP-related adverse events.

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.

MRI-findings in idiopathic intracranial hypertension (Pseudotumor cerebri)

BACKGROUND

 Pseudotumor cerebri, also known as idiopathic intracranial hypertension, is a disorder of increased intracranial pressure of unknown etiology. Main symptom is headache which has a characteristic similar to other headache diseases, therefore the idiopathic intracranial hypertension often remains undetected. The incidence is 1/100 000 with the number of unreported cases being much higher. This article highlights the essential role of MRI in the differential diagnosis.

METHODS

 A literature search was carried out on idiopathic intracranial hypertension and Pseudotumor cerebri in English and German. Original and Review articles as well as case reports were taken into account. Since the main focus of the article is MRI diagnostics, some images were selected to illustrate the characteristic MRI morphological features.

RESULTS AND CONCLUSION

 The diagnosis of idiopathic intracranial hypertension is based on an exclusion procedure. Most common syndromes are headache, transient visual obscurations, pulsatile tinnitus and nausea. In the presence of an underlying cause for the increased intracranial pressure one speaks of a secondary intracranial hypertension. The diagnostics include a detailed medical history, neurological and ophthalmic examination, lumbar puncture, and neuroradiological imaging procedures. MRI, in particular, has become increasingly important in recent years, since signs for changes in cerebrospinal fluid pressure are now detectable and well-defined. The therapeutic approaches are symptom-oriented and aim to lower the pressure. With a precise diagnosis and timely start of therapy, idiopathic intracranial hypertension has a good prognosis, especially with regard to the preservation of eyesight.

KEY POINTS

  · The idiopathic intracranial hypertension is an important differential diagnosis for unspecific headache and impaired vision. · Overweight women in childbearing age are particularly affected. · The most important component in diagnostics is MRI.

CITATION FORMAT

· Juhász J, Hensler J, Jansen O. MRT-Befunde bei der idiopathischen intrakraniellen Hypertension (Pseudotumor cerebri). Fortschr Röntgenstr 2021; DOI: 10.1055/a-1447-0264.

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.

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.

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.

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.

Vascular parkinsonism or idiopathic NPH? New insights from CSF pressure analysis

Differential diagnosis between vascular parkinsonism (VP) and idiopathic normal pressure hydrocephalus (iNPH) is particularly challenging due to similar clinical and neuroradiological features. The objective of this study is to differentiate VP with radiological evidence of ventricular enlargement (REVE) from iNPH on the basis of cerebrospinal fluid (CSF) hydrodynamics. CSF pressure components were investigated in patients with a clinical diagnosis of VP and REVE. Data of eight patients (seven men; age 76 ± 3.9 years; disease duration 26.5 ± 15.6 months) were evaluated. CSF opening pressure values were normal in all patients. Also, mean CSF pressure values during short-term monitoring were normal, except in one patient. Four out of the eight patients had raised values of pulse wave amplitude (PWA) during the opening phase (mean ± SD 57.1 ± 19.9 mmH₂O), meanwhile during short-term monitoring, seven out of the eight patients showed raised values of mean PWA (76.8 ± 23 mmH₂O). We found that most of patients with clinical characteristics of VP and REVE showed elevated PWA during the short-term monitoring of CSF pressure as observed in iNPH patients. Patients clinically identified as VP may be part of the clinical spectrum of iNPH.

Incidence and predictors of dural venous sinus pressure gradient in idiopathic intracranial hypertension and non-idiopathic intracranial hypertension headache patients: results from 164 cerebral venograms

OBJECTIVE Cerebral venous pressure gradient (CVPG) from dural venous sinus stenosis is implicated in headache syndromes such as idiopathic intracranial hypertension (IIH). The incidence of CVPG in headache patients has not been reported. METHODS The authors reviewed all cerebral venograms with manometry performed for headache between January 2008 and May 2015. Patient demographics, headache etiology, intracranial pressure (ICP) measurements, and radiographic and manometric results were recorded. CVPG was defined as a difference ≥ 8 mm Hg by venographic manometry. RESULTS One hundred sixty-four venograms were performed in 155 patients. There were no procedural complications. Ninety-six procedures (58.5%) were for patients with IIH. The overall incidence of CVPG was 25.6% (42 of 164 procedures): 35.4% (34 of 96 procedures) in IIH patients and 11.8% (8 of 68 procedures) in non-IIH patients. Sixty procedures (36.6%) were performed in patients with preexisting shunts. Seventy-seven patients (49.7%) had procedures preceded by an ICP measurement within 4 weeks of venography, and in 66 (85.7%) of these patients, the ICP had been found to be elevated. CVPG was seen in 8.3% (n = 5) of the procedures in the 60 patients with a preexisting shunt and in 0% (n = 0) of the 11 procedures in the 77 patients with normal ICP (p < 0.001 for both). Noninvasive imaging (MR venography, CT venography) was assessed prior to venography in 112 (68.3%) of 164 cases, and dural venous sinus abnormalities were demonstrated in 73 (65.2%) of these cases; there was a trend toward CVPG (p = 0.07). Multivariate analysis demonstrated an increased likelihood of CVPG in patients with IIH (OR 4.97, 95% CI 1.71-14.47) and a decreased likelihood in patients with a preexisting shunt (OR 0.09, 95% CI 0.02-0.44). CONCLUSIONS CVPG is uncommon in IIH patients, rare in those with preexisting shunts, and absent in those with normal ICP.

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.

Intracranial pressure in unresponsive chronic migraine

To assess the prevalence and possible pathogenetic involvement of raised intracranial pressure in patients presenting with unresponsive chronic migraine (CM), we evaluated the intracranial opening pressure (OP) and clinical outcome of a single cerebrospinal fluid withdrawal by lumbar puncture in 44 consecutive patients diagnosed with unresponsive chronic/transformed migraine and evidence of sinus stenosis at magnetic resonance venography. The large majority of patients complained of daily or near-daily headache. Thirty-eight (86.4 %) had an OP >200 mmH₂O. Lumbar puncture-induced normalization of intracranial pressure resulted in prompt remission of chronic pain in 34/44 patients (77.3 %); and an episodic pattern of headache was maintained for 2, 3 and 4 months in 24 (54.6 %), 20 (45.4 %) and 17 (38.6 %) patients, respectively. The medians of overall headache days/month and of disabling headache days/month significantly decreased (p < 0.0001) at each follow-up versus baseline. Despite the absence of papilledema, 31/44 (70.5 %) patients fulfilled the ICHD-II criteria for “Headache attributed to Intracranial Hypertension”. Our findings indicate that most patients diagnosed with unresponsive CM in specialized headache clinics may present an increased intracranial pressure involved in the progression and refractoriness of pain. Moreover, a single lumbar puncture with cerebrospinal fluid withdrawal results in sustained remission of chronic pain in many cases. Prospective controlled studies are needed before this procedure can be translated into clinical practice. Nonetheless, we suggest that intracranial hypertension without papilledema 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.

Does bilateral transverse cerebral venous sinus stenosis exist in patients without increased intracranial pressure?

OBJECTIVE

Transverse cerebral venous sinus stenosis (TSS) is common among patients with idiopathic intracranial hypertension. TSS likely also exists among individuals with normal intracranial pressure (ICP) but the prevalence is unclear. The goal of this study was to identify patients with incidental TSS and normal ICP and describe their characteristics.

METHODS

Among 240 adult patients who underwent brain magnetic resonance imaging (MRI) with magnetic resonance venography (MRV) with contrast at our institution between September 2009 and September 2011, 44 had isolated TSS without further substantial imaging abnormality. Medical records were reviewed for symptoms of increased ICP, papilledema, cerebrospinal fluid (CSF) constituents and opening pressure (OP), and reason for brain imaging. Of these, 37 were excluded for confirmed or possible idiopathic intracranial hypertension. Of the remainder, 5 had CSF-OP≤25 cmH2O without papilledema, and 2 did not have measured ICP, but had no papilledema or symptoms of increased ICP. Imaging was re-interpreted to assess for signs suggestive of elevated ICP and to characterize the TSS further.

RESULTS

All patients were women (mean age: 41, mean BMI: 37.1). CSF contents were normal, but OPs were at the upper limit of normal (22-25 cmH2O). Indications for MRI/MRV included query pituitary abnormality (1), migraine (4), and anomalous-appearing optic nerves (2). All had bilateral TSS. Six had short TSS and an empty sella; 1 had long TSS and no empty sella; 1 had flattening of the posterior sclera; 2 had prominence of peri-optic nerve CSF.

CONCLUSION

Asymptomatic bilateral TSS exists in patients with ICP≤25 cmH2O, but is likely uncommon. CSF-OP was at the upper limit of normal in our patients, who also had other radiologic signs suggestive (but not specific) of chronically-raised ICP. Findings of bilateral TSS on imaging should prompt funduscopic examination for papilledema.

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.