The Pseudotumor Cerebri Syndrome

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

Multiple skull base defects in the setting of spontaneous cerebrospinal fluid rhinorrhea; a dual institution view

PURPOSE

Idiopathic intracranial hypertension (IIH) is a condition of high cerebrospinal fluid (CSF) pressure that presents with CSF leak. The implications of multiple skull base defects (SBD) and associated synchronous CSF leaks have not been previously explored.

MATERIALS AND METHODS

A dual institutional case-control study examined multiple SBD's and encephaloceles on the risk of CSF leak and postoperative failures post-repair. IIH patients with CSF leaks and IIH controls without leaks were selected retrospectively. Chi square analysis evaluated for statistically significant alterations in probability with CSF leak development.

RESULTS

192 patients were selected with 108 IIH controls and 84 spontaneous CSF leak cases. Signs and symptoms for IIH controls and CSF leak cases respectively were pulsatile tinnitus (60.2 % and 29.8 %), headaches (96.3 % and 63.1 %), papilledema (74.1 % and 12.5 %), visual field defects (60.8 % and 13 %) (p < 0.001). Encephalocele formation in controls was 3.7 % compared to cases at 91.6 % (p < 0.001). Multiple SBD's in controls compared cases was 0.9 % and 46.4 % respectively (p < 0.001). Subgroup analysis of CSF leak cases showed 15 patients with two CSF leak repairs due to a recurrence. 27 (39.1 %) single leak cases had multiple SDB's while 12 (80 %) recurrent leaks had multiple SDB's (p = 0.004).

CONCLUSIONS

Patients with radiographic evidence of multiple SBD's and encephaloceles represent a high-risk population with a propensity for CSF leaks. Secondary SBD's are common in patients with spontaneous CSF rhinorrhea and higher in patients with a recurrence.

Seizures as the Initial Manifestation of Idiopathic Intracranial Hypertension Spectrum Disorder

Idiopathic intracranial hypertension (IIH) is a syndrome of isolated elevated intracranial pressure of unknown aetiology. The IIH spectrum has evolved over the past decade making the diagnosis and management more challenging. The neurological examination in IIH is typically normal except for papilloedema and possible cranial nerve 6 palsy. Recent publications have highlighted skull base thinning and remodelling in patients with chronic IIH. Resulting skull base defects can cause meningo-encephalocoeles, which are potential epileptogenic foci. We describe the clinical and radiological characteristics of five IIH patients with seizures and meningo-encephalocoeles as the presenting manifestations of IIH spectrum disorder.

Combined surgical repair and venous sinus stenting for patients with skull base encephaloceles secondary to dural venous sinus stenosis

BACKGROUND

Chronically elevated intracranial pressure (ICP) seen in idiopathic intracranial hypertension (IIH) can cause the development of skull base encephaloceles and cerebrospinal fluid (CSF) leaks. Surgical repair and ventriculoperitoneal shunt (VPS) placement are mainstays of treatment. Venous sinus stenting (VSS) is a newly accepted treatment modality. The goal of this study was thus to determine if VSS can be used to treat symptoms and prevent recurrence after surgical encephalocele repair.

METHODS

Retrospective chart review of patients that had surgical repair of encephaloceles followed by VSS for symptomatic stenosis with elevated pressure gradient.

RESULTS

A total of 13 patients underwent a combined encephalocele repair and VSS. Seventy-two percent were female; 46% had headaches, 69% pulsatile tinnitus, and 92% CSF rhinorrhea or otorrhea. One had seizures. Mean lumbar opening pressure was 23.3 ± 2.6 cm H2O; the average sagittal-to-jugular pressure gradient was 12.7 ± 1.8 cmH2O and was elevated in all patients. Four patients had middle fossa craniotomy for repair of tegmen defect (one bilateral); one had a retrosigmoid craniotomy for repair of a sigmoid plate defect. Eight had an endoscopic endonasal repair for sphenoid or cribriform plate encephalocele. There were no VSS procedural complications or complications associated with dual antiplatelet therapy. One patient had meningitis after endoscopic repair that was treated with antibiotics. One patient had recurrence of both CSF leak and venous stenosis adjacent to the stent requiring repeat repair and VSS. There was no further recurrence.

CONCLUSION

In patients with dural sinus stenosis and encephaloceles requiring repair, VSS can be performed safely within weeks of surgery for relief of symptoms, resolution of underlying pathology, and prevention of CSF leak recurrence.

The expanding spectrum of idiopathic intracranial hypertension

Once considered a rare and often difficult diagnosis in the era predating routine MRI, idiopathic intracranial hypertension has become an everyday concern in ophthalmology and neurology clinics where, especially in the latter, essentially every young overweight woman with headaches is initially presumed to have IIH. Has the diagnosis of IIH become too easy, and are we over-diagnosing IIH in this period of an accelerating obesity crisis? Or are we actually missing cases of IIH because they do not fit the classic clinical profile? We think it is both: at the same time IIH is being diagnosed in excess in obese women without papilledema, often resulting in unnecessary procedures, inappropriate treatment and even iatrogenic complications, the spectrum of this disorder is expanding to include a broad array of clinical presentations that involve multiple specialists beyond just the ophthalmologist and neurologist.

"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.

Spontaneous skull base cerebrospinal fluid leak during pregnancy: a case report and review of the literature

BACKGROUND

Idiopathic intracranial hypertension can lead to dural defects and spontaneous leakage of cerebrospinal fluid (CSF) from the skull base. Skull base CSF leaks are rarely reported in pregnancy but pose unique challenges for obstetricians and anesthesiologists.

CASE PRESENTATION

A 31-year-old G4P1021 at 14 weeks developed debilitating headaches and CSF rhinorrhea. Brain imaging revealed a bony defect of the sphenoid sinus with a meningoencephalocele and a partially empty sella, consistent with CSF leakage from a skull base defect. The patient was neurologically stable without signs of meningitis; thus, management was focused on symptomatic alleviation. A planned cesarean section was performed at 38 weeks under spinal anesthesia. The patient had spontaneous marked improvement of her symptoms postpartum.

CONCLUSION

Pregnancy may exacerbate skull base CSF leaks, requiring careful management with a multidisciplinary team. Neuraxial anesthesia can safely be performed in pregnant individuals with spontaneous skull base CSF leakage, but further studies are needed to determine the safest mode of delivery in these patients.

Expanding the clinical spectrum of idiopathic intracranial hypertension

PURPOSE OF REVIEW

Idiopathic intracranial hypertension (IIH) is a disorder of raised intracranial pressure (ICP). Although the majority of patients with IIH present classically with headache and papilledema, some patients may have unusual presentations or manifestations. Recent advancements in neuroimaging have facilitated the identification of other presentations associated with IIH. This review provides an overview of the expanding clinical spectrum of IIH.

RECENT FINDINGS

Presentations of IIH that are considered unusual include highly asymmetric or unilateral papilledema, IIH without papilledema, and IIH associated with cranial nerve involvement. These presentations likely reflect differences in the way cerebrospinal fluid (CSF) pressure is transmitted intracranially. Radiological signs of intracranial hypertension are increasingly recognized in patients with IIH and provide further insights into the effects of raised ICP on intracranial structures. Osseous changes in the skull base leading to formation of meningoceles and encephaloceles have been identified in patients with IIH, spontaneous skull base CSF leak, and drug-resistant temporal lobe epilepsy, suggesting a possible association.

SUMMARY

Clinicians should be familiar with the expanding clinical spectrum of IIH and the implications for the management of these presentations.

Symptoms Underestimate the Presence of Obstructive Sleep Apnea in Patients with Spontaneous Cerebrospinal Fluid Leaks of the Temporal Bone

OBJECTIVE

To determine the severity of symptoms and degree of obstructive sleep apnea (OSA) in patients with spontaneous cerebrospinal fluid (sCSF) leaks of the temporal bone given the known association between sCSF leaks and OSA.

STUDY DESIGN

Retrospective case review.

SETTING

Ambulatory clinics in tertiary referral centers.

PATIENTS

Polysomnogram testing in 34 consecutive patients who had been diagnosed with sCSF leaks of the temporal bone was examined. Diagnosis of sCSF leak was defined as biochemically confirmed CSF from middle ear fluid with no other obvious source.

INTERVENTION

Diagnostic.

MAIN OUTCOMES MEASURES

Patient characteristics (age, sex, body mass index, Epworth Sleepiness Scale score, presence of hypoxia, overnight change in blood pressure, and apnea hypopnea index [AHI]) were recorded. Diagnosis of OSA was defined as mild when AHI ≥5 and <15/h, moderate when AHI ≥15 and <30/h, and severe when AHI ≥30/h.

RESULTS

Of the 34 patients, 28 (82%) had a confirmed diagnosis of OSA. There was a male predisposition in those with OSA, and 17 of 28 (61%) were male. A majority were overweight, and the mean body mass index was 30.1 (SD, 4.8; range, 23.2-40) kg/m2. The mean severity of OSA was moderate, and the mean AHI was 28.7 (SD, 21.9; range, 5.4-92.8). Of the 28 patients, 13 with OSA (46%) had Epworth Sleepiness Scale scores higher than 8, suggesting that many were asymptomatic for excessive daytime sleepiness at the time of presentation.

CONCLUSION

OSA is highly prevalent among patients with sCSF leaks of the temporal bone. Patients with sCSF leaks irrespective of symptoms of OSA should undergo formal polysomnogram testing.

Idiopathic Intracranial Hypertension: Implications for the Otolaryngologist

Idiopathic intracranial hypertension (IIH) is a triad of headaches, visual changes, and papilledema in the absence of a secondary cause for elevated intracranial pressure. There is an association with obesity, and the incidence is rising in parallel with the obesity epidemic. Sometimes these patients present to an otolaryngologist with complaints like tinnitus, dizziness, hearing loss, and otorrhea or rhinorrhea from cerebrospinal fluid leak. IIH diagnosis in conjunction with neurology and ophthalmology, including neuroimaging and lumbar puncture with opening pressure, is key to managing of this condition. Otolaryngologists should recognize IIH as a possible diagnosis and initiate appropriate referrals and treatment.

Idiopathic Intracranial Hypertension - Challenges and Pearls

Idiopathic intracranial hypertension (IIH) is defined as a syndrome of raised intracranial pressure with normal imaging of the brain and cerebrospinal fluid (CSF) composition. There is a rising incidence and prevalence of this disease related to the increased prevalence of obesity. It typically affects women of working age, and headache is the predominant morbidity in over 90%. The disease is also more prevalent in young males. There are many controversies and myths that surround IIH. There are currently few treatment options for IIH, management is typically medical with those experiencing progressive visual loss undergoing surgical procedures. Weight loss and venous sinus stenting are a few therapies directed at the etiology.

Imaging of Acquired Skull Base Cerebrospinal Fluid Leaks

Acquired skull base cerebrospinal fluid (CSF) leaks can result from trauma, tumors, iatrogenic causes, or may be spontaneous. Spontaneous skull base CSF leaks are likely a manifestation of underlying idiopathic intracranial hypertension. The initial assessment of rhinorrhea or otorrhea which is suspected to be due to an acquired skull base CSF leak requires integration of clinical assessment and biochemical confirmation of CSF. Imaging with high-resolution CT is performed to locate osseous defects, while high-resolution T2w MRI may detect CSF traversing the dura and bony skull base. When leaks are multiple or if samples of fluid cannot be obtained for testing, then recourse to invasive cisternography may be necessary.

MR findings suggestive of idiopathic intracranial hypertension in 117 patients with spontaneous cerebrospinal fluid rhinorrhea

PURPOSE

The purpose of this study is to document the prevalence of MR findings suggestive of idiopathic intracranial hypertension (IIH) in patients undergoing endoscopic repair of spontaneous CSF rhinorrhea (SCSFR).

METHODS

In a retrospective study, MR images of 117 consecutive patients who had undergone endoscopic repair of SCSFR were evaluated for features suggestive of IIH (empty sella, widened optic nerve sheath, tortuous optic nerve, flattened posterior globe, and enlarged Meckel's cave). Pituitary height was used to diagnose partial and complete empty sella. MR images were independently evaluated by two of the authors without knowledge of the clinical findings. Consensus method was used to resolve differences between the two evaluators.

RESULTS

Empty or partially empty sella was diagnosed in the MR of 105 (89.7%) patients. In 38/105 (36.2%) patients with empty/partial empty sella, no additional MR findings were present. In 43/105 (41%) patients, one or more of the MR features with high specificity for diagnosis of IIH (flattened posterior globe and enlarged Meckel's cave) were seen. In the other 24 (22.9%) additional MR findings, less specific for IIH (widened optic nerve sheath, tortuous optic nerve) were noted. Papilledema was seen in 11 of 60 (18.3%) patients who underwent funduscopic examination. All patients with papilledema had empty/partial empty sella, and 9/11 (81.8%) had an additional MR finding suggestive of IIH.

CONCLUSION

The majority of patients with SCSFR have MR imaging features of IIH. These imaging features should be a major component of previously published modified diagnostic criteria for IIH in patients with SCSFR.

Transverse sinus stenting without surgical repair in idiopathic CSF rhinorrhea associated with transverse sinus stenoses: a pilot study

OBJECTIVE

Based on their clinical and radiological patterns, idiopathic CSF rhinorrhea and idiopathic intracranial hypertension can represent different clinical expressions of the same underlying pathological process. Transverse sinus stenoses are associated with both diseases, resulting in eventual restriction of the venous CSF outflow pathway. While venous sinus stenting has emerged as a promising treatment for idiopathic intracranial hypertension, its efficiency on idiopathic CSF leaks has not been very well addressed in the literature so far. The purpose of this study was to report the results of transverse sinus stenting in patients with spontaneous CSF rhinorrhea associated with transverse sinus stenoses.

METHODS

From a prospectively collected database, the authors retrospectively collected the clinical and radiological features of the patients with spontaneous CSF leakage who were treated with venous sinus stenting.

RESULTS

Five female patients were included in this study. Transverse sinus stenoses were present in all patients, and other radiological signs of idiopathic intracranial hypertension were present in 4 patients. The median transstenotic pressure gradient was 6.5 mm Hg (range 3-9 mm Hg). Venous stenting resulted in the disappearance of the leak in 4 patients with no recurrence and no subsequent meningitis during the follow-up (median 12 months, range 6-63 months).

CONCLUSIONS

According to the authors' results, venous sinus stenting may result in the disappearance of the leak in many cases of idiopathic CSF rhinorrhea. Larger comparative studies are needed to assess the efficiency and safety of venous stenting as a first-line approach in patients with spontaneous CSF rhinorrhea associated with transverse sinus stenoses.

Imaging Characteristics of Sigmoid Sinus Wall Anomalies, Idiopathic Intracranial Hypertension, and Spontaneous CSF Leaks

OBJECTIVE

To assess the frequency of radiographic features of elevated intracranial pressure (ICP) in patients with sigmoid sinus wall anomalies (SSWA) and compare to those in idiopathic intracranial hypertension (IIH) and spontaneous CSF (sCSF) leaks.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary care center.

PATIENTS

110 patients - 62 SSWAs, 19 IIH, 29 sCSF leaks.

MAIN OUTCOME MEASURES

Demographics, comorbidities and radiographic features by diagnosis.

RESULTS

Imaging findings indicative of elevated ICP were similar across all three groups, as were body mass index, hyperlipidemia and diabetes. On univariate analysis, sCSF leak patients were significantly older than SSWA (60 vs. 41 years, p < 0.001) and IIH (60 vs. 40 years, p < 0.001) patients. They had a greater prevalence of arachnoid granulations than SSWA (75.8% vs. 37.1%, p < 0.01) and tegmen dehiscence than both SSWA and IIH (93.1% vs. 75.8% vs. 57.8%, p = 0.01), though a lower prevalence of empty sella than SSWA (44.8% vs. 72.5%, p < 0.001). SSWAs were present in roughly 44.3% of IIH and sCSF leak patients, and IIH in roughly 15.8% of SSWA and sCSF leak patients. Age (OR = 1.1, p = 0.001), hypertension (OR = 8.3, p = 0.01) and empty sella (OR = 0.1, p = 0.01) were predictive of sCSF leaks compared to SSWAs on multivariate analysis.

CONCLUSIONS

Many radiographic and clinical features of elevated ICP are found at similar rates among patients with SSWA, IIH and sCSF leaks, suggesting a common underlying process. SSWAs seem to present earlier along this spectrum of phenotypes, while sCSF leaks present later. Differences in age, metabolic syndrome and ICP may influence a patient's clinical presentation.

Modified Transpterygoid Approach to Sphenoid Meningoencephaloceles: A Shorter Run for a Longer Slide

OBJECTIVES

Cerebrospinal fluid (CSF) leaks and meningoencephaloceles originating in the lateral recess of the sphenoid sinus can be challenging. The traditional transpterygoid approach through the pterygopalatine fossa (PPF) is time consuming and places important structures at risk, which can lead to significant morbidity. We report a multi-institutional experience using a simplified, endoscopic modified transpterygoid approach (MTPA), which spares the PPF contents in the management of lateral sphenoid sinus meningoencephaloceles and CSF leaks.

STUDY DESIGN

Multi-Institutional, Retrospective Case Series.

METHODS

Patients with lateral sphenoid recess CSF leaks and meningoencephaloceles between 2014 and 2020 who underwent the MTPA at two academic medical centers were identified. Repair techniques and outcomes were evaluated.

RESULTS

Thirty-three patients underwent the MTPA for management. Skull base reconstruction was performed using a free mucosal graft (24/33, 72.7%), nasoseptal flap (4/33, 12.1%), bone grafts (3/33, 9.1%), and abdominal fat grafts (2/33, 6.1%). Lumbar drains and perioperative intracranial pressure measurements were routinely employed. Postoperative complications were uncommon and included three patients (9.7%) with temporary V2 anesthesia, one patient (3.2%) with prolonged V2 anesthesia, and one patient (3.2%) with subjective dry eye, all of which resolved at 9 months postoperatively. There were no recurrent CSF leaks resulting in a 100% success rate. Average follow-up was 13 months.

CONCLUSION

The MTPA reduces morbidity and greatly simplifies access to the lateral sphenoid sinus for the management of CSF leaks and meningoencephaloceles, without compromising exposure. This technique avoids the need for extensive PPF dissection and should be considered for the management of benign lesions involving the lateral sphenoid sinus.

LEVEL OF EVIDENCE

IV Laryngoscope, 2021.

A Unique Subset: Idiopathic Intracranial Hypertension Presenting as Spontaneous CSF Leak of the Anterior Skull Base

Introduction Spontaneous cerebrospinal fluid (CSF) leaks represent a unique clinical presentation of idiopathic intracranial hypertension (IIH), lacking classical features of IIH, including severe headaches, papilledema, and markedly elevated opening pressures.

Methods Following a single-institution retrospective review of patients undergoing spontaneous CSF leak repair, we performed a literature review of spontaneous CSF leak in patients previously undiagnosed with IIH, querying PubMed.

Results Our literature review yielded 26 studies, comprising 716 patients. Average age was 51 years with 80.8% female predominance, and average body mass index was 35.5. Presenting symptoms included headaches (32.5%), visual disturbances (4.2%), and a history of meningitis (15.3%). Papilledema occurred in 14.1%. An empty sella was present in 77.7%. Slit ventricles and venous sinus stenosis comprised 7.7 and 31.8%, respectively. CSF leak most commonly originated from the sphenoid sinus (41.1%), cribriform plate (25.4%), and ethmoid skull base (20.4%). Preoperative opening pressures were normal at 22.4 cm H2O and elevated postoperatively to 30.8 cm H2O. 19.1% of patients underwent shunt placement. CSF leak recurred after repair in 10.5% of patients, 78.6% involving the initial site. A total of 85.7% of these patients were managed with repeat surgical intervention, and 23.2% underwent a shunting procedure.

Conclusion Spontaneous CSF leaks represent a distinct variant of IIH, distinguished by decreased prevalence of headaches, lack of visual deficits, and normal opening pressures. Delayed measurement of opening pressure after leak repair may be helpful to diagnose IIH. Permanent CSF diversion may be indicated in patients exhibiting significantly elevated opening pressures postoperatively, refractory symptoms of IIH, or recurrent CSF leak.

Atypical presentations of idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a disorder of unknown etiology that results in isolated raised intracranial pressure. Classic symptoms and signs of IIH include headache, papilledema, diplopia from sixth nerve palsy and divergence insufficiency, and pulsatile tinnitus. Atypical presentations include: (1) highly asymmetric or even unilateral papilledema, and IIH without papilledema; (2) ocular motor disturbances from third nerve palsy, fourth nerve palsy, internuclear ophthalmoplegia, diffuse ophthalmoplegia, and skew deviation; (3) olfactory dysfunction; (4) trigeminal nerve dysfunction; (5) facial nerve dysfunction; (6) hearing loss and vestibular dysfunction; (7) lower cranial nerve dysfunction including deviated uvula, torticollis, and tongue weakness; (8) spontaneous skull base cerebrospinal fluid leak; and (9) seizures. Although atypical findings should raise a red flag and prompt further investigation for an alternative etiology, clinicians should be familiar with these unusual presentations.