Atypical Presentations of Intracranial Hypotension: Comparison with Classic Spontaneous Intracranial Hypotension

Spontaneous intracranial hypotension

Spontaneous intracranial hypotension (SIH) is a highly disabling but treatable secondary cause of headache. Recent progress in neuroradiological techniques has catalysed understanding of its pathophysiological basis and clinical diagnosis, and facilitated the development of more effective investigation and treatment methods. A UK-based specialist interest group recently produced the first multidisciplinary consensus guideline for the diagnosis and treatment of SIH. Here, we summarise a practical approach to its clinical and radiological diagnosis, symptomatic and non-targeted interventional treatment, radiological identification of leak site and targeted treatment of the leak once it has been localised.

Real-life study of the use of oto-acoustic emissions in the diagnosis of intracranial hypotension

BACKGROUND

The diagnosis of spontaneous or post-traumatic intracranial hypotension (IH) mainly relies on clinical features and neuro-imaging. However, the results of brain and spine magnetic resonance imaging are not always contributive. There is an interest for other non-invasive procedures, able to confirm or refute the diagnosis. The use of oto-acoustic emissions (OAE) was previously reported on isolated cases of IH associated with endolymphatic hydrops (ELH). The aim of this study was to assess the real-life utilization of this electrophysiological method in a larger population of suspected IH.

METHODS

A retro-prospective cohort study was conducted from November 2013 to July 2022 in patients with a suspected or doubtful diagnosis of IH. They were assessed for ELH by recording bilateral distortion product of oto-acoustic emissions (DPOAE) in sitting then in supine position.

RESULTS

Among the 32 patients assessed, the diagnostic of IH was confirmed in 18 patients. An ELH was shown in 15 of them (83%), but also in seven other patients. They had several differential diagnoses: chronic migraine, Chiari malformation, rebound intracranial hypertension and perilymph fistula.

CONCLUSIONS

This procedure seems to be insufficient to exclude differential diagnosis when intracranial hypotension is suspected.

Patient-reported symptomatology and its course in spontaneous intracranial hypotension - Beware of a chameleon

OBJECTIVE

Although orthostatic headache is the hallmark symptom of spontaneous intracranial hypotension (SIH), patients can present with a wide range of different complaints and thereby pose a diagnostic challenge for clinicians. Our aim was to describe and group the different symptoms associated with SIH and their course over time.

METHODS

We retrospectively surveyed consecutive patients diagnosed and treated for SIH at our institution from January 2013 to May 2020 with a specifically designed questionnaire to find out about their symptomatology and its course.

RESULTS

Of 112 eligible patients, 79 (70.5%) returned the questionnaire and were included in the analysis. Of those, 67 (84.8%) reported initial orthostatic headaches, whereas 12 (15.2%) denied having this initial symptom. All except one (98.7%) patients reported additional symptoms: most frequently cephalic pressure (69.6%), neck pain (68.4%), auditory disturbances (59.5%), nausea (57%), visual disturbances (40.5%), gait disturbance (20.3%), confusion (10.1%) or sensorimotor deficits (21.5%). Fifty-seven (72.2%) patients reported a development of the initial symptoms predominantly in the first three months after symptom onset. Age and sex were not associated with the symptomatology or its course (p > 0.1).

CONCLUSION

Although characteristic of SIH, a relevant amount of patients present without orthostatic headaches. In addition, SIH can manifest with non-orthostatic headaches at disease onset or during the course of the disease. Most patients report a wide range of associated complaints. A high degree of suspicion is crucial for an early diagnosis and targeted treatment.

Brain Sagging Dementia

PURPOSE OF REVIEW

Brain sagging dementia (BSD) is a rare but devastating form of early-onset dementia characterized by intracranial hypotension and behavioral changes resembling behavioral variant frontotemporal dementia. This review aims to provide a comprehensive overview of BSD, highlighting its pathomechanism, diagnostic tools, and available treatment options.

RECENT FINDINGS

BSD exhibits a complex clinical manifestation with insidious onset and gradual progression of behavioral disinhibition, apathy, inertia, and speech alterations. Additionally, patients may exhibit brainstem and cerebellar signs such as hypersomnolence and gait disturbance. Although headaches are common, they may not always demonstrate typical orthostatic features. Recent radiological advances have improved the detection of CSF leaks, enabling targeted treatment and favorable outcomes. Understanding the pathomechanism and available diagnostic tools for BSD is crucial for a systematic approach to timely diagnosis and treatment of this reversible form of early-onset dementia, as patients often endure a complex and lengthy clinical course.

When does too little pressure become too much? A case of spontaneous intracranial hypotension presenting with acute loss of consciousness

Background

We present a unique case of spontaneous intracranial hypotension (SIH) presenting with acute collapse and loss of consciousness.

Case Description

The affected patient suffered an abrupt decline in level of consciousness several weeks after initial diagnosis. The patient was urgently transferred to a specialist neurosurgical unit. Imaging showed bilateral subdural fluid collections with significant associated local mass effect. The treating team faced a clinical conundrum with a lack of clarity as to whether this sudden deterioration was secondary to the local pressure effect on brainstem traction from reduced intracranial pressure. A decision was made to proceed with urgent burr-hole decompression of the bilateral subdural fluid collections.

Conclusion

After a protracted, complex postoperative course, the patient recovered to full functional independence. To the author's knowledge, this is the first case in literature describing successful surgical management of SIH, with bilateral burr-hole evacuation to relieve the paradoxical mass effect of bilateral subdural fluid collections.

Cerebrospinal Venous Fistula Presenting with Cognitive Decline: Systematic Literature Review and Report of Two Cases

OBJECTIVE

A cerebrospinal fluid (CSF) venous fistula (CVF) is an aberrant connection between the subarachnoid space and a vein resulting in CSF loss. The presentation and management of CVF with cognitive decline is incompletely understood.

METHODS

A systematic review was completed following the PRISMA guidelines. Articles that included at least 1 case of imaging-confirmed CVF with details on patient treatment were included. A separate review of cases of patients with spontaneous intracranial hypotension (SIH) with frontotemporal dementia (FTD) or dementia symptoms was also completed.

RESULTS

Ten CVF articles (69 patients; average age, 51.5 years) and 5 SIH with FTD or dementia articles (n = 41; average age, 55.9 years) were identified. Only 1 patients with CVF with cognitive abnormalities was identified. The most common symptom was headache in both reviews. Brain sag was identified in all patients, whereas CSF leak was identified in only 2 patients with SIH with FTD or dementia (4.9%). An epidural blood or fibrin glue patch was used in all patients with CVF and in 33 patients with SIH with FTD or dementia. Fifty-five patients with CVF (79.7%) and 27 patients with SIH with FTD or dementia (65.9%) had surgery.

CONCLUSIONS

The 2 cases and literature reviews show the difficulty in diagnosis and treatment of CVF with cognitive decline. Novel imaging techniques should be used in patients with cognitive decline in whom a CSF leak is suspected. Transvenous embolization or surgery should be considered before patching for treatment of CVF-induced brain sag and resulting dementia.

Case report: Post-traumatic Tourette syndrome resolving with treatment of jugular venous narrowing; reconciling organic brain dysfunction following whiplash trauma with the absence of direct brain injury

We describe a man aged 33 years who developed multiple symptoms, personality change, and a severe tic disorder following a road traffic accident, which were undiminished for 3 years until jugular venous narrowing between the styloid process of the skull and the transverse process of the C1 vertebra was treated by surgical decompression. Immediately following surgery, his abnormal movements almost completely resolved, with no regression in 5 years of follow-up. Vigorously debated at the time was whether or not his condition represented a functional disorder. Unrecognized throughout his illness, however, was a complaint of intermittent, profuse discharge of clear fluid from his nose that began on the day of the accident and continued up to the time of surgery, after which it was substantially reduced. This outcome reinforces the idea that jugular venous narrowing can cause or perpetuate a cerebrospinal fluid leak. It suggests that the interaction between these two pathological defects may have a profound effect on brain function in the absence of any demonstrable brain lesion. It invites a reevaluation of normal head and neck venous anatomy. It should strike a cautionary note in the diagnosis of functional illness. It invites exploration of a remediable structural cause for Tourette syndrome.

Spontaneous intracranial hypotension: updates from diagnosis to treatment

Spontaneous intracranial hypotension (SIH) is caused by spinal cerebrospinal fluid (CSF) leaks, which result in continued loss of CSF volume and multiple debilitating clinical manifestations. The estimated annual incidence of SIH is 5/100,000. Diagnostic methods have evolved in recent years due to improved understanding of pathophysiology and implementation of advanced myelographic techniques. Here, we synthesize recent updates and contextualize them in an algorithm for diagnosis and treatment of SIH, highlighting basic principles and points of practice variability or continued debate. This discussion includes finer points of SIH diagnosis, CSF leak classification systems, less common types and variants of CSF leaks, brain MRI Bern scoring, potential SIH complications, key technical considerations, and positioning strategies for different types of dynamic myelography. The roles of conservative measures, non-targeted or targeted blood patches, surgery, and recently developed endovascular techniques are presented.

The reversible impairment of behavioral variant frontotemporal brain sagging syndrome: Challenges and opportunities

Introduction

Due to loss of brain buoyancy, spontaneous spinal cerebrospinal fluid (CSF) leaks cause orthostatic headaches but also can cause symptoms indistinguishable from behavioral variant frontotemporal dementia (bvFTD) due to severe brain sagging (including the frontal and temporal lobes), as visualized on brain magnetic resonance imaging. However, the detection of these CSF leaks may require specialized spinal imaging techniques, such as digital subtraction myelography (DSM).

Methods

We performed DSM in the lateral decubitus position under general anesthesia in 21 consecutive patients with frontotemporal dementia brain sagging syndrome (4 women and 17 men; mean age 56.2 years [range: 31-70 years]).

Results

Nine patients (42.8%) were found to have a CSF-venous fistula, a recently discovered type of CSF leak that cannot be detected on conventional spinal imaging. All nine patients underwent uneventful surgical ligation of the fistula. Complete or near-complete and sustained resolution of bvFTD symptoms was obtained by all nine patients, accompanied by reversal of brain sagging, but in only three (25.0%) of the twelve patients in whom no CSF-venous fistula could be detected (P = 0.0011), and who were treated with non-targeted therapies.

Discussion

Concerns about a spinal CSF leak should not be dismissed in patients with frontotemporal brain sagging syndrome, even when conventional spinal imaging is normal. However, even with this specialized imaging the source of the loss of spinal CSF remains elusive in more than half of patients.

Secondary Headache Disorders: Approach, Workup, and Special Considerations for Select Populations

Headache is one of the most common diagnoses in neurology. A thorough understanding of the clinical presentation of secondary headache, which can be life-threatening, is critical. This review provides an overview of the diagnostic approach to a patient with headache, including discussion of "red," "orange," and "green" flags. We emphasize particular scenarios to help tailor the clinical workup to individual circumstances such as in pregnant women, when particular attention must be paid to the effects of blood pressure and hypercoagulability, as well as in older adults, where there is a need for higher suspicion for an intracranial mass lesion or giant cell arteritis. Patients with risk factors for headache secondary to alterations in intracranial pressure, whether elevated (e.g., idiopathic intracranial hypertension) or decreased (e.g., cerebrospinal fluid leak), may require more specific diagnostic testing and treatment. Finally, headache in patients with COVID-19 or long COVID-19 is increasingly recognized and may have multiple etiologies.

Role of MRI and CT in the Evaluation of Headache in Pregnancy and the Postpartum Period

Approximately 35% of acute headaches in pregnant women are secondary to an underlying condition. Headaches are also common in the postpartum period where they occur in 30% to 40% of patients. The majority of secondary headaches are due to hypertensive disorders: preeclampsia-eclampsia, posterior reversible encephalopathy syndrome, and acute arterial hypertension. Other causes include reversible cerebral vasoconstriction syndrome and pituitary apoplexy, as well as life-threatening conditions such as cerebral venous thrombosis. In this article, we review general recommendations for imaging the pregnant patients and discuss the imaging findings of common causes of headaches in pregnancy and the postpartum period.

Brain Sagging Dementia -- Diagnosis, Treatment, and Outcome: A Review

Brain sagging dementia (BSD), caused by spontaneous intracranial hypotension (SIH), is a rare syndrome that is only recently recognized, mimicking the clinical findings of behavioral variant frontotemporal dementia (bvFTD). Being aware of its signs and symptoms is essential for early diagnosis and treatment in this potentially reversible form of dementia. Our objective was to identify cases with BSD in the literature and present its clinical characteristics, diagnostic workup, treatment options, and outcome.The review was reported according to PRISMA guidelines and registered with the PROSPERO database (CRD42020150709). MEDLINE, EMBASE, PsychINFO, and Cochrane Library were searched. There was no date restriction. The search was updated in April 2021.A total of 983 articles were screened and assessed for eligibility. Twenty-nine articles (25 case reports and four series) and 70 patients were selected for inclusion. No cranial leak cases were identified. BSD diagnosis should be made based on clinical signs and symptoms and radiological findings. There is a male predominance (F: M ratio 1:4) and a peak incidence in the 6^th decade of life. The main clinical manifestation is insidious onset, gradually progressive cognitive and behavioral changes characteristic for bvFTD. Headache is present in the majority of patients (89%). The presence of brain sagging and absence of frontotemporal atrophy is an absolute criterion for the diagnosis. The CSF leak is identified with myelography and digital subtraction myelography. The treatment and repair depend on the etiology and extent of the dural defect, although an epidural blood patch is the first-line treatment in most cases. With treatment, 81% experienced partial and 67% complete resolution of their symptoms. This review highlights the most important clinical aspects of BSD. Due to the sparse evidence and lack of BSD awareness, many patients are most likely left undiagnosed. Recognizing this condition is essential to provide early treatment to reverse the cognitive and behavioral changes that may otherwise progress and fully impair the patient. Moreover, patients with longstanding SIH must be carefully assessed for cognitive and behavioral changes.

Parkinsonism and cerebrospinal fluid disorders

BACKGROUND

Although various motor manifestations can be seen in patients with cerebrospinal fluid (CSF) disorders, such as hydrocephalus or intracranial hypotension, the clinical presentation with parkinsonism is not clearly elucidated.

METHODS

We searched the literature for studies describing the occurrence of parkinsonism in subjects with normal pressure hydrocephalus (NPH), obstructive hydrocephalus, and intracranial hypotension. We analyzed the clinical presentation (particularly with respect to bradykinesia, rigidity, rest tremor, and gait disturbance/postural instability) as well as the response to treatment.

RESULTS

Parkinsonism was most commonly reported in NPH patients. Although gait disturbance/postural instability is a well-known motor symptom of NPH, other cardinal signs include upper limb involvement or asymmetric presentation. As for obstructive hydrocephalus, parkinsonism was mainly observed in subjects with aqueductal stenosis and more often after shunt surgery. Patients with NPH or obstructive hydrocephalus rarely improved with levodopa therapy, while most subjects only improved with shunt surgery. Although the mechanism is still controversial, a functional involvement of nigrostriatal pathway has been hypothesized based on imaging studies and case reports. Brain imaging is also helpful for atypical cases of intracranial hypotension presenting with parkinsonism. Parkinsonism improved after treatment in such cases as well.

CONCLUSIONS

Studies exploring the relationship between CSF disorders and parkinsonism are mainly descriptive and their quality is generally poor. However, considering that these disorders can be treated, clinicians' awareness of the differential diagnosis is important and future studies better exploring the underlying pathophysiological mechanisms are warranted. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Spontaneous intracranial hypotension: diagnostic and therapeutic workup

Spontaneous intracranial hypotension (SIH) is an orthostatic headache syndrome with typical MRI findings among which engorgement of the venous sinuses, pachymeningeal enhancement, and effacement of the suprasellar cistern have the highest diagnostic sensitivity. SIH is in almost all cases caused by spinal CSF leaks. Spinal MRI scans showing so-called spinal longitudinal extradural fluid (SLEC) are suggestive of ventral dural tears (type 1 leak) which are located with prone dynamic (digital subtraction) myelography. As around half of the ventral dural tears are located in the upper thoracic spine, additional prone dynamic CT myelography is often needed. Leaking nerve root sleeves typically associated with meningeal diverticulae (type 2 leaks) and CSF-venous fistulas (type 3 leaks) are proven via lateral decubitus dynamic digital subtraction or CT myelography: type 2 leaks are SLEC-positive if the tear is proximal and SLEC-negative if it is distal, and type 3 leaks are always SLEC-negative. Although 30–70% of SIH patients show marked improvement following epidural blood patches applied via various techniques definite cure mostly requires surgical closure of ventral dural tears and surgical ligations of leaking nerve root sleeves associated with meningeal diverticulae or CSF-venous fistulas. For the latter, transvenous embolization with liquid embolic agents via the azygos vein system is a novel and valuable therapeutic alternative.

Spontaneous intracranial hypotension presenting with progressive cognitive decline

A 63-year-old woman presented with headache, progressive somnolence, neurocognitive decline and urinary incontinence through a year. Medical history was unremarkable except for hypertension and hypercholesterolaemia. Neurological examination was normal. Brain MRI showed findings typical for spontaneous intracranial hypotension (subdural fluid collection, pachymeningeal enhancement, brain sagging) and pituitary tumour. The patient's complaints improved dramatically but temporarily after treatment with each of repeated targeted as well as non-targeted blood patches and a trial with continuous intrathecal saline infusion. Extensive work up including repeated MRI-scans, radioisotope cisternographies, CT and T2-weighted MR myelography could not localise the leakage, but showed minor root-cysts at three levels. Finally, lateral decubitus digital subtraction dynamic myelography with subsequent CT myelography identified a tiny dural venous fistula at the fourth thoracic level. After surgical venous ligation, the patient fully recovered. Awareness of spontaneous dural leaks and their heterogeneous clinical picture are important and demands an extensive workup.

Comparisons of clinical characteristics, brain MRI findings, and responses to epidural blood patch between spontaneous intracranial hypotension and post-dural puncture headache: retrospective study

BACKGROUND

Spontaneous intracranial hypotension and post-dural puncture headache are both caused by a loss of cerebrospinal fluid but present with different pathogeneses. We compared these two conditions concerning their clinical characteristics, brain imaging findings, and responses to epidural blood patch treatment.

METHODS

We retrospectively reviewed the records of patients with intracranial hypotension admitted to the Neurology ward of the Pusan National University Hospital between January 1, 2011, and December 31, 2019, and collected information regarding age, sex, disease duration, hospital course, headache intensity, time to the appearance of a headache after sitting, associated phenomena (nausea, vomiting, auditory symptoms, dizziness), number of epidural blood patch treatments, and prognosis. The brain MRI signs of intracranial hypotension were recorded, including three qualitative signs (diffuse pachymeningeal enhancement, venous distention of the lateral sinus, subdural fluid collection), and six quantitative signs (pituitary height, suprasellar cistern, prepontine cistern, mamillopontine distance, the midbrain-pons angle, and the angle between the vein of Galen and the straight sinus).

RESULTS

A total of 105 patients (61 spontaneous intracranial hypotension patients and 44 post-dural puncture headache patients) who met the inclusion criteria were reviewed. More patients with spontaneous intracranial hypotension required epidural blood patch treatment than those with post-dural puncture headache (70.5% (43/61) vs. 45.5% (20/44); p = 0.01) and the spontaneous intracranial hypotension group included a higher proportion of patients who underwent epidural blood patch treatment more than once (37.7% (23/61) vs. 13.6% (6/44); p = 0.007). Brain MRI showed signs of intracranial hypotension in both groups, although the angle between the vein of Galen and the straight sinus was greater in the post-dural puncture headache group (median [95% Confidence Interval]: 85° [68°-79°] vs. 74° [76°-96°], p = 0.02).

CONCLUSIONS

Patients with spontaneous intracranial hypotension received more epidural blood patch treatments and more often needed multiple epidural blood patch treatments. Although both groups showed similar brain MRI findings, the angle between the vein of Galen and the straight sinus differed significantly between the groups.

Spontaneous Intracranial Hypotension

PURPOSE OF REVIEW

Spontaneous intracranial hypotension is a disorder caused by spinal CSF leakage. This article reviews the clinical presentation, diagnosis, and treatment of spontaneous intracranial hypotension.

RECENT FINDINGS

The hallmark symptom of spontaneous intracranial hypotension is acute orthostatic headache; however, clinical presentations can be heterogeneous. New evidence shows that lumbar puncture is not always necessary or sufficient to establish the diagnosis. Some patients may have normal opening pressure, which suggests that insufficiency of CSF volume (hypovolemia) rather than CSF pressure might be the underlying mechanism. Several neuroimaging modalities can aid in diagnosis and localization of the CSF leakage, including brain MRI, spinal MRI, CT myelography, digital subtraction myelography, and radionuclide cisternography. Complications, such as subdural hematoma, can lead to a change in the headache pattern and potentially life-threatening consequences. Conservative treatments, such as fluid supplementation, can provide temporary relief; however, epidural blood patches, especially targeted ones, are more effective and definitive. For patients with refractory spontaneous intracranial hypotension, surgical repair of spinal CSF leakages should be considered.

SUMMARY

Brain and spinal MRIs are important for the diagnosis and treatment of patients with spontaneous intracranial hypotension. Early treatment with epidural blood patches may be considered to shorten the disease duration and minimize the potential risk of complications.

Delayed recurrence of spontaneous intracranial hypotension syndrome mimicking a Chiari I malformation: Case report with a review of the literature

INTRODUCTION

Cerebellar tonsils descent seen on brain MRI is, along with other findings, a recognized radiological sign of possible spontaneous intracranial hypotension (SIH). The short-term outcome of SIH is usually favorable with symptoms improvement and reversibility of the low-lying tonsils. Nevertheless, data on the long-term outcome are lacking or inconsistent.

CASE REPORT

A 32-year-old woman presented to her general practitioner with a six months history of non-specific headaches. An MRI brain with gadolinium showed a 12mm tonsillar descent with no other remarkable findings. Headaches were initially managed conservatively as migraines. Following the onset of progressive upper back and shoulder pain at rest, nausea, photophobia and fogging in her vision, the patient was referred to our Department with a suspicion of symptomatic Chiari I malformation. After an in-depth anamnesis, it emerged a previous history of SIH, 14 years earlier, successfully treated conservatively in another center. A whole spine MRI confirmed the suspicion of recurrent SIH showing an anterior cervico-thoracic epidural fluid collection. The patient underwent an epidural blood patch with complete resolution of the symptoms and radiological signs.

DISCUSSION

To our knowledge, this case is the first report of delayed recurrence of a SIH successfully treated conservatively over 10 years earlier. The etiopathogenesis and management of this rarity with literature review is discussed.

CONCLUSION

An isolated cerebellar tonsil descent with no other remarkable findings on brain MRI and a previous history of SIH should always alert the clinician of a possible late recurrence of a CSF leak and avoid unnecessary Chiari I malformation surgical procedures.

Spinal cerebrospinal fluid leak in the context of pars interarticularis fracture

Background

Spinal cerebrospinal fluid (CSF) leak can lead to intracranial hypotension and is an important differential diagnosis to consider in patients with sudden-onset chronic daily headaches. Pars interarticularis (PI) fracture is a potential rare cause of suspected spinal CSF leak.

Methods

This is a retrospective case series of 6 patients with suspected spinal CSF leak evaluated between January 2016 and September 2019. All patients received a magnetic resonance imaging (MRI) of the brain with and without gadolinium, MRI whole spine and full spine computed tomography (CT) myelogram. Targeted epidural patches with fibrin sealant were performed. Treatment response at return visit (3 months post-patch) was documented.

Results

Six patients (4 females, 2 males) were diagnosed with a suspected spinal CSF leak and PI fracture. Mean age at the time of headache onset was 39 years old, and a range from 32 to 50 years old. Mean time to targeted epidural patches with fibrin sealant was 4.5 years. All 6 patients had PI fractures identified on CT myelogram and received targeted epidural patches with fibrin sealant at the site of the PI fracture. All patients had significant improvement in their headache intensity.

Conclusion

Our study highlights: 1) the importance of PI fracture as a possible culprit of suspected spinal CSF leak in patients with intracranial hypotension; 2) the added benefit of CT imaging for detecting bony abnormalities such as fractures in patients with intracranial hypotension; and 3) the successful treatment of suspected spinal CSF leak when targeting the fracture site.

Frontotemporal brain sagging syndrome: Craniospinal hypovolemia secondary to a T6-T7 cerebrospinal fluid-venous fistula

Background:

The frontotemporal brain sagging syndrome (FTBSS) is defined as an insidious/progressive decline in behavior and executive functions, hypersomnolence, and orthostatic headaches attributed to cerebrospinal fluid (CSF) hypovolemia. Here, a T6 CSF-venous fistula (e.g., between the subarachnoid CSF and a paraspinal vein) resulted in a CSF leak responsible for craniospinal hypovolemia.

Case Description:

A 56-year-old male started with orthostatic headaches and fatigue after scuba diving. His symptoms included progressive, vertigo, tinnitus, nausea, lack of judgment, inappropriate behavior, memory dysfunction, apathy, tremor, orofacial dyskinesia, dysarthria, dysphagia, and hypersomnolence. The lumbar puncture revealed an opening pressure of 0 cm H2O. Magnetic resonance imaging (MRI) findings included brain sagging, bilateral temporal lobe herniation, and pachymeningeal enhancement. The computed tomography (CT) myelogram showed a thoracic diverticulum and a CSF-venous leak at the T6-T7 level. Surgery, which comprised a T6-T7 laminotomy, allowed for dissecting, clipping, and ligating the diverticulum/fistula. The patient improved postoperatively (e.g., cognitive, behavioral, and brainstem symptoms). The follow-up MRI’s showed the reversion of the sagging index/uncal herniation.

Conclusion:

The FTBSS should be considered in the differential diagnosis of an early onset frontotemporal dementia. Establishing the diagnosis and localizing the site of a spinal CSF/venous leak warrant both MRI and myelogram CT studies, to pinpoint the CSF leak site for proper surgical clipping/ligation of these thoracic diverticulum/CSF-venous leaks.

Assessing Spinal Cerebrospinal Fluid Leaks in Spontaneous Intracranial Hypotension With a Scoring System Based on Brain Magnetic Resonance Imaging Findings

Importance

Various signs may be observed on brain magnetic resonance imaging (MRI) in patients with spontaneous intracranial hypotension (SIH). However, the lack of a classification system integrating these findings limits decision making in clinical practice.

Objective

To develop a probability score based on the most relevant brain MRI findings to assess the likelihood of an underlying spinal cerebrospinal fluid (CSF) leak in patients with SIH.

Design, Setting, and Participants

This case-control study in consecutive patients investigated for SIH was conducted at a single hospital department from February 2013 to October 2017. Patients with missing brain MRI data were excluded. Three blinded readers retrospectively reviewed the brain MRI scans of patients with SIH and a spinal CSF leak, patients with orthostatic headache without a CSF leak, and healthy control participants, evaluating 9 quantitative and 7 qualitative signs. A predictive diagnostic score based on multivariable backward logistic regression analysis was then derived. Its performance was validated internally in a prospective cohort of patients who had clinical suspicion for SIH.

Main Outcomes and Measures

Likelihood of a spinal CSF leak based on the proposed diagnostic score.

Results

A total of 152 participants (101 female [66.4%]; mean [SD] age, 46.1 [14.3] years) were studied. These included 56 with SIH and a spinal CSF leak, 16 with orthostatic headache without a CSF leak, 60 control participants, and 20 patients in the validation cohort. Six imaging findings were included in the final scoring system. Three were weighted as major (2 points each): pachymeningeal enhancement, engorgement of venous sinus, and effacement of the suprasellar cistern of 4.0 mm or less. Three were considered minor (1 point each): subdural fluid collection, effacement of the prepontine cistern of 5.0 mm or less, and mamillopontine distance of 6.5 mm or less. Patients were classified into groups at low, intermediate, or high probability of having a spinal CSF leak, with total scores of 2 points or fewer, 3 to 4 points, and 5 points or more, respectively, on a scale of 9 points. The discriminatory ability of the proposed score could be demonstrated in the validation cohort.

Conclusions and Relevance

This 3-tier predictive scoring system is based on the 6 most relevant brain MRI findings and allows assessment of the likelihood (low, intermediate, or high) of a positive spinal imaging result in patients with SIH. It may be useful in identifying patients with SIH who are leak positive and in whom further invasive myelographic examinations are warranted before considering targeted therapy.

The splenium of the corpus callosum: embryology, anatomy, function and imaging with pathophysiological hypothesis

BACKGROUND AND PURPOSE

The splenium of the corpus callosum is the most posterior part of the corpus callosum. Its embryological development, anatomy, vascularization, function, imaging of pathology, possible pathophysiological mechanisms by which pathology may develop and the clinical consequences are discussed.

METHODS

A literature-based description is provided on development, anatomy and function. MR and CT images are used to demonstrate pathology. The majority of pathology, known to affect the splenium, and the clinical effects are described in three subsections: (A) limited to the splenium, with elaboration on pathophysiology of reversible splenial lesions, (B) pathology in the cerebral white matter extending into or deriving from the splenium, with special emphasis on tumors, and (C) splenial involvement in generalized conditions affecting the entire brain, with a hypothesis for pathophysiological mechanisms for the different diseases.

RESULTS

The development of the splenium is preceded by the formation of the hippocampal commissure. It is bordered by the falx and the tentorium and is perfused by the anterior and posterior circulation. It contains different caliber axonal fibers and the most compact area of callosal glial cells. These findings may explain the affinity of specific forms of pathology for this region. The fibers interconnect the temporal and occipital regions of both hemispheres reciprocally and are important in language, visuospatial information transfer and behavior. Acquired pathology may lead to changes in consciousness.

CONCLUSION

The development, location, fiber composition and vascularization of the splenium make it vulnerable to specific pathological processes. It appears to play an important role in consciousness.

A clinical analysis on 40 cases of spontaneous intracranial hypotension syndrome

OBJECTIVE

To investigate clinical and imaging features of 40 patients with spontaneous intracranial hypotension (SIH).

METHODS

40 cases of spontaneous intracranial hypotension (SIH) diagnosed in our hospital from June 2013 to September 2017 were collected and retrospectively analyzed.

RESULTS

In our study, the male to female ratio was 2:3. The average age of onset was 43.0 ± 15.0 years. There were 12 (30.0%) patients with clear incentives, mostly catching cold. The average length of hospital stay was 11.2 ± 6.3 days. All the patients showed orthostatic headaches, 62.5% patients with nausea or vomiting, 40.0% patients with neck stiffness, 17.5% patients with dizziness and vertigo, 10.0% patients with numbness and weakness of limbs, 5% patients with neck discomfort, and 2.5% patients with visual symptoms (visual impairment, photophobia, diplopia). 24 patients underwent CT scans which showed no abnormalities in 20 cases (83.3%), subdural fluid accumulation in 3 cases (12.5%), and subdural haematoma in 1 case (2.5%). Cranial contrast-enhanced MR scans showed diffuse pachymeningeal enhancement (95.83%, 23/24), signs of pituitary hyperaemia in 5 cases (20.8%), subdural fluid accumulation and subdural hematoma in 4 cases (16.7%), sagging of the brain in 3 cases (12.5%), and engorgement of venous structures in 1 case (4.1%). Six patients underwent plain and contrast-enhanced spinal MR scans which showed varying degrees of dural thickening and enhanced performance in all the patients. 92.5% (37/40) of patients had cerebrospinal fluid pressure <60 mmH₂O on lumbar puncture. 97.5% of patients underwent conservative treatment with drugs and had a good outcome.

CONCLUSION

Orthostatic headache and cranial MRI diffuse pachymeningeal enhancement are characteristic features of SIH. Cranial contrast-enhanced MR scan is recognized as the first and non-invasive investigation in the diagnosis of SIH. Most patients had cerebrospinal fluid pressure <60 mmH₂O. The vast majority of patients improved with fluid replacement.

Behavioral Variant Frontotemporal Dementia as a Serious Complication of Spontaneous Intracranial Hypotension

BACKGROUND

Behavioral variant frontotemporal dementia (bvFTD) is a devastating early onset dementia. Symptoms of bvFTD may be caused by spontaneous intracranial hypotension (SIH), a treatable disorder, but no comprehensive study of such patients has been reported.

OBJECTIVE

To describe detailed characteristics of a large cohort of patients with SIH and symptoms of bvFTD.

METHODS

We identified patients with SIH who met clinical criteria for bvFTD. Patients were compared to a cohort of SIH patients without bvFTD.

RESULTS

The mean age for the 21 men and 8 women was 52.9 yr (range, 37–65 yr). All 29 patients with bvFTD symptoms had hypersomnolence. Magnetic resonance imaging showed brain sagging in all patients, cerebrospinal fluid (CSF) opening pressure low in about half of patients, but a spinal CSF leak could not be detected in any patient. All patients underwent epidural blood patching, but 26 patients eventually underwent 1 or more surgical procedures. Overall, a good outcome was obtained in 21 patients (72%); 20 (91%) of 22 patients who had not undergone prior Chiari surgery compared to 1 (14%) of 7 patients who did undergo Chiari surgery (P &lt; .003). Compared to SIH patients without symptoms of bvFTD (n = 547), those with bvFTD symptoms were older, more often male, less often demonstrated CSF leak on spinal imaging, and more often underwent surgery (P &lt; .02).

CONCLUSION

bvFTD in SIH is rare and associated with brain sagging and hypersomnolence. Spinal CSF leaks are rarely detected. bvFTD symptoms are often refractory to the usual percutaneous procedures but most patients can be cured.

Differential diagnosis with other rapid progressive dementias in human prion diseases

Prion diseases are unique in medicine as in humans they occur in sporadic, genetic, and acquired forms. The most common human prion disease is sporadic Creutzfeldt-Jakob disease (CJD), which commonly presents as a rapidly progressive dementia (RPD) with behavioral, cerebellar, extrapyramidal, and some pyramidal features, with the median survival from symptom onset to death of just a few months. Because human prion diseases, as well as other RPDs, are relatively rare, they can be difficult to diagnose, as most clinicians have seen few, if any, cases. Not only can prion diseases mimic many other conditions that present as RPD, but some of those conditions can present similarly to prion disease. In this article, the authors discuss the different etiologic categories of conditions that often present as RPD and also present RPDs that had been misdiagnosed clinically as CJD. Etiologic categories of conditions are presented in order of the mnemonic used for remembering the various categories of RPDs: VITAMINS-D, for vascular, infectious, toxic-metabolic, autoimmune, mitochondrial/metastases, iatrogenic, neurodegenerative, system/seizures/sarcoid, and demyelinating. When relevant, clinical, imaging, or other features of an RPD that overlap with those of CJD are presented.