Spontaneous Intracranial Hypotension: Clinical Presentation, Diagnosis, and Treatment Strategies.

Spontaneous intracranial hypotension (SIH) typically presents as an acute orthostatic headache during an upright position, secondary to spinal cerebrospinal fluid leaks. New evidence indicates that a lumbar puncture may not be essential for diagnosing every patient with SIH. Spinal neuroimaging protocols used for diagnosing and localizing spinal cerebrospinal fluid leaks include brain/spinal MRI, computed tomography myelography, digital subtraction myelography, and radionuclide cisternography. Complications of SIH include subdural hematoma, cerebral venous thrombosis, and superficial siderosis. Treatment options encompass conservative management, epidural blood patches, and surgical interventions. The early application of epidural blood patches in all patients with SIH is suggested.

Headache associated with intracranial hypotension: diagnostic challenges and difficulties in everyday neurological practice.

Low pressure of cerebrospinal fluid (CSF) is a rare cause of headache, except when the patient undergoes a lumbar puncture. Headache associated with a low CSF pressure i.e. intracranial hypotension causes diagnostic difficulties. Headaches related to spontaneous intracranial hypotension (SIH) pose a significant diagnostic challenge in everyday neurological practice. Patients with headaches due to SIH are usually diagnosed only after a long delay. Diagnostic problems may result in unnecessary invasive diagnostic procedures, or even neurosurgical operations. Diagnosing headaches attributed to SIH requires the consideration of several clinical scenarios, and the disease's features causing primary or secondary disturbances. In this review, we discuss the differential diagnosis of SIH-related headaches with reference to accumulated knowledge, including meta-analyses, guidelines, casuistry, and the applicable criteria of the International Classification of Headache Disorders. In addition, we discuss head and spine magnetic resonance imaging abnormalities, which may indicate intracranial hypotension.

The cervical blood patch: A therapeutic "miraculous" for cerebrospinal fluid leaks: A case report.

RATIONALE: Cerebrospinal fluid (CSF) leaks, arising from abnormal openings in the protective layers surrounding the spinal cord and brain, are a significant medical concern. These leaks, triggered by various factors including trauma, medical interventions, or spontaneous rupture, lead to the draining of CSF-an essential fluid safeguarding the nervous system. A classic symptom of CSF leaks is an incapacitating headache exacerbated by sitting or standing but relieved by lying down. Spontaneous intracranial hypotension (SIH) denotes the clinical condition marked by postural headaches due to spontaneous CSF leakage and hypotension, often misdiagnosed or underdiagnosed. While orthostatic headaches are the hallmark, SIH may manifest with an array of symptoms including nausea, tinnitus, hearing loss, visual disturbances, and dizziness. Treatment options encompass conservative measures, epidural blood patches (EBP), and surgery, with EBP being the primary intervention. PATIENT CONCERN: The patient did not express any specific concerns regarding their medical diagnosis. However, they did harbor apprehensions that their condition might necessitate surgical intervention in the future. DIAGNOSIS: The patient had been treated with antibiotics with a pre-diagnosis of sinusitis and was admitted to the neurology department of our hospital when his symptoms failed to improve. Cranial magnetic resonance imaging was interpreted as thickening of the dural surfaces and increased contrast uptake, thought to be due to intracranial hypotension. Cranial MR angiography was normal. Full-spine magnetic resonance imaging revealed a micro-spur at the C2 to 3 level and the T1 to 2 level in the posterior part of the corpus. INTERVENTIONS: The cervical EBP was performed in the prone position under fluoroscopic guidance. There were no complications. OUTCOMES: The patient was invited for follow-up 1 week after the procedure, and control examination was normal. LESSONS: SIH poses a diagnostic challenge due to its diverse clinical presentation and necessitates precise imaging for effective intervention. Cervical EBP emerges as a promising treatment modality, offering relief and improved quality of life for individuals grappling with this condition. However, clinicians must carefully assess patients and discuss potential risks and benefits before opting for cervical blood patches.

Cerebrospinal Fluid Refill Test as a Novel Diagnostic Tool for Cerebrospinal Fluid Hypovolemia: Preliminary Result.

OBJECTIVE: Cerebrospinal fluid (CSF) hypovolemia presents with orthostatic headaches due to CSF leakage. However, a direct association between the lack of CSF and clinical symptoms has not been found. CSF hypovolemia can be improved by refilling CSF. Therefore, we assessed the validity of a CSF refill test. METHODS: From November 2019 to August 2021, we included 10 patients (≥18 years old) with potential CSF hypovolemia, clear orthostatic headaches, and a CSF opening pressure <10 cmH2O. In the CSF refill test, 10 mL of artificial CSF was injected intrathecally. The primary outcome was improvement in orthostatic headache assessed using a visual analog scale (VAS), while the secondary outcomes were the 10-m walk time and adverse events. When the symptoms temporarily improved after intrathecal injection, the patients underwent radiologic imaging to identify the CSF leak, and an epidural blood patch was proposed accordingly. RESULTS: All patients showed post-test improvements in the VAS score (median [interquartile range], pretest 63.0 [50.3-74.3] vs. post-test 1.5 [0.0-26.0]). The 10-m walk time also significantly improved (9.5 [8.5-10.2] s vs. 8.2 [7.9-8.7] s). One patient experienced temporary right leg numbness associated with a lumbar puncture. After radiologic investigation, 9 patients underwent epidural blood patches, of which 6 were completely cured, and 3 revealed partial improvement. CONCLUSIONS: The cerebrospinal fluid (CSF) refill test was safe and effective in demonstrating the direct association between the lack of CSF and clinical symptoms and may help predict the outcome of an epidural blood patch.

Surgical closure of spinal cerebrospinal fluid leaks improves symptoms in patients with superficial siderosis.

BACKGROUND AND PURPOSE: Spinal cerebrospinal fluid (CSF) leaks may cause a myriad of symptoms, most common being orthostatic headache. In addition, ventral spinal CSF leaks are a possible etiology of superficial siderosis (SS), a rare condition characterized by hemosiderin deposits in the central nervous system (CNS). The classical presentation of SS involves ataxia, bilateral hearing loss, and myelopathy. Unfortunately, treatment options are scarce. This study was undertaken to evaluate whether microsurgical closure of CSF leaks can prevent further clinical deterioration or improve symptoms of SS. METHODS: This cohort study was conducted using data from a prospectively maintained database in two large spontaneous intracranial hypotension (SIH) referral centers in Germany and Switzerland of patients who meet the modified International Classification of Headache Disorders, 3rd edition criteria for SIH. Patients with spinal CSF leaks were screened for the presence of idiopathic infratentorial symmetric SS of the CNS. RESULTS: Twelve patients were included. The median latency between the onset of orthostatic headaches and symptoms attributed to SS was 9.5 years. After surgical closure of the underlying spinal CSF leak, symptoms attributed to SS improved in seven patients and remained stable in three. Patients who presented within 1 year after the onset of SS symptoms improved, but those who presented in 8-12 years did not improve. We could show a significant association between patients with spinal longitudinal extrathecal collections and SS. CONCLUSIONS: Long-standing untreated ventral spinal CSF leaks can lead to SS of the CNS, and microsurgical sealing of spinal CSF leaks might stop progression and improve symptoms in patients with SS in a time-dependent manner.

CSF-Venous Fistula of the Clival Skull Base: A Unique Case Study and Literature Review.

An adolescent male presented with orthostatic headaches following head trauma. MRI showed cerebellar tonsil displacement and a bony defect in the clival skull base. Digital subtraction myelography (DSM) confirmed a cerebrospinal fluid-venous fistula (CVF). This was repaired endoscopically. CVFs cause uncontrolled flow of CSF into the venous system resulting in symptoms of intracranial hypotension. They're often difficult to identify on initial imaging. This is the first reported CVF originating in the central skull base, and the first treated via endoscopic trans-nasal approach. CVFs may elude initial imaging, making DSM crucial for unexplained spontaneous intracranial hypotension. Laryngoscope, 134:645-647, 2024.

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.

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.

Temporal Characteristics of CSF-Venous Fistulas on Dynamic Decubitus CT Myelography: A Retrospective Multi-Institution Cohort Study.

BACKGROUND AND PURPOSE: CSF-venous fistula can be diagnosed with dynamic decubitus CT myelography. This study aimed to analyze the temporal characteristics of CSF-venous fistula visualization on multiphase decubitus CT myelography. MATERIALS AND METHODS: A retrospective, multisite study was conducted on patients diagnosed with CSF-venous fistula at 2 institutions between June 2017 and February 2023. Both institutions perform decubitus CT myelography with imaging immediately following injection and usually with at least 1 delayed scan. The conspicuity of CSF-venous fistula was assessed on each phase of imaging. RESULTS: Forty-eight patients with CSF-venous fistula were analyzed. CSF-venous fistulas were better visualized on the early pass in 25/48 cases (52.1%), the delayed pass in 6/48 cases (12.5%) and were seen equally on both passes in 15/48 cases (31.3%). Of 25 cases in which the CSF-venous fistula was better visualized on the early pass, 21/25 (84%) fistulas were still at least partially visible on a delayed pass. Of 6 cases in which the CSF-venous fistula was better visualized on a delayed pass, 4/6 (67%) were partially visible on the earlier pass. Six of 48 (12.5%) CSF-venous fistulas were visible only on a single pass. Of these, 4/6 (66.7%) were seen only on the first pass, and 2/6 (33.3%) were seen only on a delayed pass. One fistula was found with one pass only, and one fistula was discovered upon contralateral decubitus imaging without a dedicated second injection. CONCLUSIONS: A dynamic decubitus CT myelography imaging protocol that includes an early and delayed phase, likely increases the sensitivity for CSF-venous fistula detection. Further studies are needed to ascertain the optimal timing and technique for CSF-venous fistula visualization on dynamic decubitus CT myelography and its impact on patient outcomes.

[Spontaneous intracranial hypotension]. / ABC om Spontan intrakraniell hypotension.

Spontaneous intracranial hypotension (SIH) is a disease presenting mostly with orthostatic head and neck pain due to a spontaneous cerebrospinal fluid (CSF) leak or a CSF-venous fistula in the spinal region. It demonstrates typical MRI findings with sagging of the brain causing tension of the meninges and sometimes the cranial nerves. It shares some clinical similarities with post puncture headache but differs in its pathophysiological cause, diagnosis, and treatment. Many patients remain misdiagnosed or wait too long for the correct diagnosis. The diagnostic work-up includes an MRI of the head and spine in search of typical SIH signs. Myelography and CT scans are performed to identify the location of the CSF leak or CSF-venous fistula. Treatment options may involve (1) initial conservative treatment with bed rest, caffein and fluids, (2) interventions such as epidural blood patch, fibrin patch, and embolization, or (3) surgical closure of the leak.

Spontaneous intracranial hypotension: a case series and literature review.

Spontaneous intracranial hypotension (SIH) is a condition of negative intracranial pressure resulting from cerebrospinal fluid (CSF) leakage from the dural sac and is a well-known cause of orthostatic headache. Diagnosis and management can be difficult, often requiring coordination between multiple disciplines. Low CSF pressure and diffuse meningeal enhancement on brain MRI are the major instrumental features of the classic syndrome. Neuroimaging plays a key role in diagnosing SIH, particularly in atypical clinical presentations, by recognizing the specific findings of brain sagging on MRI and detecting the level of CSF leak on spinal imaging, thus guiding therapy accordingly. Since SIH could present with such a heterogeneous clinical picture, careful history taking and increased awareness of atypical presentations are of utmost importance. We review the existing SIH literature, illustrate management, clinical and neuroimaging findings of four consecutive patients with atypical SIH, who were recently referred to our hospital for evaluation to simplify and streamline the management of SIH.

Spontaneous Intracranial Hypotension in Pregnancy.

PURPOSE OF REVIEW: Spontaneous intracranial hypotension (SIH) is a debilitating disease typically featuring orthostatic headache and caused by a spinal CSF leak. This review will describe the characteristics of SIH in pregnant patients and the associated unique management and treatment considerations. RECENT FINDINGS: Herein, a novel case is reported of a 41-year-old woman who presented with SIH pre-conception but saw marked improvement of symptoms after 5 weeks antepartum and symptom recurrence 2 months post-partum. A literature review of SIH in pregnancy revealed 14 reported patients across 10 studies since 2000. All the reported cases resulted in delivery of healthy infants and symptomatic improvement with conservative management or a variety of treatment modalities including non-targeted epidural blood patch (EBP). Clinical and imaging features of SIH in pregnancy are reviewed. We hypothesize an antenatal protective mechanism against SIH symptoms through cephalad redistribution of CSF volume from the spinal to intracranial compartments related to uterine growth and decreased CSF volume within the lumbar cistern. Treatment recommendations are discussed including duration of bed rest and decision for non-targeted multi-site EBPs. When required, non-invasive diagnostic spine MRI using fat-suppressed axial T2-weighted imaging may be helpful.

Bed Rest as a Protective Factor for Subdural Hematoma in Spontaneous Intracranial Hypotension: A Retrospective Study.

BACKGROUND: Subdural hematoma (SDH) is a potentially life-threatening complication in patients with spontaneous intracranial hypotension (SIH). Though bed rest is the basis of conservative treatment, no clear evidence exists regarding the association between bed rest and the later complication of SDH in these patients. OBJECTIVES: This study aimed to evaluate the association between bed rest and SDH development in patients with SIH. STUDY DESIGN: A retrospective study was conducted from March 2013 through December 2019. Four hundred twenty adult patients diagnosed with SIH were enrolled. Clinical presentations and radiographic findings were recorded. The cumulative duration of bed rest in hours was used to measure the bed rest length. The clinical outcomes during follow-up were assessed. METHODS: Categorical data were compared using chi-square tests; continuous data were compared using the Mann-Whitney U test or Kruskal-Wallis test. A backwards stepwise Cox proportional hazard regression model adjusted with confounders which differed between SDH and non-SDH in univariate analysis was used to estimate the risk of cumulative duration of bed rest for SDH. A stratified Cox regression was performed to exclude the effect of the treatment algorithm. RESULTS: Of the 420 patients with SIH, 88 (21%) were in the SDH Group and 332 (79%) were in the non-SDH (NSDH) Group. The cumulative duration of bed rest in hours was a protective factor for SDH in SIH (Hazard Ratio [HR] = 0.997; P < 0.001). A stratified Cox regression analysis showed that the cumulative duration of bed rest remained a protective factor for SDH both in patients who received conservative treatment before admission (HR = 0.997; P < 0.001) and in those who did not (HR = 0.996; P = 0.061). Age (HR = 1.029, 95% CI, 1.009-1.050; P = 0.004) and orthostatic headache (HR = 4.770, 95% 95% CI, 2.177-10.450; P < 0.001) were risk factors for SDH in SIH. The clinical outcomes, including length of hospital stay, epidural blood patch (EBP) therapy, and repeated EBP therapy, were higher in the SDH Group. The revisit rate was similar between the 2 groups. LIMITATIONS: Retrospective studies are susceptible to different radiological procedures and therapeutic strategies. A bed rest score based on a patient's memory is susceptible to recognition and reporting bias. This is a single-center study and the sample size is not large. The validity of the bed rest scale has not been previously evaluated in any other study. CONCLUSIONS: Bed rest was a protective factor for SDH in patients with SIH. With more time and proper treatment, patients with SIH who have an SDH can achieve good prognosis in the long term.

Case Report: Unilateral Cranial Nerve VI Palsy Secondary to Intracranial Hypotension.

SIGNIFICANCE: Intracranial hypotension is a condition that occurs from a cerebrospinal fluid leak. Various visual symptoms have been associated with this condition. Cranial nerve VI (CN VI) palsies are the most common ocular manifestation, as the abducens nerve is prone to injury because of its intracranial anatomical course. PURPOSE: This case report presents a CN VI palsy secondary to intracranial hypotension from ventriculoperitoneal shunt overfiltration. Diagnosis, treatment, and management considerations are discussed. No identifiable health information was included in this case report. CASE REPORT: A 70-year-old White man was referred to the eye clinic for evaluation of binocular horizontal diplopia. The patient had a recent history of a left ventriculoperitoneal shunt for a persistent cerebrospinal fluid leak after complex mastoid surgery. The patient was also symptomatic for positional headaches, which improved in a recumbent position. He was diagnosed with a left CN VI palsy secondary to intracranial hypotension from a ventriculoperitoneal shunt overfiltration. The patient was followed up by neurosurgery for shunt adjustments to resolve the overfiltration. Binocular horizontal diplopia was managed conservatively with Fresnel prism. CONCLUSIONS: Intracranial hypotension should be considered in patients presenting with cranial nerve palsies and positional headaches. Obtaining neuroimaging and comanaging with neurology or neurosurgery are advised to make prompt diagnosis and treatment. Careful clinical monitoring and conservative diplopia therapy are recommended as visual symptoms improve upon resolution of the cerebrospinal fluid leak.

Validity of the Bern Score as a Surrogate Marker of Clinical Severity in Patients with Spontaneous Intracranial Hypotension.

BACKGROUND AND PURPOSE: The Bern score is a quantitative scale characterizing brain MR imaging changes in spontaneous intracranial hypotension. Higher scores are associated with more abnormalities on brain MR imaging, raising the question of whether the score can serve as a measure of disease severity. However, the relationship between clinical symptom severity and the Bern score has not been evaluated. Our purpose was to assess correlations between Bern scores and clinical headache severity in spontaneous intracranial hypotension. MATERIALS AND METHODS: This study was a single-center, retrospective cohort of patients satisfying the International Classification of Headache Disorders-3 criteria for spontaneous intracranial hypotension. Fifty-seven patients who completed a pretreatment headache severity questionnaire (Headache Impact Test-6) and had pretreatment brain MR imaging evidence of spontaneous intracranial hypotension were included. Pearson correlation coefficients (ρ) for the Headache Impact Test-6 and Bern scores were calculated. Receiver operating characteristic curves were used to assess the ability of Bern scores to discriminate among categories of headache severity. RESULTS: We found low correlations between clinical headache severity and Bern scores (ρ = 0.139; 95% CI, -0.127-0.385). Subgroup analyses examining the timing of brain MR imaging, symptom duration, and prior epidural blood patch showed negligible-to-weak correlations in all subgroups. Receiver operating characteristic analysis found that the Bern score poorly discriminated subjects with greater headache severity from those with lower severity. CONCLUSIONS: Pretreatment Bern scores show a low correlation with headache severity in patients with spontaneous intracranial hypotension. This finding suggests that brain imaging findings as reflected by Bern scores may not reliably reflect clinical severity and should not replace clinical metrics for outcome assessment.

Resisted Inspiration Improves Visualization of CSF-Venous Fistulas in Spontaneous Intracranial Hypotension.

BACKGROUND AND PURPOSE: CSF-venous fistulas are an important cause of spontaneous intracranial hypotension but are challenging to detect. A newly described technique known as resisted inspiration has been found to augment the CSF-venous pressure gradient and was hypothesized to be of potential use in CSF-venous fistula detection but has not yet been investigated in patients with spontaneous intracranial hypotension. The purpose of this investigation was to determine whether resisted inspiration results in improved visibility of CSF-venous fistulas on CT myelography in patients with spontaneous intracranial hypotension. MATERIALS AND METHODS: A retrospective cohort of patients underwent CT myelography from November 2022 to January 2023. Patients with an observed or suspected CSF-venous fistula identified during CT myelography using standard maximum suspended inspiration were immediately rescanned using resisted inspiration and the Valsalva maneuver. The visibility of the CSF-venous fistula among these 3 respiratory phases was compared, and changes in venous drainage patterns between phases were assessed. RESULTS: Eight patients with confirmed CSF-venous fistulas who underwent CT myelography using the 3-phase respiratory protocol were included. Visibility of the CSF-venous fistula was greatest during resisted inspiration in 5/8 (63%) of cases. Visibility was optimal with the Valsalva maneuver and maximum suspended inspiration in 1 case each, and it was equivalent in all respiratory phases in 1 case. In 2/8 (25%) cases, the pattern of venous drainage shifted between respiratory phases. CONCLUSIONS: In patients with spontaneous intracranial hypotension, resisted inspiration improved visualization of CSF-venous fistulas in most, but not all, cases. Further investigation is needed to determine the impact of this technique on the overall diagnostic yield of myelography in this condition.

[Guidelines for the Diagnosis and Treatment of Spontaneous Intracranial Hypotension]. / Protocolo de Abordagem Diagnóstica e Terapêutica da Hipotensão Intracraniana Espontânea.

Spontaneous intracranial hypotension (SIH) is a syndrome characterized by disabling orthostatic headache, due to reduced cerebrospinal fluid (CSF) volume probably caused by a CSF fistula. It affects mostly women of working-age, although it is probably underdiagnosed. The aim of this article is to present a practical approach to the diagnosis and treatment of SIH. After a description of its symptoms and signs, we present a step-by-step approach to the confirmation of the diagnosis and treatment, considering different clinical scenarios. This is intended to guide clinical decision making, through a systematized and individualized management, aimed at the best interest of the patient.

A hipotensão intracraniana espontânea (HIE) é uma síndrome caracterizada por cefaleia ortostática incapacitante, fruto de uma redução do volume de líquido cefalorraquidiano (LCR) provavelmente causada por uma fístula de LCR. Afeta sobretudo mulheres em idade ativa, estando provavelmente subdiagnosticada. Este protocolo visa apresentar uma proposta de abordagem prática ao diagnóstico e tratamento da HIE. Após uma secção descritiva das manifestações clínicas da HIE, apresentamos um modelo de atuação passo-a-passo para a confirmação do seu diagnóstico e tratamento, considerando diferentes cenários clínicos. Pretende-se, assim, facilitar a decisão clínica através de uma conduta sistematizada e individualizada, visando o melhor interesse do doente.

Multidisciplinary consensus guideline for the diagnosis and management of spontaneous intracranial hypotension.

BACKGROUND: We aimed to create a multidisciplinary consensus clinical guideline for best practice in the diagnosis, investigation and management of spontaneous intracranial hypotension (SIH) due to cerebrospinal fluid leak based on current evidence and consensus from a multidisciplinary specialist interest group (SIG). METHODS: A 29-member SIG was established, with members from neurology, neuroradiology, anaesthetics, neurosurgery and patient representatives. The scope and purpose of the guideline were agreed by the SIG by consensus. The SIG then developed guideline statements for a series of question topics using a modified Delphi process. This process was supported by a systematic literature review, surveys of patients and healthcare professionals and review by several international experts on SIH. RESULTS: SIH and its differential diagnoses should be considered in any patient presenting with orthostatic headache. First-line imaging should be MRI of the brain with contrast and the whole spine. First-line treatment is non-targeted epidural blood patch (EBP), which should be performed as early as possible. We provide criteria for performing myelography depending on the spine MRI result and response to EBP, and we outline principles of treatments. Recommendations for conservative management, symptomatic treatment of headache and management of complications of SIH are also provided. CONCLUSIONS: This multidisciplinary consensus clinical guideline has the potential to increase awareness of SIH among healthcare professionals, produce greater consistency in care, improve diagnostic accuracy, promote effective investigations and treatments and reduce disability attributable to SIH.

Efficacy of Epidural Blood Patching or Surgery in Spontaneous Intracranial Hypotension: A Systematic Review and Evidence Map.

BACKGROUND: Spontaneous intracranial hypotension is an important cause of treatable secondary headaches. Evidence on the efficacy of epidural blood patching and surgery for spontaneous intracranial hypotension has not been synthesized. PURPOSE: Our aim was to identify evidence clusters and knowledge gaps in the efficacy of treatments for spontaneous intracranial hypotension to prioritize future research. DATA SOURCES: We searched published English language articles on MEDLINE (Ovid), the Web of Science (Clarivate), and EMBASE (Elsevier) from inception until October 29, 2021. STUDY SELECTION: We reviewed experimental, observational, and systematic review studies assessing the efficacy of epidural blood patching or surgery in spontaneous intracranial hypotension. DATA ANALYSIS: One author performed data extraction, and a second verified it. Disagreements were resolved by consensus or adjudicated by a third author. DATA SYNTHESIS: One hundred thirty-nine studies were included (median, 14 participants; range, 3-298 participants). Most articles were published in the past decade. Most assessed epidural blood patching outcomes. No studies met level 1 evidence. Most were retrospective cohort or case series (92.1%, n = 128). A few compared the efficacy of different treatments (10.8%, n = 15). Most used objective methods for the diagnosis of spontaneous intracranial hypotension (62.3%, n = 86); however, 37.7% (n = 52) did not clearly meet the International Classification of Headache Disorders-3 criteria. CSF leak type was unclear in 77.7% (n = 108). Nearly all reported patient symptoms using unvalidated measures (84.9%, n = 118). Outcomes were rarely collected at uniform prespecified time points. LIMITATIONS: The investigation did not include transvenous embolization of CSF-to-venous fistulas. CONCLUSIONS: Evidence gaps demonstrate a need for prospective study designs, clinical trials, and comparative studies. We recommend using the International Classification of Headache Disorders-3 diagnostic criteria, explicit reporting of CSF leak subtype, inclusion of key procedural details, and using objective validated outcome measures collected at uniform time points.