Spontaneous intracranial hypotension: review and expert opinion

Treatment Outcomes of Epidural Blood Patch Guided by a Novel Overflow Leak Test with Computed Tomography Myelography in Patients with Intracranial Hypotension: A Case Series

OBJECTIVE

To describe the treatment outcomes of epidural blood patch (EBP) guided by a novel overflow leak test (OLT) combined with computed tomography myelography (CTM) in patients with intracranial hypotension, with focus on consistency and discrepancy between CTM and OLT findings.

METHODS

CTM followed by OLT was performed in 18 adults with a cerebrospinal fluid pressure of ≤60 mmH2O. Patients were categorized according to consistency or discrepancy between CTM and OLT findings: Group A, matching leak signals in CTM and OLT; Group B, leak signals detected by OLT only; Group C, discrepancy in leak signal sites between CTM and OLT; Group D, no leak signal detected by both CTM and OLT. EBPs were applied according to the treatment policy, and associations between the radiological categorization and treatment outcomes were determined. Thereafter, using CT and magnetic resonance imaging phantoms, we investigated the minimal amount of injected agent leaking from the lumbar puncture site visible, which could result in a false-positive signal in CTM and OLT.

RESULTS

Complete recovery following EBP was achieved for 13 (72%) patients; these included 50%, 82%, 100%, and 0% patients in Groups A, B, C, and D, respectively. In CT myelography phantoms, even 1 μL of contrast agent produced positive findings, whereas OLT phantoms required a minimum of 1000 μL.

CONCLUSIONS

These results suggest the potential additive diagnostic value of OLT when performed with CTM. The discrepancy in radiological findings could be partly explained by susceptibility to the contrast agent leaking from the lumbar puncture site.

Spinal Cerebrospinal Fluid Leaks/Intracranial Hypotension

Spinal cerebrospinal fluid (CSF) leaks occur due to CSF volume loss at the level of the spine. They can occur spontaneously, from trauma, or iatrogenic causes. Classically, patients present with orthostatic headache, but atypical presentations also occur. Initial workup involves ruling out other etiologies with careful history, neurologic examination, and MRI of brain/spine. Treatment starts with conservative measures and nontargeted epidural blood patching (EBP). If not successful, precise leak localization is required with myelography. Targeted therapy can be offered, including EBP/fibrin glue, endovascular treatment for CSF-venous fistulas, and spine surgery in appropriate cases. Early diagnosis and treatment improve outcomes.

Dural Arteriovenous Fistulas in Spontaneous Intracranial Hypotension

The occurrence of dural arteriovenous fistulas (DAVFs) in patients with spontaneous intracranial hypotension (SIH) is exceptionally rare. While DAVF is a known complication of cerebral venous thrombosis (CVT), the role of CVT as one of the early events in the genesis of DAVFs is still debated. This is because only a small number of patients with CVT develop DAVFs, and not all DAVFs are associated with CVT. Although several hypotheses have been proposed to explain the link between CVT and DAVFs, the relationship between DAVFs and SIH in the absence of CVT remains unclear. To delineate the association between DAVFs and SIH. We reviewed the medical records of 460 SIH patients who were observed and treated over the past several years, looking specifically for cases of SIH complicated by DAVFs. We also reviewed all published case reports reporting patients with SIH and DAVFs. Of the 460 SIH patients reviewed, two (0.4%) were also diagnosed with DAVFs. Both patients had orthostatic headache, diffuse pachymeningeal enhancement, and brain sagging on brain magnetic resonance imaging, which are typical neuroimaging findings of SIH. Patient n.1 reported DAVF caused by left transverse/sigmoid sinus thrombosis, while patient n.2 presented DAVF as a complication of SIH in the absence of CVT. We speculate that SIH, even without CVT, might represent the start of a cascade of events leading to DAVFs. The pathogenic mechanism involved in DAVF formation in SIH patients could be explained by the opening of preexisting microscopic vascular channels within the dura mater, secondary to extreme venodilation related to SIH.

Cervical epidural blood patch treatment is a choice for spontaneous intracranial hypotension

BACKGROUND

Epidural blood patch (EBP) is a minimally invasive and effective treatment for spontaneous intracranial hypotension (SIH). But, cervical epidural blood patch for SIH has little attention.

OBJECTIVE

In this study, The clinical data was recorded and the treatment efficacy and safety of cervical EBP in SIH were evaluated.

METHODS

: Fifty-nine cases of intractable SIH were examined by computed tomography (CT) guided cervical EBP at the Chinese PLA General Hospital from August 2014 to March 2024.

RESULTS

The mean age of the fifty-nine patients at symptom onset was 40.8 ± 9.5 years. 54/59 (91.5%) patients experienced orthostatic headache. Preoperative spine T2 scans with extensive fluid collection at the upper cervical region in 43/46 (93.5%). 45/59 (76.3%) patients had symptomatic relief with initial cervical EBP, and 14/59 (23.7%) patients received further cervical EBPs. In the first one to three days following the EBP procedure, 11 (18.6%) patients reported pain at the puncture site and 15 (25.4%) experienced neck pain. No other complications were observed during or after the procedure. At the latest follow-up, all patients showed good recovery. The mean follow-up was 28.9 ± 22.7 months.

CONCLUSION

CT-guided cervical EBP is a effective and safe treatment for patients with intractable SIH, especially in patients who had extensive fluid collection at the upper cervical region.

Diagnosis and treatment of disorders of intracranial pressure: consensus statement of the Spanish Society of Neurology's Headache Study Group

Primary intracranial pressure disorders include idiopathic intracranial hypertension and spontaneous intracranial hypotension. Remarkable advances have been made in the diagnosis and treatment of these 2entities in recent years. Therefore, the Spanish Society of Neurology's Headache Study Group (GECSEN) deemed it necessary to prepare this consensus statement, including diagnostic and therapeutic algorithms to facilitate and improve the management of these disorders in clinical practice. This document was created by a committee of experts belonging to GECSEN, and is based on a systematic review of the literature, incorporating the experience of the participants, and establishes practical recommendations with levels of evidence and grades of recommendation.

Spontaneous intracranial hypotension in a patient without corpus callosum: A case report

RATIONALE

Spontaneous intracranial hypotension (SIH) is a well-established condition typically presenting with disabling orthostatic headache. Corpus callosum agenesis (CCA) is one of the most common human brain malformations with a wide spectrum of associated malformations, chromosomal abnormalities, and clinical syndromes.

PATIENT CONCERNS

A 53-year-old woman presented with recurrent orthostatic headache for about 1 month. The head computed tomography examination of the patient showed CCA and the initial pressure of subsequent lumbar puncture was only 5 centimeters cerebrospinal fluid. Magnetic resonance imaging examination confirmed CCA with gray matter heterotopia.

DIAGNOSIS

The final diagnose was SIH related headache with CCA.

INTERVENTION

The patient's symptom improved after oral hydration, intravenous fluids, and bed rest.

OUTCOME

Favorable outcome was observed.

LESSONS

Although this co-occurrence of SIH and CCA is probably coincidental, this finding suggests that the developmental malformations of the brain may lead to structural changes in brain tissue or disturbances in cerebrospinal fluid production and reflux, resulting in pathological changes over time.

Iatrogenic intracranial hypotension secondary to subarachnoid-pleural fistula after transthoracic surgery for the treatment of lateral thoracic meningocele

Subarachnoid-pleural fistula (SPF), a rare complication following transthoracic spinal surgery, results in the accumulation of cerebrospinal fluid (CSF) in the pleural space. Hindered spontaneous closure, attributed to negative pleural pressure, gives rise to CSF hypotension and subdural blood collections. Despite numerous reported cases, achieving consensus on management remains elusive. Treatment options encompass conservative measures, surgical repair, epidural blood patch, and diverse approaches such as multilayer dural closure or meningocele resection. Presented herein is a distinctive case following lateral thoracic meningocele surgery, where SPF-induced CSF hypotension found successful resolution through the innovative use of titanium hemostatic clips to occlude the meningocele. This novel approach, emphasizing the utility of titanium clips, deviates from conventional strategies. Surgical SPF exclusion, particularly leveraging titanium clips, emerges as a potential solution, effectively alleviating symptoms of CSF hypotension. The article also aims to present a personal experience, contributing an effective and alternative approach for the etiological treatment of thoracic meningocele.

Diagnosis and Treatment of Spontaneous Intracranial Hypotension: Role of Epidural Blood Patching

Purpose of Review

This review focuses on the challenges of diagnosing and treating spontaneous intracranial hypotension (SIH), a condition caused by spinal CSF leakage. It emphasizes the need for increased awareness and advocates for early and thoughtful use of empirical epidural blood patches (EBPs) in suspected cases.

Recent Findings

SIH diagnosis is hindered by variable symptoms and inconsistent imaging results, including normal brain MRI and unreliable spinal opening pressures. It is crucial to consider SIH in differential diagnoses, especially in patients with connective tissue disorders. Early EBP intervention is shown to improve outcomes.

Summary

SIH remains underdiagnosed and undertreated, requiring heightened awareness and understanding. This review promotes proactive EBP use in managing suspected SIH and calls for continued research to advance diagnostic and treatment methods, emphasizing the need for innovative imaging techniques for accurate diagnosis and timely intervention.

A Low-Volume Epidural Blood Patch for the Treatment of Spontaneous Intracranial Hypotension: A Case Report

Spontaneous intracranial hypotension (SIH) is a rare neurological syndrome. We report the case of a 47-year-old woman with acute, severe orthostatic headache after surgery, chemotherapy, and radiotherapy for breast cancer. The brain and spine magnetic resonance imaging showed signs of intracranial hypotension. We describe the results of a non-targeted epidural blood patch with 10 mL of the patient's blood administered after unsuccessful conservative treatment. After the procedure, the patient reported gradual headache relief. This effect persisted over one year. The case shows that a single non-targeted low-volume epidural blood patch can be an effective treatment option for a patient with SIH when conservative treatment fails.

Spontaneous Intracranial Hypotension: Case Report and Update on Diagnosis and Treatment

Spontaneous intracranial hypotension (SIH) is an important cause of daily headaches that occur in young and middle-aged, active persons and is often misdiagnosed, leading to prolonged inactivity and rather high healthcare expenditures. Its diagnosis requires a high degree of clinical suspicion and careful interpretation of imaging studies. We present a case of SIH, which was successfully treated but which posed serious diagnostic challenges, ranging from cerebro-vascular disease and meningitis to granulomatous diseases, and for whom every therapeutic attempt just worsened the patient's condition until we finally reached the correct diagnosis. To raise awareness of this condition, we also present an updated overview of the clinical picture, evaluation, and treatment options for SIH.

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.

Closing the Gap: A Case Report on a Blood Patch Solution for Cerebrospinal Fluid Leak

Spontaneous intracranial hypotension is a condition resulting from cerebrospinal fluid leaks at the spinal level that disrupt the regulation of intracranial pressure. This disorder is an uncommon cause of debilitating headaches but can have variable clinical manifestations, which contributes to delayed diagnosis and potentially severe consequences. The standard treatment consists of conservative measures such as bed rest, hydration, and a pharmacological approach with paracetamol, caffeine, ergotamine, and dexamethasone. When conservative measures fail, an epidural blood patch is the gold standard treatment, where a small amount of blood is injected into the epidural space to form a clot to seal any existing leak. Recent studies showed a success rate of 64% without the need for further intervention. The authors report a case of a 55-year-old woman with a three-month history of daily severe headaches. Imaging exams showed subdural collections, suggesting the hypothesis of cerebrospinal fluid hypotension. After the failure of conservative measures, an epidural blood patch was performed with progressive clinical improvement.  This case demonstrates the potential effectiveness of an epidural blood patch in the management of spontaneous intracranial hypotension and its complications, offering an encouraging option for those unresponsive to conservative measures. It also highlights the importance of a multidisciplinary approach involving neurologists and anesthesiologists.

Spontaneous Intracranial Hypotension: An Uncommon Cause of Postural Vestibulocochlear Symptoms

Spontaneous intracranial hypotension is an uncommon but increasingly recognized condition characterized by an orthostatic headache secondary to low cerebrospinal fluid pressure. Vestibulocochlear symptoms are common but rarely the only presenting feature and can be challenging to differentiate from Meniere's disease. We present a case series that highlights the common vestibulocochlear symptoms and a review of the literature to increase awareness amongst otolaryngologists and highlight the path to diagnosis and management of this condition.

Rare cause of cerebral venous sinus thrombosis: Spontaneous intracranial hypotension syndrome: A case report

BACKGROUND

Spontaneous intracranial hypotension syndrome is a relatively uncommon neurological disorder of unknown etiology with a good prognosis. Cerebral venous sinus thrombosis is a specific type of cerebrovascular disease caused by multiple etiologies of cerebral venous sinus or vein thrombosis that obstructs cerebral venous return and is associated with impaired cerebrospinal fluid absorption; this entity is rarely seen clinically. Spontaneous intracranial hypotension syndrome is one of the causes of cerebral venous sinus thrombosis, and the probability of their combined occurrence is only 1%-2%. As such, it is easily overlooked clinically, thus increasing the difficulty of diagnosis and treatment.

CASE SUMMARY

A 29-year-old young woman presented with postural headache. Lumbar puncture suggested a pressure of 50 mmH₂O (normal 80 mmH₂O-180 mmH₂O), and magnetic resonance imaging cerebral venography suggested thrombosis of the supratentorial sinus. These findings were considered indicative of cerebral venous sinus thrombosis due to spontaneous intracranial hypotension syndrome after ruling out immunological causes, tumor, infection, abnormal coagulation mechanism, and hypercoagulable state, etc. She was treated with rehydration and low-molecular heparin anticoagulation for 15 d, and follow-up magnetic resonance imaging cerebral venography suggested resolution of the thrombus. The patient had complete improvement of her headache symptoms.

CONCLUSION

Spontaneous intracranial hypotension syndrome is one of the rare causes of cerebral venous sinus thrombosis, which is frequently misdiagnosed or missed and deserves consideration by clinicians during differential diagnosis. Dehydration should be avoided in such patients, and early rehydration and anticoagulation therapy are effective treatment options.

[Guidelines for the Diagnosis and Treatment of Spontaneous Intracranial Hypotension]

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.

Comparison of clinical characteristics with spontaneous intracranial hypotension complicated with subdural hematoma between surgical treatment and non-surgical treatment

OBJECTIVES

The aim of this current study was to analyze the possible surgical predictive factors about spontaneous intracranial hypotension (SIH) complicated with subdural hematoma (SDH).

METHODS

178 patients diagnosed with both SIH and SDH were retrospectively reviewed. All the participants were divided into as EBP group (BPG) and surgical treatment group (STG). The demographic, clinical manifestations, radiographic and treatment data of the two groups were collected and compared by the electrical medical history system.

RESULTS

The male patients accounted for the majority in the STG (77.88 %), which was significantly larger than those in the BPG(p = 0.004). Patients who regularly smoked and drunk alcohol in the STG group were significantly greater than those in the BPG group (p_(smoking)= 0.049, p_(drinking)= 0.014). The headache occurring in the temporal position in the STG accounted for 44.44 % which was significantly greater than those in the BPG (25.17 %, p = 0.040). The durations days of symptoms were 54.85 ± 34.78 and 33.72 ± 34.97 in the STG and BPG respectively (p = 0.005). The midline shift degree in the STG was also significantly greater than that in the BPG (p = 0.001). The largest hematoma depth in the STG was significantly greater than that in the BPG (p = 0.000). The frequency of blood patch in the STG was significantly greater than that in the BPG(p = 0022).

CONCLUSION

Male, unhealthy living habits, temporal headache, duration of headache, midline shift, hematoma depth and blood patch frequency were possible related factors with the poor outcome of blood patch and surgical treatment.

Neuroimaging in the diagnosis and treatment of intracranial pressure disorders

OBJECTIVE

To review the clinical features, proposed pathophysiology, and the role of medical imaging in the diagnosis and treatment of idiopathic intracranial hypertension and spontaneous intracranial hypotension.

METHODS

The authors conducted a narrative review of the current literature on intracranial hypertension and hypotension syndromes, with a focus on imaging findings and role of neurointerventional radiology as a therapeutic option for these pathologies.

RESULTS

Idiopathic intracranial hypertension commonly presents in obese women of childbearing age, being headache and papilledema the main clinical manifestations. Characteristic radiological findings consist of increased cerebrospinal fluid around the optic nerve, partially empty sella turcica and stenosis of the transverse sinuses. Transverse sinus stenting is a treatment alternative that has proven valuable utility in the recent years. Spontaneous intracranial hypotension in most of cases presents with orthostatic headache and has predilection for female population. The typical radiological features in the brain consist of subdural fluid collections, enhancement of the dura, engorgement of the venous structures, pituitary enlargement, and sagging of the brain. In this pathology, a cerebrospinal fluid leak in the spine associated with a defect in the dura, meningeal diverticulum, or a cerebrospinal fluid-venous leak must be actively ruled out.

CONCLUSIONS

Neurologic complaints secondary to changes in intracranial pressure exhibit certain clinical features that in combination with fairly specific radiological patterns allow a highly accurate diagnosis. The diverse specialists in neurosciences should be aware of the multiple image modalities in the study of these syndromes as well as the treatment alternatives by neurointerventional radiology.

Thunderclap headache revealing dural tears with symptomatic intracranial hypotension: Report of two cases

Cerebrospinal fluid (CSF) leakage is considered the cause of spontaneous intracranial hypotension (SIH), an important etiology for new daily persistent headaches and a potentially life-threatening condition. Minor traumatic events rarely lead to CSF leakage, contrasting with iatrogenic interventions such as a lumbar puncture or spinal surgery, which are commonly complicated by dural tears. Most meningeal lesions are found in the cervicothoracic region, followed by the thoracic region, and rarely in the lumbar region, and extremely rarely in the sacral region. We describe two patients admitted to our hospital for severe headaches aggravated in the orthostatic position, with a recent history of minor trauma and sustained physical effort, respectively. In the first case, a bone fragment pierced an incidental congenital meningocele creating a dural fistula. An extensive extradural CSF collection, spanning the cervicothoracic region (C4-T10), was described in the second case. In both patients, the clinical evolution was favorable under conservative treatment.

Lumbar epidural blood patch: An effective treatment for intracranial hypotension

Background:

The literature has demonstrated the efficacy of lumbar epidural blood patch (LEBP) in the management of spontaneous intracranial hypotension (SIH). However, the underlying pathophysiology of such management remains unclear. In this study, we aim to evaluate the utility of LEBP injections in the management of SIH and develop a potential management algorithm used in the triage and management of SIH patients.

Methods:

We retrospectively examined the clinical case notes of 14 patients with SIH (age: 25–69 years) who were managed with LEBP injections during the year of 2016–2021. We evaluated the presenting symptoms of each selected patient and radiological findings as well as treatment outcomes. Our aim is to evaluate the effectiveness of LEBP in the treatment of SIH patients through follow-up clinical and imaging assessment.

Results:

About 93% of patients describe the presence of headache at presentation, while 43% describe it as being of an orthostatic nature. All patients demonstrated typical findings on magnetic resonance imaging brain. Treatment success assessed through symptomatic improvement and radiological resolution was found in 85% of our patients at a 2-month interval.

Conclusion:

LEBP injection is an effective method of management in patients with a diagnosis of SIH. It should be considered in all SIH patients irrespective of whether a “dural leak” can be localized through radiological investigations.

Detection rate of MR myelography without intrathecal gadolinium in patients with newly diagnosed spontaneous intracranial hypotension

AIM

To evaluate the detection rate of magnetic resonance (MR) myelography without intrathecal gadolinium for cerebrospinal fluid (CSF) leakage in patients with newly diagnosed spontaneous intracranial hypotension (SIH) and to validate a published scoring system for predicting CSF leakage.

MATERIALS AND METHODS

This retrospective, observational, single-institution study included patients with newly diagnosed SIH between March 2015 and April 2021. Patients were included if they (a) had newly diagnosed SIH and (b) underwent initial brain MR imaging and preprocedural MR myelography with two- and three-dimensional turbo spin-echo sequences. Patients who underwent spine surgery or procedures including epidural injection and acupuncture were excluded. The detection rate was defined as the proportion of patients with a true-positive MR myelography result among all patients with confirmed CSF leakage. The interobserver agreement for the MR myelography results between two radiologists was analysed using weighted kappa statistics.

RESULTS

A total of 136 patients (mean age, 48 years; 70 women) with suspected SIH were included. Of these patients, 120 (88%, 120/136) were confirmed to have CSF leakage. Of the patients with confirmed CSF leakage, 90 (75%, 90/120) had epidural fluid collection. The detection rate of MR myelography for CSF leakage was 88% (105/120). The interobserver agreement between the two readers for detecting CSF leakage (κ = 0.76) or epidural fluid collection (κ = 0.76) on MR myelography was high. Among 24 patients with normal brain MR imaging results, 16 had CSF leakage (67%, 16/24).

CONCLUSIONS

Non-invasive MR myelography without intrathecal gadolinium should be considered to detect CSF leakage in patients with suspected SIH.

Current perspectives on the recognition and diagnosis of low CSF pressure headache syndromes

INTRODUCTION

Headaches occur when cerebrospinal fluid (CSF) pressure drops following dural puncture or trauma or spontaneously. As the features of these headaches and their accompanying symptoms might not be typical, low CSF pressure headache syndromes, and spontaneous intracranial hypotension in particular, are often misdiagnosed and underdiagnosed.

AREAS COVERED

The aim of this narrative review is to summarize the most recent evidence regarding the clinical presentation and the diagnosis of low CSF pressure headache syndromes.

EXPERT OPINION

The clinical spectrum low CSF pressure headache syndromes varies significantly and key signs might be missing. Low CSF pressure headache syndromes should be included in the differential diagnosis of any case of refractory headache, even when the headache is not orthostatic, or there are normal neuroimaging findings, and/or lumbar puncture opening pressure is within normal limits. Future research should focus on controlled interventional studies on the treatment of low CSF pressure headache syndromes, which are currently lacking.

Case report: Epidural blood patches are effective in treating intracranial hypotension due to a subarachnoid-pleural fistula

Background

Intracranial hypotension (IH) is usually associated with cerebrospinal fluid (CSF) leakage and/or CSF hypotension, and epidural blood patch (EBP) therapy has been proven to be effective for treating spontaneous IH and post-dural puncture headaches. Tarlov cysts (TCs) are common lesions of the sacral spine. They have rarely been reported in thoracic locations and are even less common in the posterior mediastinum, which can lead to their misdiagnosis as neurogenic tumors.

Case presentation

Here, we report the case of a 60-year-old woman who developed an orthostatic headache after the thoracoscopic resection of a TC in the posterior mediastinum that was presumed to be a schwannoma preoperatively. The patient was finally diagnosed with IH caused by a subarachnoid-pleural fistula (SPF) and was cured by targeted EBP treatment.

Conclusion

This is a case to show that a single targeted EBP treatment is effective for a patient with IH caused by an SPF after thoracoscopic resection of a TC. This case reminds us to be vigilant that a TC may be masquerading as a posterior mediastinal neurogenic tumor, and a detailed examination should be performed to identify it before deciding on a surgical procedure. In addition, postural headache after thoracoscopic spinal surgery should be alert to the possibility of IH induced by an SPF. Once it occurs, early treatment is necessary, and targeted EBP treatment can serve as a safe and effective alternative when conservative treatment fails.

Treating Spontaneous Intracranial Hypotension with an Anesthetic Modality: The Role of the Epidural Blood Patch

Background: Spontaneous intracranial hypotension (SIH) is a rare syndrome characterized by heterogeneity of presentation and prognosis, which can occasionally result in serious complications, such as the formation of subdural hematomas (SDHs). This case series aims to emphasize that SIH remains a diagnostic and therapeutic challenge; it can present with a broad clinical spectrum of symptoms, can lead to SDH and, if conservative treatment fails, an epidural blood patch (EBP) is a viable treatment option. Although the exact etiology of SIH is not known, it is believed to be due to cerebrospinal fluid (CSF) leak or a low CSF pressure. Case Series: Three patients (two males and one female) with ages ranging between 38 and 53 years old who presented with complaints of not only an orthostatic headache, but also a variety of symptoms of SIH, including the formation of two SDHs in one of them, were included in this series. These patients did not respond to conservative management and, subsequently, given the clinical and radiological evidence of SIH, were referred to the Anesthesiology Department for an EBP. Diagnostic workup was facilitated by imaging modalities, including magnetic resonance imaging (MRI) of the brain and spinal cord, prior to the EBP. All three patients were subjected to an EBP with an 18-gauge epidural needle. A total of between 30 and 43 mL of autologous blood was collected from the patients and was injected into the epidural space under strict aseptic conditions. Two lumbar (L₁-L₂, L₂-L₃) EBPs and one thoracic (T₁₁-T₁₂) EBP were performed on the three patients, respectively. All patients reported complete resolution of symptoms following the EBPs, while MRI improved substantially. Conclusions: This report describes three cases of SIH with CSF leak originating from the cervical, the thoracic and the lumbar level. The EBP restored CSF pressure and relieved the patients' persistent symptoms. MRI helps in revealing indirect signs of a low volume of CSF, though it may not be possible to locate the actual site of the leak. In conclusion, EBP is a well-accepted and beneficial treatment modality for SIH when conventional measures fail.

Catheter-guided multilevel epidural blood patches in an adolescent boy

Background

There is increasing evidence for the use of multilevel epidural catheter-guided blood patches to treat spontaneous cerebrospinal fluid leaks in adults. Yet, there are scarce data for their use in children. Furthermore, higher level epidural blood patches are uncommon in both adult and pediatric populations.

Case presentation

An adolescent boy with multilevel cerebrospinal fluid leaks associated with status migrainosus failed conservative pain management treatment. As he remained severely symptomatic, epidural blood patches were required to mitigate his symptoms. Given his multilevel leaks, a catheter-guided blood patch approach was used to treat multiple cervicothoracic and thoracolumbar leaks. After three separate uneventful blood patch procedures, the patient was free of symptoms. Other than some rebound intracranial hypertension, the patient maintained full neurological capacity without further complications. Following the resolution of treatment, he has not sought help for pain since his last blood patch over a year ago.

Conclusions

Multilevel catheter-guided blood patches have the potential to be administered to higher level spinal regions to the pediatric population suffering from multiple spontaneous cerebrospinal fluid leaks.

Chronic CSF leak from lumbar-peritoneal shunt tract: A case report

Background

We describe a case of long-standing intracranial hypotension caused by an iatrogenic arachnoid diverticulum. This case illustrates two learning points. First, excessive CSF absorption may occur through an acquired arachnoid-epidural venous plexus at a dural defect. Second, a long-standing CSF leak may benefit from definitive surgical repair in the first instance.

Case Description

A 55-year-old female, with known idiopathic intracranial hypertension, presented with disabling chronic low-pressure symptoms after having a lumboperitoneal shunt removed 5 years previously. MRI scan revealed a Chiari I malformation (CMI) and a small dural interruption at the L3/4 space. CT myelography confirmed the abnormality. Intraoperatively, a dural defect and arachnoid bleb with an overlying attachment of adipose tissue and a vessel were found. Postoperatively, the patient has marked resolution of her headaches and dizziness and is mobilizing independently.

Conclusion

Excessive CSF absorption appears to have occurred through an acquired arachnoid-epidural venous plexus. A high index of suspicion for intracranial hypotension is required in patients with low pressure symptoms and a CMI.

Significance of Pseudomeningocele After Decompressive Surgery for Chiari I Malformation

Background

Pseudomeningoceles (PMCs) as abnormal collections of cerebrospinal fluid are quite common findings on follow-up MRI after Chiari decompression surgery (CDS). However, the importance of their identification has not been truly determined, especially when PMCs are described occasionally in the process of radiological follow-up. We retrospectively analyzed surgical outcomes and imaging findings after CDS depending upon the occurrence and thickness of PMCs.

Methods

A total of 76 adult patients who underwent CDS were analyzed. The clinical and radiological outcomes of patients with a pseudomeningocele (wPMC) were evaluated and compared to those of patients without a pseudomeningocele (w/oPMC). Radiological morphometric measurements were performed and compared between groups. Comparisons of the maximal PMC thickness were made within the wPMC group.

Results

PMCs were recognized in 27 (35.5%) patients, of whom 3 (11.1%) required reoperation. Differences in satisfactory result rates regarding gestalt assessment and Chicago Chiari Outcome Scale were statistically insignificant between the w/oPMC and wPMC groups (p = 1 and p = 0.56, respectively). The postoperative syringomyelia decrease and cerebellar tonsil elevation were similar between the groups (p = 1 and p = 0.74, respectively) in the long-term follow-up. Additionally, the clinical or radiological outcomes with radiological details were not related to PMC thickness in the long-term follow-up. However, radiological details showed the cooccurrence of PMCs with a postsurgical of cerebello-tentorial distance increase (p < 0.05), basion-pontomedullary sulcus distance decrease (p < 0.05) and tonsillo-graft distance decrease (p < 0.05).

Conclusions

We found no significant relationships between PMC presence or thickness and clinical or radiological outcomes. However, postoperative changes within the posterior fossa associated with PMCs resemble brain sagging, which occurs in intracranial hypotension. Therefore, extradural cerebrospinal fluid escape may also be responsible for symptoms in some patients with PMCs after CDS.

Early and Delayed Rebound Intracranial Hypertension following Epidural Blood Patch in a Case of Spontaneous Intracranial Hypotension

Background. Spontaneous intracranial hypotension (SIH) is a secondary headache that has been attributed to a cerebrospinal fluid (CSF) leak. It may resolve spontaneously or require conservative treatment. An epidural blood patch (EBP) with autologous blood is performed in cases exhibiting an inadequate response to conservative methods. Rebound intracranial hypertension (RIH) can develop following an EBP in up to 27% of patients. It is characterized by a change in the headache features and is often accompanied by nausea, blurred vision, and diplopia. Symptoms commonly begin within the first 36 hours, but could develop over days to weeks. It is important to differentiate this rebound phenomenon from unimproved SIH, as the treatment options differ. Case Presentation. Here, we present an interesting case of a patient with SIH who was treated with EBP and developed both immediate RIH after 24 hours and delayed RIH 3 weeks following EBP. Conclusions. Following EBP for treatment of SIH, new onset of headache having a different pattern and location should always be monitored for the occurrence of RIH. A lumbar puncture should be done if the symptoms of elevated CSF pressure become intolerable or if the diagnosis is uncertain. Lack of early diagnosis and treatment and differentiation from SIH can cause complications and could affect the optic nerves.

Recent update on epidural blood patch

Epidural blood patch (EBP) is the injection of autologous blood into the epidural space with the intent of sealing off a dural tear and stopping the leakage of cerebrospinal fluid (CSF). EBP may cause an increase in intracranial pressure due to the mass effect of the injected blood volume, causing CSF from the spinal compartment to enter the intracranial compartment. EBP is usually considered in the management of moderate to severe headache (HA) attributed to low CSF pressure, such as post-dural puncture HA (PDPH), CSF fistula HA, and HA attributed to spontaneous intracranial hypotension (SIH) that does not respond to conservative management. However, prophylactic administration of EBP after accidental dural puncture can hardly be substantiated at present. EBP is generally safe but may rarely be associated with serious complications. Therefore, it should be carefully planned and performed under C-arm fluoroscopic guidance. Although many studies on PDPH and SIH have been conducted until recently, only few reviews have summarized the effectiveness of EBP from the perspective of a pain physician. This article reviews the current literature on the indication, contraindication, procedural consideration, post-procedural management, outcomes, and complications of EBP and the considerations for EBP in patients with COVID-19.

[Spinal CSF-venous fistula: case report and literature review]

Syndrome of spontaneous intracranial hypotension is increasingly described in the literature as a multifactorial disease with impairment of the quality of life and risk of mortality. CSF-venous fistula as a cause of intracranial hypotension syndrome is extremely rare and requires complex diagnosis and timely surgical treatment.

OBJECTIVE

We present a 55-year-old patient with acute spontaneous intracranial hypotension and spinal CSF-venous fistula. Literature data are also analyzed.

RESULTS

Algorithm for diagnosis and efficacy of microsurgical resection of CSF-venous fistula is demonstrated.

CONCLUSION

Intracranial hypotension following spinal fistula requires careful examination. Accurate understanding of pathophysiological and anatomical features of this disease is necessary to select an effective treatment method.

Spontaneous intracranial hypotension following spinal anesthesia initially misdiagnosed as postdural puncture headache

Spontaneous intracranial hypotension (SIH) is not rare, but its diagnosis remains challenging. SIH tends to be misdiagnosed as postdural puncture headache when orthostatic headache develops subsequent to spinal anesthesia because both have similar symptoms. We report the case of a 35-year-old man with orthostatic headache following spinal anesthesia, who did not respond to conventional therapy for postdural puncture headache. SIH was confirmed after epidural fluid collection was identified at the thoracic spine level on magnetic resonance myelography. Physicians must consider SIH despite a history of neuraxial block. Diagnostic work-up is necessary to identify potential cerebrospinal fluid leakage in refractory cases.

Magnetic resonance imaging predicted the therapeutic response of patients with spinal cerebrospinal fluid leakage undergoing targeted epidural blood patch

OBJECTIVE

Most patients with spinal cerebrospinal fluid (CSF) leakage require an epidural blood patch (EBP); however, the response to treatment is varied. This study aimed to compare the MRI findings at follow-up between EBP effective and non-effective groups and to identify imaging findings that predict EBP treatment failure.

METHODS

We retrospectively reviewed 48 patients who received EBP treatment for spinal CSF leakage. These patients were stratified into two groups: EBP effective (n = 27) and EBP non-effective (n = 21) using the results of the 3 month MRI as the end point.

RESULTS

Compared to the EBP non-effective group, the patients in the EBP effective group had a lower spinal CSF leakage number (2.67 vs 12.48; p = 0.001), lower spinal epidural fluid accumulation levels (3.00 vs 7.48; p = 0.004), brain descend (11.11% vs 38.10%; p = 0.027), pituitary hyperemia (18.52% vs 57.14%; p = 0.007), and decreased likelihood of ≥three numbers of spinal CSF leakage (25.93% vs 90.48%; p = 0.001) in the post-EBP MRI. Clinical non-responsiveness (OR: 57.84; 95% CI: 3.47-972.54; p = 0.005) and ≥three numbers of spinal CSF leakage (OR: 15.13; 95% CI: 1.45-159.06; p = 0.023) were associated with EBP failure. Between these variables, ≥three numbers of spinal CSF leakage identified using the post-EBP MRI demonstrated greater sensitivity in predicting EBP failure compared to clinical non-responsiveness (90.48% vs 61.9%).

CONCLUSION

The number of spinal CSF leakage identified using the post-EBP MRI with a cut-off value of three is an effective predictor of EBP failure.

ADVANCES IN KNOWLEDGE

Compared to clinical responsiveness, the post-EBP MRI provided a more objective approach to predict the effectiveness of EBP treatment in patients with spinal CSF leakage.

Risk factors for nonresponsive hydration in patients with spinal cerebrospinal fluid leakage

BACKGROUND

Spinal cerebrospinal fluid (CSF) leakage is frequently encountered clinically after lumbar puncture or spontaneous events. Although some patients recover without treatment or after intensive hydration, some require an epidural blood patch (EBP). The risks of nonresponsive hydration remain unknown. Therefore, we identified the risk factors for patients with spinal CSF leakage nonresponsive to hydration.

METHODS

We retrospectively reviewed patients diagnosed with spinal CSF leakage between January 2010 and March 2021. Clinical data, including patient age, sex, etiology, and radiological indications in magnetic resonance imaging, were compared between patients who were responsive and non-responsive to hydration.

RESULTS

Of the 74 patients with spinal CSF leakage, 25 were responsive to hydration and 49 required EBP. Patients who were nonresponsive to hydration were older (39.27 vs. 34.32 years, P = 0.01), had a higher percentage of spontaneous intracranial hypotension (93.88% vs. 68.00%, P = 0.005), had more spinal CSF leakage (12.04 vs. 8.04, P = 0.01), and had a higher percentage of dural sinus engorgement (81.63% vs. 60.00%, P = 0.044). Spontaneous intracranial hypotension (odds ratio [OR]: 4.63; 95% confidence interval [CI]: 1.00-21.38) and having ≥9 spinal CSF leakages (OR: 3.29; 95% CI: 1.08-10.01), as indicated by magnetic resonance myelography, are considered risk factors for noneffective hydration.

CONCLUSIONS

Patients with spinal CSF leakage who have spontaneous intracranial hypotension and those with ≥9 spinal CSF leakages are considered at risk for noneffective hydration. EBP should be considered early in these patients.

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.

Zipline Into a Case of Spontaneous Cerebrospinal Fluid Rhinorrhea

Spontaneous cerebrospinal fluid (CSF) rhinorrhea is an uncommon phenomenon. One of the complications associated with CSF rhinorrhea is meningitis, which is associated with high mortality. Therefore, the prompt diagnosis of CSF rhinorrhea is essential. We present a case of a patient, who after zip-lining, developed CSF rhinorrhea. She had no history of trauma and none of the conventional comorbidities associated with spontaneous CSF rhinorrhea. She was diagnosed with the help of radiological studies and biochemical tests. Our case is unique as there are no published case reports of spontaneous CSF rhinorrhea occurring after atraumatic zip-lining.

Cerebral venous thrombosis in spontaneous intracranial hypotension: A report of 8 cases and review of the literature

BACKGROUND

The occurrence of cerebral venous thrombosis (CVT) in patients with spontaneous intracranial hypotension (SIH) raises difficult practical questions regarding the management of the two conditions. The first-line therapy for CVT is anticoagulation (AC); however, its potential benefit in SIH/CVT patients, especially if complicated by subdural haematoma, must be carefully evaluated taking account of the intracranial haemorrhage risk. Venous system recanalization and good prognosis in SIH/CVT patients treated with epidural blood patch (EBP), the main treatment option for SIH, have been already described.

METHODS

We reviewed our cases of SIH complicated by CVT among a cohort of 445 SIH patients observed and treated during the last years. All published case reports and case series reporting patients with SIH and CVT were also ascertained and reviewed.

RESULTS

Eight (2%) out of 445 patients suffering with SIH, were also diagnosed with CVT. All patients observed had orthostatic headache, three of them experienced a change in their headache pattern over the SIH course. Six out of eight patients received both AC and EBP treatments. Two patients were treated using only AC or EBP. A bilateral subdural haematoma enlargement after 1 month of AC was observed in one case. Complete CVT recanalization after treatment was obtained in three patients, including two with multiple CVT at baseline; partial CVT recanalization was achieved in two patients. Three patients experienced no CVT recanalization. After 6-48 months' follow-up all patients were still asymptomatic.

CONCLUSIONS

The use of AC therapy should be weighed against the intracranial haemorrage risk and should be monitored carefully if initiated. Effective and prompt EBP, even without AC therapy, might lead to a good prognosis in selected cases.

Evaluating thunderclap headache

PURPOSE OF REVIEW

Thunderclap headache (TCH) is an abrupt-onset of severe headache that needs to be thoroughly investigated because the most common secondary cause is subarachnoid hemorrhage (SAH). There has been no consensus guideline regarding the diagnostic workup. This review aims to provide an update on the evaluation of TCH.

RECENT FINDINGS

The most important update in the 2019 American College of Emergency Physicians guideline for evaluation of acute headache in the emergency department is that negative noncontrast brain computed tomography (CT) findings within 6 h from ictus essentially excludes SAH. Additionally, the updated guideline recommends that after a negative brain CT, CT angiogram is a reasonable alternative to lumbar puncture if clinical suspicion of an intracranial source of SAH is high. An important update of reversible vasoconstriction syndrome (RCVS), the second most common etiology of TCH, is the RCVS2 score development based on clinical and radiological features, providing high specificity and sensitivity for distinguishing RCVS from other intracranial arteriopathies.

SUMMARY

Although the evaluation of TCH is exhaustive, the potentially catastrophic consequence of a missed diagnosis of sentinel headache justifies the efforts. Awareness of the clinical features and application of diagnostic tools specific for different pathological conditions can facilitate the diagnostic workup.

Predictors Associated with Outcomes of Epidural Blood Patch in Patients with Spontaneous Intracranial Hypotension

An autologous epidural blood patch (EBP) is a mainstay of treatment in patients with spontaneous intracranial hypotension (SIH). EBP, however, is less effective for SIH than post-dural puncture headaches. Therefore, patients with SIH frequently require an additional EBP. The aim of this study was to identify factors associated with poor response to EBP. This single-center retrospective observational study used the institutional registry records of 321 patients who underwent EBP between September 2001 and March 2016. Patients were divided into two groups, a poor responder group, consisting of patients who underwent EBP at least three times or more, and a good responder group of patients who experienced sufficient symptom relief after two or fewer EBP. The demographic characteristics, clinical features, radiologic findings, procedural data, and laboratory data were analyzed. Univariate analysis showed that the neutrophil-to-lymphocyte ratio (NLR; p = 0.004) and platelet-to-lymphocyte ratio (p = 0.015) were significantly lower in poor than in good responders. Multivariate analysis found that NLR was the only independent factor associated with a poor response (odds ratio = 0.720; p = 0.008). These findings indicate that a low NLR was associated with three or more EBP administrations for the sufficient improvement of symptoms in patients with SIH.

A systematic review and meta-analysis of factors affecting the outcome of the epidural blood patching in spontaneous intracranial hypotension

Spontaneous intracranial hypotension (SIH) is an often misdiagnosed condition resulting from non-iatrogenic cerebrospinal fluid (CSF) hypovolemia, typically secondary to spinal CSF leakage. Patients commonly present with posture-related headache, nausea, and vomiting. Following failure of conservative measures, epidural blood patching (EBP) is the most commonly performed intervention for spinal CSF leaks. The authors performed a systematic review and meta-analysis of existing literature to evaluate the role of different factors possibly affecting the efficacy of the EBP procedure. In accordance with the PRISMA guidelines, PubMed/Medline and SCOPUS databases were searched. Six eligible articles were retrieved. Five hundred patients were treated for SIH with EBP, of which 300 reported good response defined as complete remission of symptoms within 48 h after the first EBP requiring no further invasive treatment. Among the factors available for meta-analysis, none was found to be statistically significant in affecting the efficacy of the EBP procedure. A largely symmetrical funnel plot is reported for all the variables evaluated, indicating that publication bias did not play a significant role in the observed effects. The current knowledge about SIH and the EBP is scarce. The existing literature is contradictory and insufficient to aid in clinical practice. More studies are needed to draw significant conclusions that may help in the identification of patients at higher risk of EBP failure, who may benefit from different approaches.

Rapid Cognitive Decline Secondary to CSF Venous Fistula With Postoperative Rebound Intracranial Hypertension and a Hyperintense Paraspinal Vein Sign Seen Retrospectively

A 56-year-old female with 2 prior Chiari decompressions presented with rapidly progressive cognitive decline. Brain magnetic resonance imaging, computed tomography myelogram, and prone digital subtraction myelography revealed signs of brain sag and left T9 perineural cysts but no cerebrospinal fluid leaks. Symptoms improved after multilevel blood patches but recurred. Lateral decubitus digital subtraction myelography revealed a spinal cerebrospinal fluid venous fistula (SCVF), which resolved after neurosurgeons ligated the nerve root. Rebound headaches with papilledema occurred on postoperative day 9 and then resolved 2 months after acetazolamide was started. A hyperintense paraspinal vein was seen retrospectively on T2-weighted magnetic resonance imaging with Dixon fat suppression sequencing. This case is unique in the acuity of cognitive decline secondary to SCVF. Acetazolamide at the time of treatment may potentially be used as prophylaxis for rebound intracranial hypertension. The hyperintense paraspinal vein may have utility in future diagnosis of SCVF.

Orthostatic hearing loss: audiovestibular manifestations of spontaneous intracranial hypotension

A 36-year-old woman with severe postural headaches caused by spontaneous intracranial hypotension developed bilateral hearing loss. Her hearing loss varied in severity and also at times affected one ear more than the other. She noticed her hearing returned to normal on lying flat, and this was confirmed on audiometry. Her hearing fully recovered after treatment with blood patches. Audiovestibular symptoms affect up to 70% of people with spontaneous intracranial hypotension but are probably under-reported. Cerebrospinal fluid and inner ear fluids are related in two separate channels: the vestibular and the cochlear aqueducts. We discuss their role in the postural hearing loss of spontaneous intracranial hypotension.

Spontaneous intracranial hypotension: key features for a frequently misdiagnosed disorder

Spontaneous intracranial hypotension (SIH) is a rare neurological condition caused by low cerebrospinal fluid (CSF) volume, most commonly due to a CSF leak. The most common presenting symptom is an orthostatic headache, but some patients may present with atypical neurological manifestations such as cranial nerve palsies, an altered mental status, and movement disorders, which complicate the clinical diagnosis. Therefore, the diagnosis is based on the combination of clinical signs and symptoms, neuroimaging, and/or a low cerebrospinal fluid pressure. In this review, we describe the wide variety of neurological manifestations and complications seen in patients with SIH as well as the most common features described on imaging studies, including both subjective and objective measurements, in order to lead the clinician to a correct diagnosis. The prompt and correct management of patients with SIH will help prevent the development of life-threatening complications, such as subdural hematomas, cerebral venous thrombosis, and coma, and avoid unnecessary invasive procedures.

Brain volume changes in spontaneous intracranial hypotension: Revisiting the Monro-Kellie doctrine

OBJECTIVES

In the application of the Monro-Kellie doctrine in spontaneous intracranial hypotension, the brain tissue volume is generally considered as a fixed constant. Traditionally, cerebral venous dilation is thought to compensate for decreased cerebrospinal fluid. However, whether brain tissue volume is invariable has not yet been explored. The objective of this study is to evaluate whether brain tissue volume is fixed or variable in spontaneous intracranial hypotension patients using automatic quantitative methods.

METHODS

This retrospective and longitudinal study analyzed spontaneous intracranial hypotension patients between 1 January 2007 and 31 July 2015. Voxel-based morphometry was used to examine brain volume changes during and after the resolution of spontaneous intracranial hypotension. Brain structure volume was analyzed using Statistical Parametric Mapping version 12 and FMRIB Software Library v6.0. Post-treatment neuroimages were used as surrogate baseline measures.

RESULTS

Forty-four patients with spontaneous intracranial hypotension were analyzed (mean [standard deviation] age, 37.8 [8.5] years; 32 female and 12 male). The whole brain tissue volume was decreased during spontaneous intracranial hypotension compared to follow-up (1180.3 [103.5] mL vs. 1190.4 [93.1] mL, difference: -10.1 mL [95% confidence interval: -18.4 to -1.8 mL], p = 0.019). In addition, ventricular cerebrospinal fluid volume was decreased during spontaneous intracranial hypotension compared to follow-up (15.8 [6.1] mL vs. 18.9 [6.9] mL, difference: -3.2 mL [95% confidence interval: -4.5 to -1.8 mL], p < 0.001). Longer anterior epidural cerebrospinal fluid collections, as measured by number of vertebral segments, were associated with greater reduction of ventricular cerebrospinal fluid volume (Pearson's r = -0.32, p = 0.036).

CONCLUSION

The current study found the brain tissue volume and ventricular cerebrospinal fluid are decreased in spontaneous intracranial hypotension patients. The change in ventricular cerebrospinal fluid volume, but not brain tissue volume change, was associated with the severity of spinal cerebrospinal fluid leakage. These results challenge the assumption that brain tissue volume is a fixed constant.