Intracranial hypotension: clinical presentation, imaging findings, and imaging-guided therapy

Spontaneous intracranial hypotension - a spinal disease

Spontaneous intracranial hypotension (SIH) remains an underdiagnosed condition despite increasing awareness due to recent scientific advances. Diagnosis can be delayed by the broad clinical presentation and imaging pitfalls. This results in a high degree of physical impairment for patients, including social and psychological sequelae as well as long-term damage in the case of delayed diagnosis and treatment.The study is based on a selective literature search on PubMed including articles from 1990 to 2023 and the authors' clinical experience from working in a CSF center.SIH mostly affects middle-aged women, with the primary symptom being position-dependent orthostatic headache. In addition, there is a broad spectrum of possible symptoms that can overlap with other clinical conditions and therefore complicate the diagnosis. The causative spinal CSF loss can be divided into three main types: ventral (type 1) or lateral (type 2) dural leak and CSF-venous fistula (type 3). The diagnosis can be made using a two-stage workup. As a first step, noninvasive MRI of the head and spine provides indicators of the presence of SIH. The second step using focused myelography can identify the exact location of the cerebrospinal fluid leak and enable targeted therapy (surgical or interventional). Intrathecal pressure measurement or intrathecal injection of gadolinium is no longer necessary for primary diagnosis. Serious complications in the course of the disease can include space-occupying subdural hematomas, superficial siderosis, and symptoms of brain sagging, which can lead to misinterpretations. Treatment consists of closing the dural leak or the cerebrospinal fluid fistula. Despite successful treatment, a relapse can occur, which highlights the importance of follow-up MRI examinations and emphasizes the chronic nature of the disease. This paper provides an overview of the diagnostic workup of patients with suspected SIH and new developments in imaging and therapy. · SIH is an underdiagnosed condition with a wide range of possible symptoms.. · The first diagnostic step using MRI provides indications of the presence of SIH.. · The second diagnostic step using (dynamic) myelography can identify the CSF leak.. · Collaboration with a CSF center is advisable for further diagnosis and treatment.. · Prompt detection and treatment of SIH improves the outcome.. · Zander C, Wolf K, El Rahal A et al. Spontaneous intracranial hypotension - a spinal disease. Fortschr Röntgenstr 2024; DOI 10.1055/a-2318-8994.

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.

Sacral Dural Tears as a Cause of Spontaneous Intracranial Hypotension

PURPOSE

Dural tears at the level of the cervical, thoracic, and lumbar spine cause spontaneous intracranial hypotension (SIH) in patients with a spinal longitudinal extradural CSF collection (SLEC); however, sacral dural tears have rarely been reported so far. This study focuses on sacral dural tears as a cause of SIH.

METHODS

Retrospective data from SIH patients with confirmed sacral dural tears studied between October 2020 and November 2022 were analyzed with respect to demographic, clinical and imaging features. Digital subtraction myelography (DSM) and lumbar epidural blood patch (EBP) were modified by placing the patient in reversed Trendelenburg position.

RESULTS

Of the SIH patients, 9 (all women; mean age, 38.5 years; mean body mass index, BMI, 22.9) out of 149 had a sacral dural leak (6%) that occurred spontaneously in 7/9, while 2/9 were likely associated with minor trauma. None had a sacral fracture. The mean SIH score was 6.8. All patients showed SLEC on heavily T2-weighted MR myelography (T2-MRM), 4/9 exclusively sacral and 5/9 with partial or complete involvement of the remaining spine. 4/9 had none, but 5/9 had meningeal sacral cysts, 2/5 had large cysts/ectasia. Confirmation of the sacral origin of the leak was provided in 4/9 by T2-MRM, in 2/9 by DSM and 3/9 by CT myelography (CTM) whereas 0/9 revealed the exact site of leak within the sacrum.

CONCLUSION

Sacral dural tears should be considered as a possible cause for SIH. It is concluded to implement T2-MRM covering the entire sacrum in the standard MRI protocol and propose EBP in the reverse Trendelenburg position as a therapeutic approach.

Direct comparison of digital subtraction myelography versus CT myelography in lateral decubitus position: evaluation of diagnostic yield for cerebrospinal fluid-venous fistulas

BACKGROUND

Cerebrospinal fluid (CSF)-venous fistulas (CVFs) are increasingly identified as a cause of spontaneous intracranial hypotension (SIH). Lateral decubitus digital subtraction myelography (LD-DSM) and CT myelography (LD-CTM) are mainly used for detection, but the most sensitive method is yet unknown.

OBJECTIVE

To compare LD-DSM with LD-CTM for diagnostic yield of CVFs.

METHODS

Patients with SIH diagnosed with a CVF between January 2021 and December 2022 in which the area of CVF(s) was covered by both diagnostic modalities were included. LD-CTM immediately followed LD-DSM without repositioning the spinal needle, and the second half of the contrast agent was injected at the CT scanner. Patients were awake or mildly sedated. Retrospectively, two neuroradiologists evaluated data independently and blinded for the presence of CVF.

RESULTS

Twenty patients underwent a total of 27 combined LD-DSM/LD-CTM examinations (4/20 with follow-up and 3/20 with bilateral examinations). Both raters identified significantly more CVFs with LD-CTM than with LD-DSM (rater 1: 39 vs 9, P<0.001; rater 2: 42 vs 12, P<0.001). Inter-rater agreement was substantial for LD-DSM (κ=0.732) and LD-CTM (κ=0.655). The results remained significant after considering the senior rating for cases of disagreement (39 vs 10; P<0.001), and no CVF detected on LD-DSM was missed on LD-CTM.

CONCLUSION

In this study, LD-CTM has a higher diagnostic yield for the detection of CVFs than LD-DSM and should supplement LD-DSM, but further studies are needed. LD-CTM can be easily acquired in awake or mildly sedated patients with the second half of contrast injected just before CT scanning, or it may be considered as a stand-alone investigation.

Intracranial Hypotension Syndrome after Lumbar Drainage in Skull Base Surgery: Diagnosis and Correct Management

Lumbar drainage is commonly used in skull base surgery; however, very few cases of intracranial hypotension syndrome are reported to be caused by this procedure. We present a clinical case of lumbar drainage-assisted orbital and optic canal decompression surgery for a recurrent voluminous spheno-orbital meningioma, together with a literature review. A 49-year-old woman became confused and drowsy on postoperative day 3, after initially experiencing neurologic stability. Computed tomography (CT) scan of the head showed extradural frontotemporal fluid collection with moderate right to left midline shift. Magnetic resonance imaging (MRI) of the brain showed signs of intracranial hypotension, such as brain sagging and diffuse dural contrast enhancement. Conservative treatment with bed rest, aggressive hydration, steroids, and aminophylline led to progressive neurologic improvement. A systematic literature review was also performed, and previous reported cases were analyzed. Overall, neurosurgeons must be aware of the lumbar drainage-induced hypotension syndrome in skull base surgeries, because immediate diagnosis is essential for therapeutic decision-making. In this setting, conservative management is the first-line treatment as surgery may lead to severe complications.

The "Crossing Collection Sign": A Diagnostic Tool on Spine Magnetic Resonance Imaging For Localizing Cerebrospinal Fluid Leak

OBJECTIVE

The aim of the study is to determine whether the site of "cross" between ventral and dorsal spinal longitudinal extradural CSF collections (SLECs) seen on magnetic resonance imaging during initial workup of patients with suspected CSF leaks can predict the subsequently confirmed leakage site on computed tomography myelography or surgical repair.

METHODS

This was an institutional review board-approved, retrospective study performed from 2006 to 2021. Patients with SLECs who underwent total spine magnetic resonance imaging at our institution, followed by myelography and/or surgical repair for CSF leak, were included. Patients with incomplete workup including lack of computed tomography myelography and/or surgical repair and patients severely motion degraded imaging were excluded from our study. The site of cross between ventral and dorsal SLECs was defined as the "crossing collection sign" and was compared with the anatomically confirmed site of leak on myelography and/or at surgical repair.

RESULTS

Thirthy-eight patients met inclusion criteria with 18 females and 11 males ranging in age from 27 to 60 years (median, 40 years; interquartile range, 14 years). The crossing collection sign was seen in 76% of patients (n = 29). The distributions of confirmed CSF leak were as follows: cervical (n = 9), thoracic (n = 17), and lumbar spine (n = 3). The crossing collection sign predicted the site of CSF leak in 14 of 29 patients (48%) and was within 3-vertebral segments in 26 of 29 cases (90%).

CONCLUSIONS

The crossing collection sign can help prospectively identify spinal regions with highest likelihood for CSF leak in patients with SLECs. This can potentially help optimize the more invasive subsequent steps in the workup for these patients, including dynamic myelography and surgical exploration for repair.

Minimally invasive surgery for spinal cerebrospinal fluid leaks in spontaneous intracranial hypotension

OBJECTIVE

Spinal CSF leaks cause spontaneous intracranial hypotension (SIH). Surgical closure of spinal CSF leaks is the treatment of choice for persisting leaks. Surgical approaches vary, and there are no studies in which minimally invasive techniques were used. In this study, the authors aimed to detail the safety and feasibility of minimally invasive microsurgical sealing of spinal CSF leaks using nonexpandable tubular retractors.

METHODS

Consecutive patients with SIH and a confirmed spinal CSF leak treated at a single institution between April 2019 and December 2020 were included in the study. Surgery was performed via a dorsal 2.5-cm skin incision using nonexpandable tubular retractors and a tailored interlaminar fenestration and, if needed, a transdural approach. The primary outcome was successful sealing of the dura, and the secondary outcome was the occurrence of complications.

RESULTS

Fifty-eight patients, 65.5% of whom were female (median age 46 years [IQR 36-55 years]), with 38 ventral leaks, 17 lateral leaks, and 2 CSF venous fistulas were included. In 56 (96.6%) patients, the leak could be closed, and in 2 (3.4%) patients the leak was missed because of misinterpretation of the imaging studies. One of these patients underwent successful reoperation, and the other patient decided to undergo surgery at another institution. Two other patients had to undergo reoperation because of insufficient closure and a persisting leak. The rate of permanent neurological deficit was 1.7%, the revision rate for a persisting or recurring leak was 3.4%, and the overall revision rate was 10.3%. The rate of successful sealing during the primary closure attempt was 96.6% and 3.4% patients needed a secondary attempt. Clinical short-term outcome at discharge was unchanged in 14 patients and improved in 25 patients, and 19 patients had signs of rebound intracranial hypertension.

CONCLUSIONS

Minimally invasive surgery with tubular retractors and a tailored interlaminar fenestration and, if needed, a transdural approach is safe and effective for the treatment of spinal CSF leaks. The authors suggest performing a minimally invasive closure of spinal CSF leaks in specialized centers.

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.

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

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

Intracranial hypotension due to ventral thoracic dural tear secondary to osteophyte complex: resolution after transdural thoracic microdiscectomy with dural repair. Illustrative case

BACKGROUND

Intracranial hypotension (IH) manifests with orthostatic headaches secondary to cerebrospinal fluid (CSF) hypovolemia. Common iatrogenic etiologies include lumbar punctures and spinal surgery. Although much rarer, structural defects such as osteophytes and herniated calcified discs can violate dural integrity, resulting in CSF leak.

OBSERVATIONS

The authors reported the case of a 32-year-old woman who presented with progressively worsening orthostatic headaches. During an extensive examination, magnetic resonance imaging of her thoracic spine revealed a cervicothoracic ventral epidural collection of CSF, prompting a dynamic computed tomography myelogram, which not only helped to confirm severe cerebral hypotension but also suggested underlying pathology of a dorsally projecting disc osteophyte complex at T2–3. Conservative and medical management failed to alleviate symptoms, and a permanent surgical cure was eventually sought. The patient underwent a transdural thoracic discectomy with dural repair, which resulted in resolution of her symptoms.

LESSONS

Clear guidelines regarding the management strategy of IH secondary to disc osteophyte complexes are yet to be established. A thorough literature review noted only 24 reported cases between 1998 and 2019, in which 13 patients received surgery. There is a 46% symptom resolution rate with conservative management, lower than that for iatrogenic etiologies. For patients in whom conservative management failed, surgical intervention proved effective in resolving symptoms, with a success rate of 92.3%.

How I do it: the trans-laminar, facet-joint sparing minimal invasive approach for ventral dural repair in spontaneous intracranial hypotension-a 2-dimensional operative video

BACKGROUND

We describe the minimally invasive, facet-sparing postero-lateral approach to the thoracic spine for a ventral dural repair in a patient with intracranial hypotension secondary to a spontaneous dural breach.

METHODS

We performed a minimally invasive approach using a short paramedian posterior skin incision followed by a 10 × 10 mm targeted trans-laminar approach, to achieve a microsurgical repair of a symptomatic ventral dural defect causing severe disability.

CONCLUSION

The facet-sparing postero-lateral approach is safe and effective in the surgical management of thoracic dural tears, even in the most anterior ones, and avoids the traditional costotransversectomy.

Support Vector Machine-based Spontaneous Intracranial Hypotension Detection on Brain MRI

BACKGROUND AND PURPOSE

To develop a fully automatic algorithm for the magnetic resonance imaging (MRI) identification of patients with spontaneous intracranial hypotension (SIH).

MATERIAL AND METHODS

A support vector machine (SVM) was trained with structured reports of 140 patients with clinically suspected SIH. Venous sinuses and basal cisterns were segmented on contrast-enhanced T1-weighted MPRAGE (Magnetization Prepared-Rapid Gradient Echo) sequences using a convolutional neural network (CNN). For the segmented sinuses and cisterns, 56 radiomic features were extracted, which served as input data for the SVM. The algorithm was validated with an independent cohort of 34 patients with proven cerebrospinal fluid (CSF) leaks and 27 patients who had MPRAGE scans for unrelated reasons.

RESULTS

The venous sinuses and the suprasellar cistern had the best discriminative power to separate SIH and non-SIH patients. On a combined score with 2 points, mean SVM score was 1.41 (±0.60) for the SIH and 0.30 (±0.53) for the non-SIH patients (p < 0.001). Area under the curve (AUC) was 0.91.

CONCLUSION

A fully automatic algorithm analyzing a single MRI sequence separates SIH and non-SIH patients with a high diagnostic accuracy. It may help to consider the need of invasive diagnostics and transfer to a SIH center.

Spontaneous intracranial hypotension: diagnostic and therapeutic workup

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

[Spontaneous intracranial hypotension: A rare cause of headache in systemic lupus erythematosus]

INTRODUCTION

Spontaneous intracranial hypotension (SIH), a rare cause of headache, may be idiopathic or secondary, in particular to Systemic Lupus Erythematosus (SLE) where it remains exceptionally evoked or documented.

CASE REPORT

A 36-year-old woman presented with postural headache, recurrent nausea and vomiting. The discovery of a nephrotic syndrome led to the diagnosis of SLE with lupus nephropathy (class IV-G-(A)). A brain MRI showed signs of intracranial hypotension with tonsil ptosis and a left parietal hypersignal, and leading to a diagnosis of neurolupus with SIH. Treatment with prednisone, cyclophosphamide, and then mycophenolate mofetil allowed a rapid complete response of all systemic, renal and neurological manifestations, including the iconographic signs of intracranial hypotension.

CONCLUSION

Headaches are frequent and often unexplained during SLE. Their orthostatic character should, if appropriate, suggests a SIH and lead to perform a brain MRI, even in the absence of other neurological signs.

Acute subdural hematoma recurrence during drain removal associated with spontaneous intracranial hypotension – A non-reported complication

Background:

Spontaneous intracranial hypotension (SIH) is an uncommon, benign, and generally self-limiting condition caused by low cerebrospinal fluid (CSF) volume and pressure usually caused by a CSF leak. Patients with SIH have an increased incidence of subdural hematomas (SDH), which may be bilateral and recurrent.

Case Description:

We report a unique case of a man presenting with SIH and bilateral SDH that were drained with bilateral craniotomies. During drain removal, the patient had an acute neurological deterioration and a CT scan showed SDH recurrence. The patient had two new recurrent SDH afterwards. After the third surgical intervention, the drain was removed in the OR with concomitant subdural saline infusion, there was no recurrence of SDH after that and the patient has had no further complications after a 2-year follow-up.

Conclusion:

Patients with intracranial hypotension are predisposed to form SDH. In this case, drain removal caused further decrease in intracranial pressure and triggered a new SDH formation, subdural saline irrigation masked atmospheric pressure and prevented this complication from happening again.

Spontaneous Intracranial Hypotension Complicated by Subdural Effusions Treated by Surgical Relief of Cranial Venous Outflow Obstruction

Spontaneous intracranial hypotension describes the clinical syndrome brought on by a cerebrospinal fluid (CSF) leak. Orthostatic headache is the key symptom, but others include nausea, vomiting, and dizziness, as well as cognitive and mood disturbance. In severe cases, the brain slumps inside the cranium and subdural collections develop to replace lost CSF volume. Initial treatment is by bed rest, but when conservative measures fail, attention is focused on finding and plugging the leak, although this can be very difficult and some patients remain bedbound for months or years. Recently, we have proposed an alternative approach in which obstruction to cranial venous outflow would be regarded as the driving force behind a chronic elevation of CSF pressure, which eventually causes dural rupture. Instead of focusing on the site of rupture, therefore, investigation and treatment can be directed at locating and relieving the obstructing venous lesion, allowing intracranial pressure to fall, and the dural defect to heal. The case we describe illustrates this idea. Moreover, since there was a graded clinical response to successive interventions relieving venous obstruction, and eventual complete resolution, it also provides an opportunity to consider particular symptoms in relation to cerebral venous insufficiency in its own right.

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.

Spontaneous Intracranial Hypotension

BACKGROUND

Spontaneous intracranial hypotension (SIH) is an underdiagnosed disease. Its incidence is estimated at 5 per 100 000 persons per year.

METHODS

This review is based on a selective literature search in PubMed covering the years 2000-2019, as well as on the authors' personal experience.

RESULTS

The diagnostic and therapeutic methods discussed here are supported by level 4 evidence. SIH is caused by spinal leakage of cerebrospinal fluid (CSF) out of ventral dural tears or nerve root diverticula, or, in 2-5% of cases, through a fistula leading directly into the periradicular veins (CSF-venous fistula). In half of all patients, no CSF leak is demonstrable. A low CSF opening pressure on lumbar puncture is present in only one-third of patients; imaging studies are thus needed to confirm and localize a spinal CSF leak. Half of all patients in whom myelographic computed tomography (CT) reveals contrast medium reaching the epidural space have ventral dural tears, which tend to be located at upper thoracic spinal levels. Epidural blood patches applied under fluoroscopic or CT guidance can seal the CSF leak in 30-70% of patients, but 90% of patients with ventral dural tears will need operative closure. Some patients who have no visible epidural contrast medium on CT presumably do not have SIH, while others do, in fact, have a CSF leak from a diverticulum or a CSF-venous fistula and will need to have the site of the leak demonstrated with the aid of further studies, such as dynamic (subtraction) myelography in the lateral decubitus position.

CONCLUSION

The management of patients with SIH calls for complementary imaging studies to demonstrate the causative spinal CSF leak. Often, successful treatment requires surgical closure of the leak. In view of the sparse evidence available to date, controlled studies should be performed.

Cerebrospinal Fluid Hypovolemia and Posterior Reversible Encephalopathy Syndrome

Posterior reversible encephalopathy syndrome (PRES) is a reversible neuroradiological syndrome characterized by reversible vasogenic edema. The pathophysiological mechanism is still unclear, but PRES may be triggered by various etiologies. To date, only a few PRES cases linked to cerebrospinal fluid (CSF) hypovolemia were reported. The association between PRES and CSF hypovolemia needs to be explored. We presented a case of PRES with CSF hypovolemia as a result of an inadvertent dural puncture and reviewed the literature to identify the clinical characterization and pathophysiological mechanism of PRES following CSF hypovolemia. A total of 31 cases of PRES-CSF hypovolemia was included for analysis. The median age was 33 years, with a notable female predominance (87.1%). Fifteen patients (48.4%) didn't have either a history of hypertension nor an episode of hypertension. The most common cause of CSF hypovolemia was epidural or lumbar puncture (n = 21), followed by CSF shunt (n = 6). The median interval between the procedure leading to CSF hypovolemia and PRES was 4 days. Seizure, altered mental state, and headache were the most frequent presenting symptom. The parietooccipital pattern was most frequent (71.0%). Conservative management remains the mainstay of treatment with excellent outcomes. Three patients had a second episode of PRES. CSF hypovolemia is a plausible cause of PRES via a unique pathophysiologic mechanism including arterial hyperperfusion and venous dysfunction. Patients with CSF hypovolemia is more susceptible to PRES, which is potentially life-threatening. Given that CSF hypovolemia is a common complication of anesthetic, neurological, and neurosurgical procedures, PRES should be early considered for prompt diagnosis and appropriate management.

In vivo detection of venous sinus distension due to intracranial hypotension in small animal using pulsed-laser-diode photoacoustic tomography

Intracranial hypotension (IH) is a pathophysiological condition of reduced intracranial pressure caused by low cerebrospinal fluid (CSF) volume due to dural injuries from lumbar puncture, surgery, or trauma. Understanding the prognosis of IH in small animal models is important to gain insights on the complications associated with it such as orthostatic headache, cerebral venous thrombosis, coma, and so forth. Photoacoustic tomography (PAT) offers a novel and cost-effective way to perceive and detect IH in small animal models. In this study, a pulsed laser diode (PLD)-based PAT imaging system was used to examine the changes in the venous sinuses of the rat brain due to IH, induced through CSF extraction. After the CSF extraction, an increase in the sagittal sinus area by ~30% and width by 40% ± 5% was observed. These results provide supportive evidence that the PLD-PAT can be employed for detecting changes in sagittal sinus due to IH in rat model.

A clinical analysis on 40 cases of spontaneous intracranial hypotension syndrome

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Superior sagittal sinus thrombosis as a rare complication of spontaneous intracranial hypotension syndrome: a case report and review of the literature

In addition to an orthostatic headache, spontaneous intracranial hypotension syndrome can lead to subdural hematoma and diffusion, subarachnoid hemorrhage, and brain sag. However, cerebral venous sinus thrombosis is rarely reported in patients with spontaneous intracranial hypotension. We present the case of a 35-year-old male who developed an orthostatic headache, nausea, vomiting, and photophobia for 5 days. An enhanced brain magnetic resonance image showed extensive linear pachymeningeal enhancement in the bilateral cerebral hemispheres. Lumbar puncture showed that cerebrospinal fluid pressure was 80 mmH₂O. Subsequent magnetic resonance scans demonstrated subdural effusion of the bilateral frontoparietal lobes, hyperintense T1-weighted images, and T2WI lesions within the superior sagittal sinus in 17 days. The patient was given low molecular weight heparin and adverse events occurred. Head computed tomography showed cerebral external fluid accumulation in the bilateral frontoparietal lobes. Then, digital subtraction angiography was performed at 22 days, which confirmed superior sagittal sinus thrombosis, and the patient recovered fully after therapy. The evolution of the disease and radiological findings support the diagnosis of spontaneous intracranial hypotension with superior sagittal sinus thrombosis. To the best of our knowledge, there are very few case reports describing superior sagittal sinus thrombosis as a complication of spontaneous intracranial hypotension. When spontaneous intracranial hypotension and cerebral venous thrombosis occur together, difficult practical questions arise regarding the treatment of these two conditions.

Multilevel, ultra-large-volume epidural blood patch for the treatment of neurocognitive decline associated with spontaneous intracranial hypotension: case report

Spontaneous intracranial hypotension (SIH) is a progressive clinical syndrome characterized by orthostatic headaches, nausea, emesis, and occasionally focal neurological deficits. Rarely, SIH is associated with neurocognitive changes. An epidural blood patch (EBP) is commonly used to treat SIH when conservative measures are inadequate, although some patients require multiple EBP procedures or do not respond at all. Recently, the use of a large-volume (LV) EBP has been described to treat occult leak sites in treatment-refractory SIH. This article describes the management of a patient with profound neurocognitive decline associated with SIH, who was refractory to conservative management and multiple interventions. The authors describe the successful use of an ultra-LV-EBP of 120 ml across multiple levels, the largest volume reported in the literature, and describe the technical aspects of the procedure. This procedure has resulted in dramatic and sustained symptom resolution.

Predictors and incidence of orthostatic headache associated with lumbar drain placement following endoscopic endonasal skull base surgery

BACKGROUND

Orthostatic headache (OH) is a potential complication of lumbar drainage (LD) usage. The incidence and risk factors for OH with the use of lumbar drainage during endoscopic endonasal procedures have not been documented.

OBJECTIVE

To investigate the incidence of post-procedure OHs associated with placement of LD in patients undergoing endoscopic endonasal procedures.

METHODS

We prospectively noted the placement of LDs in a consecutive series of endoscopic endonasal skull base surgeries. Charts were retrospectively reviewed, and patients were divided into two groups: those with OH and those without. The patient demographics, drain durations, imaging findings of intracranial hypotension, pathologies and need for a blood patch were compared between the two groups.

RESULTS

Two hundred forty-nine patients were included in the study. Seven patients (2.8%) suffered post-dural puncture OH, which was mild to moderate and disappeared 2-8 days (median 3 days) after treatment. Blood patches were used in four patients. Significant predisposing factors were age (33.0 vs. 53.5, P = 0.014) and a strong trend for female gender (85.7% vs. 47.9%, P = 0.062). BMI and drain duration were not significant. Postoperative intracranial hypotension was diagnosed radiographically in 43% of OH patients and in 5.4% of those without OH (P = 0.003). Four (1.6%) patients required treatment with an epidural blood patch.

CONCLUSION

OH associated with intracranial hypotension in patients undergoing endoscopic endonasal procedures with LDs is an infrequent complication seen more commonly in young female patients. Radiographic signs of intracranial hypotension are a specific but not sensitive test for OH.

Application of time-spatial labeling inversion pulse magnetic resonance imaging in the diagnosis of spontaneous intracranial hypotension due to high-flow cerebrospinal fluid leakage at C1-2

BACKGROUND

Spontaneous intracranial hypotension (SIH) due to cerebrospinal fluid (CSF) leakage at C1-2 poses diagnostic and therapeutic challenges to spine surgeons. Although computed tomography (CT) myelography has been the diagnostic imaging modality of choice for identifying the CSF leakage point, extradural CSF collection at C1-2 on conventional CT myelography or magnetic resonance imaging (MRI) may often be a false localizing sign.

CASE DESCRIPTION

The present study reports the successful application of time-spatial labeling inversion pulse (T-SLIP) MRI, which enabled the precise identification of the CSF leakage point at C1-2 in a 28-year-old woman with intractable SIH. After identifying the leakage point using both CT myelography and T-SLIP MRI, surgery was performed to seal the CSF leak. Intraoperatively, a pouch suggestive of an extradural arachnoid cyst around the left C2 nerve root was found, which was repaired by packing the pouch with muscle and fibrin glue. Clinical improvement was observed shortly after surgery, and postoperative imaging revealed the disappearance of the CSF leakage.

CONCLUSIONS

T-SLIP MRI may provide useful information on the flow dynamics of CSF in SIH patients due to high-flow leakage. However, further experience is required to assess its sensitivity and specificity as an imaging modality for identifying CSF leakage points.

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

BACKGROUND AND PURPOSE

Atypical clinical presentations of spontaneous intracranial hypotension include obtundation, memory deficits, dementia with frontotemporal features, parkinsonism, and ataxia. The purpose of this study was to compare clinical and imaging features of spontaneous intracranial hypotension with typical-versus-atypical presentations.

MATERIALS AND METHODS

Clinical records and neuroimaging of patients with spontaneous intracranial hypotension from September 2005 to August 2014 were retrospectively evaluated. Patients with classic spontaneous intracranial hypotension (n = 33; mean age, 41.7 ± 14.3 years) were compared with those with intracranial hypotension with atypical clinical presentation (n = 8; mean age, 55.9 ± 14.1 years) and 36 controls (mean age, 41.4 ± 11.2 years).

RESULTS

Patients with atypical spontaneous intracranial hypotension were older than those with classic spontaneous intracranial hypotension (55.9 ± 14.1 years versus 41.7 ± 14.3 years; P = .018). Symptom duration was shorter in classic compared with atypical spontaneous intracranial hypotension (3.78 ± 7.18 months versus 21.93 ± 18.43 months; P = .015). There was no significant difference in dural enhancement, subdural hematomas, or cerebellar tonsil herniation. Patients with atypical spontaneous intracranial hypotension had significantly more elongated anteroposterior midbrain diameter compared with those with classic spontaneous intracranial hypotension (33.6 ± 2.9 mm versus 27.3 ± 2.9 mm; P < .001) and shortened pontomammillary distance (2.8 ± 1 mm versus 5.15 ± 1.5 mm; P < .001). Patients with atypical spontaneous intracranial hypotension were less likely to become symptom-free, regardless of treatment, compared with those with classic spontaneous intracranial hypotension (χ(2) = 13.99, P < .001).

CONCLUSIONS

In this sample of 8 patients, atypical spontaneous intracranial hypotension was a more chronic syndrome compared with classic spontaneous intracranial hypotension, with more severe brain sagging, lower rates of clinical response, and frequent relapses. Awareness of atypical presentations of spontaneous intracranial hypotension is paramount.

Brain Slump Caused by Jugular Venous Stenoses Treated by Stenting: A Hypothesis to Link Spontaneous Intracranial Hypotension with Idiopathic Intracranial Hypertension

Spontaneous intracranial hypotension, of which brain slump is an extreme expression, is caused by a cerebrospinal fluid leak. The reason the leak develops in the first place, however, is unknown, and some cases can be very difficult to manage. We describe a patient with severe symptoms of spontaneous intracranial hypotension and brain slump documented by magnetic resonance imaging whose clinical syndrome and structural brain anomaly resolved completely after treatment directed exclusively at improving cranial venous outflow. Diagnostics included computed tomography (CT) venography, catheter venography, and jugular venoplasty. CT venography showed narrowing of both internal jugular veins below the skull base. Catheter venography confirmed that these were associated with pressure gradients. Jugular venoplasty performed on two separate occasions as a clinical test gave temporary respite. Lasting remission (2 years of follow-up) was achieved by stenting the dominant internal jugular vein. These findings and this outcome suggest a mechanism for the development of spontaneous intracranial hypotension that would link it to idiopathic intracranial hypertension and have cranial venous outflow obstruction as the underlying cause.

Spontaneous intracranial hypotension manifesting as a unilateral subdural hematoma with a marked midline shift

Spontaneous intracranial hypotension (SIH) is a syndrome in which hypovolemia of the cerebrospinal fluid (CSF) results in various symptoms. Although its prognosis is usually benign, cases with a rapid neurologic deterioration resulting in an altered mental status have been reported. One of the characteristic radiographic findings in such cases is the presence of bilateral accumulation of subdural fluid (hematoma/hygroma). When SIH-related subdural hematoma is present only unilaterally with a concomitant midline shift, making an accurate diagnosis may be challenging, and inadvertent hematoma evacuation may result in further neurologic deterioration. We report a 58-year-old woman with an altered mental status who had visited a local hospital and in whom a brain CT showed a unilateral subdural hematoma with a marked midline shift. She was referred to our department because of her neurologic deterioration after hematoma evacuation. A CT myelography revealed a massive CSF leakage in the entire thoracic epidural space. She made a full neurologic recovery following blood patch therapy. Our case is unique and educational because the suspicion for SIH as an underlying cause of subdural hematoma is warranted in nongeriatric patients not only with bilateral but also unilateral lesions. An immediate search for CSF leakage may be important in cases with failed hematoma evacuation surgery.