Pediatric Meningeal Diseases: What Radiologists Need to Know

Evaluating altered mental status and suspected meningeal disorders in children often begins with imaging, typically before a lumbar puncture. The challenge is that meningeal enhancement is a common finding across a range of pathologies, making diagnosis complex. This review proposes a categorization of meningeal diseases based on their predominant imaging characteristics. It includes a detailed description of the clinical and imaging features of various conditions that lead to leptomeningeal or pachymeningeal enhancement in children and adolescents. These conditions encompass infectious meningitis (viral, bacterial, tuberculous, algal, and fungal), autoimmune diseases (such as anti-MOG demyelination, neurosarcoidosis, Guillain-Barré syndrome, idiopathic hypertrophic pachymeningitis, and NMDA-related encephalitis), primary and secondary tumors (including diffuse glioneuronal tumor of childhood, primary CNS rhabdomyosarcoma, primary CNS tumoral metastasis, extracranial tumor metastasis, and lymphoma), tumor-like diseases (Langerhans cell histiocytosis and ALK-positive histiocytosis), vascular causes (such as pial angiomatosis, ANCA-related vasculitis, and Moyamoya disease), and other disorders like spontaneous intracranial hypotension and posterior reversible encephalopathy syndrome. Despite the nonspecific nature of imaging findings associated with meningeal lesions, narrowing down the differential diagnoses is crucial, as each condition requires a tailored and specific treatment approach.

Evaluation of MR Elastography as a Noninvasive Diagnostic Test for Spontaneous Intracranial Hypotension

BACKGROUND AND PURPOSE

Spontaneous intracranial hypotension is a condition resulting from a leak of CSF from the spinal canal arising independent of a medical procedure. Spontaneous intracranial hypotension can present with normal brain MR imaging findings and nonspecific symptoms, leading to the underdiagnosis in some patients and unnecessary invasive myelography in others who are found not to have the condition. Given the likelihood that spontaneous intracranial hypotension alters intracranial biomechanics, the goal of this study was to evaluate MR elastography as a potential noninvasive test to diagnose the condition.

MATERIALS AND METHODS

We performed MR elastography in 15 patients with confirmed spontaneous intracranial hypotension from September 2022 to April 2023. Age, sex, symptom duration, and brain MR imaging Bern score were collected. MR elastography data were used to compute stiffness and damping ratio maps, and voxelwise modeling was performed to detect clusters of significant differences in mechanical properties between patients with spontaneous intracranial hypotension and healthy control participants. To evaluate diagnostic accuracy, we summarized each examination by 2 spatial pattern scores (one each for stiffness and damping ratio) and evaluated group-wise discrimination by receiver operating characteristic curve analysis.

RESULTS

Patients with spontaneous intracranial hypotension exhibited significant differences in both stiffness and damping ratio (false discovery rate-corrected, Q < 0.05). Pattern analysis discriminated patients with spontaneous intracranial hypotension from healthy controls with an area under the curve of 0.97 overall, and the area under the curve was 0.97 in those without MR imaging findings of spontaneous intracranial hypotension.

CONCLUSIONS

Results from this pilot study demonstrate MR elastography as a potential imaging biomarker and a noninvasive method for diagnosing spontaneous intracranial hypotension, including patients with normal brain MR imaging findings.

Optic Nerve Sheath MR Imaging Measurements in Patients with Orthostatic Headaches and Normal Findings on Conventional Imaging Predict the Presence of an Underlying CSF-Venous Fistula

BACKGROUND AND PURPOSE

Spontaneous spinal CSF leaks typically cause orthostatic headache, but their detection may require specialized and invasive spinal imaging. We undertook a study to determine the value of simple optic nerve sheath MR imaging measurements in predicting the likelihood of finding a CSF-venous fistula, a type of leak that cannot be detected with routine spine MR imaging or CT myelography, among patients with orthostatic headache and normal conventional brain and spine imaging findings.

MATERIALS AND METHODS

This cohort study included a consecutive group of patients with orthostatic headache and normal conventional brain and spine imaging findings who underwent digital subtraction myelography under general anesthesia to look for spinal CSF-venous fistulas.

RESULTS

The study group consisted of 93 patients (71 women and 22 men; mean age, 47.5 years; range, 17-84 years). Digital subtraction myelography demonstrated a CSF-venous fistula in 15 patients. The mean age of these 8 women and 7 men was 56 years (range, 23-83 years). The mean optic nerve sheath diameter was 4.0 mm, and the mean perioptic subarachnoid space was 0.5 mm in patients with a CSF-venous fistula compared with 4.9 and 1.2 mm, respectively, in patients without a fistula (P < .001). Optimal cutoff values were found at 4.4 mm for optic nerve sheath diameter and 1.0 mm for the perioptic subarachnoid space. Fistulas were detected in about 50% of patients with optic nerve sheath diameter or perioptic subarachnoid space measurements below these cutoff values compared with <2% of patients with optic nerve sheath diameter or perioptic subarachnoid space measurements above these cutoff values. Following surgical ligation of the fistula, optic nerve sheath diameter increased from 4.0 to 5.3 mm and the perioptic subarachnoid space increased from 0.5 to 1.2 mm (P < .001).

CONCLUSIONS

Concerns about a spinal CSF leak should not be dismissed in patients with orthostatic headache when conventional imaging findings are normal, and simple optic nerve sheath MR imaging measurements can help decide if more imaging needs to be performed in this patient population.

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.

Factors to predict recurrence after epidural blood patch in patients with spontaneous intracranial hypotension

OBJECTIVES

This study aimed to identify predictors for the recurrence of spontaneous intracranial hypotension (SIH) after epidural blood patch (EBP).

BACKGROUND

Epidural blood patch is the main treatment option for SIH; however, the characteristics of patients who experience relapse after successful EBP treatment for SIH remain understudied.

METHODS

In this exploratory, retrospective, case-control study, we included 19 patients with SIH recurrence after EBP and 36 age- and sex-matched patients without recurrence from a single tertiary medical institution. We analyzed clinical characteristics, neuroimaging findings, and volume changes in intracranial structures after EBP treatment. Machine learning methods were utilized to predict the recurrence of SIH after EBP treatment.

RESULTS

There were no significant differences in clinical features between the recurrence and no-recurrence groups. Among brain magnetic resonance imaging signs, diffuse pachymeningeal enhancement and cerebral venous dilatation were more prominent in the recurrence group than no-recurrence group after EBP (14/19 [73%] vs. eight of 36 [22%] patients, p = 0.001; 11/19 [57%] vs. seven of 36 [19%] patients, p = 0.010, respectively). The midbrain-pons angle decreased in the recurrence group compared to the no-recurrence group after EBP, at a mean (standard deviation [SD]) of -12.0 [16.7] vs. +1.8[18.3]° (p = 0.048). In volumetric analysis, volume changes after EBP were smaller in the recurrence group than in the no-recurrence group in intracranial cerebrospinal fluid (mean [SD] -11.6 [15.3] vs. +4.8 [17.1] mL, p = 0.001) and ventricles (mean [SD] +1.0 [2.0] vs. +2.0 [2.5] mL, p = 0.003). Notably, the random forest classifier indicated that the model constructed with brain volumetry was more accurate in discriminating SIH recurrence (area under the curve = 0.80 vs. 0.52).

CONCLUSION

Our study suggests that volumetric analysis of intracranial structures may aid in predicting recurrence after EBP treatment in patients with SIH.

Spontaneous Intracranial Hypotension and Subdural Hematomas Treatment Management Using MMA Embolization and Target Blood Patch: A Case Report

We report a patient suffering from spontaneous intracranial hypotension (SIH) who, following a non-selective lumbar blood patch, returned to his healthcare provider with severe symptoms of neurological deficits. It was subsequently discovered that the aforementioned deficits were due to a bilateral subdural hematoma, and an emergency surgical drainage of the hematoma has been performed. However, the hematoma reformed and potential cerebrospinal fluid leakage was consequently investigated through myelography. Following the diagnostic finding of a venous diverticulum, a selective blood patch was executed in the affected area, and in order to stabilize the hematoma, an embolization of the middle meningeal arteries was performed. The combination of such operations allowed for the resorption of the hematoma and the improvement of neurological symptoms.

Immune-Mediated Hypertrophic Pachymeningitis and its Mimickers: Magnetic Resonance Imaging Findings

Hypertrophic pachymeningitis (HP) is a rare and chronic inflammatory disorder presenting as localized or diffuse thickening of the dura mater. It can be idiopathic or an unusual manifestation of immune-mediated, infectious, and neoplastic conditions. Although some cases may remain asymptomatic, HP can lead to progressive headaches, cranial nerve palsies, hydrocephalus, and other neurological complications, which makes its recognition a fundamental step for prompt treatment. Regarding the diagnosis workup, enhanced MRI is the most useful imaging method to evaluate dural thickening. This article addresses the MR imaging patterns of immune-mediated HP, including immunoglobulin G4-related disease, neurosarcoidosis, granulomatosis with polyangiitis, rheumatoid pachymeningitis, and idiopathic HP. The main infectious and neoplastic mimicking entities are also discussed with reference to conventional and advanced MR sequences.

The Spectrum of Headache in Leptomeningeal Metastases: A Comprehensive Review with Clinical Management Guidelines

PURPOSE OF REVIEW

Headaches are a common, oftentimes debilitating symptom in patients with leptomeningeal metastases.

RECENT FINDINGS

The third edition of the International Classification of Headache Disorders provides a useful diagnostic framework for headaches secondary to leptomeningeal metastases based on the temporal relationship of headache with disease onset, change in headache severity in correlation with leptomeningeal disease burden, and accompanying neurologic signs such as cranial nerve palsies and encephalopathy. However, headaches in patients with leptomeningeal metastases can be further defined by a wide range of varying cancer- and treatment-related pathophysiologies, each requiring a tailored approach. A thorough review of the literature and expert opinion on five observed headache sub-classifications in patients with leptomeningeal metastases is provided, with attention to necessary diagnostic testing, recommended first-line treatments, and prevention strategies.

Normal measurements of brainstem and related structures for all ages: An MRI-based morphometric study

Background

Knowledge of the normal size of the brain stem and certain related structures play an important role in diagnosis of aging and neurodegenerative conditions affecting the brain. There is no well-established normative data for development and age-related changes pertaining to the brain stem and related structures in the Indian context. The objective of this study was to assess various linear and angle measurements of the brain stem, cerebral peduncles, middle cerebellar peduncles, and proximal cervical cord for all ages in patients who have undergone MRI brain for unrelated pathologies.

Methods

A record-based retrospective cross-sectional and analytical study. T1WI axial and sagittal images were studied for the following variables: Cerebral peduncle transverse thickness, Interpeduncular angle, Middle cerebellar peduncle transverse thickness, Ventral midbrain anteroposterior thickness, Midbrain height, Mamillopontine distance (MPD), Pontomesencephalic angle (PMA), Pons anteroposterior thickness, Medulla anteroposterior thickness and Spinal cord anteroposterior diameter.

Results

Significant differences (p = 0.001) were observed in nearly all the variables among various age groups. Males demonstrated significantly higher mean values (at 5% level of significance) for a majority of the variables. Most of the variables measured, e.g. Cerebral peduncle, Middle cerebellar peduncle, Ventral midbrain thickness, Midbrain height, Pons, Medulla, and Spinal Cord diameter, showed a steady and sharp increase in values from infancy and reached maximum values during the third decade, followed by a variable degree of decline in values.

Conclusion

Magnetic Resonance Imaging (MRI) morphometry of brainstem and related structures is easily doable and is also reproducible. Present study lays down normative data for the brainstem and certain related structures for all ages, which can be referred to in day-to-day practice.

The SIH-EBP Score: A grading scale to predict the response to the first epidural blood patch in spontaneous intracranial hypotension

BACKGROUND

To develop and validate an easy-to-use scoring system to predict the response to the first epidural blood patching in patients with spontaneous intracranial hypotension.

METHODS

This study recruited consecutive patients with spontaneous intracranial hypotension receiving epidural blood patching in a tertiary medical center, which were chronologically divided into a derivation cohort and a validation cohort. In the derivation cohort, factors associated with the first epidural blood patching response were identified by using multivariable logistic regression modeling. A scoring system was developed, and the cutoff score was determined by using the receiver operating characteristic curve. The findings were verified in an independent validation cohort.

RESULTS

The study involved 280 patients in the derivation cohort and 78 patients in the validation cohort. The spontaneous intracranial hypotension-epidural blood patching score (range 0-5) included two clinical variables (sex and age) and two radiological variables (midbrain-pons angle and anterior epidural cerebrospinal fluid collections). A score of ≥3 was predictive of the first epidural blood patching response, which was consistent in the validation cohort. Overall, patients who scored ≥3 were more likely to respond to the first epidural blood patching (odds ratio = 10.3).

CONCLUSION

For patients with spontaneous intracranial hypotension-epidural blood patching score ≥3, it is prudent to attempt at least one targeted epidural blood patching before considering more invasive interventions.

Outcome of epidural blood patch for imaging-negative spontaneous intracranial hypotension

BACKGROUND

Spontaneous intracranial hypotension is diagnosed by an abnormal finding in brain MRI, spinal imaging, or lumbar puncture. However, the sensitivity of each test is low. We investigated whether patients with suspected spontaneous intracranial hypotension and negative imaging findings would respond to epidural blood patch.

METHODS

We prospectively recruited patients with new-onset orthostatic headache admitted at the Samsung Medical Center from January 2017 to July 2021. In patients without abnormal imaging findings and no history of prior epidural blood patch, treatment outcome-defined as both 50% response in maximal headache intensity and improvement of orthostatic component-was collected at discharge and three months after epidural blood patch.

RESULTS

We included 21 treatment-naïve patients with orthostatic headache and negative brain and spinal imaging results who received epidural blood patch. After epidural blood patch (mean 1.3 times, range 1-3), 14 (66.7%) and 19 (90.5%) patients achieved both 50% response and improvement of orthostatic component at discharge and three months post-treatment, respectively. Additionally, complete remission was reported in 11 (52.4%) patients at three-month follow-up, while most of the remaining patients had only mild headaches. Among nine (42.9%) patients who underwent lumbar puncture, none had an abnormally low opening pressure (median 13.8 cm H₂O, range 9.2-21.5).

CONCLUSION

Given the high responder rates of epidural blood patch in our study, empirical epidural blood patch should be considered to treat new-onset orthostatic headache, even when brain and spinal imaging are negative. The necessity of lumbar puncture is questionable considering the high response rate of epidural blood patch and low rate of "low pressure."

Cavernous Sinus Swelling and Abducens Nerve Paresis Due to Intracranial Hypotension

The most common neurological symptom of spontaneous intracranial hypotension (SIH) is abducens nerve paresis, and the precise pathophysiology is unclear. The accepted explanation is traction on the cranial nerves caused by the downward displacement of the cranial content. We herein report magnetic resonance imaging of SIH that can explain the mechanism underlying abducens nerve paresis. The cavernous sinuses were particularly thickened compared with the surrounding dura. This phenomenon can be explained by venous swelling, which can occur after leakage of cerebrospinal fluid in a closed cavity. This swelling pushes the abducens nerve up, which then causes abducens nerve paresis.

Utility of Neuroimaging in the Management of Chronic and Acute Headache

Imaging plays an important role in identifying the cause of the much less common secondary headaches. Such headaches may be caused by a variety of pathologic conditions which can be categorized as intracranial and extracranial. Idiopathic intracranial hypertension imaging findings include "empty sella," orbital changes, and dural venous sinus narrowing. Intracranial hypotension (ICH) is frequently caused by CSF leaks. Imaging findings include loss of the CSF spaces, downward displacement of the brain, as well as dural thickening and enhancement. Severe cases of ICH may result in subdural hematomas. A variety of intracranial and skull base tumors may cause headaches due to dural involvement. Extracranial tumors and lesions that frequently present with headaches include a variety of sinonasal tumors as well as mucoceles. Neurovascular compression disorders causing headaches include trigeminal and glossopharyngeal neuralgia. Imaging findings include displacement and atrophy of the cranial nerve caused by an adjacent arterial or venous structure.

Spontaneous intracranial hypotension: the role of radiology in diagnosis and management

Spontaneous intracranial hypotension (SIH) is a condition that results from leakage of cerebrospinal fluid (CSF) from the spine, and which typically presents with debilitating orthostatic headache, but can be associated with a wide range of other symptoms. The causes of spontaneous CSF leaks that lead to SIH include dural tears, leaking meningeal diverticula, and CSF-venous fistulas. Imaging plays a central role in the initial diagnosis of SIH and in its subsequent investigation and management. This article reviews the typical neuroimaging manifestations of SIH and discusses the utility of different myelographic techniques for localising spinal CSF leaks as well as the role of image-guided treatment.

Identification and surgical ligation of spinal CSF-venous fistula

Background:

CSF-venous fistulas (CVF) may cause incapacitating positional headaches resulting from spontaneous intracranial hypotension/hypovolemia (SIH). Their etiology remains unknown, although unrecognized local trauma may precipitate SIH. In addition, they are diagnostically challenging despite various imaging tools available. Here, we present CVF identification using magnetic resonance myelography (MRM) and elaborate on their surgical management techniques.

Methods:

Retrospective charts of confirmed and treated CVF patients with attention to their diagnostic imaging modalities and management techniques were further reviewed.

Results:

Six cases were identified of which three are presented here. There were two females and one male patient. All had fistulas on the left side. Two were at T7-T8 while the third was at T9-T10 level. Two underwent hemilaminotomies at the T7-T8 while the third underwent a foraminotomy at T9 level to access the fistula site. All CVF were closed with a combination of an aneurysm clip and a silk tie. On follow-up, all had complete resolution of symptoms with no evidence of recurrence.

Conclusion:

Of the various imaging modalities available, MRM is particularly sensitive in localizing CVF spinal nerve level and their laterality. In addition, the technique of aneurysm clip ligation and placement of a silk tie is curative for these lesions.

Differentiation of Chiari malformation type 1 and spontaneous intracranial hypotension using objective measurements of midbrain sagging

OBJECTIVE

Chiari malformation type 1 (CM-1) and spontaneous intracranial hypotension (SIH) are causes of headache in which cerebellar tonsillar ectopia (TE) may be present. An accurate method for differentiating these conditions on imaging is needed to avoid diagnostic confusion. Here, the authors sought to determine whether objective measurements of midbrain morphology could distinguish CM-1 from SIH on brain MRI.

METHODS

This is a retrospective case-control series comparing neuroimaging in consecutive adult subjects with CM-1 and SIH. Measurements obtained from brain MRI included previously reported measures of brain sagging: TE, slope of the third ventricular floor (3VF), pontomesencephalic angle (PMA), mamillopontine distance, lateral ventricular angle, internal cerebral vein-vein of Galen angle, and displacement of iter (DOI). Clivus length (CL), an indicator of posterior fossa size, was also measured. Measurements for the CM-1 group were compared to those for the entire SIH population (SIHall) as well as a subgroup of SIH patients with > 5 mm of TE (SIHTE subgroup).

RESULTS

Highly significant differences were observed between SIHall and CM-1 groups in the following measures: TE (mean ± standard deviation, 3.1 ± 5.7 vs 9.3 ± 3.5 mm), 3VF (-16.8° ± 11.2° vs -2.1° ± 4.6°), PMA (44.8° ± 13.1° vs 62.7° ± 9.8°), DOI (0.2 ± 4.1 vs 3.8 ± 1.6 mm), and CL (38.3 ± 4.5 vs 44.0 ± 3.3 mm; all p < 0.0001). Eight (16%) of 50 SIH subjects had TE > 5 mm; in this subgroup (SIHTE), a cutoff value of < -15° for 3VF and < 45° for PMA perfectly discriminated SIH from CM-1 (sensitivity and specificity = 1.0). DOI showed perfect specificity (1.0) in detecting SIH among both groups. No subjects with SIH had isolated TE without other concurrent findings of midbrain sagging.

CONCLUSIONS

Measures of midbrain sagging, including cutoff values for 3VF and PMA, discriminate CM-1 from SIH and may help to prevent misdiagnosis and unnecessary surgery.

The time sequence of brain MRI findings in spontaneous intracranial hypotension

OBJECTIVES

To investigate the time sequence of brain magnetic resonance imaging findings of spontaneous intracranial hypotension.

METHODS

We retrospectively reviewed the medical records and brain magnetic resonance imaging findings of consecutive patients with spontaneous intracranial hypotension hospitalized between January 2007 and December 2017. Patients were divided into quartiles based on intervals between initial spontaneous intracranial hypotension symptom onset and brain magnetic resonance imaging scan. Six categorical and five continuous brain magnetic resonance imaging findings were assessed, including venous distension sign, enlarged pituitary gland, diffuse pachymeningeal enhancement, mid-brain pons deformity, subdural fluid collection, flattening of pons, midbrain-pons angle, descent of cerebral aqueduct, mamillopontine distance, distance of suprasellar cistern, and distance of prepontine cistern. In addition, we also calculated the neuroimaging scores with a score ≥5 classified as 'high probability of spontaneous intracranial hypotension' and a score ≥3 as 'intermediate-to-high probability.' Then, we analyzed the linkage between the onset-neuroimaging interval and brain magnetic resonance imaging findings, as well as different neuroimaging scores.

RESULTS

A total of 173 patients (57 males and 116 females) were included in the analysis, and the range of onset-neuroimaging interval was 1 to 89 days (median [interquartile range]  =  17 [7 to 30 days]). We divided the patients into quartiles based on their onset-neuroimaging interval (the first quartile: 0-6 days; the second quartile: 7-16 days; the third quartile: 17-29 days; the fourth quartile: ≥30 days). Among brain magnetic resonance imaging findings, the incidence of venous distension sign was high (>75%), with no difference among quartiles (p = 0.876). The incidence of diffuse pachymeningeal enhancement (p = 0.001), severe midbrain-pons deformity (p = 0.001), and subdural fluid collection (<0.001) followed a significant stepwise increase from the first quartile to fourth quartile. Patients with shorter onset-neuroimaging intervals were less likely to have neuroimaging scores ≥5 (<17 vs. ≥17 days: 72.9% vs. 86.4%; odds ratio = 2.3 [95% CI 1.1-5.1], p = 0.028), but not neuroimaging scores ≥3 (<17 vs. ≥17 days: 92.9% vs. 92.0%, p = 0.824).

CONCLUSIONS

The emergence of brain magnetic resonance imaging findings of spontaneous intracranial hypotension depended on disease duration and appeared sequentially. When using brain magnetic resonance imaging findings or neuroimaging scores for diagnostic purposes, the onset-neuroimaging interval should be considered.

Neuroimaging of Dizziness and Vertigo

Dizziness and vertigo are common symptoms in the primary care and emergency settings, resulting in a significant decrease in quality of life and a high cost burden to the US health care system. The etiology of these symptoms is difficult to elucidate owing to a wide range of diseases with overlapping manifestations. The broad differential diagnosis based on whether the disease process is central or peripheral is showcased. Each differential will be categorized into neoplastic, infectious or inflammatory, structural, traumatic, and iatrogenic causes. Computed tomography scans, MRI, and vascular imaging are frequently complimentary in providing diagnoses and guidance in management.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Brain Herniation and Intracranial Hypertension

This article introduces the basic concepts of intracranial physiology and pressure dynamics. It also includes discussion of signs and symptoms and examination and radiographic findings of patients with acute cerebral herniation as a result of increased as well as decreased intracranial pressure. Current best practices regarding medical and surgical treatments and approaches to management of intracranial hypertension as well as future directions are reviewed. Lastly, there is discussion of some of the implications of critical medical illness (sepsis, liver failure, and renal failure) and treatments thereof on causation or worsening of cerebral edema, intracranial hypertension, and cerebral herniation.

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.

Acute subdural haemorrhage complicating cerebral venous thrombosis in a patient with protein C deficiency

Cerebral venous thrombosis (CVT) directly causing subdural haemorrhage (SDH) is a rare entity. We present a case of an 18-year-old female patient who presented with severe occipital headache. Neuroimaging showed acute SDH and CVT. She was eventually discovered to have underlying protein C deficiency. She was treated with anticoagulation and made an uneventful recovery. We aim to highlight the epidemiology, risk factors and aetiopathogenesis of CVT. We have included a literature review of previously described 13 case studies/reports describing SDH associated with CVT and a brief discussion of the dilemmas associated with management.

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.

Skull Base-related Lesions at Routine Head CT from the Emergency Department: Pearls, Pitfalls, and Lessons Learned

Routine non-contrast material-enhanced head CT is one of the most frequently ordered studies in the emergency department. Skull base-related pathologic entities, often depicted on the first or last images of a routine head CT study, can be easily overlooked in the emergency setting if not incorporated in the interpreting radiologist's search pattern, as the findings can be incompletely imaged. Delayed diagnosis, misdiagnosis, or lack of recognition of skull base pathologic entities can negatively impact patient care. This article reviews and illustrates the essential skull base anatomy and common blind spots that are important to radiologists who interpret nonenhanced head CT images in the acute setting. The imaging characteristics of important "do not miss" lesions are emphasized and categorized by their cause and location within the skull base, and the potential differential diagnoses are discussed. An interpretation checklist to improve diagnostic accuracy is provided. ^©RSNA, 2019.

Lumbar epidural blood patch: effectiveness on orthostatic headache and MRI predictive factors in 101 consecutive patients affected by spontaneous intracranial hypotension

OBJECTIVE

Although epidural blood patch (EBP) is considered the gold-standard treatment for drug-resistant orthostatic headache in spontaneous intracranial hypotension (SIH), no clear evidence exists regarding the best administration method of this technique (blind vs target procedures). The aim of this study was to assess the long-term efficacy of blind lumbar EBP and predictors on preoperative MRI of good outcome.

METHODS

Lumbar EBP was performed by injecting 10 ml of autologous venous blood, fibrin glue, and contrast medium in 101 consecutive patients affected by SIH and orthostatic headache. Visual analog scale (VAS) scores for headache were recorded preoperatively, at 48 hours and 6 months after the procedure, and by telephone interview in July 2017. Patients were defined as good responders if a VAS score reduction of at least 50% was achieved within 48 hours of the procedure and lasted for at least 6 months. Finally, common radiological SIH findings were correlated with clinical outcomes.

RESULTS

The median follow-up was 60 months (range 8-135 months); 140 lumbar EBPs were performed without complications. The baseline VAS score was 8.7 ± 1.3, while the mean VAS score after the first EBP procedure was 3.5 ± 2.2 (p < 0.001). The overall response rate at the 6-month follow-up was 68.3% (mean VAS score 2.5 ± 2.4, p < 0.001). Symptoms recurred in 32 patients (31.7%). These patients underwent a second procedure, with a response rate at the 6-month follow-up of 78.1%. Seven patients (6.9%) did not improve after a third procedure and remained symptomatic. The overall response rate at the last follow-up was 89.1% with a mean VAS score of 2.7 ± 2.3 (p < 0.001). The only MRI predictors of good outcome were location of the iter > 2 mm below the incisural line (p < 0.05) and a pontomesencephalic angle (PMA) < 40° (p < 0.05).

CONCLUSIONS

Lumbar EBP may be considered safe and effective in cases of drug-refractory SIH. The presence of a preprocedural PMA < 40° and location of the iter > 2 mm below the incisural line were the most significant predictors of good outcome. Randomized prospective clinical trials comparing lumbar with targeted EBP are warranted to validate these results.

The Interpeduncular Angle: A Practical and Objective Marker for the Detection and Diagnosis of Intracranial Hypotension on Brain MRI

BACKGROUND AND PURPOSE

Classic findings of intracranial hypotension on MR imaging, such as brain stem slumping, can be variably present and, at times, subjective, potentially making the diagnosis difficult. We hypothesize that the angle between the cerebral peduncles correlates with the volume of interpeduncular cistern fluid and is decreased in cases of intracranial hypotension. We aimed to investigate its use as an objective assessment for intracranial hypotension.

MATERIALS AND METHODS

Brain MRIs of 30 patients with intracranial hypotension and 30 age-matched controls were evaluated by 2 fellowship-trained neuroradiologists for classic findings of intracranial hypotension and the interpeduncular angle. Group analysis was performed with a Student t test, and receiver operating characteristic analysis was used to identify an ideal angle threshold to maximize sensitivity and specificity. Interobserver reliability was assessed for classic findings of intracranial hypotension using the Cohen κ value, and the interpeduncular angle, using the intraclass correlation.

RESULTS

The interpeduncular angle had excellent interobserver reliability (intraclass correlation coefficient value = 0.833) and was significantly lower in the intracranial hypotension group compared with the control group (25.3° versus 56.3°; P < .001). There was significant correlation between the interpeduncular angle and the presence of brain stem slumping (P < .001) and in cases with ≥3 classic features of intracranial hypotension (P = .01). With a threshold of 40.5°, sensitivity and specificity were 80% and 96.7%, respectively.

CONCLUSIONS

The interpeduncular angle is a sensitive and specific measure of intracranial hypotension and is a reliably reproducible parameter on routine clinical MR imaging.

Solving the Riddle of "Idiopathic" in Idiopathic Intracranial Hypertension and Normal Pressure Hydrocephalus: An Imaging Study of the Possible Mechanisms - Monro-Kellie 3.0

Background

Idiopathic intracranial hypertension (IIH) and normal pressure hydrocephalus (NPH) represent a cluster of typical clinical and imaging findings, with no evident etiological cause noted. In this study, we have proposed a model for IIH and NPH called Monroe-Kellie 3.0 (MK 3.0). IIH and NPH may be entities which represent opposite sides of the same coin with venous system and cerebrospinal fluid (CSF) as core drivers for both these entities.

Materials and Methods

IIH and NPH volume data were collected, voxel-based morphometry analysis was performed without normalization, and the distribution of the individual volumes of gray matter, white matter, and CSF was statistically analyzed. Visual morphometry analyses of segmented data were performed, and the findings in routine magnetic resonance imaging (MRI) were noted to build a model for IIH and NPH.

Results

In IIH and NPH when the volumes were compared with controls, the distribution was similar. Furthermore, the morphometric changes noted in the MRI and segmented volume data were analyzed and the results were suggestive of changes in elastic property of brain causing a remodeling of brain shape and resulting in minor brain shift in the skull vault, and the resulting passive displacement of CSF which has been termed as MK 3.0.

Conclusion

This model helps to put the clinical and imaging findings and complications of treatment in single perspective.

The Importance of Measuring Mamillopontine Distance as a Diagnostic Criterion of Hydrocephalus Degrees

OBJECTIVES

The occurrence of obstructive hydrocephalus (ObH) as sequelae of deep midline brain tumors (third and lateral ventricles, thalamic, pineal region, brainstem, and fourth ventricle) can be estimated up to 90% of cases. We believe that the mamillopontine distance (MPD) - the distance between the lower surface of the mammillary body and the upper surface of the pons in the sagittal images - can be a sufficiently reliable alternative to the Evans' index (EI) for the diagnosis of ObH.

PATIENTS AND METHODS

The results of mamillopontine distance (MPD), Evans' index (EI), and angle of corpus callosum (ACC) measurement of 43 patients with non-communicative hydrocephalus were analyzed compared with results of 30 people without brain pathology.

RESULTS

Findings revealed that MPD is a strong and reliable alternative to the EI. MPD showed high specificity and sensitivity in the diagnosis of occlusive hydrocephalus. Moreover, from those findings, we have proposed classification of the degree of hydrocephalus severity, depending on the MPD.

CONCLUSION

MPD one of the more accurate and powerful method for defining presence of hydrocephalus in-patient even in early stage of occlusion. It has high specificity and sensitivity and capable classify hydrocephalus into grades according to severity.

Hypertrophic pachymeningitis associated with antineutrophil cytoplasmic antibody-associated vasculitis: a case series of 15 patients

OBJECTIVE

We aimed to describe the clinical characteristics and treatment course of hypertrophic pachymeningitis (HPM) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

METHODS

We retrospectively analysed 15 patients (11 men and four women). HPM was diagnosed based on thickening and enhancing of the brain and/or spinal dura mater on gadolinium-enhanced magnetic resonance imaging (MRI) T1 sequence.

RESULTS

The median age at HPM onset was 60 years. Headache and cranial nerve impairment were observed in 14 and 10 patients, respectively. Otitis media and/or mastoiditis were found as complications of AAV in 11 patients. Fourteen patients were classified as having granulomatosis with polyangiitis (GPA). Single-positive myeloperoxidase-ANCA, single-positive proteinase 3-ANCA, and double-positive ANCA were identified in seven patients, five patients, and one patient, respectively. With MRI, thickening of the dura mater in the cranial fossa and tentorium cerebelli was found in 10 and eight patients, respectively. For remission induction, all patients were treated with corticosteroids, and immunosuppressants were added in 10 patients. Dura mater thickening partially improved in all patients, and cranial neuropathy completely remitted in eight patients. In a median follow-up of 43 months, four patients had HPM relapse and underwent reinduction therapy. All six patients treated with cyclophosphamide at initial therapy did not relapse.

CONCLUSIONS

HPM was mostly associated with patients with GPA with otitis media and/or mastoiditis having either type of ANCA serology. Treatment with corticosteroids with or without immunosuppressants was effective. However, HPM relapse occasionally occurred, especially when cyclophosphamide was not used in initial treatment.

Correlations among brain and spinal MRI findings in spontaneous intracranial hypotension

Objectives

Several brain and spinal magnetic resonance imaging signs have been described in spontaneous intracranial hypotension. Their correlations are not fully studied. This study aimed to explore potential mechanisms underlying cerebral neuroimaging findings and to examine associations among spinal and brain magnetic resonance imaging signs.

Methods

We conducted a retrospective review of magnetic resonance myelography and brain magnetic resonance imaging records of patients with spontaneous intracranial hypotension. Categorical principal component analysis was employed to cluster brain neuroimaging findings. Spearman correlation was employed to analyze associations among different brain neuroimaging findings and between brain and spinal neuroimaging findings.

Results

In patients with spontaneous intracranial hypotension (n = 148), categorical principal component analysis of brain neuroimaging signs revealed two clusters: Cerebral venous dilation and brain descent. Among all brain magnetic resonance imaging signs examined, only midbrain-pons angle associated with anterior epidural cerebrospinal fluid collection length (surrogate spinal cerebrospinal fluid leak severity) (n = 148, Spearman’s ρ = −0.38, p < .001). Subgroup analyses showed that the association between midbrain-pons angle (within brain descent cluster) and spinal cerebrospinal fluid leak severity was presented in patients with convex margins of the transverse sinuses (n = 122, Spearman’s ρ = −0.43, p < .001), but not in patients without convex margins (n = 26, Spearman’s ρ = −0.19, p = .348). The association between severity of transverse sinus distension and spinal cerebrospinal fluid leak severity was only presented in patients without convex margins (n = 26, Spearman’s ρ = 0.52, p = .006).

Conclusion

This study indicates that there are two factors behind the brain neuroimaging findings in spontaneous intracranial hypotension: Cerebral venous dilation and brain descent. Certain brain neuroimaging signs correlate with spinal cerebrospinal fluid leakage severity, depending on different circumstances.

Benign paroxysmal positional vertigo in spontaneous intracranial hypotension

OBJECTIVES

To assess the prevalence and related factors of benign paroxysmal positional vertigo (BPPV) in patients with spontaneous intracranial hypotension (SIH).

METHODS

We retrospectively reviewed 156 consecutive inpatients with SIH, and collected the clinical and radiological data. These patients were divided into BPPV group and non-BPPV group according to the clinical manifestation and the results of Dix-Hallpike or supine roll tests during hospitalization period. We performed a univariate analysis and a further multiple logistic regression analysis to identify the related factors of the development of BPPV in SIH patients.

RESULTS

BPPV was detected in 18 patients among the total 156 SIH patients (11.54%). The univariate analysis showed a low cerebrospinal fluid (CSF) pressure (P = 0.018), a small pontomesencephalic angle (P = 0.012) and a positive venous distension sign (VDS) (P = 0.045) were associated with the presence of BPPV. But the multivariate analysis only demonstrated a low CSF pressure was related to the presence of BPPV (OR = 1.022, 95% CI: 1.001-1.043, P = 0.044).

CONCLUSION

BPPV is common in SIH patients. SIH patients with low CSF pressure may be prone to develop BPPV.

Spontaneous Intracranial Hypotension: 10 Myths and Misperceptions

OBJECTIVE

To discuss common myths and misperceptions about spontaneous intracranial hypotension (SIH), focusing on common issues related to diagnosis and treatment, and to review the evidence that contradicts and clarifies these myths.

BACKGROUND

Recognition of SIH has increased in recent years. With increasing recognition, however, has come an increased demand for management by neurologists and headache specialists, some of whom have little prior experience with the condition. This dearth of practical experience, and lack of awareness of recent investigations into SIH, produces heterogeneity in diagnostic and treatment pathways, driven in part by outdated, confusing, or unsubstantiated conceptions of the condition. We sought to address this heterogeneity by identifying 10 myths and misperceptions that we frequently encounter when receiving referrals for suspected or confirmed SIH, and to review the literature addressing these topics.

METHODS

Ten topics relevant to diagnosis and treatment SIH were generated by the authors. A search for studies addressing SIH was conducted using PubMed and EMBASE, limited to English language only, peer reviewed publications from inception to 2018. Individual case reports were excluded. The resulting studies were reviewed for relevance to the topics in question.

RESULTS

The search generated 557 studies addressing SIH; 75 case reports were excluded. Fifty-four studies were considered to be of high relevance to the topics addressed, and were included in the data synthesis. The topics are presented in the form of a narrative review.

CONCLUSIONS

The understanding of SIH has evolved over the recent decades, leading to improvements in knowledge about the pathophysiology of the condition, diagnostic strategies, and expanded treatments. Awareness of these changes, and dispelling outdated misconceptions about SIH, is critical to providing appropriate care for patients and guiding future investigations going forward.

Secondary intracranial hypertension (pseudotumor cerebri) presenting as post-traumatic headache in mild traumatic brain injury: a case series

BACKGROUND

Cerebral edema peaks 36-72 h after moderate traumatic brain injury but thought to be uncommon after mild traumatic brain injury. Post-traumatic headache can develop 48-72 h post-injury, perhaps reflecting the developing cerebral edema. Pseudotumor cerebri can result from various causes, including cerebral edema, and is characterized by increased intracranial pressure, headache, visual, and other common symptoms. Our objective was to report a phenotypically identifiable post-traumatic headache subtype.

CASE SERIES PRESENTATION

This case series of six pediatric patients with post-traumatic pseudotumor cerebri was assessed at 48-120 h post-primary injury with new or a change in symptoms such as headache, vision, auditory, balance, and cognition. Clinical findings included slight fever, neck/head pain, papilledema or cranial nerve deficit (6th), and lack of coordination. Elevated cerebral spinal fluid pressure was documented by lumbar puncture, with no infection. Symptoms improved with treatment specific to post-traumatic headache subtype (lumbar puncture, topiramate, or acetazolamide).

CONCLUSIONS

Recognition of specific post-traumatic headache subtypes after mild traumatic brain injury will expedite treatment intervention to lower intracranial pressure and resolve symptoms.

An Objective Study of Anatomic Shifts in Intracranial Hypotension Using Four Anatomic Planes

PURPOSE

Intracranial hypotension (IH) often remains undetected using current MR diagnostic criteria. This project aims to demonstrate that central incisural herniation is highly effective in helping to make this diagnosis.

MATERIALS AND METHODS

Magnetic resonance imaging (MRI) was analyzed in 200 normal and 81 clinically known IH patients. MRI reference lines approximating the plane of the incisura, the plane of the diaphragma sella, the plane of the foramen magnum, and the plane of the visual pathway were utilized to measure the position of selected brain structures relative to these reference lines.

RESULTS

All IH patients had highly statistically significant (p < 0.0001) measurable evidence of downward central incisural herniation when compared to normal controls. The first of the important observations was a downward shift of the mammillary bodies, which shortened the midsagittal width of the interpeduncular fossa cistern. A concurrent downward shift and deformity of the tuber cinereum accompanied the mammillary body shift. The second essential observation was an abnormal clockwise rotation of the long axis of the visual pathway. A severity grading system is proposed based on the extent of these shifts as well as secondary shifts of the brain stem, splenium, and cerebellar tonsils.

CONCLUSION

This study objectively delineates the anatomic shifts of brain structures adjacent to the incisura and foramen magnum. This methodology is sufficient to recognize the features of IH and to stratify the spectrum of IH findings into a functional grading system for quantifying the results of interventional therapy.

Intracranial structural alteration predicts treatment outcome in patients with spontaneous intracranial hypotension

Background Intracranial structural dislocation in spontaneous intracranial hypotension (SIH) can be measured by various intracranial angles and distances. We aimed to identify the clinical significance of structural dislocation in relation to treatment outcome in patients with SIH. Methods In this retrospective analysis, we identified patients with SIH who received an epidural blood patch (EBP) at Samsung Medical Center from January 2005 to March 2015. Structural dislocation in pretreatment MRIs of SIH patients was assessed by measuring tonsillar herniation, mamillopontine distance, the angle between the vein of Galen and straight sinus (vG/SS angle), the pontomesencephalic angle, and the lateral ventricular angle. After the first EBP, poor response was defined as the persistence of symptoms that prompted a repeat EBP. Results Out of the 95 patients included, 31 (32.6%) showed poor response. Among the radiological markers of structural dislocation, the vG/SS angle was associated with poor response (49.82 ± 16.40° vs 66.58 ± 26.08°, p = 0.002). Among clinical variables, premorbid migraine ( p = 0.036) was related to poor response. In multivariate analysis, reduced vG/SS angle was independently associated with poor response (OR 1.04 [95% CI 1.01 - 1.07] per 1° decrease, p = 0.006). In 23 patients who underwent MRI after successful treatment, the vG/SS angle significantly increased after the EBP ( p < 0.001, by paired t-test), while two patients with aggravation or recurrence showed a further reduction of their vG/SS angles. Conclusions Intracranial structural dislocation, measured by the vG/SS angle, is associated with poor response to the first EBP in patients with SIH. Successful treatment can reverse the structural dislocation.

Intracranial hypotension: An uncommon entity with common presentation

Headache disorders are among the most common presenting complaints in any neurology outpatient department. International Headache Society classifies headaches as "primary" or "secondary". The causes of secondary headaches are varied and intracranial hypotension is one of them. It typically presents clinically with postural headaches but most of the times, its diagnosis is delayed, as it is an uncommon cause and there is poor awareness among the medical fraternity about this condition. Imaging, especially magnetic resonance imaging (MRI), plays a crucial role in the diagnosis of intracranial hypotension by not only confirming the diagnosis but also detecting the cause in some cases. This case series tries to highlight the MRI findings of intracranial hypotension in three cases with different etiologies.

Intracranial Hypotension Following Traumatic Brain Injury: A Diagnostic and Therapeutic Challenge

BACKGROUND

Intracranial hypotension (IH) is a recognized cause of coma; however, the diagnosis is often challenging, especially in patients with superimposed traumatic brain injury.

CASE DESCRIPTION

A 67-year-old woman became comatose following evacuation of bilateral acute subdural hematomas with concurrent respiratory failure. Imaging and intraparenchymal intracranial pressure monitoring confirmed secondary IH. She was managed with an epidural blood patch and a 72-hour period in the Trendelenburg position guided by intracranial pressure monitoring and clinical assessment. She subsequently made an excellent neurologic recovery from an initial Glasgow Coma Scale score of 3 to a score of 15.

CONCLUSIONS

Secondary IH can easily be missed in patients who have sustained a primary brain injury. In patients with a poor neurologic recovery, clinicians should rule out secondary IH as a potential cause, as immediate treatment can lead to profound clinical improvement.