Reversible Cerebral Vasoconstriction Syndrome with Multivessel Cervical Artery Dissections and a Double Aortic Arch

The Role of Hemodynamics through the Circle of Willis in the Development of Intracranial Aneurysm: A Systematic Review of Numerical Models

Background: The role of regional hemodynamics in the intracranial aneurysmal formation, growth, and rupture has been widely discussed based on numerical models over the past decades. Variation of the circle of Willis (CoW), which results in hemodynamic changes, is associated with the aneurysmal formation and rupture. However, such correlation has not been further clarified yet. The aim of this systematic review is to investigate whether simulated hemodynamic indices of the CoW are relevant to the formation, growth, or rupture of intracranial aneurysm. Methods: We conducted a review of MEDLINE, Web of Science, and EMBASE for studies on the correlation between hemodynamics indices of the CoW derived from numerical models and intracranial aneurysm up to December 2020 in compliance with PRISMA guidelines. Results: Three case reports out of 1046 publications met our inclusion and exclusion criteria, reporting 13 aneurysms in six patients. Eleven aneurysms were unruptured, and the state of the other two aneurysms was unknown. Wall shear stress, oscillatory shear index, von-Mises tension, flow velocity, and flow rate were reported as hemodynamic indices. Due to limited cases and significant heterogeneity between study settings, meta-analysis could not be performed. Conclusion: Numerical models can provide comprehensive information on the cerebral blood flow as well as local flow characteristics in the intracranial aneurysm. Based on only three case reports, no firm conclusion can be drawn regarding the correlation between hemodynamic parameters in the CoW derived from numerical models and aneurysmal formation or rupture. Due to the inherent nature of numerical models, more sensitive analysis and rigorous validations are required to determine its measurement error and thus extend their application into clinical practice for personalized management. Prospero registration number: CRD42021125169.

Illicit Drugs and Reversible Cerebral Vasoconstriction Syndrome

Reversible cerebral vasoconstriction syndrome (RCVS) is a condition characterized by thunderclap headache and associated vasospasm of the cerebral vasculature. A multitude of factors are considered to potentially predispose to the development of RCVS. These potential precipitants include numerous illicit drugs. In this study, we investigated the role of illicit drugs as a precipitating factor for RCVS, through systematic review of the relevant literature. We found the strongest evidence for cannabis, but a relative lack of evidence to support other illicit drugs, particularly as individual precipitating factors. We also identified a lack of the consistent application of diagnostic criteria for RCVS, which undoubtedly hampers advancement of knowledge in this field. Consistent adherence to diagnostic criteria will be important for future studies. Ultimately, a prospective registry of RCVS cases would be advantageous to advance understanding of the condition and its underlying causes.

Cerebrovascular Complications Associated with Marijuana Use

PURPOSE OF REVIEW

In the last few years, the attitude toward marijuana in many parts of the world has shifted from illicit to legalized for medical use and to decriminalized. In parallel, there has been a gradual increase in the consumption of this product in the general population, particularly among adolescents and young adults. Marijuana is generally perceived as a harmless drug. However, data obtained in observational studies and preclinical models have established associations between cannabis use and cardiovascular events. In addition, there is emerging evidence linking marijuana use to cerebrovascular complications. Here we provide a critical review of the literature with special emphasis on the association of cannabinoids with stroke and the possible pathogenic mechanisms involved.

RECENT FINDINGS

Ischemic and hemorrhagic stroke have been described in association with cannabis use, particularly in young individuals. Cerebral infarction remains the most commonly reported stroke subtype seen in marijuana users. Several pathogenic mechanisms have been proposed to explain this association, including multifocal intracranial stenosis, reversible cerebral vasoconstriction syndrome, and coexisting vascular risk factors. Cannabis use is increasingly recognized in young individuals presenting with acute stroke. Our understanding of the pathogenic mechanisms associated with cannabis use and stroke is limited but rapidly evolving. Healthcare providers should educate patients about the potential cardiovascular and cerebrovascular complications related to marijuana or cannabinoids use.

Harmful Effects of Smoking Cannabis: A Cerebrovascular and Neurological Perspective

Apart from being used as a medicine, cannabis or marijuana is the most widely abused recreational drug all over the world. The legalization and decriminalization of cannabis in Canada and various states of USA may be the underlying reason of the widespread popularity of it among young population. Various studies have reported about the relationship between cannabis use and different detrimental effects like cardiovascular, cerebrovascular, and neurological complications among different age groups. Specifically, the young population is getting adversely affected by this, harmful yet, readily accessible recreational drug. Although the mechanism behind cannabis mediated neurological and cerebrovascular complications has not been elucidated yet, the results of these studies have confirmed the association of these diseases with cannabis. Given the lack of comprehensive study relating these harmful complications with cannabis use, the aim of this narrative literature review article is to evaluate and summarize current studies on cannabis consumption and cerebrovascular/neurological diseases along with the leading toxicological mechanisms.

Strokes are possible complications of cannabinoids use

It is critically important to identify all factors that may play a role in the recent increase of the incidence of stroke among the young population. Considering the worldwide use of cannabinoids (cannabis and synthetic cannabinoids), the recent legalization of their consumption in some countries, and their supposed involvement in cardiovascular events, we evaluated their role in the occurrence of neurovascular complications among the young. Ninety-eight patients were described in the literature as having a cannabinoids-related stroke (85 after cannabis use and 13 after synthetic cannabinoids). The distribution by type of stroke was as follows: 4 patients with an undetermined type of stroke, 85 with an ischemic stroke and/or a transient ischemic attack, and 9 with a hemorrhagic stroke. The mean age of patients was 32.3±11.8years (range 15-63), and the majority of them were male with a sex ratio of 3.7:1. Cannabis was often smoked with tobacco in 66% of cases. Most of the patients with cannabinoids-related strokes were chronic cannabis users in 81% of cases, and for 18% of them, there was a recent increase of the amount of cannabis consumption during the days before the occurrence of stroke. Even if the prognosis of stroke was globally favorable in 46% of cases, with no or few sequelae, 5 patients died after the neurovascular event. One striking element reported in the majority of the reports was a temporal relationship between cannabinoids use, whether natural or synthetic, and the occurrence of stroke. However, a temporal correlation does not mean causation, and other factors may be involved. Cannabis may be considered as a risk factor of stroke until research shows evidence of an underlying mechanism that, alone or in association with others, contributes to the development of stroke. As of today, reversible cerebral vasoconstriction triggered by cannabinoids use may be a convincing mechanism of stroke in 27% of cases. Indeed, despite the widespread use of cannabinoids, the low frequency of neurovascular complications after their use may be due to a genetic predisposition to their neurovascular toxicity in some individuals. Further studies should focus on this point. More importantly however, this low frequency may be underestimated because the drug consumption may not be systematically researched, neither by questioning nor by laboratory screening. Besides this vascular role of cannabinoids in the occurrence of stroke, a cellular effect of cannabis on brain mitochondria was recently suggested in an experimental study. One of the mechanisms involved in young cannabis users with stroke may be the generation of reactive oxygen species leading to an oxidative stress, which is a known mechanism in stroke in humans. It is useful to inform the young population about the real potential risk of using cannabinoids. We suggest to systematically ask all young adults with stroke about their drug consumption including cannabinoids, to screen urine for cannabis or to include a specific diagnostic test to detect synthetic cannabinoids, and to obtain non-invasive intracranial arterial investigations (i.e. CT-angiography or cerebral MRA) in order to search for cerebral vasoconstriction. However, several questions remained unresolved and further research is still needed to assess the pathophysiological mechanisms involved in young cannabinoids users with stroke. This article is part of a Special Issue entitled "Cannabinoids and Epilepsy".

Coexisting vascular lesions in reversible cerebral vasoconstriction syndrome

Background

The pathophysiology of reversible cerebral vasoconstriction syndrome (RCVS) is not known. Published cases have documented coexisting cervical artery dissection and unruptured aneurysms, raising the possibility that ultrastructural vessel wall abnormalities underlie the development of vascular lesions as well as RCVS.

Methods

In this retrospective study we compared the frequency of neurovascular abnormalities in 158 consecutive RCVS patients, 44 patients with primary angiitis of the central nervous system (PACNS, positive controls), and 177 non-stroke patients with acute neurological symptoms (non-arteriopathy controls).

Results

Coexisting neurovascular abnormalities were significantly higher ( p < 0.001) in RCVS (23%) as compared to the PACNS (5%) or non-arteriopathy groups (8%). Cervical artery dissections were noted only in the RCVS group (8%, p < 0.001). The RCVS group had more unruptured aneurysms than PACNS (13% vs. 5%, p = 0.099) or non-arteriopathy controls (13% vs. 7%, p = 0.05). Seven RCVS patients also had other vascular malformations (venous anomaly, cavernous malformations, fibromuscular dysplasia). There was no significant association between coexisting vascular abnormalities and brain lesions or discharge clinical outcome in the RCVS group.

Conclusion

The high prevalence and heterogeneous anatomy of coexisting vascular lesions suggest that subtle ultrastructural arterial wall abnormalities may contribute to their development and also predispose to RCVS.

Reversible cerebral vasoconstriction syndrome - A narrative revision of the literature

Reversible Cerebral Vasoconstriction Syndrome (RCVS) is a not very well known clinical-imaging entity; it is characterized by thunderclap headache, which mimics an aneurysmal subarachnoid haemorrhage, and a diffuse and segmental constriction of cerebral arteries, that resolves spontaneously within 3 months. The pathophysiology remains unknown. The female gender is the more affected and more than half of cases occur in the puerperium or after exposure to vasoactive substances. Typically, RCVS is self-limited and has a benign course, although it may have more serious complications with permanent neurologic sequelae and death. Treatment is predominantly supportive and directed to the symptoms.

The Link Between Migraine, Reversible Cerebral Vasoconstriction Syndrome and Cervical Artery Dissection

Headache is the common thread of migraine, reversible cerebral vasoconstriction syndrome (RCVS) and cervical artery dissection (CeAD), three medical conditions that otherwise appear to be very different. However, epidemiological, clinical and genetic data suggest that these conditions share common and complex features and are, at least partly, linked. The purpose of this manuscript is to review existing evidence for an association between migraine, RCVS and CeAD and discuss the potential underlying mechanisms.

Cannabis and stroke: systematic appraisal of case reports

BACKGROUND AND PURPOSE

An increasing number of case reports link cannabis consumption to cerebrovascular events. Yet these case reports have not been scrutinized using criteria for causal inference.

METHODS

All case reports on cannabis and cerebrovascular events were retrieved. Four causality criteria were addressed: temporality, adequacy of stroke work-up, effects of rechallenge, and concomitant risk factors that could account for the cerebrovascular event.

RESULTS

There were 34 case reports on 64 patients. Most cases (81%) exhibited a temporal relationship between cannabis exposure and the index event. In 70%, the evaluation was sufficiently comprehensive to exclude other sources for stroke. About a quarter (22%) of patients had another stroke after subsequent re-exposure to cannabis. Finally, half of patients (50%) had concomitant stroke risk factors, most commonly tobacco (34%) and alcohol (11%) consumption.

CONCLUSIONS

Many case reports support a causal link between cannabis and cerebrovascular events. This accords well with epidemiological and mechanistic research on the cerebrovascular effects of cannabis.

Reversible Cerebral Vasoconstriction Syndrome, Part 2: Diagnostic Work-Up, Imaging Evaluation, and Differential Diagnosis

The diagnostic evaluation of a patient with reversible cerebral vasoconstriction syndrome integrates clinical, laboratory, and radiologic findings. Imaging plays an important role by confirming the presence of cerebral vasoconstriction; monitoring potential complications such as ischemic stroke; and suggesting alternative diagnoses, including CNS vasculitis and aneurysmal subarachnoid hemorrhage. Noninvasive vascular imaging, including transcranial Doppler sonography and MR angiography, has played an increasingly important role in this regard, though conventional angiography remains the criterion standard for the evaluation of cerebral artery vasoconstriction. Newer imaging techniques, including high-resolution vessel wall imaging, may help in the future to better discriminate reversible cerebral vasoconstriction syndrome from primary angiitis of the CNS, an important clinical distinction.

Reversible Cerebral Vasoconstriction Syndrome, Part 1: Epidemiology, Pathogenesis, and Clinical Course

Reversible cerebral vasoconstriction syndrome is a clinical and radiologic syndrome that represents a common presentation of a diverse group of disorders. The syndrome is characterized by thunderclap headache and reversible vasoconstriction of cerebral arteries, which can either be spontaneous or related to an exogenous trigger. The pathophysiology of reversible cerebral vasoconstriction syndrome is unknown, though alterations in cerebral vascular tone are thought to be a key underlying mechanism. The syndrome typically follows a benign course; however, reversible cerebral vasoconstriction syndrome may result in permanent disability or death in a small minority of patients secondary to complications such as ischemic stroke or intracranial hemorrhage.