Primary Angiitis of the CNS: A Systematic Review and Meta-analysis

Pearls & Oy-sters: Tumour-Like Mass Lesion Secondary to Primary CNS Vasculitis

Primary CNS vasculitis (PCNSV) is uncommonly considered in the differential diagnosis of tumor-like lesions. This case report of tumefactive PCNSV highlights imaging features that should increase clinical suspicion for CNS vasculitis, potentially lending to earlier diagnosis and treatment. A 62-year-old man presented with a 1-month history of focal motor seizures and cortical sensory loss localizing to the right frontoparietal lobe. Noncontrast head CT was suggestive of glioma, resulting in intravenous dexamethasone administration and admission to neurosurgery. MRI appearance was atypical for glioma, with relative preservation of regional anatomy, intralesional microhemorrhage, and patchy peripheral enhancement. Despite normal CT angiogram, CSF, and serum inflammatory markers, brain biopsy was suggestive of lymphocytic vasculitis. Extensive workup for secondary causes was negative, and he was diagnosed with tumefactive PCNSV. Treatment with corticosteroids and cyclophosphamide resulted in sustained clinical and radiologic improvement. Tumefactive PCNSV is an angiogram-negative small-vessel vasculitis that has a lymphocytic histologic pattern. Tumefactive PCNSV constitutes over 10% of PCNSV cases and can be recognized by the presence of intralesional microhemorrhages, absence of diffusion restriction, and a patchy or nodular enhancement pattern. The most important mimicker is CNS lymphoma, which has a similar imaging and histologic pattern. If individuals with tumefactive PCNSV do not have a sustained immunotherapy response, repeat biopsy should be promptly performed.

[Inflammatory causes of stroke-Diagnostics and treatment]

Inflammatory causes of stroke are frequent and often pose diagnostic and therapeutic challenges due to the scarcity of randomized trials and the absence of clear guideline recommendations for many scenarios. Following the publication of the recommendations of the European Stroke Organization on primary angiitis of the central nervous system (PACNS) last year, the German Neurological Society (DGN) has issued very clear guidelines this year on the diagnostics and treatment of PACNS and updated the recommendations for systemic vasculitides; however, stroke often occurs not only as a result of primary vascular inflammation but also as a complication of another organ infection. Approximately 5% of all patients with sepsis, ca. 20% of patients with bacterial meningitis and up to 40% of patients with bacterial endocarditis suffer from a stroke as a complication. This article summarizes the key characteristics of these inflammatory causes of stroke and particularly focuses on the current recommendations for diagnostic and therapeutic management.

Prognostic Factors and Outcome Measures After Rituximab Therapy in Central Nervous System Vasculitis: A Systematic Review

Given the growing popularity of Rituximab (Rmab) treatment as a potential substitute for cyclophosphamide, we conducted this review to determine aspects related to Rmab therapy in central nervous system vasculitis (CNSV) patients, aiming to establish both the beneficial and detrimental consequences of Rmab while providing clinical guidance for managing patients' conditions. This systematic review was prepared following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The PubMed, Web of Science, and Scopus databases were utilized to investigate Rmab treatment in CNSV from January 2015 to May 2024. The research question was structured using the Population, Intervention, Comparison, Outcome, and Study Design (PICOS) criteria. Case series with only three or more unique cases, prospective or retrospective non-randomized studies, and randomized controlled trials (RCTs) were addressed. The initial evaluations were performed in PubMed, Scopus, and Web of Science. After removing duplicate entries, 177 publications were obtained, and 41 were chosen for full-text assessment. The review then incorporated information gathered from 27 studies, including 4 case series, 15 non-randomized cohorts, and 8 RCTs. Rmab is generally regarded as effective for CNSV therapy. Given its success, induction Rmab therapy is now frequently employed as maintenance therapy for CNSV patients. Rmab is a viable option for the induction of remission and maintenance treatment, with a successful reduction in relapse rates.

Predictive Value of Clinical, CSF and Vessel Wall MRI Variables in Diagnosing Primary Angiitis of the CNS

Background and Objectives

Without brain biopsy, there are limited diagnostic predictors to differentiate primary angiitis of the CNS (PACNS) from intracranial atherosclerotic disease (ICAD). We examined the utility of clinical, CSF, and quantitative vessel wall magnetic resonance imaging (VWMRI) variables in predicting PACNS from ICAD.

Methods

In this cross-sectional design, observational study, we reviewed electronic medical records to identify patients (18 years and older) who presented to our medical center between January 2015 and December 2021 for ischemic stroke due to intracranial vasculopathy. Patients with biopsy-proven PACNS, probable PACNS, or ICAD were included. Patients with secondary CNS vasculitis or no VWMRI data were excluded. On VWMRI, for each patient, a total of 20 vessel wall segments were analyzed for percent concentricity, percent irregularity, and concentricity to eccentricity (C/E) ratios. We also collected several clinical and CSF variables. Using logistic regression models, we assessed the diagnostic value of VWMRI, CSF, and clinical variables in predicting PACNS in patients with biopsy-proven disease. We then performed a sensitivity analysis to assess predictors of biopsy-proven and probable PACNS.

Results

Thirty-two patients with ICAD (54.2%) and 27 patients with PACNS (45.8%) were included. Of the patients with PACNS, 21 (77.8%) were not biopsied and considered probable PACNS. Twenty-four patients with ICAD (75%) and 6 biopsy-proven patients with PACNS (22.2%) showed large vessel involvement and were included in the primary analysis. Encephalopathy (odds ratio [OR], 7.60; 95% CI 1.07-54.09) and seizure (OR 23.00; 95% CI 1.77-298.45) were significantly associated with PACNS. All patients were included in the sensitivity analysis, in which headache significantly predicted PACNS (OR 7.60; 95% CI 1.07-54.09). In the primary analysis, for every 1 white blood cell/µL increase in CSF, there was a 47% higher odds of PACNS (OR 1.47; 95% CI 1.04-2.07). On VWMRI, a C/E ratio >1 (OR 115.00; 95% CI 6.11-2165.95), percent concentricity ≥50% (OR 55.00; 95% CI 4.13-732.71), and percent irregularity <50% (OR 55.00; 95% CI 4.13-732.71) indicated significantly higher odds of PACNS compared with ICAD.

Discussion

Our results suggest that quantitative VWMRI metrics, CSF pleocytosis, and clinical features of encephalopathy, seizure, and headache significantly predict a diagnosis of probable PACNS when compared with ICAD.

Cerebral Amyloid Angiopathy-Related Inflammation and Biopsy-Positive Primary Angiitis of the CNS: A Comparative Study

BACKGROUND AND OBJECTIVES

Cerebral amyloid angiopathy-related inflammation (CAA-RI) and biopsy-positive primary angiitis of the CNS (BP-PACNS) have overlapping clinicoradiologic presentations. It is unknown whether clinical and radiologic features can differentiate CAA-RI from BP-PACNS and whether both diseases have different relapse rates. The objectives of this study were to compare clinicoradiologic presentations and relapse rates in patients with CAA-RI vs BP-PACNS.

METHODS

Patients with CAA-RI and BP-PACNS were enrolled from 2 retrospective multicenter cohorts. Patients with CAA-RI were biopsy-positive or met probable clinicoradiologic criteria. Patients with BP-PACNS had histopathologic confirmation of CNS angiitis, with no secondary etiology. A neuroradiologist read brain MRIs, blinded to the diagnosis of CAA-RI or BP-PACNS. Clinicoradiologic features were compared using univariable logistic regression models. Relapse rates were compared using a univariable Fine-Gray subdistribution hazard model, with death as a competing risk.

RESULTS

This study enrolled 104 patients with CAA-RI (mean age 73 years, 48% female sex) and 52 patients with BP-PACNS (mean age 45 years, 48% female sex). Patients with CAA-RI more often had white matter hyperintense lesions meeting the probable CAA-RI criteria (93% vs 51%, p < 0.001), acute subarachnoid hemorrhage (15% vs 2%, p = 0.02), cortical superficial siderosis (27% vs 4%, p < 0.001), ≥1 lobar microbleed (94% vs 26%, p < 0.001), past intracerebral hemorrhage (17% vs 4%, p = 0.04), ≥21 visible centrum semiovale perivascular spaces (34% vs 4%, p < 0.01), and leptomeningeal enhancement (70% vs 27%, p < 0.001). Patients with BP-PACNS more often had headaches (56% vs 31%, p < 0.01), motor deficits (56% vs 36%, p = 0.02), and nonischemic parenchymal gadolinium enhancement (82% vs 16%, p < 0.001). The prevalence of acute ischemic lesions was 18% in CAA-RI and 22% in BP-PACNS (p = 0.57). The features with the highest specificity for CAA-RI were acute subarachnoid hemorrhage (98%), cortical superficial siderosis (96%), past intracerebral hemorrhage (96%), and ≥21 visible centrum semiovale perivascular spaces (96%). The probable CAA-RI criteria had a 71% sensitivity (95% CI 44%-90%) and 91% specificity (95% CI 79%-98%) in differentiating biopsy-positive CAA-RI from BP-PACNS. The rate of relapse in the first 2 years after remission was lower in CAA-RI than in BP-PACNS (hazard ratio 0.46, 95% CI 0.22-0.96, p = 0.04).

CONCLUSION

Clinicoradiologic features differed between patients with CAA-RI and those with BP-PACNS. Specific markers for CAA-RI were hemorrhagic signs of subarachnoid involvement, past intracerebral hemorrhage, ≥21 visible centrum semiovale perivascular spaces, and the probable CAA-RI criteria. A biopsy remains necessary for diagnosis in some cases of CAA-RI. The rate of relapse in the first 2 years after disease remission was lower in CAA-RI than in BP-PACNS.

Cortical Microhemorrhage Presentation of Small Vessel Primary Angiitis of the Central Nervous System

OBJECTIVE

Primary angiitis of the central nervous system (PACNS) is a rare vasculitis restricted to the brain, spinal cord, and leptomeninges. This study aimed to describe the imaging characteristics of patients with small vessel PACNS (SV-PACNS) using 7 T magnetic resonance imaging (MRI).

METHODS

This ongoing prospective observational cohort study included patients who met the Calabrese and Mallek criteria and underwent 7 T MRI scan. The MRI protocol includes T1-weighted magnetization-prepared rapid gradient echo imaging, T2 star weighted imaging, and susceptibility-weighted imaging. Two experienced readers independently reviewed the neuroimages. Clinical data were extracted from the electronic patient records. The findings were then applied to a cohort of patients with large vessel central nervous system (CNS) vasculitis.

RESULTS

We included 21 patients with SV-PACNS from December 2021 to November 2023. Of these, 12 (57.14%) had cerebral cortical microhemorrhages with atrophy. The pattern with microhemorrhages was described in detail based on the gradient echo sequence, leading to the identification of what we have termed the "coral-like sign." The onset age of patients with coral-like sign (33.83 ± 9.93 years) appeared younger than that of patients without coral-like sign (42.11 ± 14.18 years) (P = 0.131). Furthermore, the cerebral lesions in patients with cortical microhemorrhagic SV-PACNS showed greater propensity toward bilateral lesions (P = 0.03). The coral-like sign was not observed in patients with large vessel CNS vasculitis.

INTERPRETATION

The key characteristics of the coral-like sign represent cerebral cortical diffuse microhemorrhages with atrophy, which may be an important MRI pattern of SV-PACNS. ANN NEUROL 2024;96:194-203.

Primary Angiitis of the CNS: Differences in the Profile Between Subtypes and Outcomes From an Indian Cohort

BACKGROUND AND OBJECTIVES

Primary angiitis of the CNS (PACNS) is a rare disease that has significant morbidity and mortality. Subtypes of PACNS can have different presentations that could be missed with certain diagnostic modalities, further increasing diagnostic complexity. We sought to distinguish the subtypes of PACNS and describe their outcomes in an Indian cohort.

METHODS

Adult patients in this retrospective single-center cohort study were reviewed from the PACNS database between 2000 and 2019. Diagnosis was made as per Calabrese and Malleck criteria. Small and medium vessel vasculitis was defined, and their clinical and radiologic profile, treatment, and outcomes were compared. Functional outcomes were noted at 6-month, 1-year, and at last follow-up, while relapses were noted at last follow-up. A poor outcome was defined as modified Rankin Scale >2.

RESULTS

Seventy-two patients fulfilled the inclusion criteria of whom 50 (69.4%) were male. The small vessel vasculitis subtype had a younger age at onset (30.5 vs 40.5 years, p = 0.014), presented less often as a stroke (22% vs 62%, p = 0.001), and had greater delay in diagnosis and treatment initiation (median of 620 days vs 118 days, p = 0.001) compared with medium vessel vasculitis subtype. Although no difference was noted at 6 months, the small vessel vasculitis group had poor outcomes at 1-year and last follow-up (57% vs 20%, p = 0.011 and 72% vs 34%, p = 0.005, respectively) and had more relapses at last follow-up (89% vs 30%, p < 0.001) when compared with the medium vessel vasculitis group. On analyzing the entire cohort, 50 of 72 (69%) and 37 of 53 (69.8%) patients had a good outcome at 6 months and 1 year, respectively. Relapse was noted in 35 of 72 (49%) at final follow-up. The choice of the treatment regimen did not predict outcomes or relapses.

DISCUSSION

The small vessel vasculitis subtype of PACNS is a distinct entity that has diagnostic and treatment delays with poor long-term outcomes and more relapses. Recognizing the different subtypes of PACNS may help to expedite diagnosis and plan treatment.

Comparison of patients with biopsy positive and negative primary angiitis of the central nervous system

OBJECTIVE

There is limited evidence on when to obtain a central nervous system (CNS) biopsy in suspected primary angiitis of the central nervous system (PACNS). Our objective was to identify which clinical and radiological characteristics were associated with a positive biopsy in PACNS.

METHODS

From the multicentre retrospective Cohort of Patients with Primary Vasculitis of the CNS (COVAC), we included adults with PACNS based on a positive CNS biopsy or otherwise unexplained intracranial stenoses with additional findings supportive of vasculitis. Baseline findings were compared between patients with a positive and negative biopsy using logistic regression models.

RESULTS

Two hundred patients with PACNS were included, among which a biopsy was obtained in 100 (50%) and was positive in 61 (31%). Patients with a positive biopsy were more frequently female (odds ratio [OR] 2.90; 95% CI: 1.25, 7.10; P = 0.01) and more often presented with seizures (OR 8.31; 95% CI: 2.77, 33.04; P < 0.001) or cognitive impairment (OR 2.58; 95% CI: 1.11, 6.10; P = 0.03). On imaging, biopsy positive patients more often had non-ischaemic parenchymal or leptomeningeal gadolinium enhancement (OR 52.80; 95% CI: 15.72, 233.06; P < 0.001) or ≥1 cerebral microbleed (OR 8.08; 95% CI: 3.03, 25.13; P < 0.001), and less often had ≥1 acute brain infarct (OR 0.02; 95% CI: 0.004, 0.08; P < 0.001). In the multivariable model, non-ischaemic parenchymal or leptomeningeal gadolinium enhancement (adjusted OR 8.27; 95% CI: 1.78, 38.46; P < 0.01) and absence of ≥1 acute brain infarct (adjusted OR 0.13; 95% CI: 0.03, 0.65; P = 0.01) were significantly associated with a positive biopsy.

CONCLUSION

Baseline clinical and radiological characteristics differed between biopsy positive and negative PACNS. These results may help physicians individualize the decision to obtain a CNS biopsy in suspected PACNS.

Temporal evolution of primary angiitis of the central nervous system (PACNS) on MRI following immunosuppressant treatment

PURPOSE

To systematically analyse the time course of vessel wall enhancement and associated stenosis in patients with primary angiitis of the central nervous system (PACNS) following immunosuppressive therapy.

MATERIAL AND METHODS

Two neuroradiologists retrospectively analysed MRIs of patients with PACNS seen at the Bern University Hospital and the St. Gallen Cantonal Hospital between 2015 and 2020. MRIs were examined for the presence of vessel wall enhancement, length of vessel wall enhancement (mm), circumferential extent of enhancement (degree) and degree of stenosis (%). Descriptive statistics and measurements of interobserver reliability were obtained. To investigate the temporal profiles of the variables following the commencement of immunosuppressant treatment, four series of Bayesian generalised multi-level models were generated.

RESULTS

A total of 23 patients with 43 affected vessels identified from 209 MRI exams were evaluated (mean follow-up: 715 days, standard deviation ± 487 days), leading to a complete dataset of 402 entries. Vessel wall enhancement and circumferential extent of enhancement decreased for approximately 1 year after the initiation of immunosuppressant therapy. Changes were more pronounced in younger patients. Disappearance of vessel wall enhancement (in at least one vessel) was seen in about half of patients after a median of 172 days interquartile range 113-244, minimum 54 days, maximum 627 days.

CONCLUSIONS

This study evaluated the typical time course of vessel wall enhancement in patients with PACNS. Our results could be a useful reference for radiologists and clinicians interpreting follow-up imaging in patients with PACNS.

CRITICAL RELEVANCE STATEMENT

Routine clinical exams can be interpreted with more confidence when radiologists are aware of the typical temporal evolution of vessel wall enhancement in patients with primary angiitis of the central nervous system after initiation of immunosuppressive therapy.

KEY POINTS

Few data exist for vessel wall imaging of primary angiitis of the central nervous system. Following immunosuppressant therapy, vessel wall enhancement decreases for approximately one year. These results may serve as a reference for radiologists performing follow-up imaging.

Progressive leukoencephalopathy as a manifestation of primary angiitis of the central nervous system: case report and review of the literature

BACKGROUND AND OBJECTIVE

Primary angiitis of the central nervous system (PACNS) is a rare form of vasculitis solely affecting the vessels of the brain, spinal cord, and leptomeninges. A range of magnetic resonance imaging (MRI) features have been associated with PACNS, including cerebral infarction, hemorrhage, and parenchymal or leptomeningeal contrast enhancement.

METHODS AND RESULTS

We describe a 51-year-old man with a case of PACNS manifesting as akinetic mutism with progressive leukoencephalopathy.

DISCUSSION

Progressive leukoencephalopathy has not been well defined as a manifestation of PACNS. We review a small number of cases with comparable features, providing additional context on this PACNS manifestation with consideration of clinical subtypes.

Vasculitis in the Central Nervous System: Etiology, Characteristics, and Outcomes in a Large Single-Center Cohort

Background and Purpose

For the management of central nervous system (CNS) vasculitis, it is crucial to differentiate between primary and secondary CNS vasculitis and to understand the respective etiologies. We assessed the etiology, characteristics, and outcomes of patients with CNS vasculitis.

Methods

A single-center retrospective chart review was conducted at the University of Utah, Department of Neurology, between February 2011 and October 2022.

Results

The median age of the 44 included patients at diagnosis was 54 years; 25.0% were men. Compared to primary CNS vasculitis, secondary CNS vasculitis exhibits higher fever incidence (observed in infectious and connective tissue disorder [CTD]-associated vasculitis), low glucose levels (mostly in infectious vasculitis) and unique cerebrospinal fluid oligoclonal bands (observed in infectious and CTD-associated vasculitis). Patients with inflammatory cerebral amyloid angiopathy (CAA) were older and more commonly had microhemorrhage than primary angiitis of the CNS (PACNS). All patients with CTD-associated vasculitis had a known history of CTD at presentation. Brain biopsies were performed on 10 of 17 PACNS patients and 4 of 8 inflammatory CAA patients, confirming vasculitis in 7 and 4 patients, respectively. Intravenous methylprednisolone was the predominant induction therapy (63.6%), and cyclophosphamide was the most used adjunctive therapy. Cyclophosphamide, rituximab, azathioprine, and mycophenolate mofetil were utilized as maintenance therapy, often with concurrent prednisone. Patients with inflammatory CAA had a higher tendency for relapse rates than PACNS.

Conclusions

This study highlights the variations in patients' characteristics, symptoms, and treatment for CNS vasculitis. Understanding these differences can lead to more efficient diagnostic and management strategies.

Autoimmune and inflammatory neurological disorders in the intensive care unit

PURPOSE OF REVIEW

The present review summarizes the diagnostic approach to autoimmune encephalitis (AE) in the intensive care unit (ICU) and provides practical guidance on therapeutic management.

RECENT FINDINGS

Autoimmune encephalitis represents a group of immune-mediated brain diseases associated with antibodies that are pathogenic against central nervous system proteins. Recent findings suggests that the diagnosis of AE requires a multidisciplinary approach including appropriate recognition of common clinical syndromes, brain imaging and electroencephalography to confirm focal pathology, and cerebrospinal fluid and serum tests to rule out common brain infections, and to detect autoantibodies. ICU admission may be necessary at AE onset because of altered mental status, refractory seizures, and/or dysautonomia. Early management in ICU includes prompt initiation of immunotherapy, detection and treatment of seizures, and supportive care with neuromonitoring. In parallel, screening for neoplasm should be systematically performed. Despite severe presentation, epidemiological studies suggest that functional recovery is likely under appropriate therapy, even after prolonged ICU stays.

CONCLUSION

AE and related disorders are increasingly recognized in the ICU population. Critical care physicians should be aware of these conditions and consider them early in the differential diagnosis of patients presenting with unexplained encephalopathy. A multidisciplinary approach is mandatory for diagnosis, ICU management, specific therapy, and prognostication.

The Hemorrhagic Side of Primary Angiitis of the Central Nervous System (PACNS)

Primary Angiitis of the Central Nervous System (PACNS) is a rare cerebrovascular disease involving the arteries of the leptomeninges, brain and spinal cord. Its diagnosis can be challenging, and the current diagnostic criteria show several limitations. Among the clinical and neuroimaging manifestations of PACNS, intracranial bleeding, particularly intracerebral hemorrhage (ICH), is poorly described in the available literature, and it is considered infrequent. This review aims to summarize the available data addressing this issue with a dedicated focus on the clinical, neuroradiological and neuropathological perspectives. Moreover, the limitations of the actual data and the unanswered questions about hemorrhagic PACNS are addressed from a double point of view (PACNS subtyping and ICH etiology). Fewer than 20% of patients diagnosed as PACNS had an ICH during the course of the disease, and in cases where ICH was reported, it usually did not occur at presentation. As trigger factors, both sympathomimetic drugs and illicit drugs have been proposed, under the hypothesis of an inflammatory response due to vasoconstriction in the distal cerebral arteries. Most neuroradiological descriptions documented a lobar location, and both the large-vessel PACNS (LV-PACNS) and small-vessel PACNS (SV-PACNS) subtypes might be the underlying associated phenotypes. Surprisingly, amyloid beta deposition was not associated with ICH when histopathology was available. Moreover, PACNS is not explicitly included in the etiological classification of spontaneous ICH. This issue has received little attention in the past, and it could be addressed in future prospective studies.

Imaging of Small Artery Vasculitis

Small artery vasculitis of the CNS is a rare and serious condition characterized by the inflammation of blood vessels within the brain and spinal cord. There are two groups of small artery vasculitis determined by the presence or absence of immunoglobulin complex deposition in the vessel wall. The former includes anti-glomerular basement membrane disease, cryoglobulinemic vasculitis, and IgA vasculitis. Absence of immune complex deposition is associated with anti-neutrophil cytoplasmic antibody (ANCA) and includes microscopic polyangiitis, granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, and primary angiitis of the CNS. These conditions present a diagnostic challenge in which imaging plays a crucial role.

Pathology of Primary Angiitis of the Central Nervous System

Primary angiitis of the central nervous system (PACNS) is a rare and potentially severe form of vasculitis that is limited to the brain, spinal cord, and meninges. Despite extensive research, the etiology and underlying immunologic mechanisms of PACNS remain largely unknown. PACNS presents with a variety of clinical, radiological, and pathologic features, but it is generally characterized by inflammation and destruction of the walls of blood vessels in the CNS, which can lead to tissue ischemia and/or hemorrhage. Three main histopathologic patterns have been identified, namely granulomatous, lymphocytic, and necrotizing vasculitis.

European Stroke Organisation (ESO) guidelines on Primary Angiitis of the Central Nervous System (PACNS)

The European Stroke Organisation (ESO) guideline on Primary Angiitis of the Central Nervous System (PACNS), developed according to ESO standard operating procedures (SOP) and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology, was elaborated to assist clinicians in the diagnostic and treatment pathway of patients with PACNS in their decision making. A working group involving vascular neurologists, neuroradiologists, rheumatologists, a neuropathologist and a methodologist identified 17 relevant clinical questions; these were addressed according to the patient/population, intervention, comparison and outcomes (PICO) framework and systematic literature reviews were performed. Notably, each PICO was addressed with respect to large vessel (LV)-PACNS and small vessel (SV)-PACNS. Data to answer many questions were scarce or lacking and the quality of evidence was very low overall, so, for some PICOs, the recommendations reflect the ongoing uncertainty. When the absence of sufficient evidence precluded recommendations, Expert Consensus Statements were formulated. In some cases, this applied to interventions in the diagnosis and treatment of PACNS which are embedded widely in clinical practice, for example patterns of cerebrospinal fluid (CSF) and Magnetic Resonance Imaging (MRI) abnormalities. CSF analysis for hyperproteinorrachia and pleocytosis does not have evidence supporting their use as diagnostic tools. The working group recommended that caution is employed in the interpretation of non-invasive vascular imaging due to lack of validation and the different sensitivities in comparison with digital subtraction angiography (DSA) and histopathological analyses. Moreover, there is not a neuroimaging pattern specific for PACNS and neurovascular issues are largely underreported in PACNS patients. The group's recommendations on induction and maintenance of treatment and for primary or secondary prevention of vascular events also reflect uncertainty due to lack of evidence. Being uncertain the role and practical usefulness of current diagnostic criteria and being not comparable the main treatment strategies, it is suggested to have a multidisciplinary team approach in an expert center during both work up and management of patients with suspected PACNS. Highlighting the limitations of the currently accepted diagnostic criteria, we hope to facilitate the design of multicenter, prospective clinical studies and trials. A standardization of neuroimaging techniques and reporting to improve the level of evidence underpinning interventions employed in the diagnosis and management of PACNS. We anticipate that this guideline, the first comprehensive European guideline on PACNS management using GRADE methodology, will assist clinicians to choose the most effective management strategy for PACNS.

Primary Angiitis of the Central Nervous System in Adults: A Comprehensive Review of 76 Biopsy-Proven Case Reports

Purpose

Primary angiitis of the adult central nervous system (PACNS) is an increasingly recognized but limited disease. Using previous case reports, we sought to summarize the clinical symptoms, imaging manifestations, treatment, and prognosis of patients with biopsy-confirmed PACNS to guide clinical diagnosis and management.

Methods

We searched the Web of Science database for studies published from January 2000 to April 2023, with the language set to English and the document type limited to [Article or Review or Letter or Editorial Material]. A systematic review of all case reports met the inclusion and exclusion criteria was performed. These patients' clinical, pathological, and imaging characteristics were analyzed, and treatment and prognostic data were summarized.

Results

We analyzed 69 articles, including 76 patients with biopsy-confirmed PACNS. And 57.9% of the patients were male, the median age at presentation was 47.0 years, and focal neurological deficits were the most common symptom in patients (78.9%), followed by headache (52.6%). The median duration of biopsy was 1.1 months, of which 49 (64.5%) patients were lymphocytic, 13 (17.1%) were granulomatous, 11 (14.5%) were amyloidotic, and 3 (3.9%) were necrotizing PACNS. Relapse events occurred in 41 (53.9%) patients, including 34 (44.2%) relapses and 8 (10.5%) deaths. Univariate logistic regression analysis revealed that symptomatic epilepsy, prolonged biopsy time window, and CD20 expression in pathological tissues might be independent risk factors for recurrent events in patients (HR=4.69, 95% CI: 1.51-14.54, p=0.007; HR=1.11, 95% CI: 1.00-1.22, p=0.043; HR=5.33, 95% CI: 1.07-26.61, p=0.041).

Conclusion

Adult PACNS is associated with frequent relapses and high mortality. Symptomatic epilepsy, prolonged biopsy time window, and CD20 expression in pathological tissue may be associated with recurrent events.

Neuroimaging Scoring Tools to Differentiate Inflammatory Central Nervous System Small-Vessel Vasculitis: A Need for Artificial Intelligence/Machine Learning?-A Scoping Review

Neuroimaging has a key role in identifying small-vessel vasculitis from common diseases it mimics, such as multiple sclerosis. Oftentimes, a multitude of these conditions present similarly, and thus diagnosis is difficult. To date, there is no standardized method to differentiate between these diseases. This review identifies and presents existing scoring tools that could serve as a starting point for integrating artificial intelligence/machine learning (AI/ML) into the clinical decision-making process for these rare diseases. A scoping literature review of EMBASE and MEDLINE included 114 articles to evaluate what criteria exist to diagnose small-vessel vasculitis and common mimics. This paper presents the existing criteria of small-vessel vasculitis conditions and mimics them to guide the future integration of AI/ML algorithms to aid in diagnosing these conditions, which present similarly and non-specifically.

Focal CNS vasculitis masquerading as new-onset focal aware seizures

Primary angiitis of the central nervous system (PACNS) is an autoimmune disease with myriad presentations in the form of headache, focal neurological deficits, seizures and rapid cognitive decline. Predilection or isolated and recurrent involvement of one hemisphere is rarely described in literature. This leads to low clinical suspicion and often delayed diagnosis of PACNS, if clinical and radiological involvement is focal. We describe the case of a young man presenting with new-onset focal seizures with imaging suggestive of focal involvement and the brain biopsy clinched an early diagnosis. The 1-year follow-up showed clinical and radiological resolution.

Advances in Management of the Stroke Etiology One-Percenters

PURPOSE OF REVIEW

Uncommon causes of stroke merit specific attention; when clinicians have less common etiologies of stoke in mind, the diagnosis may come more easily. This is key, as optimal management will in many cases differs significantly from "standard" care.

RECENT FINDINGS

Randomized controlled trials (RCT) on the best medical therapy in the treatment of cervical artery dissection (CeAD) have demonstrated low rates of ischemia with both antiplatelet and vitamin K antagonism. RCT evidence supports the use of anticoagulation with vitamin K antagonism in "high-risk" patients with antiphospholipid antibody syndrome (APLAS), and there is new evidence supporting the utilization of direct oral anticoagulation in malignancy-associated thrombosis. Migraine with aura has been more conclusively linked not only with increased risk of ischemic and hemorrhagic stroke, but also with cardiovascular mortality. Recent literature has surprisingly not provided support the utilization of L-arginine in the treatment of patients with mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS); however, there is evidence at this time that support use of enzyme replacement in patients with Fabry disease. Additional triggers for reversible cerebral vasoconstriction syndrome (RCVS) have been identified, such as capsaicin. Imaging of cerebral blood vessel walls utilizing contrast-enhanced MRA is an emerging modality that may ultimately prove to be very useful in the evaluation of patients with uncommon causes of stroke. A plethora of associations between cerebrovascular disease and COVID-19 have been described. Where pertinent, authors provide additional tips and guidance. Less commonly encountered conditions with updates in diagnosis, and management along with clinical tips are reviewed.

[Vasculitis as a cause of stroke]

The review considers the clinical picture, key aspects of the diagnosis and treatment of vasculitis that are the causes of strokes (giant cell arteritis, polyarteritis nodosa, varicella zoster virus vasculopathy, cerebrovascular pathology caused by herpes simplex virus types 1 and 2, primary CNS angiitis, adenosine deaminase-2 deficiency).

Vessel Wall Magnetic Resonance Imaging in Cerebrovascular Diseases

Cerebrovascular diseases are a leading cause of disability and death worldwide. The definition of stroke etiology is mandatory to predict outcome and guide therapeutic decisions. The diagnosis of pathological processes involving intracranial arteries is especially challenging, and the visualization of intracranial arteries’ vessel walls is not possible with routine imaging techniques. Vessel wall magnetic resonance imaging (VW-MRI) uses high-resolution, multiparametric MRI sequences to directly visualize intracranial arteries walls and their pathological alterations, allowing a better characterization of their pathology. VW-MRI demonstrated a wide range of clinical applications in acute cerebrovascular disease. Above all, it can be of great utility in the differential diagnosis of atherosclerotic and non-atherosclerotic intracranial vasculopathies. Additionally, it can be useful in the risk stratification of intracranial atherosclerotic lesions and to assess the risk of rupture of intracranial aneurysms. Recent advances in MRI technology made it more available, but larger studies are still needed to maximize its use in daily clinical practice.