The spectrum of CNS vasculitis in children and adults

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.

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.

Neuropsychiatric involvement in juvenile-onset systemic lupus erythematosus (jSLE)

Systemic lupus erythematosus (SLE) is a rare autoimmune/inflammatory disease with significant morbidity and mortality. Approximately 15-20% of SLE patients develop the disease during childhood or adolescence (juvenile-onset SLE/jSLE). Patients with jSLE exhibit more variable and severe disease when compared to patients with disease-onset during adulthood. Neuropsychiatric (NP) involvement is a clinically heterogenous and potentially severe complication. Published reports on the incidence and prevalence of NP-jSLE are scarce, and the exact pathophysiology is poorly understood.This manuscript provides a review of the existing literature, suggesting NP involvement in 13.5-51% of jSLE patients. Among patients with NP-jSLE affecting the CNS, we propose two main subgroups: (i) a chronic progressive, predominantly type 1 interferon-driven form that poorly responds to currently used treatments, and (ii) an acutely aggressive form that usually presents early during the disease that may be primarily mediated by auto-reactive effector lymphocytes. While this hypothesis requires to be tested in large collaborative international cohort studies, it may offer future patient stratification and individualised care.

Childhood Cerebral Vasculitis : A Multidisciplinary Approach

Cerebral vasculitis is increasingly recognized as a common cause of pediatric arterial stroke. It can present with focal neurological deficits, psychiatric manifestations, seizures, and encephalopathy. The etiopathogenesis of childhood cerebral vasculitis (CCV) is multifactorial, making an inclusive classification challenging. In this review, we describe the common and uncommon CCV with a comprehensive discussion of etiopathogenesis, the role of various imaging modalities, and advanced techniques in diagnosing CCV. We also highlight the implications of relevant clinical, laboratory, and genetic findings to reach the final diagnosis. Based on the clinicoradiological findings, a stepwise diagnostic approach is proposed to facilitate CCV diagnosis and rule out potential mimics. Identification of key clinical manifestations, pertinent blood and cerebrospinal fluid results, and evaluation of central nervous system vessels for common and disease-specific findings will be emphasized. We discuss the role of magnetic resonance imaging, MR angiography, and vessel wall imaging as the imaging investigation of choice, and reservation of catheter angiography as a problem-solving tool. We emphasize the utility of brain and leptomeningeal biopsy for diagnosis and exclusion of imitators and masqueraders.

Adult and childhood vasculitis

Vasculitis refers to heterogeneous clinicopathologic disorders that share the histopathology of inflammation of blood vessels. Unrecognized and therefore untreated, vasculitis of the nervous system leads to pervasive injury and disability, making this a disorder of paramount importance to all clinicians. There has been remarkable progress in the pathogenesis, diagnosis, and treatment of primary CNS and PNS vasculitides, predicated on achievement in primary systemic forms. Primary neurological vasculitides can be diagnosed with assurance after intensive evaluation that incudes tissue confirmation whenever possible. Clinicians must choose from among the available immune modulating, suppressive, and targeted immunotherapies to induce and maintain remission status and prevent relapse, unfortunately without the benefit of RCTs, and tempered by the recognition of anticipated medication side effects. It may be said that efforts to define a disease are attempts to understand the very concept of the disease. This has been especially evident in systemic and neurological disorders associated with vasculitis. For the past 100 years, since the first description of granulomatous angiitis of the brain, the CNS vasculitides have captured the attention of generations of clinical investigators around the globe to reach a better understanding of vasculitides involving the central and peripheral nervous system. Since that time it has become increasingly evident that this will necessitate an international collaborative effort.

Human Leukocyte Antigen (HLA) Modulates the Dependence on Age of the Variability of Synchronous Neural Interactions

Recent evidence documented a protective effect of Class II human leukocyte antigen (HLA) DRB1*13 on brain health across the lifespan including evidence of reduced neural network variability relative to non-carriers. Here, in an extension of those findings, we evaluated the influence of a large number of Class I and Class II HLA alleles on aging-related changes in neural network variability. Cognitively healthy women (N = 178) ranging in age from 28 to 99 years old underwent a magnetoencephalography scan from which neural network variability was calculated and provided a blood sample from which HLA and apolipoprotein E (ApoE) genotype were determined. The primary analyses assessed the dependence of network variability on age in carriers of a specific HLA allele compared to non-carriers. Effects were considered protective if there was a significant increase of network variability with age in the absence of a given HLA allele but not in its presence, and were considered to confer susceptibility if the converse was documented; HLA alleles that did not influence the dependence of network variability on age in their presence or absence were considered neutral. Of 50 alleles investigated, 22 were found to be protective, 7 were found to confer susceptibility, and 21 were neutral. The frequencies of those 50 alleles were not associated significantly with ApoE genotype. The findings, which document the influence of HLA on age-related brain changes and highlight the role of HLA in healthy brain function, are discussed in terms of the role of HLA in the human immune response to foreign antigens.

Utility of high-resolution magnetic resonance vessel wall imaging in differentiating between atherosclerotic plaques, vasculitis, and arterial dissection

PURPOSE

Differentiating between atherosclerosis, vasculitis, and dissection is a diagnostic challenge because of inconclusive findings on conventional imaging and some overlap in the vessel wall patterns. The aim of this study was to determine whether vessel wall MRI patterns can differentiate between these vasculopathies.

METHODS

We retrospectively reviewed 3T high-resolution vessel wall imaging studies of patients diagnosed with atherosclerotic plaques, vasculitis, and dissection. The patterns of involvement, wall enhancement, and T1 and T2 signals, as well as the specific patterns, were assessed and compared between the three diseases.

RESULTS

Fifty-nine patients with atherosclerosis (n = 33), vasculitis (n = 13), and dissection (n = 13) were enrolled. There were significant differences in the pattern of involvement between the three groups (P < 0.001), with concentric wall thickening in vasculitis patients (84.6%) and eccentric wall thickening in atherosclerosis (97%) and dissection (92.3%) patients. There was also a significant difference in the specific pattern (P < 0.001), with intimal flap (76.9%) and intramural hematoma (23.1%) in dissection patients and intraplaque hemorrhage (18.2%) in atherosclerosis patients. Furthermore, subgroup analysis showed a significant difference in the wall enhancement pattern between atherosclerosis and vasculitis patients (P < 0.05). Finally, there was a significant difference in the location of involvement between the three groups (P < 0.001).

CONCLUSION

By using the pattern of involvement, wall enhancement, and specific patterns, vessel wall MRI can help differentiate between atherosclerosis, vasculitis, and dissection.

A case of childhood unilateral relapsing primary angiitis of the central nervous system

The patient was a 17-year-old girl with transient right-sided weakness and dysesthesia associated with headache and nausea. Head magnetic resonance imaging (MRI) revealed white matter lesions confined to the left hemisphere. Initially, multiple sclerosis was suspected, and methylprednisolone (mPSL) pulse therapy was administered, followed by fingolimod hydrochloride. However, on day 267, the patient again experienced transient hypesthesia. Cranial MRI showed expansion of the highly infiltrated areas of the left hemisphere on fluid-attenuated inversion recovery (FLAIR) and T2 weighted image, accompanied by edema. Multiple contrasting areas were also observed. Susceptibility-weighted imaging demonstrated several streaks and some corkscrew-like appearances with low signals from the white matter to the cortex, suggestive of occluded or dilated collateral vessels. Multiple dotted spots indicating cerebral microbleeds (MBs) were also observed. A brain biopsy revealed lymphocytic, non-granulomatous inflammation in and around the vessels. Vascular occlusion and perivascular MBs were prevalent. The patient was diagnosed with relapsing primary angiitis of the central nervous system (PACNS), and immunosuppressive treatment was initiated, mPSL 1000 mg/day pulse therapy. The patient's clinical symptoms and neuroradiological abnormalities gradually improved. She is now receiving oral prednisolone (6 mg/day) and mycophenolate mofetil (1750 mg/day). This case corresponds to unilateral relapsing, which has recently been reported as a specific clinicopathological subtype of PACNS.

Case Report: Interest of Positron Emission Tomography in Pediatric Small Vessel Primary Angiitis of the Central Nervous System

Primary angiitis of the central nervous system (PACNS) is a rare inflammatory disease affecting central nervous system vessels. The diagnosis, which requires confirmation by brain biopsy, remains challenging due to unspecific clinical presentation and low specificity of imaging and laboratory exams. In these two pediatric biopsy-proven cases of svPACNS we demonstrate that brain positron emission tomography (PET) show a high metabolic activity that extends beyond brain MRI abnormalities. Therefore, combining MRI and PET abnormalities to adequately guide brain biopsy might increase the diagnostic yield of this rare condition.

The Role of Pediatric Rheumatologists in Autoimmune Brain Disease

The spectrum of autoimmune and inflammatory brain diseases continues to evolve with medical advances facilitating both the detection of inflammation of the central nervous system and the discovery of novel disease mechanisms. The clinical overlap of these disorders with primary rheumatic diseases and the efficacy of immunotherapy have led to strong partnerships between pediatric rheumatologists, neurologists, psychiatrists, and other providers in the care of children with these conditions. Early diagnosis and initiation of targeted therapy improve clinical outcomes, highlighting the importance of interdisciplinary collaborative care.

Isolated sixth nerve palsy as an initial presentation of primary angiitis of the central nervous system

BACKGROUND

Primary angiitis of the central nervous system (PACNS) is a newly-emerging disease, and it is known that early diagnosis with treatment is important for the improvement of prognosis.

CASE DESCRIPTION

Here, we report the case of a previously healthy 13-year-old girl who presented with right eye abduction failure, attributed to isolated right sixth nerve palsy, as the initial symptom of PACNS. Magnetic resonance angiography (MRA) showed stenosis in the distal portion of the right internal carotid artery, and delay alternating with nutation for tailored excitation (DANTE)-prepared contrast-enhanced magnetic resonance imaging confirmed vasculitis at the same site. The patient was subsequently treated with three courses of pulse corticosteroid therapy (methylprednisolone intravenously 30 mg/kg/day for three consecutive days). Diplopia completely resolved within 3 months after three course of steroid pulse therapy, and when taking 10 mg PSL daily. Follow-up MRA confirmed complete resolution of the arterial narrowing, and no relapse was observed after 2 months of steroid cessation.

DISCUSSION

This case report illustrates an unusual presentation of PACNS with isolated sixth nerve palsy. PACNS was thought to cause insults on a single cranial nerve either through local spread of inflammation or hypoxic-ischemic insults on the nerve root due to involvement of feeding microvessels. The decision to perform imaging studies in cases of isolated sixth nerve palsy remains controversial because of the possibility of spontaneous recovery. Our case supports the existing literature that recommends that even an isolated symptom of unilateral abducens nerve palsy requires timely imaging studies.

Arteriopathy in pediatric stroke: an underestimated clinical entity

BACKGROUND

Pediatric arterial ischemic stroke (AIS), which was thought to be a rare disorder, is being increasingly recognized as an important cause of neurological morbidity, thanks to new advances in neuroimaging.

OBJECTIVE

The aim of this study was to review the main etiologies of stroke due to arteriopathy in children.

METHODS

Using a series of cases from our institution, we addressed its epidemiological aspects, physiopathology, imaging findings from CT, MR angiography, MR conventional sequences and MR DWI, and nuclear medicine findings.

RESULTS

Through discussion of the most recent classification for childhood AIS (Childhood AIS Standardized Classification and Diagnostic Evaluation, CASCADE), we propose a modified classification based on the anatomical site of disease, which includes vasculitis, varicella, arterial dissection, moyamoya, fibromuscular dysplasia, Takayasu's arteritis and genetic causes (such as ACTA-2 mutation, PHACE syndrome and ADA-2 deficiency). We have detailed each of these separately. Conclusions: Prompt recognition of AIS and thorough investigation for potential risk factors are crucial for a better outcome. In this scenario, neurovascular imaging plays an important role in diagnosing AIS and identifying children at high risk of recurrent stroke.

The potential for immune checkpoint modulators in cerebrovascular injury and inflammation

Introduction: Neuroinflammation has been linked to poor neurologic and functional outcomes in many cerebrovascular disorders. Immune checkpoints are upregulated in the setting of traumatic brain injury, intracerebral hemorrhage, ischemic stroke, central nervous systems vasculitis, and post-hemorrhagic vasospasm, and are potential mediators of pathologic inflammation. Burgeoning evidence suggests that immune checkpoint modulation is a promising treatment strategy to decrease immune cell recruitment, cytokine secretion, brain edema, and neurodegeneration.Areas covered: This review discusses the role of immune checkpoints in neuroinflammation, and the potential for therapeutic immune checkpoint modulation in inflammatory cerebrovascular disorders. A search of Pubmed and clinicaltrials.gov was performed to find relevant literature published within the last 50 years.Expert opinion: The clinical success of immune-activating checkpoint modulators in human cancers has shown the immense clinical potential of checkpoint-based immunotherapy. Given that checkpoint blockade can also precipitate a pathologic pro-inflammatory or autoimmune response, it is plausible that these pathways may also be targeted to quell aberrant inflammation. A limited but growing number of studies suggest that immune checkpoints play a critical role in regulating the immune response in the central nervous system in a variety of contexts, and that immune-deactivating checkpoint modulators may be a promising treatment strategy for acute and chronic neuroinflammation in cerebrovascular disorders.

Diagnosis and Treatment of Angiography Positive Medium to Large Vessel Childhood Primary Angiitis of Central Nervous System (p-cPACNS): An International Survey

Childhood Primary Angiitis of Central Nervous System (cPACNS) is rare, but can cause significant damage and result in disability or even death. Because of its rarity, the sometimes acute and variable presentation, limited awareness, and the absence of widely accepted diagnostic and therapeutic standards, cPACNS is a diagnostic and therapeutic challenge. Three subcategories of cPACNS exist, including angiography-positive non-progressive p-cPACNS, angiography-positive progressive p-cPACNS which both affects the medium to large vessels, and angiography-negative small vessel sv-cPACNS. Diagnosis and treatment of cPACNS relies on personal experience, expert opinion and case reports/case series. To collect information on diagnostic and therapeutic approaches to transient and progressive cPACNS, a survey was shared among international clinicians (German Society for Pediatric Rheumatology, the Pediatric Rheumatology European Society, the German speaking "Network Pediatric Stroke," and members of the American College of Rheumatology/CARRA Pediatric Rheumatology list server). Results from this survey will be used to define statements toward a consensus process allowing harmonization of diagnostic and therapeutic approaches and the generation of evidence in a rare condition.

Diagnosis and Treatment of Small Vessel Childhood Primary Angiitis of the Central Nervous System (sv-cPACNS): An International Survey

Childhood primary angiitis of the Central Nervous System (cPACNS) is a rare autoimmune and inflammatory disease. It can result in significant neuronal damage, neurodevelopmental delay and potentially death. Childhood PACNS is divided into subcategories: angiography-positive p-cPACNS that affects medium and large vessels, and angiography-negative small vessel sv-cPACNS. Due to its rarity, variable clinical representation, and the lack of a diagnostic criteria and therapeutic plans, diagnosis and treatment of cPACNS is challenging and approaches vary. This survey collected information on diagnostic and therapeutic approaches to sv-PACNS. It was shared with international clinician networks, including the German Society for Paediatric Rheumatology, the Paediatric Rheumatology European Society, the "Network Paediatric Stroke," and members of the American College of Rheumatology/CARRA Paediatric Rheumatology list server. This project has shown consensus in numerous diagnostic and therapeutic treatment approaches, highlighting key areas which will be utilised to develop statements in the use of expert consensus meetings to standardise diagnostic and therapeutic approaches in this rare inflammatory disease.

Tumefactive Primary Central Nervous System Vasculitis: Imaging Findings of a Rare and Underrecognized Neuroinflammatory Disease

Primary central nervous system vasculitis (PCNSV) is a poorly understood neuroinflammatory disease of the CNS affecting the intracranial vasculature. Although PCNSV classically manifests as a multifocal beaded narrowing of the intracranial vessels, some patients may not have angiographic abnormalities. A rare subset of patients with PCNSV present with masslike brain lesions mimicking a neoplasm. In this article, we retrospectively review 10 biopsy-confirmed cases of tumefactive PCNSV (t-PCNSV). All cases of t-PCNSV in our series that underwent CTA or MRA were found to have normal large and medium-sized vessels. T-PCNSV had a variable MR imaging appearance with most cases showing cortical/subcortical enhancing masslike lesion (70%), often with microhemorrhages (80%). Diffusion restriction was absent in all lesions. In summary, normal vascular imaging does not exclude the diagnosis of t-PCNSV. Advanced imaging techniques including MR perfusion and MR spectroscopy failed to demonstrate specific findings for t-PCNSV but assisted in excluding neoplasm in the differential diagnosis. Biopsy remains mandatory for definitive diagnosis.

IVIG in childhood primary angiitis of the central nervous system: A case report

Aggressive immunosuppressive therapies have been proposed to treat primary angiitis of the central nervous system (PACNS). Here, we report the first successfully stabilized case of childhood, small-vessel PACNS with intravenous immunoglobulin (IVIG) therapy. A 12-year-old boy was admitted to our hospital complaining of recurrent headaches and upper-left homonymous quadrantanopia, since the age of 11 years. Brain computed tomography scans revealed fine calcification in the right temporal and occipital lobes. Brain magnetic resonance imaging scans revealed white matter lesions, with gadolinium enhancement, which waxed, waned, and migrated for 1 year, without immunomodulatory therapies. A cerebrospinal fluid study showed pleocytosis (12 cells per µl). No clinical or serological findings suggested systemic inflammation or vasculitis. Brain angiography was unremarkable. Brain biopsy revealed thickened and hyalinized small vessels, with intramural infiltration of inflammatory cells, which confirmed the diagnosis of small-vessel PACNS. Because the patient developed surgical site infection following biopsy, the administration of monthly IVIG (2 g/kg) was prescribed, instead of immunosuppressive agents. After IVIG therapy, the patient remained stable, except for a single episode of mild radiological exacerbation at 16 months, which occurred when the IVIG interval was expanded. Oral prednisone was added and gradually tapered. At 50 months, his intellectual abilities and motor functions were normal, although he showed residual upper-left homonymous quadrantanopia and post-exercise headache. A temporary headache, associated with the immunoglobulin infusion, was resolved by slowing the infusion rate. PACNS should be treated aggressively to improve prognosis. However, when immunosuppressants are contraindicated, IVIG may be an alternative therapeutic option.

"When should primary angiitis of the central nervous system (PACNS) be suspected?": literature review and proposal of a preliminary screening algorithm

Background

Primary angiitis of the CNS (PACNS) is a process causing variously combined neurological disturbances. Its rarity and kaleidoscopic presentation make it difficult to diagnose and even to suspect.

Objective

(1) To provide an up-to-date review on PACNS and (2) to create a preliminary screening algorithm based on clinical and radiological first-level data, useful to suspect PACNS and guide further investigations.

Methods

Review of PUBMED case series on PACNS, published from 2002 to 2017, collection of frequencies of clinical and neuroimaging features and calculation of median values. Classification of features as “major” or “minor” if frequency was higher or lower than median value. Combination of features in sets of criteria represented by all possible combinations of major and minor clinical and neuroradiological features. Application of criteria to published PACNS case reports and selection of the ones best identifying patients with definite PACNS.

Results

We reviewed 24 case series. “Major” clinical features were headache, stroke, cognitive impairment, focal neurological deficits; “minor” were seizures, altered consciousness, psychiatric disorders. “Major” neuroradiological features were multiple parenchymal lesions, parenchymal/meningeal contrast enhancement, magnetic resonance angiography vessel abnormalities, vessel wall enhancement; “minor” were parenchymal/subarachnoid hemorrhage, single parenchymal lesion. The selected sets of criteria able to identify all PACNS patients were (1) one clinical (major/minor) + one major neuroradiological feature; and (2) Two clinical (≥ 1 major) + one minor neuroradiological feature.

Conclusion

Our review provides a detailed clinical/neuroradiological picture of PACNS. The proposed algorithm should be regarded as a preliminary screening tool to move the first steps towards PACNS diagnosis that needs validation.

Childhood Small Vessel Primary Angiitis of the Central Nervous System: A Treatable Cause of Super-refractory Status Epilepticus

Childhood primary angiitis of the central nervous system (cPACNS) is a rare inflammatory disease of brain vessels. The small vessel subtype is diagnosed on brain biopsy and often presents with cognitive and behavioral changes, headaches, and seizures. However, there are few reported cases of super-refractory status epilepticus in children. We present a case of small vessel cPACNS complicated by super-refractory status epilepticus requiring burst suppression for 4 weeks in addition to multiple antiseizure medications and the ketogenic diet. Our patient was also treated with intravenous and oral steroids, intravenous immunoglobulin, and cyclophosphamide before starting maintenance therapy with mycophenolate mofetil. After prolonged rehabilitation, he recovered almost completely and has a normal neurologic examination with rare epileptiform activity on electroencephalogram (EEG). This is one of the longest cases of status epilepticus in small vessel cPACNS in the literature. We illustrate that super-refractory status epilepticus can be the first manifestation of small vessel cPACNS in previously healthy children and that symptomatic management of seizures with concurrent immunosuppression to treat the underlying pathology resulted in favorable neurologic outcomes.

Clinical Perspective on Primary Angiitis of the Central Nervous System in Childhood (cPACNS)

Non-arteriosclerotic arteriopathies have emerged as important underlying pathomechanism in pediatric arterial ischemic stroke (AIS). The pathogenesis and classification of cerebral arteriopathies in childhood are heterogeneous. Different classifications base on (i) the anatomic site; (ii) the distribution and size of the affected vessel; (iii) the time course, for example, transient vs. progressive, monophasic vs. recurrent; (iv) the putative pathogenesis; (v) the magnetic resonance imaging morphology of the vasculopathies. Inflammation affecting the cerebral vessels is increasingly recognized as common cause of pediatric AIS. Primary cerebral vasculitis or primary angiitis of the central nervous system (CNS) in childhood (cPACNS) is an important differential diagnosis in pediatric AIS. Primary angiitis of the CNS is a rare disorder, and the pathogenesis is poorly understood so far. The current classification of cPACNS is based on the affected cerebral vessel size, the disease course, and angiographic pattern. Two large subtypes are currently recognized comprising large- and medium-sized vessel CNS vasculitis referred to as angiography-positive cPACNS and angiography-negative small vessel cPACNS. As the clinical manifestations of cPACNS are rather diverse, precise diagnosis can be challenging for the treating pediatrician because of the lack of vital laboratory tests or imaging features. Initial misdiagnosis is common because of overlapping phenotypes and pediatric AIS mimics. As untreated cPACNS is associated with a high morbidity and mortality, timely diagnosis, and induction of immunomodulatory and symptomatic therapy are essential. Survival and neurological outcome depend on early diagnosis and prompt therapy. Primary angiitis of the central nervous system in childhood differs in several aspects from primary cerebral angiitis in adults. The aim of this article is to give a brief comprehensive summary on pediatric primary cerebral vasculitis focusing on the clinical perspective regarding the classification, the putative pathogenesis, the disease course, the diagnostic tools, and emerging treatment options. A modified terminology for clinical practice is discussed.

A Closer Look at Angiitis of the central nervous system

Angiitis of the central nervous system (ACNS) is a rather new disease entity that is defined as vascular inflammation limited to the central nervous system and was formally nominated in 1959. Etiologically, it can be divided into primary and secondary ACNS. However, the potential pathogenesis of ACNS remains unclear. The clinical presentation is variable, and there is no consensus concerning its diagnosis and management. Although the incidence is relatively low, ACNS is still a life-threatening condition. It is essential to get a comprehensive and updated understanding of the disease. In this paper, we reviewed the history, definition, classification, pathogenesis, and clinical manifestations of ACNS. In addition, we focused on the latest investigations and viewpoints regarding the diagnosis and treatment of ACNS.

Strategies for treatment of childhood primary angiitis of the central nervous system

Objective

Childhood primary angiitis of the CNS (cPACNS) is a devastating neurologic disease. No standardized treatment protocols exist, and evidence is limited to open-label cohort studies and case reports. The aim of this review is to summarize the literature and provide informed treatment recommendations.

Methods

A scoping review of cPACNS literature from January 2000 to December 2018 was conducted using Ovid, MEDLINE, PubMed, Embase, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, Vasculitis Foundation, European Vasculitis Society, CanVasc, Google Scholar, and Web of Science. Potentially relevant articles were selected for full-text review using the STROBE checklist if they met the following inclusion criteria: (1) reported treatment, (2) addressed pediatrics, (3) focused on the disease of interest, (4) included ≥5 patients, (5) original research, and (6) full-length articles. Reviews, expert opinions, editorials, case reports with <5 patients, articles lacking treatment information, or non-English articles were excluded. A standardized assessment tool measured study quality. Treatment and outcomes were summarized.

Results

Of 2,597 articles screened, 7 studies were deemed high quality. No trials were available so no meta-analysis was possible. Overall, treatment strategies recommended are induction with acute antithrombotic therapy subsequently followed by high-dose oral prednisone taper over 3–12 months and long-term platelet therapy. In angiography-positive progressive–cPACNS and angiography-negative–cPACNS, we also recommend 6 months of IV cyclophosphamide therapy, with trimethoprim/sulfamethoxazole as part of induction, and maintenance therapy with mycophenolate mofetil/mycophenolic acid.

Conclusion

No grade-A evidence exists; however, this review provides recommendations for treatment of cPACNS.

Granulomatous Angiitis: Twenty Years Later

Granulomatous inflammation, the prototypical histopathology of adult and childhood vasculitis, is characterized by inflammation of blood vessels accompanied by giant cells and epithelioid cells in the walls of cerebral vessels ranging from small leptomeningeal veins to large named cerebral arteries. Headache, hemiparesis, mental changes, abnormal cerebrospinal fluid protein content, and pleocytosis are suggestive features that warrant brain and leptomeningeal biopsy to make the diagnosis certain and begin cytotoxic therapy to improve outcome.

Treatment of Vasculitis of the Nervous System

The diagnosis of primary central and peripheral nerve vasculitides should be established with certainty if suspected before commencing potent immunosuppressive therapy. The aim of induction therapy is to rapidly control the underlying inflammatory response and stabilize the blood-brain and blood-nerve barriers, followed by maintenance immunosuppression tailored to the likeliest humoral and cell-mediated autoimmune inflammatory vasculitic processes.

The Blood-Brain Barrier: Implications for Vasculitis

There has been extraordinary research in the blood-brain barrier. Once considered a static anatomic barrier to the traffic of molecules in and out of the central nervous system when fully developed in adults, the blood-brain barrier is now known to be not only fully functional in development but also vital in cerebrovascular angiogenesis. Blood-brain barrier breakdown has been recognized as an important factor in a variety of primary neurologic diseases; however, such disturbances have yet to be critically analyzed. This article reviews the history, neurodevelopment, ultrastructure, function, and clinicopathologic correlation and relevance to central nervous system vasculitis.

Imaging of Childhood Inflammatory Brain Diseases

Brain has been considered as an immune-privileged site for centuries owing to the presence of blood-brain barrier, absent lymphatic drainage, and antigen-presenting cells. However, the present prevailing concept is of immune surveillance where brain is continuously surveyed by immune cells. However, the presence of immune cells in central nervous system (CNS) brings the risk of inflammation and autoimmunity involving both T and B cell mediated pathways. These mechanisms form the underlying pathology in a wide spectrum of pediatric CNS diseases manifesting as acquired neurological deficits. Overlapping, heterogenous, and ambiguous clinical features often delays the diagnosis. Although not always pathognomonic, magnetic resonance imaging can be an important biomarker leading to early diagnosis, prognostication, and systematic follow-up pf these diseases. This review describes the spectrum of different pediatric inflammatory disorders and their pertinent imaging features illustrated with clinical examples.

Health-related quality of life in children with inflammatory brain disease

OBJECTIVE

To quantify the impact of inflammatory brain diseases in the pediatric population on health-related quality of life, including the subdomains of physical, emotional, school and social functioning.

METHODS

This was a multicenter, observational cohort study of children (< 18 years of age) diagnosed with inflammatory brain disease (IBrainD). Patients were included if they had completed at least one Health Related Quality of Life Questionnaire (HRQoL). HRQoL was measured using the Pediatric Quality of Life Inventory Version 4.0 (PedsQL) Generic Core Scales, which provided a total score out of 100. Analyses of trends were performed using linear regression models adjusted for repeated measures over time.

RESULTS

In this study, 145 patients were included of which 80 (55%) were females. Cognitive dysfunction was the most common presenting symptoms (63%), and small vessel childhood primary angiitis of the CNS was the most common diagnosis (33%). The mean child's self-reported PedsQL total score at diagnosis was 68.4, and the mean parent's proxy-reported PedsQL score was 63.4 at diagnosis. Child's self-reported PedsQL scores reflected poor HRQoL in 52.9% of patients at diagnosis. Seizures or cognitive dysfunction at presentation was associated with statistically significant deficits in HRQoL.

CONCLUSION

Pediatric IBrainD is associated with significantly diminished health-related quality of life. Future research should elucidate why these deficits occur and interventions should focus on improving HRQoL in the most affected subdomains, in particular for children presenting with seizures and cognitive dysfunction.

Role of magnetic resonance imaging in the diagnosis of primary central nervous system angiitis

The present study reported on the use of magnetic resonance imaging (MRI) in the diagnosis of primary angiitis of the central nervous system (PACNS). A total of 19 consecutive patients with a clinical diagnosis of PACNS confirmed by clinical follow-up were enrolled in the present study. All patients underwent unenhanced and enhanced MRI prior to and after steroids or steroids plus immunosuppressive therapy. At baseline, all patients showed lesions on MRI in the grey and white matter. Lesions presented as slightly hypointense on T1-weighted images (T1WI), slightly hyperintense on T2WI, hyperintense on fluid-attenuated inversion recovery, iso- or slightly hyperintense on diffusion-weighted images (DWI) and hyperintense on apparent diffusion coefficient (ADC) mapping. After contrast injection, the lesions showed patchy, cord-like or goral enhancement. Seven cases had unilateral lesions and the other 12 cases had bilateral lesions. On all sequences, indistinct margins characterised most of the lesions, and certain lesions were oedematous. Treatment with steroids or steroids plus immunosuppressive agents resulted in improvement or disappearance of symptoms, and seventeen patients had evidently improved according to MRI. In conclusion, PACNS has unique characteristics on MRI; DWI, ADC mapping and enhanced images are of great importance for the diagnosis and clinical management of early-stage PACNS.

Pathways for Neuroimaging of Childhood Stroke

BACKGROUND

The purpose of this article is to aid practitioners in choosing appropriate neuroimaging for children who present with symptoms that could be caused by stroke.

METHODS

The Writing Group members participated in one or more pediatric stroke neuroimaging symposiums hosted by the Stroke Imaging Laboratory for Children housed at the Hospital for Sick Children in Toronto, Ontario, Canada. Through collaboration, literature review, and discussion among child neurologists with expertise diagnosing and treating childhood stroke and pediatric neuroradiologists and neuroradiologists with expertise in pediatric neurovascular disease, suggested imaging protocols are presented for children with suspected stroke syndromes including arterial ischemic stroke, cerebral sinovenous thrombosis, and hemorrhagic stroke.

RESULTS

This article presents information about the epidemiology and classification of childhood stroke with definitions based on the National Institutes of Health Common Data Elements. The role of imaging for the diagnosis of childhood stroke is examined in depth, with separate sections for arterial ischemic stroke, cerebral sinovenous thrombosis, and hemorrhagic stroke. Abbreviated neuroimaging protocols for rapid diagnosis are discussed. The Writing Group provides suggestions for optimal neuroimaging investigation of various stroke types in the acute setting and suggestions for follow-up neuroimaging. Advanced sequences such as diffusion tensor imaging, perfusion imaging, and vessel wall imaging are also discussed.

CONCLUSIONS

This article provides protocols for the imaging of children who present with suspected stroke.

Central nervous system vasculitis in adults and children

Primary angiitis of the central nervous system (PACNS) is an inflammatory brain disease targeting the cerebral blood vessels, leading to a wide spectrum of signs and symptoms, including neurologic deficits, cognitive dysfunction, and psychiatric symptoms. The inflammation could be reversible if diagnosed and treated early. The diagnosis requires the careful consideration and rapid evaluation of systemic underlying conditions and disease mimics. The differential diagnosis is distinctly different for angiography-positive and -negative PACNS subtypes and differs depending on age, so there is childhood PACNS or adult PACNS. Distinct disease subtypes have been described, with characteristic disease course, neuroimaging findings, and histopathologic features. Novel and traditional biomarkers, including von Willebrand factor antigen and cytokine levels, can help diagnose, and define subtype and disease activity. Treatment of PACNS should be tailored to the disease subtypes and clinical symptoms. Beyond immunosuppression it should include medications to control symptoms in order to support and enhance the child's or adult's ability to actively participate in rehabilitation. The mortality of PACNS has decreased; studies determining the morbidity and its determinants are urgently needed.

Pharmacological approaches to CNS vasculitis: where are we at now?

The diagnosis and treatment of central nervous system (CNS) vasculitis is extremely challenging. Several conditions can mimic CNS vasculitis and require totally different treatment. CNS vasculitis, once confirmed, may result from infections or systemic diseases that will warrant specific treatments, or, more rarely, be primary and isolated (PCNSV). Prospective trials to help determine the optimal treatment for PCNSV are lacking, but data from several cohorts have provided seminal data on its management. The consensus is to use glucocorticoids as first-line agents, combined with additional immunosuppressants for the most severe cases, mainly cyclophosphamide for induction, followed by less-toxic maintenance therapy with azathioprine, methotrexate, or mycophenolate mofetil. The recent identification of PCNSV subgroups and predictors of outcomes might help in deciding the adequate treatment for each patient, keeping in mind that these data are based on a small number of patients. Other agents and biologics can be considered for patients with relapsing and/or refractory disease, but evidence is limited. In practice, the diagnosis must be re-questioned in patients with PCNSV refractory to standard treatment, especially with diagnoses not based on pathology.

Advances in primary angiitis of the central nervous system

Primary angiitis of the central nervous system (PACNS) is a rare idiopathic inflammatory syndrome targeting the vessels of the brain and spinal cord. Clinical presentation is variable, insidious, and non-specific; headache and encephalopathy are the most common symptoms. Multiple strokes affecting numerous vascular territories may be seen, and both focal and diffuse neurologic dysfunction may be present. Cerebrospinal fluid (CSF) analysis is crucial; a normal CSF along with normal brain parenchymal imaging carries a high negative predictive value in excluding PACNS. The role of imaging continues to evolve, and most patients have abnormal vascular imaging; however, the specificity of imaging for PACNS has historically been poor. Cerebral and meningeal biopsy is a valuable tool in confirming the diagnosis and excluding mimics. PACNS generally responds to immunosuppressive therapy. Failure to respond should prompt evaluation for an alternative diagnosis. Given the rarity of this disorder, exclusion of mimics such as the reversible cerebral vasoconstriction syndromes (RCVS) and infectious processes is essential.

The growing spectrum of antibody-associated inflammatory brain diseases in children

Objective:

To describe the clinical spectrum, diagnostic evaluation, current management, and neurologic outcome of pediatric antibody-associated inflammatory brain diseases (AB-associated IBrainD).

Methods:

We performed a single-center retrospective cohort study of consecutive patients aged ≤18 years diagnosed with an AB-associated IBrainD at The Hospital for Sick Children, Toronto, Ontario, Canada, between January 2005 and June 2013. Standardized clinical data, laboratory test results, neuroimaging features, and treatment regimens were captured.

Results:

Of 169 children (93 female, 55%) diagnosed with an IBrainD, 16 (10%) had an AB-associated IBrainD. Median age at presentation was 13.3 years (range 3.1–17.9); 11 (69%) were female. Nine patients (56%) had anti–NMDA receptor encephalitis, 4 (25%) had aquaporin-4 autoimmunity, 2 (13%) had Hashimoto encephalitis, and 1 (6%) had anti–glutamic acid decarboxylase 65 (GAD65) encephalitis. The key presenting features in children with anti–NMDA receptor encephalitis, Hashimoto encephalopathy, and anti-GAD65 encephalitis included encephalopathy, behavioral symptoms, and seizures; patients with aquaporin-4 autoimmunity showed characteristic focal neurologic deficits. Six patients (38%) required intensive care unit admission at presentation. Median time from symptom onset to diagnosis was 55 days (range 6–358). All but 1 patient received immunosuppressive therapy. One child with anti–NMDA receptor encephalitis died due to multiorgan failure. At last follow-up, after a median follow-up time of 1.7 years (range 0.8–3.7), 27% of the children had function-limiting neurologic sequelae.

Conclusions:

Children with AB-associated IBrainD represent an increasing subgroup among IBrainD; 1 in 4 children has function-limiting residual neurologic deficits. Awareness of the different clinical patterns is important in order to facilitate timely diagnosis and initiate immunosuppressive treatment.

Cerebral vasculitis in adults: what are the steps in order to establish the diagnosis? Red flags and pitfalls

Cerebral vasculitis is a rare cause of juvenile stroke. It may occur as primary angiitis of the central nervous system (PACNS) or as CNS manifestation in the setting of systemic vasculitis. Clinical hints for vasculitis are headache, stroke, seizures, encephalopathy and signs of a systemic inflammatory disorder. Diagnostic work-up includes anamnesis, whole body examination, laboratory and cerebral spinal fluid (CSF) studies, magnetic resonance imaging (MRI), angiography and brain biopsy. Due to the rarity of the disease, exclusion of more frequent differential diagnoses is a key element of diagnostic work -up. This review summarizes the steps that lead to the diagnosis of cerebral vasculitis and describes the red flags and pitfalls. Despite considering the dilemma of angiography-negative vasculitis and false-negative brain biopsy in some cases, it is important to protect patients from 'blind' immunosuppressive therapy in unrecognized non-inflammatory differential diagnosis.

Angiogenesis in steno-occlusive vasculopathies as a common pathway for intracranial haemorrhage. A report of six cases

Vasculopathies, including vasculitis of the central nervous system, can lead to stenosed, cicatrized vessels and the development of arterio-arteriolar collateral vessels. Bleeding due to these vascular changes, although rare, does occur. We describe six patients (all female, age range, 21-52 years; mean age, 42 years) with steno-occlusive lesions of intracranial vessels who presented with an acute intracranial haemorrhage. All had arterial steno-occlusive changes in conjunction with extensive leptomeningeal and arterio-arteriolar collaterals. Within the collaterals, focal dilatations could be identified, which were in close spatial relationship with the intracranial haemorrhage. Cause of bleeding was depicted on CT angiography in four out of six patients. One patient presented in childhood with acute stroke, one patient was diagnosed with Buerger's disease and one with sickle cell disease; the other three patients had no relevant history and the exact cause remained unclear. Outcome was favourable in all patients. Despite focal vascular weaknesses, no recurrent haemorrhage was seen during follow-up, supporting, at least in this small patient group, a conservative wait-and-see policy.

Childhood inflammatory brain diseases: pathogenesis, diagnosis and therapy

Inflammatory brain diseases (IBrainDs) are a leading cause of devastating neurological deficits or neuropsychiatric syndromes in previously healthy children. The spectrum is expanding rapidly and new disease entities have been discovered in the last decade. IBrainD can occur as a primary disease or may occur secondary to an underlying cause. This review focuses on the clinical presentation, diagnostic features, pathology and histology characteristics and treatment of the primary childhood IBrainDs.

Primary granulomatous angiitis of the CNS preferentially involving small veins with a granulomatous leukoencephalitis-like lesion in the cerebrum

We have reported an autopsy case of primary granulomatous angiitis of the CNS preferentially involving the small veins with a granulomatous leukoencepalitis-like lesion in the cerebral white matter of a 48-year-old man. The latter lesion was ischemic necrosis due to circumferential multiple perivenous granulomas in the adjacent Virchow-Robin space. Multifocal progressive involvement of venular adventitia by granulomas, leaving behind mural fibrosis and luminal stenosis, was related clinically to the prolonged stepwise deterioration observed in the patient, and pathologically to diffuse loosening with dilated veins in the deep cerebral white matter and subcortical hemorrhagic infarction in the left parietal lobe through chronic venous stagnation. PCR demonstrated negativity for Mycobacterium tuberculosis and Propionibacterium acnes, and in situ hybridization with EBV-encoded small nuclear RNA probe was also negative. The possibility of subarachnoidal latent infection with an unknown avirulent agent causing exclusively perivascular granulomas is proposed. It will be necessary to examine by autopsy whether the type (artery or vein) and size of the involved vessels and the pathological subtype of angiitis is related to the etiopathogenesis and prognosis. It is also pointed out that the entity of lymphocytic angiitis is problematic.

Primary and secondary central nervous system vasculitis

Central nervous system vasculitis is an increasingly recognized inflammatory brain disease causing devastating neurological deficits and psychiatric manifestations in previously healthy children. Primary central nervous system vasculitis represents an isolated inflammatory attack targeting the cerebral vessels. In contrast, in children with secondary central nervous system vasculitis, an underlying condition can be identified. The spectrum of childhood primary and secondary central nervous system vasculitis is rapidly expanding, as is the differential diagnosis including nonvasculitic inflammatory brain diseases and noninflammatory vasculopathies. Early recognition, rapid diagnostic evaluation, and initiation of treatment have led to improved morbidity and mortality. This review focuses on clinical, laboratory, and neuroimaging characteristics of the distinct subtypes of primary childhood central nervous system vasculitis, reports the etiology of secondary central nervous system vasculitis, provides an overview of the differential diagnosis, and reviews the current approaches in treatment.

Autoinflammatory grey matter lesions in humans: cortical encephalitis, clinical disorders, experimental models

PURPOSE OF REVIEW

In recent years, evidence has accumulated that grey matter abnormalities are common in many inflammatory central nervous system (CNS) disorders, such as multiple sclerosis (MS), which is by far the most frequent autoimmune-mediated CNS disease.

RECENT FINDINGS

A recent study described comprehensively the pathology of grey matter lesions in early MS. In this study, cortical demyelination together with inflammation was frequently observed in early MS cases. This study and others serve as a basis for a model of the development of cortical MS lesions in which several consecutive events may be involved. After the activation of T cells, which may open the blood-brain barrier, the humoral immune system may mediate the inflammatory process. The inflammation may become chronic through the involvement of activated glial cells and the persistence of immune cells in the meninges.Apart from MS, other grey matter CNS disorders exist in which antibodies against neuronal structures contribute to pathophysiological events such as in limbic encephalitis. Humoral and adaptive immunity mediates the pathophysiology of Rasmussen encephalitis.

SUMMARY

This review focuses on the difference between inflammatory grey matter and white matter lesions. New insights into inflammatory grey matter lesions in MS and other CNS inflammatory processes such as limbic encephalitis are discussed.