Cerebral amyloid angiopathy-related inflammation: clinical features and treatment response in a case series

INTRODUCTION

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is an entity characterised by an inflammatory response to β-amyloid deposition in the walls of cerebral microvessels.

METHODS

We conducted a retrospective review of a series of patients with a diagnosis of CAA-ri according to histopathological study findings or clinical-radiological diagnostic criteria.

RESULTS

The study included 7 patients (5 men) with a mean age of 79 years. Disease onset was acute or subacute in 6 patients. The most frequent symptoms were cognitive impairment (n = 6), behavioural alterations (n = 5), epileptic seizures (n = 5), focal neurological signs (n = 4), and headache (n = 2). Cerebrospinal fluid was abnormal in 3 patients (lymphocytic pleocytosis and high protein levels). The most frequent MRI findings were microbleeds (n = 7), subcortical white matter hyperintensities on T2-FLAIR sequences (n = 7), and leptomeningeal enhancement (n = 6). Lesions were bilateral in 3 patients and most frequently involved the parieto-occipital region (n = 5). Amyloid PET studies were performed in 2 patients, one of whom showed pathological findings. Two patients underwent brain biopsy, which confirmed diagnosis. All patients received immunosuppressive therapy. An initially favourable clinical-radiological response was observed in all cases, with 2 patients presenting radiological recurrence after treatment withdrawal, with a subsequent improvement after treatment was resumed.

CONCLUSIONS

Early diagnosis of CAA-ri is essential: early treatment has been shown to improve prognosis and reduce the risk of recurrence. Although a histopathological study is needed to confirm diagnosis, clinical-radiological criteria enable diagnosis without biopsy.

Cerebral amyloid angiopathy related inflammation: An under recognized but treatable complication of cerebral amyloid angiopathy

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a subset of cerebral amyloid angiopathy (CAA) causing a reversible encephalopathy characterized by seizures and focal neurological deficit. Previously, biopsy was required to make this diagnosis, distinct radiological features have allowed development for clinicoradiological criteria to assist in diagnosis. CAA-ri is an important condition to recognize as patients respond to high dose corticosteroids with significant resolution of symptoms. A 79-year-old woman presents with new onset seizures and delirium with prior history of mild cognitive impairment. An initial computed tomography (CT) brain demonstrated vasogenic oedema in the right temporal lobe, and magnetic resonance imaging (MRI) showed bilateral subcortical white matter change and multiple microhemorrhages. The MRI findings were suggestive of cerebral amyloid angiopathy. Cerebrospinal fluid analysis demonstrated raised protein and oligoclonal bands. A thorough septic and autoimmune screen demonstrated no abnormality. Following a multidisciplinary discussion, a diagnosis of CAA-ri was made. She was commenced on dexamethasone and her delirium improved. CAA-ri is an important diagnostic consideration in an elderly patient who presents with new seizures. Clinicoradiological criteria are useful diagnostic tools and may avoid the need for invasive histopathological diagnosis.

Cerebral Amyloid Angiopathy-Related Inflammation (CAA-rI): Three Heterogeneous Case Reports and a Focused Literature Review

Cerebral amyloid angiopathy-related inflammation (CAA-rI) is a largely reversible, subacute encephalopathy, which is considered as a rare variant of cerebral amyloid angiopathy (CAA). Although the diagnosis of this inflammatory vasculopathy is generally clinico-pathologic, a probable or possible diagnosis can often be established based on current clinico-radiological diagnostic criteria. This is important since CAA-rI is considered as a treatable disorder, which most commonly occurs in the elderly population. Behavioral changes and cognitive deterioration are highlighted as the most common clinical signs of CAA-rI, followed by a heterogeneous spectrum of typical and atypical clinical presentations. However, despite the well-established clinical and radiological features incorporated in the current diagnostic criteria for this CAA variant, this rare disorder is still insufficiently recognized and treated. Here, we have shown three patients diagnosed with probable CAA-rI, with significant heterogeneity in the clinical and neuroradiological presentations, followed by different disease courses and outcomes after the introduction of immunosuppressive treatment. Moreover, we have also summarized up-to-date literature data about this rare, yet underdiagnosed, immune-mediated vasculopathy.

Clinical, Neuroimaging, and Genetic Markers in Cerebral Amyloid Angiopathy-Related Inflammation: A Systematic Review and Meta-Analysis

BACKGROUND

There are limited data regarding the prevalence of distinct clinical, neuroimaging and genetic markers among patients diagnosed with cerebral amyloid angiopathy-related inflammation (CAA-ri). We sought to determine the prevalence of clinical, radiological, genetic and cerebrospinal fluid biomarker findings in patients with CAA-ri.

METHODS

A systematic review and meta-analysis of published studies including patients with CAA-ri was conducted to determine the prevalence of clinical, neuroimaging, genetic and cerebrospinal fluid biomarker findings. Subgroup analyses were performed based on (1) prospective or retrospective study design and (2) CAA-ri diagnosis with or without available biopsy. We pooled the prevalence rates using random-effects models and assessed the heterogeneity using Cochran-Q and I²-statistics.

RESULTS

We identified 4 prospective and 17 retrospective cohort studies comprising 378 patients with CAA-ri (mean age, 71.5 years; women, 52%). The pooled prevalence rates were as follows: cognitive decline at presentation 70% ([95% CI, 54%-84%]; I²=82%), focal neurological deficits 55% ([95% CI, 40%-70%]; I²=82%), encephalopathy 54% ([95% CI, 39%-68%]; I²=43%), seizures 37% ([95% CI, 27%-49%]; I²=65%), headache 31% ([95% CI, 22%-42%]; I²=58%), T2/fluid-attenuated inversion recovery-hyperintense white matter lesions 98% ([95% CI, 93%-100%]; I²=44%), lobar cerebral microbleeds 96% ([95% CI, 92%-99%]; I²=25%), gadolinium enhancing lesions 54% ([95% CI, 42%-66%]; I²=62%), cortical superficial siderosis 51% ([95% CI, 34%-68%]; I²=77%) and lobar macrohemorrhage 40% ([95% CI, 11%-73%]; I²=88%). The prevalence rate of the ApoE (Apolipoprotein E) ε4/ε4 genotype was 34% ([95% CI, 17%-53%]; I²=76%). Subgroup analyses demonstrated no differences in these prevalence rates based on study design and diagnostic strategy.

CONCLUSIONS

Cognitive decline was the most common clinical feature. Hyperintense T2/fluid-attenuated inversion recovery white matter lesions and lobar cerebral microbleeds were by far the most prevalent neuroimaging findings. Thirty-four percent of patients with CAA-ri have homozygous ApoE ε4/ε4 genotype and scarce data exist regarding the cerebrospinal fluid biomarkers and its significance in these patients.

Cerebral Superficial Siderosis

Superficial siderosis (SS) of the central nervous system constitutes linear hemosiderin deposits in the leptomeninges and the superficial layers of the cerebrum and the spinal cord. Infratentorial (i) SS is likely due to recurrent or continuous slight bleeding into the subarachnoid space. It is assumed that spinal dural pathologies often resulting in cerebrospinal fluid (CSF) leakage is the most important etiological group which causes iSS and detailed neuroradiological assessment of the spinal compartment is necessary. Further etiologies are neurosurgical interventions, trauma and arteriovenous malformations. Typical neurological manifestations of this classical type of iSS are slowly progressive sensorineural hearing impairment and cerebellar symptoms, such as ataxia, kinetic tremor, nystagmus and dysarthria. Beside iSS, a different type of SS restricted to the supratentorial compartment can be differentiated, i.e. cortical (c) SS, especially in older people often due to cerebral amyloid angiopathy (CAA). Clinical presentation of cSS includes transient focal neurological episodes or “amyloid spells”. In addition, spontaneous and amyloid beta immunotherapy-associated CAA-related inflammation may cause cSS, which is included in the hemorrhagic subgroup of amyloid-related imaging abnormalities (ARIA). Because a definitive diagnosis requires a brain biopsy, knowledge of neuroimaging features and clinical findings in CAA-related inflammation is essential. This review provides neuroradiological hallmarks of the two groups of SS and give an overview of neurological symptoms and differential diagnostic considerations.

Cerebral Amyloid Angiopathy-Related Inflammation: A Single-Center Experience and a Literature Review

Background: Limited data exist regarding the prevalence of clinical, neuroimaging, and genetic markers among patients diagnosed with Cerebral Amyloid Angiopathy−related inflammation (CAA-ri). We sought to determine these characteristics in patients diagnosed in our center and to summarize available literature published either as single-case reports or small case series (<5 patients). Methods: We reported our single-center experience of patients diagnosed with CAA-ri according to international criteria during a seven-year period (2015−2022), and we abstracted data from 90 previously published cases. Results: Seven patients (43% women, mean age 70 ± 13 years) were diagnosed with CAA-ri in our center. The most common symptom at presentation was focal neurological dysfunction (71%), and the most prevalent radiological finding was the presence of T2/FLAIR white matter hyperintensities (100%). All patients were treated with corticosteroids and had a favorable functional outcome. Among 90 previously published CAA-ri cases (51% women, mean age 70 ± 9 years), focal neurological dysfunction was the most common symptom (76%), followed by a cognitive decline (46%) and headache (34%). The most prevalent neuroimaging findings were cerebral microbleeds (85%), asymmetric T2/FLAIR white matter hyperintensities (81%), and gadolinium-enhancing T1-lesions (37%). Genetic testing for the Apolipoprotein-E gene was available in 27 cases; 59% carried the APOE ε4/ε4 genotype. The majority of the published CAA-ri cases (78%) received corticosteroid monotherapy, while 17 patients (19%) were treated with additional immunosuppressive treatment. Favorable functional outcome following treatment was documented in 70% of patients. Conclusion: Improving the vigilance of clinicians regarding the early recognition and accurate diagnosis of CAA-ri is crucial for swift therapy initiation, which may result in improved functional outcomes.

Different clinical outcomes between cerebral amyloid angiopathy-related inflammation and non-inflammatory form

OBJECTIVE

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a rare manifestation related to CAA, thought to be more severe. We aimed to compare the clinical and radiological outcomes of CAA-ri and non-inflammatory CAA.

MATERIALS AND METHODS

We retrospectively included all patients with CAA-ri from 13 French centers. We constituted a sex- and age-matched control cohort with non-inflammatory CAA and similar disease duration. Survival, autonomy and cognitive evolution were compared after logistic regression. Cerebral microbleeds (CMB), intracerebral hemorrhage, cortical superficial siderosis and hippocampal atrophy were analyzed as well as CSF biomarker profile and APOE genotype when available. Outcomes were compared using Kaplan-Meier curves and log-rank tests.

RESULTS

Data from 48 CAA-ri patients including 28 already reported and 20 new patients were analyzed. Over a mean of 3.1 years, 11 patients died (22.9%) and 18 (37.5%) relapsed. CAA-ri patients were more frequently institutionalized than non-inflammatory CAA patients (30% vs 8.3%, p < 0.001); mortality rates remained similar. MMSE and modified Rankin scale scores showed greater severity in CAA-ri at last follow-up. MRI showed a higher number of CMB at baseline and last follow-up in CAA-ri (p < 0.001 and p = 0.004, respectively). CSF showed lower baseline levels of Aß42 in CAA-ri than non-inflammatory CAA (373.3 pg/ml vs 490.8 pg/ml, p = 0.05). CAA-ri patients more likely carried at least one APOE ε4 allele (76% vs 37.5%, adjusted p = 0.05) particularly as homozygous status (56% vs 6.2%, p < 0.001).

INTERPRETATION

CAA-ri appears to be more severe than non-inflammatory CAA with a significant loss of autonomy and global higher amyloid burden, shown by more CMB and a distinct CSF profile. This burden may be partially promoted by ε4 allele.

Cerebral amyloid angiopathy related inflammation: A little known but not to be underestimated disease

Cerebral amyloid angiopathy related inflammation (CAA-ri) is a rare encephalopathy resulting from perivascular inflammation after β-βamyloid (A) deposition in cerebral vessels leading to progressive dementia, focal neurological signs, seizures and intracerebral hemorrhages. This condition is characterized on magnetic resonance imaging (MRI) by patchy or confluent T2/fluid attenuation inversion recovery (FLAIR) hyperintensities in the cortex and subcortical white matter located mainly in the same areas of pre-existing multiple microhemorrhages. In this report of 2 cases of “probable” CAA-ri women aged 71 and 68, we propose a review on the pathophysiological, clinical, radiological, therapeutic and prognostic aspects of this little-known and poor outcome condition.

Even though an apparently favorable initial evolution after steroid and/or immunosuppressive treatment, CAA-ri course is unpredictable and often associated with low survival rates. We suggest the importance of timely and proper clinico-radiological evaluation in suspected CAA-ri cases, in order to start an appropriate treatment even without the brain biopsy.

Cerebral Amyloid Angiopathy-related Inflammation Presenting With a Cystic Lesion in Young-onset Alzheimer Disease

We describe a patient with cerebral amyloid angiopathy-related inflammation (CAA-ri) presenting as Alzheimer disease (AD) with a mass lesion with symptom onset at age 59. He was found to have a nonenhancing lesion in the right temporal lobe on magnetic resonance imaging without evidence of hemorrhage. He underwent a biopsy which showed amyloid beta in blood vessel walls and a perivascular inflammatory infiltrate consistent with CAA-ri. Neurofibrillary tangles were present and a flortaucipir positron emission tomography showed bilateral signal highest in the lateral temporal and parietal cortices. A lumbar puncture showed tau, p-tau, and amyloid beta levels consistent with AD without evidence of inflammation. He was homozygous for the APOE ε4 allele. He died at age 67. A focus of CAA-ri can be present in the context of AD with a mass lesion and without evidence of hemorrhage, significant ischemic changes, or overt inflammation on cerebrospinal fluid examination.

Cerebral amyloid angiopathy-related inflammation: clinical features and treatment response in a case series

INTRODUCTION

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is an entity characterised by an inflammatory response to β-amyloid deposition in the walls of cerebral microvessels.

METHODS

We conducted a retrospective review of a series of patients with a diagnosis of CAA-ri according to histopathological study findings or clinical-radiological diagnostic criteria.

RESULTS

The study included 7 patients (5 men) with a mean age of 79 years. Disease onset was acute or subacute in 6 patients. The most frequent symptoms were cognitive impairment (n = 6), behavioural alterations (n = 5), epileptic seizures (n = 5), focal neurological signs (n = 4), and headache (n = 2). Cerebrospinal fluid was abnormal in 3 patients (lymphocytic pleocytosis and high protein levels). The most frequent MRI findings were microbleeds (n = 7), subcortical white matter hyperintensities on T2-FLAIR sequences (n = 7), and leptomeningeal enhancement (n = 6). Lesions were bilateral in 3 patients and most frequently involved the parieto-occipital region (n = 5). Amyloid PET studies were performed in 2 patients, one of whom showed pathological findings. Two patients underwent brain biopsy, which confirmed diagnosis. All patients received immunosuppressive therapy. An initially favourable clinical-radiological response was observed in all cases, with 2 patients presenting radiological recurrence after treatment withdrawal, with a subsequent improvement after treatment was resumed.

CONCLUSIONS

Early diagnosis of CAA-ri is essential: early treatment has been shown to improve prognosis and reduce the risk of recurrence. Although a histopathological study is needed to confirm diagnosis, clinical-radiological criteria enable diagnosis without biopsy.

Cerebral amyloid angiopathy-related inflammation: current status and future implications

ABSTRACT

Cerebral amyloid angiopathy-related inflammation (CAA-RI) is a rare but increasingly recognized subtype of CAA. CAA-RI consists of two subtypes: inflammatory cerebral amyloid angiopathy and amyloid β (Aβ)-related angiitis. Acute or subacute onset of cognitive decline or behavioral changes is the most common symptom of CAA-RI. Rapid progressive dementia, headache, seizures, or focal neurological deficits, with patchy or confluent hyperintensity on T2 or fluid-attenuated inversion recovery sequences and evidence of strictly lobar microbleeds or cortical superficial siderosis on susceptibility-weighted imaging imply CAA-RI. The gold standard for diagnosis is autopsy or brain biopsy. However, biopsy is invasive; consequently, most clinically diagnosed cases have been based on clinical and radiological data. Other diagnostic indexes include the apolipoprotein E ε4 allele, Aβ and anti-Aβ antibodies in cerebral spinal fluid and amyloid positron emission tomography. Many diseases with similar clinical manifestations should be carefully ruled out. Immunosuppressive therapy is effective both during initial presentation and in relapses. The use of glucocorticoids and immunosuppressants improves prognosis. This article reviews the pathology and pathogenesis, clinical and imaging manifestations, diagnostic criteria, treatment, and prognosis of CAA-RI, and highlights unsolved problems in the existing research.

Association Between Immunosuppressive Treatment and Outcomes of Cerebral Amyloid Angiopathy-Related Inflammation

IMPORTANCE

Cerebral amyloid angiopathy-related inflammation (CAA-ri), a distinct subtype of cerebral amyloid angiopathy, is characterized by an autoimmune reaction to cerebrovascular β-amyloid deposits. Outcomes and response to immunosuppressive therapy for CAA-ri are poorly understood.

OBJECTIVE

To identify clinical, neuroimaging, laboratory, pathologic, or treatment-related associations with outcomes after an episode of CAA-ri.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study of prospectively identified individuals who presented from July 3, 1998, to November 27, 2017, with a median follow-up of 2.7 years (interquartile range, 1.0-5.5 years). The study included 48 consecutive patients with CAA-ri meeting diagnostic criteria who had at least 1 disease episode and subsequent outcome data. No patients refused or were excluded.

EXPOSURES

Prespecified candidate variables were immunosuppressive therapies, cerebrospinal fluid pleocytosis, magnetic resonance imaging findings of recent infarcts or contrast enhancement, and histopathologic evidence of vessel wall inflammation.

MAIN OUTCOMES AND MEASURES

Clinical improvement and worsening were defined by persistent changes in signs or symptoms, radiographic improvement by decreased subcortical foci of T2 hyperintensity or T1 enhancement, and radiographic worsening by increased subcortical T2 hyperintensity, T1 enhancement, or infarcts. Disease recurrence was defined as new-onset clinical symptoms associated with new imaging findings.

RESULTS

The 48 individuals in the study included 29 women and had a mean (SD) age of 68.9 (9.9) years. Results of presenting magnetic resonance imaging revealed that 10 of 29 patients with CAA-ri (34%) had T1 contrast enhancement, 30 of 32 (94%) had subcortical T2 hyperintensity (22 of 30 [73%] asymmetric), 7 of 32 (22%) had acute or subacute punctate infarcts, and 27 of 31 (87%) had microbleeds. Immunosuppressive treatments after first episodes included corticosteroids (33 [69%]), cyclophosphamide (6 [13%]), and mycophenolate (2 [4%]); 14 patients (29%) received no treatment. Clinical improvement and radiographic improvement were each more likely in individuals treated with an immunosuppressive agent than with no treatment (clinical improvement: 32 of 34 [94%] vs 7 of 14 [50%]; odds ratio, 16.0; 95% CI, 2.72-94.1; radiographic improvement: 24 of 28 [86%] vs 4 of 14 [29%]; odds ratio, 15.0; 95% CI, 3.12-72.1). Recurrence was less likely if CAA-ri was treated with any immunosuppressant agent than not (9 of 34 [26%] vs 10 of 14 [71%]; hazard ratio, 0.19; 95% CI, 0.07-0.48). When controlling for treatment, no variables were associated with outcomes aside from an association between APOE ɛ4 and radiographic improvement (odds ratio, 4.49; 95% CI, 1.11-18.2).

CONCLUSIONS AND RELEVANCE

These results from a relatively large series of patients with CAA-ri support the effectiveness of immunosuppressive treatment and suggest that early treatment may both improve the initial disease course and reduce the likelihood of recurrence. These results raise the possibility that early blunting of CAA-ri and the autoimmune response may have long-term benefits for the subsequent disease course.