Supplementary Material for: A case of severe cerebral amyloid angiopathy-related inflammation (CAA-ri) in a 81-year-old woman with rapid cognitive decline

Introduction
Cerebral amyloid angiopathy (CAA) is a vasculopathy characterized by amyloid-beta (Aβ) deposition in the walls of the leptomeningeal and cortical blood vessels. In a minority of patients with CAA, presence of amyloid-beta (Aβ) deposition triggers an autoimmune inflammatory reaction, referred to as CAA-related inflammation (CAA-RI). It can present in two forms, either as perivascular CAA-related inflammation (CAA-ri) or as Aβ-related angiitis (ABRA). The mechanism underlying CAA-RI remains unclear. Symptoms are subacute mental disorders and behavioral or cognitive changes, headaches, seizures and focal neurological deficits. Most commonly, CAA-ri is a monophasic illness. Relapses occur often years after the initial presentation and are correlated with corticosteroid tapering or immunosuppression cessation. Treatment is often prolonged, but effective. We present a rare and instructive case with CAA-ri characterized by rapid cognitive decline, therapy resistance and fatal outcome and discuss current literature.

Case presentation
We describe a case of an 81-year-old female who presented with progressive confusion, behaviour alterations, recurrent falls and vomiting since two weeks. There was a rapid cognitive decline and fatal outcome. The diagnosis of a probable CAA-ri was made based on the clinical presentation and brain MR imaging. To allow long-term corticosteroid replacement, azathioprine was initiated for second-line immunosuppression.

Conclusion
This case report of CAA-ri describes the diagnostic and therapeutic challenges in an elderly patient with rapid cognitive decline. It highlights the severe nature of the condition, the limitations of available treatments and the importance of early recognition based on the diagnostic criteria and MR imaging and start of the therapy, while acknowledging that outcomes may remain poor despite intervention.

引言
脑淀粉样血管病（Cerebral amyloid angiopathy, CAA）是一种以软脑膜及皮质血管壁内β淀粉样蛋白（amyloid-beta, Aβ）沉积为特征的血管病变。在少数CAA患者中，β淀粉样蛋白沉积会触发自身免疫炎症反应，这一病症被称为CAA相关炎症（CAA-related inflammation, CAA-RI）。该病症可分为两种类型：血管周围CAA相关炎症（perivascular CAA-related inflammation, CAA-ri）与β淀粉样蛋白相关血管炎（Aβ-related angiitis, ABRA）。目前CAA-RI的发病机制仍不明确。其临床表现包括亚急性精神障碍、行为或认知改变、头痛、癫痫发作及局灶性神经功能缺损。CAA-ri多为单相病程，复发通常在首次发病数年后出现，且与糖皮质激素减量或免疫抑制治疗停药相关。该疾病的治疗周期往往较长，但治疗有效。本文报告1例罕见且具有指导意义的CAA-ri病例，该患者以快速认知衰退、治疗抵抗及致死性结局为特征，并结合当前文献进行讨论。

病例报告
我们报告1例81岁女性患者，该患者在2周内出现进行性意识模糊、行为改变、反复跌倒及呕吐症状，伴随快速认知衰退并最终致死。结合临床表现与脑部磁共振成像（brain MR imaging）检查，确诊为疑似CAA-ri。为实施长期糖皮质激素替代治疗，予硫唑嘌呤行二线免疫抑制治疗。

结论
本CAA-ri病例报告阐述了老年快速认知衰退患者所面临的诊断与治疗挑战，强调了该疾病的严重性、现有治疗手段的局限性，以及基于诊断标准与磁共振成像实现早期识别并启动治疗的重要性，同时也指出即便采取干预措施，患者结局仍可能不佳。