Cerebrospinal fluid biomarkers in cerebral amyloid angiopathy: insights from a clinical case series

Abstract Cerebral amyloid angiopathy (CAA) is a small vessel disease characterized by the deposition of amyloid-beta in small cerebral vessels, which can lead to intracerebral hemorrhages and cognitive impairment. Rare variants, such as cerebral amyloid angiopathy-related inflammation (CAA-ri) and iatrogenic CAA (ICAA), may mimic other neurological conditions and challenge diagnosis in clinical practice. We present three cases that illustrate distinct CAA syndromes, along with CSF biomarker analysis. One patient experienced recurrent hemorrhagic strokes with a history of dural graft, raising concerns about amyloid transmission. Two patients presented with rapidly progressive dementia that fulfilled CAA-ri criteria. All cases exhibited decreased levels of CSF Aβ40 and Aβ42, with one showing elevated p-tau, suggesting comorbid Alzheimer's pathology. Cerebrospinal fluid biomarkers complement neuroimaging in the diagnosis of CAA, aiding in differentiation from other dementias. Early recognition and diagnosis of CAA-ri variants is crucial, because immunotherapy may improve outcomes. Further research is necessary to establish biomarker thresholds and their clinical applicability.