Cerebral Amyloid Angiopathy as An Underrecognized Cause of Delirium and Acute Cognitive Dysfunction in Older Adults: a Monocentric Retrospective Study

Background : Cerebral amyloid angiopathy (CAA) is a common age-related cerebral small vessel disease and a leading cause of lobar intracerebral hemorrhage. Although acute neurological manifestations are well recognized, the clinical presentation of CAA in older adults, particularly with respect to delirium and acute cognitive dysfunction, remains insufficiently characterized. Methods : The aim of the study was to describe the clinical, radiological and cognitive phenotype of a monocentric cohort of CAA patients in the acute setting of the stroke unit. We retrospectively reviewed 6244 consecutive non-elective tertiary stroke unit admissions between June 2018 and April 2025. Cases of CAA and CAA-related inflammation (CAA-ri) were identified through longitudinal expert adjudication using established clinicoradiological criteria and comprehensive review of imaging and clinical records. Patients were stratified according to age (≥75 vs <75 years). Clinical, radiological, and cognitive manifestations were compared between groups using univariate analyses. Results : Among 117 patients with CAA, approximately 2% of all admissions, 60 (51.3%) were aged ≥75 years. Compared with younger patients, older adults less frequently presented with impaired consciousness (20.0% vs 36.8%, p=.043) and tended to have fewer seizures (10.0% vs 21.0%, p=.098). Dyscognitive manifestations occurred in 65.0% of older patients, including delirium in 38.3%. CAA-ri was identified in 16.7% of geriatric cases and was associated with a higher prevalence of delirium than non-inflammatory CAA (70.0% vs 32.0%, p=.024). Radiological markers of CAA were largely similar across age groups, although deep and/or confluent leukoencephalopathy was more frequent in older adults (75.0% vs 56.1%, p=.032). Conclusions : In older adults, CAA is a frequent but underrecognized cause of acute hospitalization and commonly presents with delirium and other dyscognitive manifestations rather than classical neurological syndromes. Delirium accompanied by focal neurological deficits should prompt consideration of CAA, even in the absence of overt hemorrhage. Improved recognition of these presentations may facilitate diagnosis, guide management decisions, and enhance care for older adults in the era of anti-amyloid therapies.