Reversible Rapidly Progressive Dementia Due to Cerebral Amyloid Angiopathy.

Cerebral amyloid angiopathy (CAA) is a vascular disorder of the brain caused by beta-amyloid deposits in small- and medium-sized vessels. In some patients, the condition triggers an inflammatory response, which can appear in different forms based on the pattern of vessel involvement. These rare but treatable inflammatory variants may present with a syndrome of rapidly progressive dementia, which may pose a diagnostic challenge. Here, we describe a 76-year-old man who experienced two distinct episodes of rapidly progressive cognitive deterioration accompanied by diffuse weakness and seizure activity, separated by a seven-year interval. Despite extensive diagnostic evaluation during the initial presentation, a definitive diagnosis was not established. During the second episode, advanced neuroimaging revealed characteristic asymmetric white matter changes, and subsequent histopathologic examination confirmed cerebral amyloid angiopathy-related inflammation (CAA-ri). This case underscores the diagnostic complexity of CAA-ri and highlights the importance of clinicoradiologic correlation and tissue confirmation in atypical or recurrent presentations of rapidly progressive dementia.