Risk Factor Review Prior to New Alzheimer Disease Therapies Is Necessary

Background: Amyloid-related imaging abnormalities (ARIAs) on brain MRI scans can develop from treatment with the newly approved anti-amyloid monoclonal antibody medications for Alzheimer disease. Two imaging findings have been described: ARIA-E, with parenchymal edema and hyperintensities on T2-weighted MRI, and ARIA-H, with hemosiderin deposits or parenchymal microhemorrhages. Objective: To describe the causes of ARIA from new anti-amyloid monoclonal medications, findings of ARIA on brain MRI, and risk factors for ARIA. Discussion: Presumably, ARIA is caused by inflammation from the anti-amyloid monoclonal medications, which results in microhemorrhages and/or edema in the brain. The greatest risk of developing ARIA occurs after initially starting the anti-amyloid therapy. Although presence of ARIA-E or ARIA-H findings on brain MRI does not usually cause symptoms, some patients experience severe symptoms and may even die from this therapy. ARIA-E usually resolves after anti-amyloid a more...