Multiple ischemic strokes in a patient treated with Lecanemab: a case report

Amyloid-lowering therapy via administration of monoclonal antibodies against amyloid beta has been previously associated with the formation of cerebral edema and/or microhemorrhage. These changes are often picked up on MRI and referred to as amyloid-related imaging abnormalities, or ARIA. Cerebral ischemia has not been systematically reported in clinical trials involving amyloid-lowering therapy but has been reported in case reports. Here we describe an additional case of a patient with Alzheimer's Disease treated with the amyloid-lowering drug Lecanemab who developed both ARIA-H and ARIA-E, as well as multiple asymptomatic ischemic infarctions. Extensive workup did not reveal another clear cause for infarction. These infarcts, in conjunction with previous reports of ischemic infarction in the setting of anti-amyloid therapy, suggest that amyloid-lowering therapy may predispose individuals to both hemorrhagic and ischemic infarction. This result is discussed in the context of microvascular pathology known to occur in the setting of Alzheimer's Disease.