Anti-Amyloid Therapies for Alzheimer's Disease and Amyloid-Related Imaging Abnormalities: Implications for the Emergency Medicine Clinician.

Alzheimer's disease is the neurodegenerative disorder responsible for approximately 60% to 70% of all cases of dementia and is expected to affect 152 million by 2050. Recently, anti-amyloid therapies have been developed and approved by the Food and Drug Administration as disease-modifying treatments given as infusions every 2 to 5 weeks for Alzheimer's disease. Although this is an important milestone in mitigating Alzheimer's disease progression, it is critical for emergency medicine clinicians to understand what anti-amyloid therapies are and how they work to recognize, treat, and mitigate their adverse effects. Anti-amyloid therapies may be underrecognized contributors to emergency department visits because they carry the risk of adverse effects, namely amyloid-related imaging abnormalities. Amyloid-related imaging abnormalities are observed as abnormalities on magnetic resonance imaging as computed tomography is not sensitive enough to detect the microvasculature abnormalities causing vasogenic edema (amyloid-related imaging abnormalities-E) microhemorrhages and hemosiderin deposits (amyloid-related imaging abnormalities-H). Patients presenting with amyloid-related imaging abnormalities may have nonspecific neurologic symptoms, including headache, lethargy, confusion, and seizures. Anti-amyloid therapies may increase risk of hemorrhagic conversion of ischemic stroke patients receiving thrombolytics and complicate the initiation of anticoagulation. Given the novelty of anti-amyloid therapies and limited real-world data pertaining to amyloid-related imaging abnormalities, it is important for emergency medicine clinicians to be aware of these agents.