Episode 977: Amyloid Therapy and Stroke-like Events
Oct 6, 2025
Dive into the complexities of Alzheimer's treatment as advancements in anti-amyloid therapies come to light. Learn how these monoclonal antibodies aim to reduce amyloid plaques but come with risks like amyloid-related imaging abnormalities (ARIA). These side effects can mimic stroke symptoms, complicating emergency treatment. The discussion reveals the importance of MRI for detection and the critical need to check a patient's medication history before proceeding with stroke interventions.
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insights INSIGHT
Anti-Amyloid Therapies' Dual Effects
Anti-amyloid therapies target amyloid plaques to slow Alzheimer disease progression.
These treatments can paradoxically cause new neurologic symptoms by affecting amyloid distribution in the brain.
insights INSIGHT
ARIA Can Mimic Acute Stroke
Amyloid-related imaging abnormalities (ARIA) can present with headache, vertigo, or focal deficits that mimic stroke.
ARIA is only visible on MRI and may be missed on CT, complicating ED evaluation.
volunteer_activism ADVICE
Check Meds And Prefer MRI Before Thrombolysis
When an Alzheimer's patient presents with acute neurologic deficits, check whether they are on anti-amyloid drugs.
Consider MRI in the workup because CT may miss ARIA and thrombolytics carry higher bleeding risk in these patients.
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The cause of Alzheimer's disease is multifactorial, but the most widely suspected mechanism is the amyloid cascade hypothesis:
Beta-amyloid proteins accumulate in the central nervous system, forming plaques that impair neuronal function.
In recent years, advances have led to the development of targeted therapies with monoclonal antibodies. These drugs:
Work by degrading amyloid plaques
Slow the rate of cognitive decline and disease progression
Have major side effects, most notably the development of amyloid-related imaging abnormalities (ARIA)
ARIA may present as edema, effusion, or microhemorrhages, which are only detectable on MRI
Symptoms can include headache, vertigo, or focal neurologic deficits that mimic stroke
For patients presenting to the emergency department with stroke-like symptoms, it is important to consider whether they have a history of Alzheimer's disease and whether they are taking these medications.
This guides decisions about imaging and treatment:
The work-up may require MRI, which can delay thrombolytic or endovascular therapy in patients with true strokeConversely, treating a patient with ARIA using thrombolytics increases the risk of bleeding and other complications
References
Ebell MH, Barry HC, Baduni K, Grasso G. Clinically Important Benefits and Harms of Monoclonal Antibodies Targeting Amyloid for the Treatment of Alzheimer Disease: A Systematic Review and Meta-Analysis. Ann Fam Med. 2024 Jan-Feb;22(1):50-62. doi: 10.1370/afm.3050. PMID: 38253509; PMCID: PMC11233076.
Ma C, Hong F, Yang S. Amyloidosis in Alzheimer's Disease: Pathogeny, Etiology, and Related Therapeutic Directions. Molecules. 2022 Feb 11;27(4):1210. doi: 10.3390/molecules27041210. PMID: 35209007; PMCID: PMC8876037.
Perneczky R, Dom G, Chan A, Falkai P, Bassetti C. Anti-amyloid antibody treatments for Alzheimer's disease. Eur J Neurol. 2024 Feb;31(2):e16049. doi: 10.1111/ene.16049. Epub 2023 Sep 11. PMID: 37697714; PMCID: PMC11235913.
Summarized by Ashley Lyons, OMS3 | Edited by Ashley Lyons and Jorge Chalit, OMS4
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