Cerebral Amyloid Angiopathy (CAA)

Cerebral amyloid angiopathy (CAA) is a condition where a sticky protein called amyloid-beta builds up in the small blood vessels of the brain over many years. This build-up can weaken the blood vessels, making them more likely to leak and cause tiny bleeds in the brain that often go unnoticed.

Over time, these small changes can impact memory and cognitive function. In some cases, a blood vessel may burst, leading to a larger bleed and more serious symptoms, like a stroke.

Here are some important things to know about CAA:

• CAA is quite common as people get older; it’s not a rare condition.
• CAA is one of the leading causes of non-traumatic brain bleeding in people over 60.
• Over time, the changes caused by CAA can lead to cognitive problems. Sometimes, a single, larger bleed can suddenly impact memory and cognitive function. CAA is also closely linked to Alzheimer’s disease, and the two conditions often occur together.
• Short episodes of neurological symptoms, often called “amyloid spells,” can be mistaken for other conditions like mini-strokes (TIAs), migraines, or seizures. This can delay the correct diagnosis, but with the right tools and expertise, CAA can be identified and managed effectively.

• Memory problems: Difficulty remembering things and thinking clearly.
• Stroke symptoms: Sudden trouble moving or feeling one side of the body, slurred speech, trouble seeing, or loss of balance. These are usually due to a large bleed in the brain.
• Short episodes: Brief periods of numbness, tingling, or weakness on one side of the body that usually go away within 30 minutes but can last a few hours. These are called Transient Focal Neurological Episodes (TFNE) or “Amyloid Spells”.
• Inflammatory CAA: Big changes in thinking or behavior, seizures, or new headaches due to brain swelling from the body’s immune response to the disease.

Doctors use a combination of tools and tests to figure out if someone has CAA. The primary method is known as the Boston criteria, which has been developed over many years of research. It examines your symptoms and brain MRI results to estimate the likelihood that you have CAA.

While it’s not a 100% specific diagnosis, it provides doctors with a strong indication based on patterns they’ve observed in similar cases. Since other conditions can sometimes resemble CAA on scans, your doctor will also consider your personal health history and risk factors to obtain a clearer picture.

An MRI is significant for diagnosing CAA, but it’s good to know that amyloid buildup in blood vessels likely starts many years before it can be seen on a scan.

Here are some of the ways doctors might check for CAA:

• MRI scans: These are the most common tools for spotting signs of CAA. The quality of the scan and the type of images taken can affect how much doctors can see.
• Blood tests: Sometimes, doctors will check for specific markers in your blood that might support the diagnosis.
• Spinal fluid tests: Testing the fluid around your brain and spine can help in some cases, though it’s not used as often as MRI.
• Special brain scans: PET scans can be used to detect amyloid-beta in the brain, which may support the diagnosis in certain cases.
• Genetic testing: While not routine, genetic testing might check for specific gene changes tied to CAA.

Every person is different, so your physician will take an individualized approach to figure out what’s best for you.

While there is no cure for CAA yet, treatment focuses on reducing risks, managing symptoms and supporting brain health over the long term. Every treatment plan is personalized to meet your needs and may include addressing risk factors, monitoring the condition's progression, and exploring new therapies when appropriate.

Here are some key parts of CAA treatment:

• Careful use of blood thinners: Blood thinners can increase the risk of bleeding in the brain; therefore, physicians may discontinue these medications if they aren't necessary. However, this decision isn't always simple. In some cases, even with CAA, blood thinners may provide more benefits than risks. Your doctor will carefully weigh the options based on your overall health and medical history.
• Managing blood pressure: Maintaining a stable and well-controlled blood pressure is one of the most effective ways to reduce the risk of brain hemorrhage. At Ochsner, we may utilize tools such as remote blood pressure monitoring to help you achieve your goals and stay on track over time.
• Healthy lifestyle choices: Our CAA clinic encourages lifestyle changes that support both heart and brain health. We often recommend the MIND diet, which is great for brain health and regular cardiovascular exercise. We also focus on improving sleep quality, as sound sleep can enhance recovery, improve mental function, and aid the brain in clearing proteins like amyloid-beta.
• Medications: Your care team may adjust your current medications or add new ones to help reduce risks and improve your quality of life. In some cases, off-label medications or supplements might be considered, and specific treatments may be available through clinical trials. While there aren't any FDA-approved treatments specifically for CAA yet, research is ongoing.
• Immunosuppressive therapy: For people with inflammatory CAA, treatment may include medications like corticosteroids or other immunosuppressants to reduce swelling and inflammation in the brain.

Your Ochsner care team will work closely with you to create a personalized plan that meets your needs and provides ongoing support throughout your journey.

CAA often occurs alongside other neurological and vascular conditions, and understanding these connections is important for accurate diagnosis and personalized care. Here’s a closer look at some of these relationships:

• Alzheimer’s disease: CAA and Alzheimer’s disease (AD) are closely linked because they both involve the same protein, called amyloid-beta. However, this protein acts differently in each condition. In CAA, amyloid-beta builds up in the walls of blood vessels, making them weak and prone to leaking. In Alzheimer’s, the protein spreads into brain tissue, affecting memory and thinking. These conditions can happen on their own, but they often overlap. In fact, up to 80–90% of people with Alzheimer’s also have at least mild CAA when studied under a microscope.
• Rare forms of CAA: While most cases of CAA are caused by amyloid-beta, there are rare types caused by other abnormal proteins or inherited genetic mutations. These forms may look and act like typical CAA but have different underlying causes. They’re extremely rare and usually require special tests to diagnose.
• Overlap with other vascular conditions: CAA often coexists with other small blood vessel problems in the brain, like damage from long-term high blood pressure (called hypertensive arteriopathy). Over time, high blood pressure can cause small blood vessels to stiffen or narrow, reducing blood flow and leading to tiny strokes or cognitive issues. It can also cause brain bleeding that looks similar to CAA, though it usually happens in different areas. Sometimes, it’s hard to tell these conditions apart on imaging, so managing all vascular issues is key to reducing risks of bleeding and cognitive decline.
• Other neurodegenerative diseases: CAA or Alzheimer’s disease can overlap with other conditions like Parkinson’s disease, dementia or dementia with Lewy bodies. While this isn’t common for most people with CAA, it’s something doctors consider if a patient has cognitive symptoms. In these cases, a thorough evaluation, including imaging, laboratory tests, and clinical assessments, is crucial to rule out other causes of cognitive decline and ensure an accurate diagnosis and treatment plan.

Understanding these connections helps doctors provide the best care possible, tailored to your unique situation.

CAA carries a higher risk of recurrent brain bleeds compared to other causes, but the likelihood of bleeding and cognitive decline can vary from person to person. It’s not a one-size-fits-all condition. Each case requires a thorough and personalized evaluation to determine the most effective approach.

The progression of CAA varies greatly among individuals, making it difficult to determine life expectancy. Some people may have mild symptoms for many years, while others may experience severe problems sooner. Some may have stable periods followed by progressive phases with multiple hospitalizations. It's crucial to have a good care team to manage the disease and support patients in identifying progression when it happens.