People with CAA have deposits of amyloid protein in the walls of blood vessels in the brain. The protein is usually not deposited anywhere else in the body.

The major risk factor is increasing age. CAA is more often seen in people older than 55. Sometimes, it is passed down through families.

CAA can cause bleeding into the brain. Bleeding often occurs in the outer parts of the brain, called the cortex, and not the deep areas. Symptoms occur because bleeding in the brain harms brain tissue. Some people have gradual memory problems. When a CT scan is done, there are often signs that they have had bleeding in the brain that they may not have realized.

If there is a lot of bleeding, immediate symptoms occur and resemble a stroke. These symptoms include:

• Drowsiness
• Headache (usually in a certain part of the head)
• Nervous system changes that may start suddenly, including confusion, delirium, double vision, decreased vision, sensation changes, speech problems, weakness, or paralysis
• Seizures
• Stupor or coma (rarely)
• Vomiting

If bleeding is not severe or widespread, symptoms can include:

• Episodes of confusion
• Headaches that come and go
• Loss of mental function (dementia)
• Weakness or unusual sensations that come and go, and involve smaller areas
• Seizures

CAA is hard to diagnose with certainty without a sample of brain tissue. This is usually done after death or when a biopsy of the blood vessels of the brain is done.

A physical exam can be normal if the bleed is small. There may be some brain function changes. It is important for your health care provider to ask detailed questions about the symptoms and medical history. The symptoms and results of the physical exam and any imaging tests may cause your provider to suspect CAA.

Imaging tests of the head that may be done include:

• CT scan or MRI scan to check for bleeding in the brain
• MRA scan to check for large bleeds and rule out other causes of bleeding
• PET scan to check for amyloid deposits in the brain

There is no known effective treatment. The goal of treatment is to reduce risk by modifying risk factors, such as hypertension, and to relieve symptoms. In some cases, rehabilitation is needed for weakness or clumsiness. This can include physical, occupational, or speech therapy.

Sometimes, medicines that help improve memory, such as those for Alzheimer disease, are used.

Seizures, also called amyloid spells, may be treated with anti-seizure medicines.

The disorder slowly gets worse.

Complications of CAA may include:

• Dementia
• Hydrocephalus (rarely)
• Seizures
• Repeated episodes of bleeding in the brain

Go to the emergency room or call 911 or the local emergency number if you have sudden loss of movement, sensation, vision, or speech.

Amyloidosis - cerebral; CAA; Congophilic angiopathy

Polster SP, Carrión-Penagos J, Awad IA. Nonlesional spontaneous intracerebral hemorrhage. In: Winn HR, ed. Youmans and Winn Neurological Surgery. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 423.

Shoamanesh A, Kase CS. Intracerebral hemorrhage. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 66.

Updated by: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.