Cerebral Amyloid Angiopathy
Cerebral amyloid angiopathy (CAA) is a neurological condition in which amyloid protein is deposited onto the walls of the arteries of the brain (and less frequently, veins). Although CAA often does not cause symptoms, it may cause bleeding into the brain (hemorrhagic stroke), dementia, or neurologic episodes in some patients. The majority of CAA cases occur in individuals who do not have a family history.
It is not associated with systemic amyloidosis. CAA has been recognized as one of the morphologic hallmarks of Alzheimer disease (AD), but it is also often found in the brains of elderly patients who are neurologically healthy. While often asymptomatic, CAA may lead to dementia, intracranial hemorrhage (ICH), or transient neurologic events. ICH is the most recognized result of CAA. Most affected individuals die within a decade after signs and symptoms first appear, although some people with the disease have survived longer.
There are many different types of hereditary cerebral amyloid angiopathy. The different types are distinguished by their genetic cause and the signs and symptoms that occur. The various types of hereditary cerebral amyloid angiopathy are named after the regions where they were first diagnosed.
The Dutch type of hereditary cerebral amyloid angiopathy is the most common form. Stroke is frequently the first sign of the Dutch type and is fatal in about one third of people who have this condition. Survivors often develop dementia and have recurrent strokes. About half of individuals with the Dutch type who have one or more strokes will have recurrent seizures (epilepsy).
People with the Flemish and Italian types of hereditary cerebral amyloid angiopathy are prone to recurrent strokes and dementia. Individuals with the Piedmont type may have one or more strokes and typically experience impaired movements, numbness or tingling (paresthesias), confusion, or dementia.
The first sign of the Icelandic type of hereditary cerebral amyloid angiopathy is typically a stroke followed by dementia. Strokes associated with the Icelandic type usually occur earlier than the other types, with individuals typically experiencing their first stroke in their twenties or thirties.
Strokes are rare in people with the Arctic type of hereditary cerebral amyloid angiopathy, in which the first sign is usually memory loss that then progresses to severe dementia. Strokes are also uncommon in individuals with the Iowa type. This type is characterized by memory loss, problems with vocabulary and the production of speech, personality changes, and involuntary muscle twitches (myoclonus).
Two types of hereditary cerebral amyloid angiopathy, known as familial British dementia and familial Danish dementia, are characterized by dementia and movement problems. Strokes are uncommon in these types. People with the Danish type may also have clouding of the lens of the eyes (cataracts) or deafness.