Alzheimer's disease is a progressive disease that affects the brain, initially causing mild memory problems and progressing over the course of years to severe cognitive and physical impairments.
It is the most common cause of dementia, which is a gradual decline in memory, thinking, behavior, and social skills. Alzheimer's disease accounts for 60-80% of dementia cases and affects some 6.9 million Americans. Other less common types of dementia include vascular dementia from a lack of blood flow to the brain during a stroke, Lewy body dementia from a certain kind of abnormal proteins in nerve cells, and frontotemporal dementia, or frontotemporal lobar degeneration.
Alzheimer's disease risk can be partially inherited, although a single genetic cause is rare. Increasing age is the biggest known risk factor for Alzheimer's disease and other dementias. More than 70% of people with Alzheimer's disease are age 75 or older. While slower thinking and occasional problems remembering can be a normal part of aging, Alzheimer's is not part of normal aging and is not directly caused by aging.
The cause of Alzheimer's disease is complex, but one key part is build-up of proteins, called amyloid and tau, that form plaques and tangles. These clumps impair the brain cells around them and eventually make them die. The brain shrinks (atrophies) and struggles to think and remember.
The disease also results in loss of connections between neurons in the brain, which makes it difficult for them to send messages both from one part of the brain to another and from the brain out to muscles and organs in the body.
The first parts of the brain affected are those involved in learning and short term memory, the hippocampus and the entorhinal cortex. Then as the disease progresses, other areas of the brain are affected, leading to more severe memory loss, along with mood and behavior changes, confusion, and unfounded suspicion, and, in the advanced stages, difficulty speaking, swallowing, and walking. Alzheimer's is the seventh leading cause of death in the United States.
"Medical Journeys" is a set of clinical resources reviewed by doctors, meant for physicians and other healthcare professionals as well as the patients they serve. Each episode of this journey through a disease state contains both a physician guide and a downloadable/printable patient resource. "Medical Journeys" chart a path each step of the way for physicians and patients and provide continual resources and support, as the caregiver team navigates the course of a disease.