Alzheimer’s disease is a type of dementia, or a disease that causes the progressive loss of certain brain functions. Memory loss is the first cognitive symptom of Alzheimer’s disease that is noticed, but there are other cognitive impairments associated with the disease as well. Alzheimer’s disease most often develops in older individuals, which is why it is sometimes called a “senile dementia.” This article will outline the causes, pathophysiology, symptoms, diagnosis, treatment and prognosis of Alzheimer’s disease.

The exact cause of Alzheimer’s disease is unknown, but we do know that Alzheimer’s disease runs in families, so it has a genetic component. Certain environmental factors are thought to trigger the onset of the disease in genetically susceptible individuals. Some of the genes that put a person at risk for Alzheimer’s disease have been identified; they make abnormal proteins that may cause changes in the brain. A rare early-onset type of Alzheimer’s disease that runs in families involves genes that virtually guarantee that a person will develop the disease, but most cases of Alzheimer’s disease (over 95%) involve genetic and environmental factors. The risk of developing Alzheimer’s disease increases as a person gets older, but Alzheimer’s is very different from normal aging.

Alzheimer’s disease causes changes in the brain tissue over time, including the death of neurons (brain cells). Alzheimer’s disease causes a literal shrinking of brain tissue in its advanced stages. Microscopically, the brain tissue damaged by Alzheimer’s has abnormal features called plaques and tangles. Examining these plaques and tangles has given us some information about how Alzheimer’s disease develops. Plaques are made of a protein called beta-amyloid. Tangles are due to a deformed protein called tau that is present in neurons. When this protein is deformed, it kinks and twists abnormally and blocks off the transport mechanism of the cell. The presence of plaques and tangles implies that these protein abnormalities are responsible for the brain damage seen in Alzheimer’s disease.

The symptoms of Alzheimer’s disease change and worsen during the progression of the disease. The symptoms are usually broken up into stages, although doctors do not agree on the exact number of stages. The first noticeable symptom is memory loss regarding things like finding the right word and misplacing important objects like keys. It may also be difficult to concentrate occasionally. Most healthy people experience these symptoms occasionally, so it is not rational to suspect Alzheimer’s based on the early symptoms of the disease. The point at which cognitive impairments become noticeable to others is usually when a diagnosis of Alzheimer’s disease can be made. As the disease progresses, additional cognitive symptoms become apparent. Memory loss may progress to forgetting people who are close to you, forgetting what year it is or forgetting who you are. Sleep problems, difficulty writing or reading, loss of function in everyday life tasks and poor judgment are also common symptoms as Alzheimer’s disease progresses. In the end stages of the disease, sufferers lose nearly all function and can no longer recognize people or language. Motor functions, such as swallowing food and bladder control, can also be affected in late Alzheimer’s disease.

Alzheimer’s disease is usually diagnosed at the point at which a person has mild to moderate cognitive impairment and it is just getting to the point where other people are concerned that their memory loss is more than a normal person experiences. Diagnosis in the earliest stage of the disease is rare unless a person has a strong family history of the disease. Once it has been established that a person has dementia, other causes of cognitive impairment have to be ruled out. Blood tests and medical imaging are used to do this; once other causes of dementia are ruled out, the cause of the cognitive impairment is almost certainly Alzheimer’s disease, the most common type of dementia.

Alzheimer’s disease is incurable. The time it takes for a person to progress from mild memory impairment to the later stages of Alzheimer’s disease is about ten years on average, although the disease progression can take much longer in some individuals. In general, Alzheimer’s disease does shorten a person’s lifespan, but it is difficult to predict how long the disease will take to progress to the end stages. The last stage of the disease where the patient is extremely disabled can be short or long, lasting for months or several years. Alzheimer’s disease patients are prone to infections and other health complications in the end stages of the disease.

Some medications are available that may slow the progression of the symptoms of the disease, but the benefits are pretty small. Sometimes, medications are given if a person with Alzheimer’s disease becomes aggressive or anxious. Some of the symptoms and behavioral problems associated with Alzheimer’s disease can be managed, but medical treatment is limited for this condition. On the other hand, support of the patient and the family is incredibly important.