Alzheimer’S Disease

Overview, Causes, & Risk Factors

Alzheimer’s disease is a common, progressive, degenerative diseaseof the brain. It is characterized by loss ofmemory and other cognitive functions. Among people aged 65 or older, itis the most common cause of dementia.Dementia is a group of symptoms marked by the gradual loss of mentalfunction.

What is going on in the body?

People who have Alzheimer’s disease have abnormal deposits of a protein calledbeta-amyloid. Abnormal structures called plaque are formed from a combinationof destroyed nerve cells and the beta-amyloid. Tangles of nerve fibers areformed from abnormal nerve cells along with a type of protein called TAU. Asthe tangles and plaque develop, nerve cell connections are reduced. Theelimination of nerve cell connections causes damage to certain pathways in thebrain. These pathways are essential for thinking, learning, and memory.

People who have Alzheimer’s disease have smaller brains than the normal population. They alsohave lower amounts of a neurotransmitter called acetylcholine. This chemical isessential for memory and thinking.

What are the causes and risks of the disease?

The cause of Alzheimer’s disease is unknown. Factors that may increase the riskof developing Alzheimer’s disease include the following:

genetics. Scientists have found links between the disease and certainchromosomes, including chromosomes 10, 14, 19, and 21. Individuals with Down syndrome, an abnormality ofthe 21st chromosome, have a significantly higher risk of developing Alzheimer’sdisease.

age. Most people with Alzheimer’s disease are older than age 65, althoughit is sometimes seen in individuals in their 30s, 40s, and 50s. Alzheimer’sdisease is seen in 1 out of 4 people over the age of 85.

educational level or cognitive activities, which are tasks that involveactive learning in the brain. Several research studies have shown thatAlzheimer’s disease is less likely to develop in individuals who have reachedhigher educational levels or have jobs that are more intellectually stimulating.Cognitive activities such as reading are associated with a later onset ofAlzheimer’s disease.

estrogen. There is some research suggesting a possible link between thehormone estrogen and Alzheimer’sdisease in women. Menopause, the stage of life when a woman stopshaving periods and her body makes little estrogen, is associated with anincrease in the onset of Alzheimer’s disease.

head injuries. A recent studyof US armed forces veterans showed that a head injury early in life is associated with ahigher risk of Alzheimer’s disease and other forms of dementia as the veterans aged. Furthermore, the risk ofAlzheimer’s disease increased with the severity of the head injury in earlylife.

environmental toxins, such as aluminum and mercury. There has beenconflicting research about the accumulation of heavy metals in the brains ofindividuals with Alzheimer’s disease.

chemical deficiencies. People with Alzheimer’s disease have a lower thannormal level of acetylcholine in their brains.

autoimmune disorder, which is a condition in which the body attacks its owncells. Some researchers have found antibrain antibodies in the brains of peoplewith Alzheimer’s disease.

Symptoms & Signs

What are the signs and symptoms of the disease?

Symptoms include:

memory loss that affects theperson’s skills. Short-term memory, or memory of recent events, is particularlyaffected in individuals who have Alzheimer’s disease.

difficulty doing familiar activities

misplacing belongings

poor or decreased judgment

language deterioration, with difficulty finding the right words

disorientation to time and place

changes in mood, including depression

hallucinations

delusions

personality changes, including agitation and irritability

impaired ability to orient the body to the surrounding space

a loss of interest in activities that were previously pleasurable

loss of bowel and bladder control

Sometimes individuals will wander. They can have problems doing complex taskssuch as cooking or keeping track of a checkbook.

Diagnosis & Tests

How is the disease diagnosed?

The diagnosis of Alzheimer’s disease is based on a history of increasing memory loss and other cognitive impairments. Changes in behavior, personality,and judgment may also be clues to the disease.

Since there is no definitive test for Alzheimer’s disease, it is important torule out other conditions or diseases that may cause the symptoms. Theseinclude the following:

multiple strokes

Parkinson’s disease, a degenerative nerve disorder that causestremors and mental decline

normal pressure hydrocephalus,which is excessive fluid around the brain

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hypothyroidism, or low levels ofthyroid hormone

alcoholism and drug abuse

infectious diseases that cause brain degeneration, such as Creutzfeldt-Jakob disease, viral infections,or fungal infections

poisoning with carbon monoxide ormethyl alcohol

depression

medication side effects or druginteractions

brain tumors

The clinical diagnosis of Alzheimer’s can be made with an accuracy up to 90%based on these symptoms and the results of a collection of tests.

Prevention & Expectations

What can be done to prevent the disease?

Although there are no proven methods to prevent Alzheimer’s disease, recentresearch findings provide some options that may slow the onset of the diseaseor the progression of symptoms. These findings, which need further study,include:

low doses of aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs),which may work by making blood cells and vessels less sticky and improvingblood flow

actively engaging in cognitive activities such as reading, which mayincrease the nerve connections in the brain and delay the onset of thedisease

taking antioxidants such as VitaminE and selignine. In the Alzheimer’s Disease Cooperative Study, a dose of1,000 IU of vitamin E and 5 mg of selignine twice daily delayed nursing homeplacement, loss of the ability to perform self care, and severe dementia.

hormone replacement therapy formenopausal women, which may delay theonset of symptoms of Alzheimer’s disease. The relationship between the hormoneestrogen and Alzheimer’s disease stillneeds further investigation.

avoiding head injuries. A person should wear a seatbelt at all times whenriding in a motor vehicle. Sports safety guidelines for children, adolescents, and adults can behelpful in avoiding other head injuries.

What are the long-term effects of the disease?

There is no cure for Alzheimer’s disease. The disease is progressive. Thesymptoms get worse as the disease progresses. From the time the disease isrecognized until the person dies is generally about 6 to 8 years, although it canrange from less than 2 years to over 20 years.

What are the risks to others?

Alzheimer’s disease is not contagious and poses no risk to others.

Treatment & Monitoring

What are the treatments for the disease?

The 3 medications currently approved by the Food and Drug Administration fortreatment of Alzheimer’s disease are donepezil, tacrine, and rivastigmine.These medications are designed to improve memory by increasing the amount ofacetylcholine in the body.

Other medications, such as risperidone or quetiapine, may also be used to helpbehavioral problems such as hallucinations, delusions, or agitation. Someindividuals with Alzheimer’s disease may also need medications for depression, anxiety, or insomnia.

Other treatments include support and education for those caring for people withAlzheimer’s. Individual and family counseling can be beneficial. Support groupshave also been found to assist caregivers. As the disease progresses, manyfamilies are unable to care for the person with Alzheimer’s disease at home, andplacement in a special facility is needed.

What are the side effects of the treatments?

Medications used to treat Alzheimer’s disease can damage the liver, so periodicliver function tests are needed. Otherside effects may include nausea, diarrhea, insomnia, vomiting, fatigue, or muscle cramps.

What happens after treatment for the disease?

Alzheimer’s disease is a degenerative disease without a cure.Treatment is lifelong. Because the course of Alzheimer’s disease isunpredictable, individuals with the disease should make plans for end-of-lifecare while they are still able to participate in the decision-making.

Difficult issues that family members may face include the following:

promoting independence while making sure the individual is safe

removing driving privileges

finding supportive care among family, in an assisted living facility ornursing home

making business decisions

determining executors of written wills and making sure advanceddirectives are in the individual’s patient file at his or her doctor’soffice

How is the disease monitored?

Individuals with Alzheimer’s disease will have periodic visits to thehealthcare provider for evaluation and treatment. Periodic liver function tests may be ordered if the person istaking one of the medications that can cause liver damage. Any new or worseningsymptoms should be reported to the provider.

Article type: xmedgeneral