Alzheimer's disease

Definition

Dementia is a loss of brain function that occurs with certain diseases. Alzheimer's disease (AD), is one form of dementia that gradually gets worse over time. It affects memory, thinking, and behavior.

Alternative Names

Senile dementia - Alzheimer's type (SDAT); SDAT

Causes

You are more likely to get Alzheimer's disease (AD) if you:

The following may also increase your risk, although this is not well proven:

There are two types of AD:

The cause of AD is not clear. Your genes and environmental factors seem to play a role. Aluminum, lead, and mercury in the brain is no longer believed to be a cause of AD.

Alzheimer's disease

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Alzheimer's disease

Symptoms

Dementia symptoms include difficulty with many areas of mental function, including:

Dementia usually first appears as forgetfulness.

Mild cognitive impairment is the stage between normal forgetfulness due to aging, and the development of AD. People with MCI have mild problems with thinking and memory that do not interfere with everyday activities. They are often aware of the forgetfulness. Not everyone with MCI develops AD.

Symptoms of MCI include:

The early symptoms of AD can include:

As the AD becomes worse, symptoms are more obvious and interfere with your ability to take care of yourself. Symptoms can include:

People with severe AD can no longer:

Other symptoms that may occur with AD:

Exams and Tests

A skilled health care provider can often diagnose AD disease with the following steps:

A diagnosis of AD is made when certain symptoms are present, and by making sure other causes of dementia are not present.

Tests may be done to rule out other possible causes of dementia, including:

Computed tomography (CT) or magnetic resonance imaging (MRI) of the brain may be done to look for other causes of dementia, such as a brain tumor or stroke.

However, the only way to know for certain that someone has AD is to examine a sample of their brain tissue after death. The following changes are more common in the brain tissue of people with AD:

Treatment

There is no cure for AD. The goals of treatment are:

DRUG TREATMENT

Medicines are used to help slow down the rate at which symptoms become worse. The benefit from these drugs is usually small. You and your family may not notice much of a change.

Before using these medicines, ask the doctor or nurse:

Medicines for AD include:

Other medicines may be needed to control aggressive, agitated, or dangerous behaviors. Examples include haloperidol, risperidone, and quetiapine. These are usually given in very low doses due to the risk of side effects including an increased risk of death.

It may be necessary to stop any medications that make confusion worse. Such medicines may include painkillers, cimetidine, central nervous system depressants, antihistamines, sleeping pills, and others. Never change or stop taking any medicines without first talking to your doctor.

SUPPLEMENTS

Some people believe certain vitamins and herbs may help prevent or slowdown AD.

If you are considering any drugs or supplements, you should talk to your doctor first. Remember that herbs and supplements available over the counter are NOT regulated by the FDA.

Support Groups

For additional information and resources for people with Alzheimer's disease and their caregivers, see Alzheimer's disease support groups.

Outlook (Prognosis)

How quickly AD gets worse is different for each person. If AD develops quickly, it is more likely to worsen quickly.

Patients with AD often die earlier than normal, although a patient may live anywhere from 3 - 20 years after diagnosis.

The final phase of the disease may last from a few months to several years. During that time, the patient becomes totally disabled. Death usually occurs from an infection or organ failure.

Possible Complications

When to Contact a Medical Professional

Call your health care provider if someone close to you has symptoms of dementia.

Call your health care provider if a person with AD has sudden change in mental status. A rapid change may be a sign of another illness.

Talk to your health care provider if you are caring for a person with AD and you can no longer care for the person in your home.

Prevention

Although there is no proven way to prevent AD, there are some practices that may be worth incorporating into your daily routine, particularly if you have a family history of dementia. Talk to your doctor about any of these approaches, especially those that involve taking a medication or supplement.

In addition, early testing of a vaccine against AD is underway.

References

Aisen PS, Schneider LS, Sano M, Diaz-Arrastia R, van Dyck CH, et al. High-dose B vitamin supplementation and cognitive decline in Alzheimer's disease: a randomized controlled trial. JAMA. 2008;300:1774-1783.

DeKosky ST, Kaufer DI, Hamilton RL, Wolk DA, Lopez OL. The dementias. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Bradley: Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann Elsevier; 2008:chap 70.

DeKosky ST, Williamson JD, Fitzpatrick AL, Kronmal RA, Ives DG, Saxton JA, et al. Ginkgo biloba for prevention of dementia: a randomized controlled trial. JAMA. 2008;300:2253-2262.

Knopman DS. Alzheimer’s disease and other dementias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 409.

Mayeux R. Early Alzheimer's disease. N Engl J Med. 2010 Jun 10;362(4):2194-2201.

Peterson RC. Clinical practice. Mild cognitive impairment. N Engl J Med 2011 Jun 9;364(23):2227-2234.

Qaseem A, et al., American College of Physicians/American Academy of Family Physicians Panel on Dementia. Current pharmacologic treatment of dementia: a clinical practice guideline from the American College of Physicians and the American Academy of Family Physicians. Ann Intern Med 2008 Mar 4;148(5):370-8.

Querfurth HW, LaFerla FM. Alzheimer's disease. N Engl J Med. 2010 Jan 28;362(4):329-44.