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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:
- Are older. However, developing AD is not a part of normal aging.
- Have a close blood relative, such as a brother, sister, or parent with AD.
- Have certain genes linked to AD, such as APOE epsilon4 allele
The following may also increase your risk, although this is not well proven:
- Being female
- Having high blood pressure for a long time
- History of head trauma
There are two types of AD:
- Early onset AD: Symptoms appear before age 60. This type is much less common than late onset. However, it tends to get worse quickly. Early onset disease can run in families. Several genes have been identified.
- Late onset AD: This is the most common type. It occurs in people age 60 and older. It may run in some families, but the role of genes is less clear.
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.
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Symptoms
Dementia symptoms include difficulty with many areas of mental function, including:
- Emotional behavior or personality
- Language
- Memory
- Perception
- Thinking and judgment (cognitive skills)
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:
- Difficulty performing more than one task at a time
- Difficulty solving problems
- Forgetting recent events or conversations
- Taking longer to perform more difficult activities
The early symptoms of AD can include:
- Difficulty performing tasks that take some thought, but used to come easily, such as balancing a checkbook, playing complex games (such as bridge), and learning new information or routines
- Getting lost on familiar routes
- Language problems, such as trouble finding the name of familiar objects
- Losing interest in things previously enjoyed, flat mood
- Misplacing items
- Personality changes and loss of social skills
As the AD becomes worse, symptoms are more obvious and interfere with your ability to take care of yourself. Symptoms can include:
- Change in sleep patterns, often waking up at night
- Delusions, depression, agitation
- Difficulty doing basic tasks, such as preparing meals, choosing proper clothing, and driving
- Difficulty reading or writing
- Forgetting details about current events
- Forgetting events in your own life history, losing awareness of who you are
- Hallucinations, arguments, striking out, and violent behavior
- Poor judgment and loss of ability to recognize danger
- Using the wrong word, mispronouncing words, speaking in confusing sentences
- Withdrawing from social contact
People with severe AD can no longer:
- Understand language
- Recognize family members
- Perform basic activities of daily living, such as eating, dressing, and bathing
Other symptoms that may occur with AD:
- Incontinence
- Swallowing problems
Exams and Tests
A skilled health care provider can often diagnose AD disease with the following steps:
- Complete physical exam, including neurological exam
- Asking questions about your medical history and symptoms
- A mental status examination
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:
- Anemia
- Brain tumor
- Chronic infection
- Intoxication from medication
- Severe depression
- Stroke
- Thyroid disease
- Vitamin deficiency
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.
- In the early stages of dementia, brain image scans may be normal. In later stages, an MRI may show a decrease in the size of different areas of the brain.
- While the scans do not confirm the diagnosis of AD, they do exclude other causes of dementia (such as stroke and tumor).
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:
- "Neurofibrillary tangles" (twisted fragments of protein within nerve cells that clog up the cell)
- "Neuritic plaques" (abnormal clusters of dead and dying nerve cells, other brain cells, and protein)
- "Senile plaques" (areas where products of dying nerve cells have accumulated around protein).
Treatment
There is no cure for AD. The goals of treatment are:
- Slow the progression of the disease (although this is difficult to do)
- Manage symptoms, such as behavior problems, confusion, and sleep problems
- Change your home environment so you can better perform daily activities
- Support family members and other caregivers
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:
- What are the potential side effects? Is the medicine worth the risk?
- When is the best time, if any, to use these medicines?
Medicines for AD include:
- Donepezil (Aricept), rivastigmine (Exelon), and galantamine (Razadyne, formerly called Reminyl). Side effects include stomach upset, diarrhea, vomiting, muscle cramps, and fatigue.
- Memantine (Namenda). Possible side effects include agitation or anxiety.
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.
- There is no strong evidence that Folate (vitamin B6), vitamin B12, and vitamin E prevent AD or slows the disease once it occurs.
- High-quality studies have not shown that ginkgo biloba lowers the chance of developing dementia. DO NOT use ginkgo if you take blood-thinning medications like warfarin (Coumadin) or a class of antidepressants called monoamine oxidase inhibitors (MAOIs).
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
- Abuse by an over-stressed caregiver
- Bedsores
- Loss of muscle function that makes you unable to move your joints
- Infection, such as urinary tract infection and pneumonia
- Other complications related to immobility
- Falls and broken bones
- Harmful or violent behavior toward self or others
- Loss of ability to function or care for self
- Loss of ability to interact
- Malnutrition and dehydration
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.
- Consume a low-fat diet.
- Eat cold-water fish (like tuna, salmon, and mackerel) rich in omega-3 fatty acids, at least 2 to 3 times per week.
- Reduce your intake of linoleic acid found in margarine, butter, and dairy products.
- Increase antioxidants like carotenoids, vitamin E, and vitamin C by eating plenty of darkly colored fruits and vegetables.
- Maintain a normal blood pressure.
- Stay mentally and socially active throughout your life.
- Consider taking nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil, Motrin), sulindac (Clinoril), or indomethacin (Indocin). Statin drugs, a class of medications normally used for high cholesterol, may help lower your risk of AD. Talk to your doctor about the pros and cons of using these medications for prevention.
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.
Reviewed By: Luc Jasmin, MD, PhD, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles, and Department of Anatomy at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
