Alzheimer's Disease

Definition

Alzheimer's disease is the most common cause of dementia. It is a progressive condition that destroys brain cells. People with Alzheimer's disease slowly lose the ability to learn, function, and remember.

Areas of the Brain Affected by Alzheimer's Disease

© 2008 Nucleus Medical Art, Inc.

Causes

The cause of Alzheimer's disease is not yet known. Studies suggest that two main mechanisms may result in the clinical picture of the disease:

  • Plaques—abnormal deposits of a substance called beta amyloid in different areas of the brain
  • Neurofibrillary tangles—twisted fibers within nerve cells

Risk Factors

A risk factor increases your chance of getting a disease or condition.

Risk factors include:

  • Age: 65 and older
  • Previous serious, traumatic brain injury
  • Lower educational achievement
  • Down's syndrome
  • Down's syndrome in a first-degree relative
  • Women under 35 who give birth to a child with Down's syndrome
  • Smoking
  • Family history of Alzheimer's disease
  • Presence of a certain variety type of apolipoprotein (APOE-e4)
  • Depression
  • Elevated levels of homocysteine
  • Heart disease

Researchers are studying the following to see if they are related to Alzheimer's disease:

  • Poor nutrition and vitamin deficiency in childhood
  • Exposure to electromagnetic fields
  • Excess metal in the blood, especially zinc, copper, aluminum, and iron
  • Certain viral infections
  • Diabetes
  • High Cholesterol

Symptoms

The disease begins as mild memory lapses but moves to profound loss of memory and function. Alzheimer's disease is divided into three stages:

  • Early
  • Intermediate
  • Severe

Symptoms include:

  • Increasing trouble remembering things, such as
    • How to get to familiar places
    • Names of friends and family members
    • Where common objects are kept
    • Simple math
    • How to perform tasks (eg, cooking, dressing, bathing)
  • Trouble concentrating on tasks
  • Trouble completing sentences due to lost or forgotten words (progresses to a complete inability to speak)
  • Difficulty with daily life tasks such as bill paying and housekeeping
  • Inability to remember the date, time of day, season
  • Mood swings
  • Withdrawal, loss of interest in usual activities
  • Slow, shuffling walk
  • Poor coordination
  • Slowness and then loss of purposeful movement

Diagnosis

There are no tests to definitively diagnose Alzheimer's disease. The doctor will ask about your symptoms and medical history and do a physical exam. The doctor will ask many questions to rule out other causes.

Tests to rule out other medical conditions may include:

  • Neurological exam
  • Psychological and mental status testing
  • CT scan—a type of x-ray that uses a computer to make pictures of the brain
  • MRI scan—a test that uses magnetic waves to make pictures of the brain
  • Electroencephalogram (EEG)—a test that measures electrical currents in the brain
  • Blood tests and urine tests
  • Lumbar puncture—to test for levels of certain brain proteins that increase with Alzheimer’s disease and to rule out other disorders

Treatment

There are no treatments to cure Alzheimer's disease and no certain ways to slow its progression. Four medications have received US Food and Drug Administration approval for the treatment of some symptoms of Alzheimer's dementia. Various drugs are being studied to see if they can manage the symptoms or slow its course.

Medications for Symptoms and Disease Progression

Medications being used and studied include:

  • Cholinesterase inhibitors (eg, donepezil, rivastigmine, galantamine)
  • NMDA receptor antagonist (eg, memantine)
  • Antioxidants (eg, vitamin E)
  • Estrogen
  • Anti-inflammatory agents
  • Ginkgo biloba (herbal supplement)

Lifestyle Management

Managing the disease includes:

  • Creating an environment in which you can receive the care you need
  • Optimizing your quality of life
  • Keeping yourself safe
  • Helping yourself learn to deal with the frustration of your uncontrollable behavior
  • Providing a calm, quiet, predictable environment
  • Providing appropriate eyewear and hearing aids, easy-to-read clocks and calendars
  • Playing quiet music
  • Light, appropriate exercise to reduce agitation and relieve depression
  • Encouraging family and close friends to visit frequently

Psychiatric Medications

Medications to treat the psychiatric symptoms that may occur with Alzheimer’s disease include:

  • Antidepressants—to treat depression
  • Anxiolytics—to treat anxiety
  • Antipsychotics—to treat severe confusion, paranoia, and hallucinations

Caregiver Support

Caring for a person with Alzheimer's disease is extremely difficult and exhausting. The primary caregiver needs emotional support, as well as regular respite.

Prevention

There are no guidelines for preventing Alzheimer's disease because the cause is unknown.

RESOURCES:

Alzheimer's Association
http://www.alz.org/

Alzheimer's Disease Education and Referral Center
http://www.alzheimers.org/

CANADIAN RESOURCES:

Alzheimer Society
http://www.alzheimer.ca/

BC Health Guide
http://www.bchealthguide.org/

References:

Alzheimer’s disease. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Accessed February 23, 2008.

American Academy of Neurology website. Available at: http://www.aan.com/professionals/. Accessed October 12, 2005.

Goetz CG. Textbook of Clinical Neurology. Philadelphia, PA: WB Saunders Company; 1999.

Green RC, Cupples LA, Go R, et al. Risk of dementia among white and African-American relatives of patients with Alzheimer disease. JAMA. 2002;287:329-336.

Kasper DL, Braunwald E, Fauci AS, et al. Harrison's Principles of Internal Medicine. 16th ed. New York, NY: The McGraw-Hill Companies; 2005.

Rakel RE, Bope ET. Conn's Current Therapy. 53rd ed. Philadelphia, PA: WB Saunders Company; 2001.

Rowland LP, Merritt HH. Alzheimer's disease and related dementias. Merritt's Neurology. Philadelphia, PA: Lippincott Williams and Wilkins; 2000: chap 106.



Last reviewed February 2008 by J. Thomas Megerian, MD, PhD, FAAP

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.


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