Alzheimer's Disease

(Alzheimer's Dementia)

by Rosalyn Carson-DeWitt, MD

Definition

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

Areas of the Brain Affected by Alzheimer's Disease

© 2009 Nucleus Medical Media, Inc.

Causes

The cause is not yet known. Studies suggest that two main mechanisms are involved with the development of Alzheimer's disease:

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

Risk Factors

Factors that may increase your chance of Alzheimer's disease 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 protein (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
• 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. It moves to profound loss of memory and function. Alzheimer's disease is divided into three stages:

• Early—memory and cognition loss are noticeable but still able to function independently
• Intermediate—mental loss, personality changes more dependent on others for basic needs
• Severe—loss of personality and bodily functions; total dependence for care

Symptoms include:

• Increasing trouble remembering things, such as:
  • How to get to familiar locations
  • What the names of family and friends are
  • Where common objects are usually kept
  • How to do simple math
  • How to do usual tasks, such as cooking, dressing, bathing, etc.
• Having difficulty concentrating on tasks
• Having difficulty completing sentences due to lost/forgotten words (may progress to complete inability to speak)
• Forgetting the date, time of day, season
• Getting lost in familiar surroundings
• Having mood swings
• Being withdrawn, losing interest in usual activities
• Having personality changes
• Walking in a slow, shuffling way
• Having poor coordination
• Losing purposeful movement

Diagnosis

There are no tests to definitively diagnose this disease. The doctor will ask about your symptoms and medical history. A physical exam will be done. The doctor will ask many questions. This will help 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 is no cure for Alzheimer's disease. There are also no certain ways to slow its progression. Four medicines have received approval for the treatment of some symptoms. Various drugs are being studied to see if they can manage the symptoms or slow the condition's course.

If you are diagnosed with Alzheimer's disease, follow your doctor's instructions.

Prevention

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

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

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

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

Health Canada
http://www.hc-sc.gc.ca/index-eng.php/

REFERENCES:

Alzheimer's disease. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php. Updated October 2009. Accessed January 8, 2010.

Alzheimer's disease medications fact sheet. National Institute on Aging website. Available at: http://www.nia.nih.gov/Alzheimers/Publications/medicationsfs.htm. Updated September 2009. Accessed January 8, 2010.

Alzheimer's disease and non-Alzheimer’s dementia. EBSCO Natural and Alternative Treatments website. Available at: http://www.ebscohost.com/thisTopic.php?marketID=15topicID=114. Updated September 2009. Accessed January 8, 2010.

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

Carillo MC, Blackwell A, Hampel H, et al. Early risk assessment for Alzheimer's disease. Alzheimers Dement. 2009;5(2):182-196.

Dementia. EBSCO Health Library website. Available at: http://www.ebscohost.com/thisTopic.php?marketID=15topicID=81. Updated November 2009. Accessed January 8, 2010.

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.

Neugroschl J, Sano M. An update on treatment and prevention strategies for Alzheimer’s disease. Curr Neurol Neurosci Rep. 2009;9:368-376.

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.

1/8/2010 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php: Snitz BE, O'Meara ES, Carlson MC, et al. Ginkgo biloba for preventing cognitive decline in older adults: a randomized trial. JAMA. 2009;302:2663-2670.

Last reviewed October 2009 by Rimas Lukas, MD
Last Updated: 1/8/2010