Dementia can have any number of causes:
- Diseases that cause degeneration or loss of nerve cells in the brain such as Alzheimer’s, Parkinson’s and Huntington’s.
- Diseases that affect blood vessels, such as stroke, which can cause a disorder known as multi-infarct dementia.
- Toxic reactions, like excessive alcohol or drug use.
- Nutritional deficiencies, like vitamin B12 and folate deficiency.
- Infections that affect the brain and spinal cord, such as AIDS dementia complex and Creutzfeldt-Jakob disease.
- Certain types of hydrocephalus, an accumulation of fluid in the brain that can result from developmental abnormalities, infections, injury, or brain tumors.
- Head injury — either a single severe head injury or longer term smaller injuries, like in boxers.
- Illnesses other than in the brain, such as kidney, liver, and lung diseases, can all lead to dementia.
Alzheimer’s disease causes 50% to 60% of all dementias. But researchers have found that two nervous diseases, which were originally incorrectly diagnosed as Alzheimer’s, are emerging as major causes of dementia: Lewy body disease and Pick’s disease.
WebMD Medical Reference from Healthwise
Last Updated: June 17, 2009
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