Dementia

Dementia is caused by damage to or changes in the brain. After Reference Alzheimer's disease Opens New Window, stroke is the most common cause of dementia. Dementia caused by stroke is called Reference vascular dementia Opens New Window.

Some causes of dementia can be reversed with treatment, but most cannot.

Causes that cannot be reversed

Common causes of dementia that cannot be reversed are:

• Reference Parkinson's disease Opens New Window. Dementia is common in people with this condition.
• Reference Dementia with Lewy bodies Opens New Window. It can cause short-term memory loss.
• Reference Frontotemporal dementia Opens New Window, a group of diseases that includes Pick's disease.
• Severe head injury that caused a loss of consciousness.
• Vascular dementia that may occur in people who have a stroke, long-term high blood pressure, or severe hardening of the arteries (Reference atherosclerosis Opens New Window).

Less common causes of dementia that cannot be reversed include:

• Reference Huntington's disease Opens New Window.
• Leukoencephalopathies, which are diseases that affect the deeper, white-matter brain tissue.
• Creutzfeldt-Jakob disease, a rare and fatal condition that destroys brain tissue.
• Brain injuries from accidents or boxing.
• Some cases of multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS).
• Multiple-system atrophy (a group of degenerative brain diseases affecting speech, movement, and Reference autonomic Opens New Window functions).
• Infections such as late-stage syphilis. Antibiotics can effectively treat syphilis at any stage, but they cannot reverse the brain damage already done.

Causes that may be reversible

When dementia is caused by certain treatable problems, the treatment may also help the dementia. These treatable problems include:

• Underactive thyroid gland (Reference hypothyroidism Opens New Window).
• Vitamin B12 deficiency.
• Heavy-metal poisoning, such as from lead.
• Side effects of medicines or drug interactions.
• Some brain tumors.
• Reference Normal-pressure hydrocephalus Opens New Window.
• Some cases of chronic alcoholism.
• Some cases of Reference encephalitis Opens New Window.
• HIV/AIDS.

Inherited dementia

Some disorders that cause dementia can run in families. Doctors often suspect an inherited cause if someone younger than 50 has symptoms of dementia. For more information, see the topic Reference Alzheimer's Disease.

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