The most common cause of Dementia is Alzheimer’s Disease, accounting for about 75% of all cases of Dementia. The second most common cause is Multi-infarct Dementia, accounting for most of the rest of the cases. However, there are hundreds of other possible causes, which are uncommon. Some of these other causes are treatable. In evaluating patients with Dementia, the testing is designed to rule out these other causes, and particularly to look for treatable conditions. A (very) partial list of other cause of Dementia is below:

Structural causes

• Brain tumors

• Subdural Hematoma (blood clot)

• Hydrocephalus

Metabolic Causes

• Hypercalcemia

• Hypothyroidism

• Vitamin B12 malabsorbtion

Infectious Causes

• Neurosyphilis

• Jacob-Creutzfeldt (Mad Cow) Disease

• HIV infection

Inflammatory Causes

• Vasculitis

• Hashimoto’s Encephalitis

Other Neurodegenerative Causes

• Pick’s Disease - also known as Fronto-temporal dementia

• Parkinson’s Disease Dementia

• Lewy Body Dementia

Toxic Causes

• Alcoholism