You may associate dementia with Alzheimer’s disease, as many people do. However, although Alzheimer’s is a common cause of dementia, the two terms are not interchangeable.

Alzheimer’s is a disease, while dementia is a set of symptoms relating to declining mental function. According to WebMD, there are many conditions besides Alzheimer’s that can cause dementia symptoms.

Hydrocephalus

Hydrocephalus is a buildup of fluid in the brain. It can have several different causes, and certain types can cause dementia symptoms. This type of dementia may resolve after removal of the fluid.

Central nervous system infections

The central nervous system is susceptible to infection. Dementia can result from infection with HIV or from meningitis, which may be bacterial, fungal or viral in nature.

Traumatic brain injuries

A severe traumatic injury can cause damage to the brain. Symptoms of dementia can result.

Vascular disorders

Diseases of the blood vessels can prevent the brain from getting an adequate supply. Insufficient blood circulation in the brain could cause dementia.

Other degenerative neurological diseases

Alzheimer’s is one example of a neurological disease that is degenerative, i.e., gets worse over time. Other examples of degenerative neurological diseases that can cause dementia include Huntington’s disease, Parkinson’s disease and sometimes multiple sclerosis.

Another way of categorizing dementia is according to the area of the brain that it affects. Problems in the outer layer of the brain can result in cortical dementias, which cause problems with language and memory. Subcortical dementias occur due to problems deeper in the brain. They are less likely to affect memory or language but may slow the speed of one’s thinking.