With primary dementia, the patient does not have the symptoms as a result of another disease. An example of a primary dementia is Alzheimer’s disease, which accounts for 50 to 70 percent of dementia cases, according to the Cleveland Clinic.
Secondary Dementia: If a patient has secondary dementia, then the dementia resulted from an injury or another disease. Several different issues can lead to secondary dementia, such as brain infections, progressive supranuclear palsy and multiple sclerosis. While many types of dementia are degenerative, meaning the damage cannot be reversed, some types of secondary dementia can be stopped or reversed. However, this depends on the cause being identified soon.
MedlinePlus noted that reversible causes of dementia include low levels of vitamin B-12, brain tumors, chronic alcohol abuse, changes in calcium or sodium levels, or the use of certain medications. If the cause is a medication, patients should talk to their doctors.
https://www.empowher.com/dementia/content/what-are-different-types-dementia