Dementia can typically occur when there is damage to the connections of the nerve cells to the brain or when there is loss or death of nerve cells. This happens as a result of head injuries, brain tumors, stroke, and other causes. Dementia can affect the different organ systems and can interfere with their functioning. So when dementia is left untreated, it can lead to a number of complications such as the inability to perform day-to-day activities, poor nutritional status, pneumonia, personal safety challenges such as driving, walking, or living alone, and death.