Delirium and Dementia in the Elderly: Sometimes Associated or Always Together?

In the elderly, the association of delirium and dementia can cause diagnostic problems because they share the same symptom of confusion. Delirium is often misdiagnosed as dementia and treated inappropriately, ignoring that it could be successfully addressed, which can lead to increased health risks up to death.

Confusion indicates that functional reserve fails to compensate for the action of stressors. The decline in reserve is linked to aging-related changes in blood flow, mitochondria, cerebrospinal fluid, and immune function, as well as the appearance of structural precursors of disease. It is greater in dementia that adds a large burden of pathology, especially degenerative and vascular.

Based on their common background linking normal and pathological brain aging, it can be argued that delirium and dementia are always associated to some extent and can aggravate each other. The clinical approach to their association, which currently relies on the preliminary diagnosis of delirium according to ad hoc protocols, could be simplified by taking delirium for granted so that its causative stressors, usually the most common diseases of old age and/or drug abuse, could be addressed immediately. This approach would benefit all demented patients: not only those who are in such a serious condition that they need to be hospitalized due to the risk of death, but also those with clouded delirium.