Delirium vs. Dementia Dementia is an irreversible state of cognitive impairment and short term memory loss related to organic brain disease most commonly Alzheimer’s disease or multiple cerebral infarcts. Delirium is a state of cognitive impairment and confusion usually of recent onset related to another illness. There may also be clouding of consciousness. Delirium is an organic mental disorder that causes confusion, disorientation, and memory loss.
It is different than dementia in that is causes a change in level of consciousness; sufferers are not as alert, can be drowsy, semi-comatose, or comatose. The delirious person also can have difficulty with attention, may be agitated and be hallucinating. Symptoms occur rapidly – not over a long period of time. There is usually a marked changed in a person relatively quickly. Delirium can be caused by a medical problem: congestive heart failure, urinary tract infection, liver failure, and drug or alcohol abuse. People with delirium need immediate medical attention.
Delirium is often caused by changes in the chemical transmitter between the nerves, called acetylcholine. Even medications can cause this to happen. Delirium symptoms also fluctuate throughout a day. It is most important to emphasize that delirium is a sudden onset, unlike dementia which comes on more slowly. The risk of delirium increases for people who are demented, dehydrated, and taking drugs that affect the nervous system. Sometimes there are no disruptive features, just a withdrawal which makes it easy to miss.
Not all dementias are of the slow onset type like Alzheimer’s type dementia (although this is the most common form of dementia and IS slow-onset by definition). Dementia may have an rapid onset, e. g. , with stroke. However, dementia is sustained whereas delirium is typically an acute and fluctuating state. The key difference between dementia and delirium is that delirium includes an altered/fluctuating level of consciousness, whereas dementia is only diagnosed in alert patients.