Types of Dementia
Delirium is a word used to describe an acute (meaning suddenly developing or worsening) state of confusion and disorientation . It is not a dementia, but can occur in someone who has a dementia. Delirium is almost always caused by a medical problem, such as a drug reaction, an infection, a heart problem, or a stroke . It is very common in elderly people who have dementia, both because older people are more likely than the young to develop illnesses, and people with dementia are more likely to become confused when they are ill. Often, the person with dementia will not describe symptoms - instead, they will just become confused.
Delirium is usually accompanied by a decreased state of arousal and consciousness - it is as though the person is very sleepy. It can also be seen with increased arousal - the person is very alert, their eyes flit from one object to the next, and they appear to be frightened. (People who remember an episode of delirium commonly report having been very frightened when it was going on).
Often, it is difficult for people, even health care professionals to discriminate between delirium and dementia because the symptoms of each are very similar. In comparison, however, the presentation of delirium is more abrupt and the change is more noticeable. The symptoms of delirium, such as thinking, level of alertness, and attentiveness also fluctuate more on a daily basis. A person might seem well in the morning, very confused at lunch, better in the afternoon, and more confused again in the evening. With dementia, the level of confusion exists for much of the day - although it can get worse towards evening, in the so-called 'sundowning' syndrome.
You can read more about delirium in the book Delirium in Old Age, edited by James Lindesay, Kenneth Rockwood and Alastair MacDonald, and published by Oxford University Press in 2002.
About Dementia > "Understanding Dementia" > Delirium