Background:
Delirium has classically been defined in relation to dementia, at least in its temporal dimension, delirium being a short-term condition, dementia long term. From the earliest accounts in the ancient medical literature to the contemporary DSM-IV-TR definition, it has been conceptualized as a time-limited process. It is also firmly established in the literature that delirium is underrecognized.
Methods:
A literature search was undertaken using PubMed database covering the years 1966-2006 and using search terms that included delirium, organic brain syndrome, outcome, subsyndromal and identification.
Results:
When compared with patients who did not suffer from delirium, delirium is associated with significantly greater mortality, higher rates of long-term cognitive impairment, greater length of stay and increased rates of institutional placement. These poor outcomes appear to hold for subsyndromal delirium as well as frank delirium. It is plausible to suggest that unrecognized delirium is associated a fortiori with poor outcomes, but as yet there is no firm evidence that early detection results in better outcomes.
Conclusions:
The definition of delirium as a short-term condition needs to be reevaluated. It could be speculated that its conceptualization as time limited may contribute to it's underrecognition because there may a little risk associated with missing a condition that is expected to resolve. In this case, it is expected that improved education for health professionals about the serious consequences and long-term course of delirium may result in improved detection and management of this disorder.
