The Biochemical Basis of Delirium

Delirium is an important clinical diagnosis that is common in the post-operative period and in critically ill patients. It is associated with an increase in morbidity, mortality and resource utilization. Though the pathogenesis of delirium has been increasingly recognized for its importance and has been an intensively studied in recent years, the biochemical mechanism for its development is still debated. This review scrutinized a number of studies in order to better characterize the biochemical basis for delirium, with particular focus paid to the interactions of the cholinergic system, the cholinergic anti-inflammatory pathway, the immune system and neuroinflammation. Despite the clinical impact of delirium, evidence-based protocols for the prevention and treatment are still lacking. Several previous trials have attempted to prevent or treat delirium by modulation of the cholinergic system with acetylcholinesterase inhibitors, the results of which have been largely ambiguous at best. As the biochemical basis of delirium becomes more clearly defined, future research into therapeutics based on immune modulation and treatment of neuroinflammation may prove to be very promising.