Postoperative delirium.

Delirium is a common postoperative complication that is associated with substantial patient morbidity and mortality. Because of the variability in its presentation, delirium has the potential to be overlooked or misdiagnosed. There are few well-designed prospective studies looking at the incidence of delirium; however, retrospective data reveal it to be highly variable. The cause is multifactorial, with the largest predisposing factors being patient age, cerebral disease, and poor preoperative medical status. Common precipitants of delirium postoperatively include infection, hypoxia, myocardial ischemia, metabolic derangements, and anticholinergic drugs. The pathogenesis of delirium is incompletely understood; cholinergic pathways appear to play a crucial role. Physicians evaluating postoperative patients for mental status changes need to identify delirium accurately (the diagnostic criteria for which are clearly set out in the DSM-IV). Further investigations center on searching for organic precipitants, which can be treated effectively. The diagnostic workup is not algorithmic and must be tailored to the specifics of each individual case. If there is no readily identifiable cause, treatment should focus on the disorder itself. Supportive care should consist of a multidisciplinary approach aimed at preventing functional decline. Pharmacologic therapy, usually with haloperidol, may be indicated if patients remain agitated. Investigations have supported the premise that delirium is a potentially preventable condition. This prevention can be accomplished by maximizing the patient's medical status and conscientiously avoiding the conditions that are known to precipitate delirium.