Delirium and frailty

Delirium is common, though it often goes unrecognized. Under-recognition is puzzling, because risk prediction is reasonably straightforward: delirium is more common in physically frail people and in those who are cognitively impaired. Frailty is more common in patients with many comorbid illnesses, who are taking many medications, and who have impairment in their activities of daily living. Like delirium, frailty can have many causes, and the two commonly overlap. In younger people, delirium often has a single cause, whereas in people who are frail, delirium is more likely to be a sign of the high-order failure of a complex system. Delirium occurs because maintenance of consciousness is a high-order function. As with any complex system that fails, high-order functions fail first. The approach to delirium is to recognize predisposing factors and search for and treat precipitating ones. Predisposing factors include those that give rise to frailty. Good multidisciplinary clinical care in delirium is challenging but deeply rewarding.