DELIRIUM

Delirium may be the most common and serious psychiatric problem affecting hospitalized older adults. Delirium is an acute fluctuating process of brain failure affecting, especially, attention and cognition. It is associated with many negative sequelae including increased mortality, cost, duration of stay, and risk of nursing home placement, or extended care at home. Despite this fact, delirium is frequently not recognized and if recognized not properly treated.

Delirium can be conceptualized as brain failure similar to heart failure or renal failure in which the cause or precipitating event may be intrinsic to the organ or, more commonly, extrinsic to the organ. Thus infection, electrolyte imbalances, metabolic disturbances, or medications may result in delirium. Delirium is to the older adult what fever is to the infant – a non-specific manifestation of an underlying problem. In the older adult, the brain may be similar to a circuit breaker, thus the weakest link, in an electrical system, which, when subjected to overload, will be the first to fail. Delirium in the older adult is probably a more common manifestation of illness than fever or pain.

EPIDEMIOLOGY

Delirium is a frequent event in hospitalized elderly patients with 14%–24% being affected at time of admission (prevalence) with an additional 6%–56% developing delirium during the course of hospitalization (incidence). Data from the United Kingdom suggest similar prevalence and incidence with reports of 7%–61% of older patients developing delirium during hospitalization. Delirium adds greatly to the cost of care both in the hospital and postdischarge.