Understanding delirium trajectory and its importance in care provision for older people.

Delirium significantly increases morbidity and mortality in older people, especially those affected by other organic disorders, notably dementia (Siddiqi et al., 2006; Davis et al., 2012; Martins and Fernandes, 2012). Both delirium and dementia are characterized by cognitive decline through disintegration of brain functions, i.e. a "brain failure." Delirium has been described as an acute brain failure, in contrast to dementia being a chronic brain failure (Berrios, 1981). If we consider any other organ failure, for example that of kidneys, delirium superimposed on dementia resembles acute renal exacerbation superimposed on chronic renal failure. The timely recognition and treatment of acute renal failure can reverse its damaging effects, whereas chronic renal failure necessitates long-term and invasive or costly interventions (i.e. dialysis, kidney transplantation). Similarly, recognizing delirium and providing timely interventions can improve its symptoms to recover brain functions, delay cognitive decline, and alleviate distress and disability.