[Delirium in the context of intensive care medicine-Part 1: epidemiology, definitions, pathophysiology].

The prevalence of delirium syndromes is high, they are often underdiagnosed and therefore medically as well as economically highly relevant syndromes due to the long-term sequelae. In the majority of cases, delirium has a multifactorial etiology, which is why a comprehensive search for the cause is of highest priority. Surgery, administration of potentially proinflammatory drugs as well as the intensive care environment, including the underlying disease and drugs used, represent relevant etiological factors. Pathophysiology and psychopathology are complex and vary depending on the etiological factors present. Prominent impairment of attention and consciousness are central symptoms of delirium allowing the differentiation from important differential diagnoses, such as encephalopathy, depression, psychosis and dementia.