Delirium in the intensive care unit: a narrative review

Critically ill patients frequently suffer from various acute organ dysfunctions. The most common clinical manifestation of central nervous system dysfunction defined as acute encephalopathy is delirium. Since delirium in intensive care unit (ICU) patients has been associated with worse outcomes, its early diagnosis, prevention, and appropriate treatments are strongly recommended. The PADIS guidelines recommend routine monitoring of delirium with the CAM-ICU or ICDSC, which should be performed at least once during each nursing shift and whenever patients show a change in the level of consciousness. Neuroimaging is useful for studying the pathophysiology of delirium, and it might be helpful in the differential diagnosis, although various and non-specific patterns can be observed in both MRI and functional MRI. Also, the electroencephalogram (EEG) showed different non-specific patterns associated with delirium and its role in the differential diagnosis of neurological complications of the critical patient is still uncertain. This narrative review presents the epidemiology and risk factors of delirium in ICU patients, the different diagnostic tools and procedures useful for its early detection, and the pharmacological and non-pharmacological treatments required for its management.