Emergence Delirium: Revisiting a Clinical Enigma

Introduction The term delirium was used for the first time by Celsius to describe a cognitive deficit associated with fever or head trauma. Hippocrates in 500 BC introduced the term of phrenitis to describe the acute onset of mental abnormalities accompanied by a change in behavior, disturbances of sleep and cognitive deficit in patients experiencing fever [1]. At the end of the nineteenth century and the beginning of the twentieth century the general agreement was that the outcome of delirium was either death or full recovery [2]. During the twentieth century EEG recording performed in patients diagnosed with delirium found a reduction of cerebral metabolic rate, indicated by an increase in slow wave activity [3]. Delirium is defined by the DSM-V as a disturbance in attention and awareness according to several criteria [4]: A. “Disturbance in level of awareness and reduced ability to direct, focus, sustain, and shift attention (this represents a minor change from: Disturbance of consciousness (i.e., reduced clarity of awareness of the environment) with reduced ability to focus,sustain or shift attention). B. A change in cognition (such as deficits in orientation, executive ability, language, visuoperception, learning and memory)