Box.

 

Delirium is defined by the presence of disturbed consciousness (reduced clarity of awareness of the environment with reduced ability to focus, to sustain, or to shift attention) and a change in cognition (such as memory deficit, disorientation, or language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing, established or evolving dementia. The disturbance develops acutely (usually hours to days) and tends to fluctuate during the course of the day. Delirium may exhibit hyperactive or hypoactive features. Key risk factors for delirium include age, co-morbidity, an acute inflammatory precipitant, sleep deprivation and sedative medication that targets γ-aminobutyric acid (GABA)A receptors.

Reference: American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th ed. Washington, DC: APA, 1994