For more information, see Delirium and Mental Disorders Due to a General Medical Condition
A. 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 memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a preexisting, established, or evolving dementia.
C. The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.
D. There is evidence from the history, physical examination, or laboratory findings that the disturbance is caused by the direct physiological consequences of a general medical condition.
Note: If delirium is superimposed on a preexisting Dementia of the Alzheimer's Type or Vascular Dementia, indicate the delirium by recording the appropriate subtype of the dementia, e.g., Dementia of the Alzheimer's Type, With Late Onset, With Delirium.
Note: Include the name of the general medical condition, e.g., Delirium Due to Hepatic Encephalopathy.
In recording the diagnosis of Delirium Due to a General Medical Condition, the clinician should note both the delirium and the identified general medical condition judged to be causing the disturbance. In an individual with an established history of Dementia of the Alzheimer's Type or Vascular Dementia, a superimposed delirium should be noted by recording the appropriate subtype of the dementia (e.g., Dementia of the Alzheimer's Type, With Late Onset, With Delirium). For other dementias, both dementia and delirium should be recorded (e.g., Dementia Due to Parkinson's Disease and Delirium Due to Hepatic Encephalopathy). In situations in which it is unclear whether the cognitive deficits are due to delirium or to dementia, it may be useful to make a provisional diagnosis of delirium and observe the person carefully while continuing efforts to identify the nature of the disturbance.