The Confusion Assessment Method

(CAM) Diagnostic Algorithm

The diagnosis of delirium requires the presence of

• features 1 and 2 and
• either feature 3 or 4.

Feature 1. Acute Onset and Fluctuating Course

This feature is satisfied by positive responses to the following questions:

• Is there evidence of an acute change in mental status from the patient’s baseline?
• Did the (abnormal) behavior fluctuate during the day, that is,
  • tend to come and go,
  • or did it increase and decrease in severity?

Feature 2. Inattention

This feature is satisfied by a positive response to the following question: Did the patient have difficulty focusing attention - for example, being easily distractible, - or have difficulty keeping track of what was being said?

Feature 3. Disorganized Thinking

This feature is satisfied by a positive response to the following question: Was the patient’s thinking disorganized or incoherent, - such as rambling or irrelevant conversation, - unclear or illogical flow of ideas, - or unpredictable switching from subject to subject?

Feature 4. Altered Level of Consciousness

• This feature is satisfied by any answer other than “alert” to the following question:
• Overall, how would you rate the patient’s level of consciousness:
  • alert (normal)
  • vigilant (hyperalert)
  • lethargic (drowsy, easily aroused)
  • stupor (difficult to arouse)
  • coma (unarousable)?