The Confusion Assessment Method (CAM) is a diagnostic tool used to identify delirium based on four key criteria: acute onset, fluctuating course, disorganized thinking, and altered level of consciousness.

This document explains how to use the Confusion Assessment Method (CAM) to check if someone is delirious — meaning they’re suddenly confused and not thinking clearly.

To say a person has delirium using CAM, you must find BOTH Feature A AND Feature B. Then, you also need EITHER Feature C OR Feature D.

Let’s break it down:

✔ Step 1: Check for Feature A – Acute onset AND fluctuating course
- Did the confusion start suddenly? (Not slowly over weeks or months)
- Does it come and go during the day? Or get worse at night?
→ If YES to both, then Feature A is present.

✔ Step 2: Check for Feature B – Inattention
Ask yourself:
- Can the patient focus on what you’re saying?
- Do they lose track easily in conversation?
- Are they distracted by small things around them?
→ If YES to any of these, Feature B is likely present.

So far: You MUST have both A and B to even consider delirium.

✔ Step 3: Now check for EITHER Feature C OR Feature D

Feature C – Disorganized thinking
Examples:
- Talking nonsense or jumping between unrelated topics
- Saying things that don’t make sense (“I’m flying to Mars tomorrow!” when they’re in bed)
- Not knowing where they are or what time it is (if they usually do)

Feature D – Altered level of consciousness
This means their alertness is off:
- Too sleepy (hard to wake up)
- Too hyper (can’t sit still, agitated)
- Staring blankly or barely responding
- Acting very different from normal (like being super quiet when they’re usually talkative)

🎯 Final Rule:
Delirium = (A + B) + (C OR D)

Example:
Mrs. Smith became confused yesterday morning (acute onset). Today she was fine at breakfast but started yelling at nurses by lunch (fluctuating). She keeps asking “Where am I?” and can’t follow simple instructions (inattention). Also, she’s talking about her dog who died 5 years ago like he’s right here (disorganized thinking).

✔️ A = Yes (sudden + comes/goes)
✔️ B = Yes (can’t pay attention)
✔️ C = Yes (nonsensical speech)
→ Delirium confirmed!

You don’t need D if you already have C — just one of them is enough after having A and B.

Final Answer:
To diagnose delirium using CAM, you must confirm:
(1) Sudden onset AND changing symptoms during the day (Feature A),
(2) Trouble paying attention (Feature B),
AND either
(3) Messed-up thinking (Feature C)
OR
(4) Unusual alertness — too sleepy, too hyper, or staring blankly (Feature D).