Delirium is an acute disturbance in attention, awareness, and cognition, commonly seen in hospitalised patients, particularly older adults. It is associated with increased morbidity, mortality, length of stay, and long-term cognitive decline.
Despite its prevalence, delirium is often under-recognised. Early identification through structured assessment is essential to allow prompt management and reduce complications. This article provides a practical overview of delirium assessment on the ward and is the second in our series exploring patient risk assessments.
When to Suspect Delirium
Delirium should be suspected in any patient with:
- Acute change in mental state
- Fluctuating confusion
- Reduced attention or concentration
- Altered level of consciousness
- New agitation or drowsiness
Collateral history is essential to establish whether the change is acute and fluctuating, which is a key feature of delirium.
Initial Clinical Assessment
Assessment should begin with a structured clinical review:
- Take a history from patient and collateral source
- Establish baseline cognition and functional status
- Identify acute onset and fluctuation
- Perform a general clinical assessment (including observations)
Delirium is a clinical diagnosis, supported by cognitive assessment tools.
The 4AT Tool
The 4AT is a rapid bedside screening tool widely used in clinical practice.
- Takes approximately 2 minutes to complete
- Does not require special training
- Recommended in UK practice due to its accuracy and simplicity
Components of the 4AT
The 4AT assesses four key domains:
1. Alertness
- Normal, sleepy, or agitated
- Abnormal alertness suggests delirium
2. Cognition (AMT4)
- Age
- Date of birth
- Place (e.g. hospital)
- Current year
Errors suggest cognitive impairment.
3. Attention
- Ask patient to name the months of the year backwards
Inattention is a core feature of delirium.
4. Acute Change or Fluctuation
- Evidence of change from baseline
- Fluctuating course over time
This is essential for diagnosing delirium.
Interpreting the 4AT Score
- 0 → Delirium unlikely
- 1–3 → Possible cognitive impairment
- ≥4 → Possible delirium (further assessment required)
The tool supports, but does not replace, clinical judgement.
Further Assessment
If delirium is suspected:
- Perform a full clinical review to identify underlying causes
- Check:
- Blood tests (e.g. infection, electrolytes)
- Medication review
- Pain, constipation, urinary retention
- Assess for delirium vs dementia (using collateral history)
Delirium is often multifactorial, and multiple contributors should be considered.
Common Pitfalls
- Assuming confusion is “baseline” without collateral
- Missing hypoactive delirium (quiet, drowsy patients)
- Not formally assessing cognition
- Failing to reassess patients with fluctuating symptoms
Regular reassessment is essential, as delirium can change rapidly.
Documentation
Clear documentation should include:
- Results of cognitive assessment (e.g. 4AT score)
- Evidence of acute change or fluctuation
- Collateral history
- Working diagnosis and plan
Key Principles
- Delirium is common, serious, and often underdiagnosed
- Always consider delirium in patients with acute confusion
- Use a structured tool such as the 4AT to support assessment
- Collateral history is essential for diagnosis
- Reassessment is crucial due to the fluctuating nature of delirium
Further Reading
- NICE Guideline on Delirium: prevention, diagnosis and management in hospital and long-term care
- Read further on the causes and management of confirmed Delirium in our Mind The Bleep Article
Written by Dr A Sidhu (CT2)
