Category: Acute Geriatrics / General Internal Medicine
Reading Time: 5.5 minutes
Introduction: The Receiving Ward Emergency
Cognitive impairment is present in over 30% of emergency admissions to the Acute Assessment Unit (AAU). However, one of the most persistent clinical errors on the acute intake is mislabeling acute delirium as baseline dementia, or dismissing a fluctuating acute encephalopathy as “confusion typical for the patient.”
Delirium is a medical emergency with an inpatient mortality rate comparable to acute MI or severe sepsis. At Medicine24, our geriatric and acute medicine sessions emphasize that an acute drop in cognitive function or attention must trigger an immediate diagnostic search for underlying physiological stress.
1. The Diagnostic Triage: Acute Delirium vs. Baseline Dementia
Differentiating between these two distinct entities on the chaotic receiving ward requires focusing on onset, attention, and fluctuation:
[Delirium] [Dementia]
• Acute onset (hours to days) • Insidious onset (months to years)
• Inattention (inability to focus) • Early attention preserved
• Fluctuating course (lucid intervals) • Progressive, stable day-to-day
• Direct organic cause underlying • Primary neurodegenerative process
The Hallmarks of Delirium: Rapid onset, severe impairment of attention (inability to direct, focus, sustain, or shift attention), and a characteristically fluctuating course over a 24-hour period (often worsening in the evening).
The Collateral History: Never assign a diagnosis of baseline dementia without obtaining collateral history from family, carers, or primary care records. A sudden change in function over 24–72 hours is delirium until proven otherwise.
2. Systematic Workup: The “PINCH ME” Protocol
Searching for the underlying cause of delirium requires a structured, multi-system sweep. The PINCH ME mnemonic provides a rapid front-door diagnostic framework:
| Mnemonic Letter | Target Cause | Front-Door Diagnostic & Action |
| P | Pain | Assess non-verbal pain signs (grimacing, guarding); trial simple analgesia. |
| I | Infection | Screen for chest infection, UTI, cellulitis, or intra-abdominal sepsis; check bloods/CXR. |
| N | Nutrition | Screen for dehydration, electrolyte imbalances ($\text{Na}^+$, $\text{Ca}^{2+}$), or thiamine deficiency. |
| C | Constipation | Perform abdominal examination and PR if indicated; review bowel charts. |
| H | Hydration / Hypoxia | Check blood gas/sats ($\text{SpO}_2 < 92\%$), urea/creatinine, and urine output. |
| M | Medication | Audit drug chart for anticholinergics, opiates, sedatives, or sudden withdrawals. |
| E | Environment | Address sensory deprivation (missing hearing aids/glasses), sleep disruption, or transfers. |
3. Rapid Screening at the Bedside: The 4AT Tool
In the fast-paced AAU environment, formal cognitive tests like the MMSE are impractical and unreliable in acute illness. The 4AT is the validated gold-standard bedside tool for rapid delirium screening:
Alertness: Normal (fully alert/calm) vs. Mild sleepiness vs. Clearly abnormal (hyperalert or difficult to rouse).
AMT4: Age, date of birth, place (name of hospital), current year (1 point for each error).
Attention: Months of the year in reverse order (Ask: “Can you tell me the months of the year backwards, starting with December?”).
Acute Change or Fluctuating Course: Evidence of a change in mental state over the past 24 hours.
Scoring Insight: A 4AT score of 4 or more suggests delirium (with or without underlying dementia) and mandates an urgent search for underlying causes.
4. De-escalation & Environmental Management
Avoid Sedative “chemical restraints”: Antipsychotics (e.g., Haloperidol) or benzodiazepines should be reserved strictly as a last resort for severe distress or imminent physical danger to the patient or staff. They increase fall risks, prolong delirium duration, and carry stroke/mortality warnings in elderly patients.
Environmental Support: Re-orient the patient continuously, ensure personal visual and hearing aids are fitted immediately, maintain daylight exposure, and involve family or familiar carers early.
