Acute Delirium

Delirium = an acute confusional state with fluctuating course, impaired attention, and altered awareness. It is very common in older adults (affects ~20–30% of hospitalised elderly) and is associated with ↑ morbidity, mortality, and length of stay. It is a medical emergency because it often signals an underlying illness.

⚡ About

• Common cause of cognitive decline in older person. Find out pre delirium cognition.
• Determine if this is Dementia or delirium or Dementia + delirium
• Very rarely delirium can settle after 6 months but this is uncommon

⚡ Clinical Features

• ⏱️ Acute onset: Hours to days (contrast with dementia).
• 🔄 Fluctuating course: Worse at night (“sundowning”).
• ⚖️ Inattention: Can’t focus, distractible (months of the year backwards test).
• 🧭 Disorientation: Time/place/person.
• 🔊 Altered consciousness: Hyperactive (agitated, hallucinating), hypoactive (quiet, withdrawn), or mixed.

📊 Subtypes

• 🔥 Hyperactive: Agitated, hallucinations, aggressive (easier to recognise).
• 😴 Hypoactive: Quiet, withdrawn, sleepy (often missed - most common in frail elderly).
• 🔄 Mixed: Features fluctuate between hyper and hypo.

📋 Diagnosis

• 🧪 Clinical diagnosis: Based on acute onset + inattention + fluctuating course + altered awareness.
• ⚡ Bedside tests: Months backwards, digit span, attention tasks.
• 📊 Screening tools:
  • 4AT (rapid, validated, NICE recommended).
  • CAM (Confusion Assessment Method).

🧾 The 4AT – Rapid Delirium Screening Tool

The 4AT is a validated bedside tool to screen for delirium and cognitive impairment. Takes <2 minutes, no special training required. Score ≥4 = possible delirium, 1–3 = possible cognitive impairment, 0 = unlikely.

📊 Scoring Interpretation

• ≥4 = Possible delirium (+/- cognitive impairment).
• 1–3 = Possible cognitive impairment (dementia, mild cognitive impairment, or delirium).
• 0 = Delirium or cognitive impairment unlikely (but clinical judgement required).

📝 OSCE / Exam Pearls

• Demonstrate “months backwards” test confidently.
• Always mention collateral history (“Has there been a sudden change?”).
• Differentiate delirium vs dementia: attention is impaired in delirium.
• In practice: combine 4AT with full medical workup (“PINCH ME” causes).

🔎 Common Causes (“PINCH ME” mnemonic)

• 🧪 Pain
• 💉 Infection (UTI, pneumonia, sepsis)
• ⚡ Nutrition (dehydration, malnutrition, thiamine deficiency)
• 💊 Constipation/urinary retention
• 🏥 Hypoxia (PE, pneumonia, MI)
• 🧠 Medications (opioids, benzos, anticholinergics, steroids, digoxin)
• 🩸 Electrolyte/metabolic (Na, Ca, glucose, renal/hepatic failure)

🧑‍⚕️ Investigations

• 📋 Full history + collateral from carers/family (baseline cognition important).
• 🩺 Examination: systemic + neurological.
• 🧪 Bloods: FBC, U&E, Ca, CRP, glucose, LFTs, TFTs, B12/folate.
• 🦠 Urinalysis & culture, CXR, ECG.
• 🧠 CT head if head injury, neuro deficit, or cause unclear.
• 🚽 Bladder scan (urinary retention) & PR (faecal impaction).

🧑‍⚕️ Next Level Investigations

• 🧠 MRI head +/- contrast (Can be difficult if patient agitated)
• 🧠 LP and CSF for HSV and autoantibodies for viral and autoimmune encephalitis
• 🦠 Ammonia levels
• 🩸 Echocardiogram + Blood cultures
• 🩺 ABG: But usually saturations show oxygenation and VBG can show hypercarbia and acidosis
• 🩺 EEG : If non convulsive status suspected or encephalitis

🛡️ Prevention (NICE guidelines)

• 💧 Maintain hydration & nutrition.
• 💧 Treat constipation
• 🛏️ Promote sleep hygiene & avoid unnecessary bed moves.
• 👓 Sensory aids: ensure glasses/hearing aids in use.
• 🚶 Early mobilisation & physio.
• 🗓️ Orientation: clocks, calendars, regular reorientation, family involvement.
• 💊 Avoid high-risk drugs (anticholinergics, benzos, opioids if possible).
• 💊 Thiamine IV if malnourished or alcoholism
• 🚶 Ensure getting rested and getting 8 hours sleep
• 🚶 Skin protection from pressure sores

🛠️ Management Principles

• 🔍 Identify and treat underlying cause (infection, drugs, retention, constipation, metabolic disturbance).
• 🛌 Supportive environment: Quiet room, good lighting, minimise noise, consistent nursing staff.
• 💬 Reassurance: Frequent orientation, involve family/carers.
• 🚶 Encourage early mobilisation, physiotherapy, avoid restraints.
• 👓 Ensure sensory aids used consistently.
• 💊 Medications:
  • Antipsychotics only if severe distress or risk to self/others.
  • Haloperidol (0.5–1 mg PO/IM). Lorazepam if Parkinson’s/LBD.
  • Quetiapine preferred in Parkinson’s/Lewy body dementia.
  • Benzodiazepines reserved for alcohol withdrawal delirium.

🚨 Prognosis & Complications

• 📈 Delirium is associated with 2–3x ↑ mortality.
• 🧠 Can precipitate long-term cognitive decline or worsen dementia.
• 🏥 ↑ hospital stay, ↑ risk of institutionalisation.

📝 OSCE / Exam Pearls

• Always ask for collateral history (baseline vs acute change).
• Use 4AT tool in stations (rapid and examiners like it).
• Mention “PINCH ME” mnemonic for causes.
• State non-drug measures first; reserve drugs for severe distress/risk.
• Always distinguish delirium vs dementia: attention is impaired in delirium.