Delirium

Delirium: Acute Confusional State

Definition:

Delirium is an acute, fluctuating disturbance in attention, awareness, and cognition that develops over hours to days. It represents a medical emergency requiring immediate evaluation.

Key Diagnostic Criteria (DSM-5):

1. Disturbed attention (reduced ability to focus/sustain/shift attention)
2. Acute onset (hours to days) with daily fluctuations
3. Additional cognitive disturbance (memory, orientation, language, visuospatial)
4. Not better explained by pre-existing neurocognitive disorder
5. Evidence of underlying medical cause, intoxication, or medication effect

Clinical Features:

Domain	Manifestations
Attention	Easily distracted, unable to follow conversations
Consciousness	Reduced awareness of environment
Cognition	Disorientation, memory deficits, incoherent speech
Perception	Hallucinations (often visual), illusions
Psychomotor	Hyperactive (agitated) or hypoactive (lethargic) subtypes
Sleep-Wake	Reversed cycle, daytime drowsiness

Subtypes:

1. Hyperactive Delirium (15-25%)
   • Agitation, hallucinations, combativeness
   • More easily recognized
2. Hypoactive Delirium (50-75%)
   • Lethargy, decreased responsiveness
   • Often missed (“quiet confusion”)
3. Mixed Type (50%)
   • Fluctuates between hyper/hypoactive states

Common Causes (I WATCH DEATH Mnemonic):

I – Infection (UTI, pneumonia, sepsis)
W – Withdrawal (alcohol, benzodiazepines)
A – Acute metabolic (electrolytes, glucose, liver/renal failure)
T – Trauma (head injury, post-op)
C – CNS pathology (stroke, seizures, meningitis)
H – Hypoxia (COPD, heart failure, anemia)
D – Deficiencies (B12, thiamine)
E – Endocrine (thyroid, adrenal)
A – Acute vascular (shock, MI)
T – Toxins/drugs (anticholinergics, opioids, polypharmacy)
H – Heavy metals

Risk Factors:

• Patient Factors: Older age, dementia, multiple comorbidities
• Hospital Factors: ICU admission, physical restraints, bladder catheters
• Medications: Opioids, benzodiazepines, anticholinergics

Assessment Tools:

1. Confusion Assessment Method (CAM) – Gold standard
   • Acute onset + fluctuating course
   • Inattention
   • Disorganized thinking
   • Altered consciousness
2. 4AT Rapid Assessment (≥4 suggests delirium)
   • Alertness, AMT4, attention, acute change
3. Delirium Rating Scale (DRS-R-98) – Severity measure

Management:

1. Identify/Treat Underlying Cause

• Review medications (STOP anticholinergics/sedatives)
• Treat infections, correct metabolic derangements

2. Non-Pharmacologic Measures:

• Reorientation (clocks, calendars, family presence)
• Ensure adequate sleep (reduce nighttime interruptions)
• Early mobilization
• Sensory aids (glasses, hearing devices)
• Avoid physical restraints

3. Pharmacologic Therapy (LAST RESORT):

• 1st Line: Haloperidol (0.5-1mg PO/IM/IV)
• Alternatives: Atypical antipsychotics (risperidone, quetiapine)
• Contraindicated: Benzodiazepines (except alcohol/benzo withdrawal)

Complications:

• Increased mortality (up to 25% in hospitalized patients)
• Prolonged hospitalization
• Higher risk of dementia
• Functional decline

Prevention Strategies:

• Hospital Elder Life Program (HELP):
  • Orientation
  • Early mobilization
  • Hearing/vision adaptations
  • Sleep hygiene
  • Volume/nutrition repletion

Prognosis:

• Typically resolves within days-weeks with treatment
• 30-40% may have symptoms persisting months
• Hypoactive delirium has worse outcomes

Differential Diagnosis:

• Dementia (chronic, no fluctuation)
• Depression (“pseudodelirium” with psychomotor slowing)
• Psychosis (no acute medical cause)