Delirium

Background

Definition

• An acute brain dysfunction syndrome of fluctuating levels of consciousness
• Cardinal features:
  • altered mental status and fluctuating course
  • inattention
  • altered level of consciousness (i.e. RASS not zero) OR disorganized thinking

Differential Diagnosis

Life-threatening causes (WHHHHIMPS)

• Wernicke's or alcohol withdrawal
• Hypoxia/hypercarbia
• Hypoglycemia
• Hypertensive emergency
• Hyperthermia/hypothermia
• Intracerebral hemorrhage
• Meningitis/encephalitis
• Poisoning
• Status epilepticus

DIMES

• Drugs
  • Iatrogenic
    • Polypharmacy
    • Opioids (too much or too little)
    • Diphenhydramine
    • Benzodiazepines
  • Abuse: alcohol
  • Poisoning
  • Withdrawal
    • Alcohol
    • Benzodiazepine
• Infections
  • Sepsis
  • Pneumonia
  • Urinary tract infection
  • Skin and soft tissue infection or ulcer
• Metabolic
  • Endocrine: thyroid, parathyroid, pancreas, pituitary, adrenals
  • Electrolytes: sodium, calcium, magnesium, potassium
  • Hypoglycemia/hyperglycemia
  • Hypoxemia/Hypercarbia
  • Hypoosmolar/Hyperosmolar
  • Inborn errors of metabolism: porphyria, Wilson's disease
  • Nutrition: Wernicke's, B12 deficiency, niacin deficiency
• Environmental
  • Surroundings, room changes
• Structures & organs
  • CNS
    • Stroke
    • Brain injury
    • Seizure
  • Cardiac: heart failure
  • Renal: AKI/CKD
  • Gastrointestinal: constipation, volvulus
  • Genitourinary: urinary retention

Management

• Treat underlying causes

Pharmacologic

• Opioid neurotoxicity:
  • Switch opioid
  • Dose reduction
  • Hydration
• Medications: stop medication
• Dehydration: IV or hypodermoclesis (fluid given subcutaneously)
• Hypercalcemia: IV bisphosphonate (zoledronate/pamidronate)
• Infection: antibiotics
• Hepatic encepalopathy: lactulose
• Brain metastases: corticosteroids (e.g. dexamethasone)

Antipsychotics

• Mild
  • Elderly: haloperidol 0.5 mg PO/SQ/IV/IM q4h prn
  • End-of-life: haloperidol 0.5-1 mg po or subcut daily or BID + haloperidol 0.5-1 mg po/SC q1h prn
• Moderate
  • Haloperidol 2-2.5 mg po/sc bid or tid + haloperidol 2 mg po/sc q1h prn
  • Or methotrimeprazine 5-12.5 mg po/sc bid or tid + prn
• Severe
  • Elderly: haloperidol 1 mg, or quetiapine 12.5 mg if long QT
  • Midazolam 2.5-5 mg sc stat once + haloperidol 5 mg sc stat
  • Or methotrimeprazine 25 mg sc stat then po/sc
  • Follow with haloperidol 2.5-5 mg sc q30min prn (max 10-15 mg/day)
• Sundowning
  • Methotrimeprazine qhs
• Alternatives
  • Quetiapine
  • Risperidone
  • Olanzapine

Non-pharmacologic

• Reduce stimulation
• Low ambient light
• Low noise
• Correct sensory deficits (glasses, hearing aids)
• Gentle, repeated reassurances (but labour intensive)
• Do not use physical restraints