- Hypoactive delirium: lethargy, decreased responsiveness – often missed, higher mortality
- Alcohol withdrawal delirium (delirium tremens): autonomic instability, high mortality if untreated
- Wernicke’s encephalopathy: delirium + ataxia + ophthalmoplegia → give thiamine before glucose
Delirium
Must-Not-Miss / Red Flags
Patient Explanation
“Your loved one is suddenly confused because of a medical issue, not dementia. It’s usually temporary and will improve as we treat the underlying cause.”
Board Fact
“Delirium is the most common complication of hospitalization in older adults, affecting 30‑50% of patients over 65.”
ICD-10
F05
Definition & Core Concept
Delirium is an acute, fluctuating disturbance of consciousness, attention, and cognition, typically caused by an underlying medical condition, medication, or substance withdrawal, and is common in hospitalized elderly patients.
Epidemiology & Risk Factors
- Prevalence: 15‑50% in hospitalized elderly
- Associated with increased mortality, prolonged hospital stay, and functional decline
- Predisposing factors: advanced age, dementia, sensory impairment, polypharmacy
Pathophysiology (Rule of 3)
- Precipitating event (infection, electrolyte imbalance, drug toxicity) in a vulnerable brain
- Neurotransmitter imbalance: ↑dopamine, ↓acetylcholine
- Neuroinflammation and oxidative stress → widespread cerebral dysfunction
Clinical Presentation
- Acute onset and fluctuating course (worse at night – “sundowning”)
- Inattention, disorganized thinking, altered level of consciousness
- Hyperactive (agitation, hallucinations) or hypoactive (lethargy, withdrawal)
- Sleep‑wake cycle disturbance
Diagnostic Workup
Confusion Assessment Method (CAM): diagnostic tool. Labs: CBC, BMP, LFTs, urinalysis, TSH, B12, toxicology screen. Head CT: if focal neurology or head trauma. ECG: to rule out MI as precipitant.
Management Protocol
- Treat the underlying cause: antibiotics for UTI, IV fluids for dehydration, correct electrolytes
- Non‑pharmacologic interventions: frequent reorientation, family presence, minimize noise, natural lighting, early mobilization
- Pharmacologic (only if severe agitation threatens safety): Haloperidol 0.5‑1 mg PO/IM (low‑dose) or Olanzapine 2.5‑5 mg; avoid benzodiazepines (except in alcohol withdrawal)
- Prevent complications: avoid restraints, fall precautions, maintain nutrition and hydration
Complications & Prognosis
- Persistent cognitive impairment
- Functional decline and institutionalization
- Increased mortality (1‑year mortality up to 40%)
ICU Criteria
ICU admission if severe agitation requiring sedation, or if underlying critical illness (sepsis, respiratory failure).
Clinical Vignette
An 82‑year‑old man with mild dementia is admitted for a hip fracture. On post‑op day 2, he becomes acutely confused, agitated, and is pulling at his IV lines. CAM is positive. Urinalysis shows UTI.
Pearls & Pitfalls
- Hypoactive delirium is often misdiagnosed as depression or dementia – always use a validated screening tool (CAM).
- Delirium can persist for weeks to months after discharge; families need education and support.
Discharge & Follow-Up
Gradual tapering of antipsychotics after discharge. Occupational therapy for functional recovery. Educate family about the difference between delirium and dementia. Follow‑up cognitive assessment in 3 months.
Literature & Guidelines
NICE Clinical Guideline CG103: Delirium: Prevention, Diagnosis and Management (2024 update). PMID: 37540891.