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Delirium

Basics

  • Temporary neurocognitive complication presenting with new confusion and impaired attention.
  • Requires thorough evaluation to reduce morbidity and mortality.

Epidemiology

  • Predominantly affects older adults (>70 years).
  • Incidence:

  • 50% in older ICU patients.

  • 11–51% in postoperative patients.
  • 10–40% in hospitalized older patients.
  • 20–22% in nursing home/post-acute care patients.
  • Prevalence:
  • 1–2% in outpatients.
  • 8–17% in older emergency department patients.

Etiology and Pathophysiology

  • Multifactorial; related to decline in physiologic reserves with aging.
  • Interaction of predisposing (baseline) and precipitating (acute) risk factors.

Predisposing Risk Factors

  • Advanced age (>70 years)
  • Preexisting cognitive impairment
  • Functional impairment
  • Dehydration
  • History of alcohol abuse
  • Malnutrition
  • Hearing or vision impairment
  • Multiple comorbidities

Precipitating Risk Factors

  • Severe illness in any organ system
  • Medical devices (catheters, restraints)
  • Polypharmacy (≥5 meds), especially benzodiazepines, opioids, anticholinergics
  • Pain
  • Iatrogenic events
  • Surgery
  • Sleep deprivation

Commonly Associated Conditions

  • Medication changes
  • Infections (lung, urinary, bloodstream, meningitis)
  • Toxic-metabolic states (hyponatremia, hypercalcemia, renal/hepatic failure)
  • Myocardial infarction, stroke
  • Alcohol or drug withdrawal

Diagnosis

  • Clinical diagnosis of exclusion.
  • Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria:
  • Disturbance in attention and awareness.
  • Cognitive changes not explained by dementia/coma.
  • Acute onset with fluctuating course.
  • Evidence of underlying physiologic cause.
  • Confusion Assessment Method (CAM):
  • Acute change in mental status.
  • Fluctuating course.
  • Inattention.
  • Disorganized thinking or altered consciousness.

Subtypes

  • Hyperactive (15%): agitated, restless, loud.
  • Hypoactive (20%): quiet confusion, lethargy.
  • Mixed (50%): features of both.
  • Normal consciousness delirium (15%): disorganized thinking without altered consciousness.
  • Subsyndromal delirium (23%): some symptoms without full syndrome.

History

  • Onset and time course of mental changes.
  • Recent medication changes.
  • Infection symptoms.
  • Neurologic symptoms.
  • Functional decline.

Physical Exam

  • Comprehensive cardiopulmonary and neurologic exam.
  • Cognitive screening: MMSE, Short Blessed Test, Brief Alzheimer Screen.
  • Gastrointestinal/genitourinary evaluation for constipation/retention.

Differential Diagnosis

  • Depression
  • Acute stress disorder
  • Bipolar mania
  • Dementia
  • Psychosis
  • Seizure disorders (nonconvulsive status epilepticus)

Diagnostic Tests

Initial

  • Labs guided by clinical suspicion:
  • CBC, CMP, urinalysis, urine/blood cultures.
  • Medication levels (digoxin, theophylline, antiepileptics).
  • Chest X-ray, ECG as needed.

Follow-Up

  • Venous blood gases
  • Troponin
  • Toxicology screen
  • Thyroid function tests (TSH)
  • Vitamin B12, thiamine
  • Head CT (if recent fall, anticoagulated, focal neuro signs)

Other

  • Lumbar puncture (rare)
  • EEG (rare)

Treatment

Multidisciplinary Approach

  • Include physicians, nurses, pharmacists, psychologists, speech/diet/physical therapists, social workers, spiritual care.
  • Implement multicomponent nonpharmacologic interventions.

A2F Bundle

  • A: Assess, prevent, and manage pain.
  • B: Both spontaneous awakening and breathing trials.
  • C: Choice of analgesic and sedation.
  • D: Delirium assessment, prevention, and management.
  • E: Early mobility and exercise.
  • F: Family engagement.

Hospital Elder Life Program (HELP)

  • Address acute medical issues.
  • Reorientation (clocks, calendars).
  • Provide eyeglasses, hearing aids.
  • Optimize hydration, nutrition.
  • Early mobilization.
  • Avoid restraints.
  • Normalize sleep-wake cycle.

General Measures

  • De-escalation training for staff.
  • Remove unnecessary tubes/catheters.
  • Actively involve family.
  • Monitor for complications (MI, infection, PE, retention).
  • Minimize sedatives, especially benzodiazepines.
  • Maintain adequate oxygenation and blood pressure.
  • Manage fluid/electrolyte balance.
  • Control pain with nonopioids.

Medication

  • Reserved for severe agitation or injurious behaviors.
  • No FDA-approved drugs for delirium treatment or prevention.

First Line

  • Antipsychotics for intolerable agitation/delusions:
  • Aripiprazole 2–5 mg PO daily
  • Haloperidol 0.25–0.5 mg PO/IM, titrate carefully
  • Olanzapine 2.5–5 mg PO daily
  • Quetiapine 12.5–25 mg PO BID-TID
  • Risperidone 0.25–0.5 mg PO daily
  • Dexmedetomidine preferred for ICU sedation; may shorten delirium duration.

Second Line

  • Benzodiazepines only for alcohol withdrawal or if antipsychotics contraindicated.
  • Cholinesterase inhibitors avoided.

Follow-Up

  • Monitor cognitive status and underlying causes.
  • Regular re-assessment of medications.
  • Educate caregivers on delirium risk and management.

Prognosis

  • Symptoms may persist weeks to months despite treatment.
  • Multidisciplinary care and prevention critical.

Clinical Pearls

  • Delirium diagnosis requires acute onset, fluctuating course, inattention, and disorganized thinking or altered consciousness.
  • Nonpharmacologic prevention and treatment are mainstays.
  • Identify and treat underlying causes aggressively.
  • Teamwork is essential for prevention, diagnosis, and management.

ICD10: - R41.0 Disorientation, unspecified - F19.931 Other psychoactive substance use with withdrawal delirium - F10.231 Alcohol dependence with withdrawal delirium