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Post-Anesthesia Delirium: Causes, Risk Factors, and Management

Postoperative delirium (acute confusional state) affects 10–50% of older surgical patients; delusional content occurs in a subset. It is usually transient (hours–days) but independently predicts worse outcomes.

Pathophysiology (Multifactorial)

  • Neurotransmitter disruption: GABAergic (anesthetics), cholinergic (anticholinergics), dopaminergic (opioids) imbalance.
  • Neuroinflammation: Surgical stress → cytokine surge (IL-6, TNF-α) → blood-brain barrier disruption.
  • Circadian dysregulation: Sleep deprivation, ICU environment, loss of zeitgebers.
  • Metabolic/Physiologic stressors: Hypoxia, hypotension, anemia, electrolyte shifts, infection, medication side effects.

Major Risk Factors

  • Age ≥65 (strongest)
  • Pre-existing cognitive impairment / dementia
  • Functional dependence, sensory impairment
  • Alcohol use disorder
  • Multiple comorbidities, polypharmacy (especially anticholinergics, benzos, opioids)
  • Emergency, cardiac, orthopedic, or prolonged surgery
  • ICU admission

Clinical Subtypes

  • Hyperactive: Agitation, hallucinations, delusions, attempting to remove lines.
  • Hypoactive (most common, most missed): Lethargy, inattention, reduced mobility.
  • Mixed: Fluctuating between both.

Prevention (Evidence-Based Bundles)

  • Preoperative cognitive screening (Mini-Cog, MoCA).
  • Avoid/limit deliriogenic meds (Beers Criteria).
  • Multimodal analgesia (reduce opioids); regional anesthesia when possible.
  • Early mobilization, orientation cues, glasses/hearing aids, sleep hygiene.
  • Family presence/engagement.

Management

  1. Identify and treat precipitants (infection, retention, pain, drugs, metabolic).
  2. Non-pharmacologic: reorientation, mobility, sensory aids, family, reduce restraints.
  3. Low-dose antipsychotic (haloperidol 0.5–1 mg IV/PO q12h PRN; quetiapine 12.5–25 mg PO) only for severe distress/safety risk—black box warning in dementia.
  4. Daily delirium assessment (CAM-ICU, 3D-CAM, Nu-DESC).

Most resolve in days; persistent delirium warrants neurology/psychiatry consult. Early mobilization and family involvement are the most powerful interventions.

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