Description

• A temporary neurocognitive complication of illness and/or medication(s) manifested by new confusion and impaired attention
• Requires evaluation to decrease morbidity and mortality

Epidemiology

• Predominant age: older persons
• Predominant sex: male = female

Incidence

• >50% in older ICU patients
• 11–51% in postoperative patients
• 19% after intracranial surgery and 42% after neurovascular surgery (1)
• 10–40% in hospitalized older patients
• 20–22% in nursing home/post–acute-care patients

Prevalence

• 1–2% in outpatients
• 8–17% in older ED patients
• 14% in older postacute care patients
• 18–35% in hospitalized general medicine patients

Etiology and Pathophysiology

• Multifactorial: believed to result from a decline in physiologic reserves with aging, resulting in a vulnerability to new stressors
• Often interaction between predisposing and precipitating risk factors

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(s)
  • Medical devices (urinary catheter, restraints)
  • Polypharmacy (≥5 medications)
  • Specific medications, especially benzodiazepines, opioids, and anticholinergics diphenhydramine, high-dose neuroleptics
  • Pain
  • Any iatrogenic event
  • Surgery
  • Sleep deprivation

Commonly Associated Conditions

Multiple but most common are the following:

• New medicine or medicine changes
• Infections (especially lung, urine, and blood stream, but consider meningitis as well)
• Toxic metabolic (especially low sodium, elevated calcium, renal failure, and hepatic failure)
• Heart attack or stroke
• Alcohol or drug withdrawal
• Preexisting cognitive impairment increases risk.