Delirium in Elderly

Key Features

Essentials of Diagnosis

• Rapid onset and fluctuating course

• Primary deficit is in attention rather than memory

• May be hypoactive or hyperactive

• Dementia frequently coexists

General Considerations

• Delirium is the pathophysiologic consequence of an underlying general medical condition such as

  • Infection

  • Hypoxemia

  • Metabolic derangement

  • Coronary ischemia

• Although the acutely agitated (hyperactive) elderly patient often comes to mind when considering delirium, many episodes are more subtle (hypoactive)

• A key requirement is review of medications

• Maintenance of a large number of drugs, addition of a new agent, and discontinuation of an agent known to cause withdrawal symptoms are often associated with development of delirium

• Medications that are particularly likely to increase the risk of delirium include

  • Sedative/hypnotics

  • Anticholinergics

  • Opioids

  • Benzodiazepines

  • H₁- and H₂-antihistamines

• Cognitive impairment is an important risk factor for delirium

• Other risk factors

  • Severe illness

  • Polypharmacy and use of psychoactive medications

  • Sensory impairment

  • Depression

  • Alcohol use disorder

Demographics

• Occurs in 29–64% of hospitalized older adults

• Persists in 25% or more

Clinical Findings

Symptoms and Signs

• Acute, fluctuating disturbance of consciousness or mental status

• Inattention, inability to focus on tasks

• Cognitive deficits, disorientation, memory and language impairment

• Irritability

• Hyperactivity or hypoactivity

• Mental slowing

• Hallucinations or illusions

Differential Diagnosis

• Once the diagnosis of delirium has been made, an underlying cause should be sought. The underlying causes are wide-ranging.

• Depression

• Mania

• Dementia, especially Lewy body dementia

• Psychotic disorders

• Seizures

Diagnosis

Laboratory Tests

• Laboratory evaluation is aimed at finding an underlying medical condition

• Routine studies include

  • Complete blood count

  • Serum electrolytes, creatinine, glucose, calcium, albumin, liver biochemical tests; blood urea nitrogen

  • Urinalysis

  • ECG

• In selected cases, serum magnesium, drug levels, arterial blood gas measurements, blood cultures, chest radiographs, urinary toxin screens, head CT scan, and lumbar puncture may be helpful

Imaging Studies

• Consider neuroimaging if unable to obtain history, if evidence of trauma, or if focal neurologic examination

Diagnostic Procedures

• Electroencephalogram may sometimes be helpful if seizures are in the differential diagnosis

• Confusion assessment method (CAM)

  • Requires acute onset and fluctuating course, inattention, and either disorganized thinking or altered level of consciousness

  • Available as Long CAM, Short CAM, and 3D CAM (3-minute Diagnostic CAM)

  • All three perform well

  • The 3D CAM is particularly useful for the clinical assessment of delirium

  • Two variations, the CAM-ICU and the CAM-S, are useful for the intensive care unit setting and in assessing delirium severity, respectively

Treatment

Medications