Delirium in Elderly

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

  • Use of psychoactive medications

  • Sensory impairment

  • Depression

  • Alcoholism

Demographics

• Occurs in 29–64% of hospitalized older adults

• Persists in 25% or more

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

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 measurement, blood cultures, chest radiograph, urinary toxin screen, 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

Medications

• Management of established episodes of delirium combines the elements of preventive interventions with

  • Reassurance and reorientation

  • Treatment of underlying causes

  • Elimination of unnecessary medications

  • Avoidance of indwelling catheters and restraints

• Antipsychotic agents

  • Have long been a mainstay of delirium treatment in hospitalized adults

  • However, evidence is accumulating that they offer little to no benefit and can be harmful

  • Data from a 2019 systematic review of haloperidol and second-generation antipsychotics found no difference in

    • Delirium severity or duration

    • Hospital length of stay

    • Mortality when compared to placebo

  • QT interval prolongation was more common in the antipsychotic group but there was no difference in extrapyramidal effects

• In ventilated patients in the intensive care unit setting, dexmedetomidine or propofol (or both) may be useful alternatives or adjuncts to antipsychotic therapy

• In general, benzodiazepines should be avoided unless specifically used to treat alcohol withdrawal

Complications

• Delirium may lead to an increased number of iatrogenic events

Prognosis

• Delirium is associated with worse clinical outcomes (higher in-hospital and postdischarge mortality, longer lengths of stay, greater probability of placement in a nursing facility)

• Most episodes clear in a matter of days after correction of the precipitant, but delirium may last for weeks or months

Prevention

• Preventive measures include improving

  • Cognition (frequent reorientation, activities, socialization with family and friends)

  • Sleep (massage, noise reduction, minimizing interruptions at night)

  • Mobility

  • Vision (visual aids and adaptive equipment)

  • Hearing (portable amplifiers, cerumen disimpaction)

  • Hydration status (volume repletion)

When to Refer

• Refer to a neurologist, geriatrician, or psychiatrist when the etiology is not clear or the patient is not responding to therapy

When to Admit

• Patients with delirium of unknown cause should be admitted for an expedited work-up if consistent with the patient's goals of care