Delirium

Ben Johnson, reviewed by Jonathan Smith and Daniel Daunis

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Background

• Definition: acute (hours to days) fluctuating disturbance of attention and awareness due to an underlying medical condition

• Complex and multifactorial condition, often due to underlying condition, with unknown pathophysiological mechanisms

• Increased morbidity, mortality, and functional decline

• Presentation: deficits in attention, orientation, or memory; hallucinations or delusions; sleep-wake disturbances; psychomotor changes (hyperactive, hypoactive, or mixed); language impairment; anxious or depressed mood, and/or emotional lability (agitation)

  • Think about the ABC’s of Delirium

    • Affect (anxiety, paranoia, irritability, apathy, mood shifts, personality changes)

    • Behavior (hallucinations, restlessness or agitation, psychomotor abnormalities, sleep disturbances)

    • Cognition (impaired memory, disorientation, disturbances in speech)

• Delirium can persist despite identification and reversal of underlying causes, particularly in older patients or those with baseline cognitive deficits.

Evaluation

• Use screening tools to assess for delirium: Brief Confusion Assessment Method (bCAM). See critical care section for the ICU version, CAM-ICU

• Once delirium is diagnosed, evaluate for the underlying cause. Delirium has many etiologies and may occur alone or in combination (in ~10% of cases, no clear cause is found)

  • Mnemonic for common causes of delirium:

    • D- Drugs/toxins (use of benzodiazepines, opiates, anticholinergics, steroids, etc., withdrawal from ETOH, benzos, etc.)

    • E- Eyes/ears (sensory deficits)

    • L- Low perfusion states (MI, PE, heart failure, sepsis)

    • I- Infection

    • R- Retention (urine, stool)

    • I- Intracranial events (trauma, seizure, stroke, hemorrhage)

    • U- Undernutrition/dehydration

    • M- Metabolic, endocrine (Hypo or hyper Na, hyperCa, uremia, thyroid, hypoglycemia)

• Workup

  • History

    • Review current medications including those recently started or discontinued, as well as drug interactions

    • Review alcohol, sedative, substance use

    • Assess for pain and discomfort

  • Vital signs

    • Temperature, O2 sat, POC glucose, and orthostatic vitals

  • Physical exam

    • Assess for infection (SSTI, UTI, pneumonia, meningitis), abdominal pain, and sensory impairments, FND

  • Labs

    • CMP

      • Renal and hepatic function for changes in metabolism/elimination of medications

      • Glucose

    • Ammonia

    • Serum medication levels

    • Magnesium

    • TSH and free thyroxine

    • Infection – U/A, CXR, blood, urine, and sputum cultures

    • CBC

    • B12, folate, vit D

  • Imaging

    • CTH – non-contrast unless unable to get MRI (stroke, large structural changes)

    • MRIb with contrast (stroke, infection, inflammation, more subtle structural changes)

  • Medications - review anticholinergics, sedatives, opioids

    • Are changes needed to address pain control, constipation, insomnia, nausea, etc?

    • Substance use – evaluate for EtOH or BZD withdrawal state

      • Empirically load on thiamine (500mg IV tid x9 doses)

  • EEG – evaluate for seizures, confirm presence of encephalopathic changes

  • LP – if concerned for CNS infection, inflammatory condition

Management

• Treat underlying cause as above

• Cognitive impairment or dieorientation

  • Provide clock, calendar, and appropriate lighting

• Regular reorientation

  • Provide cues from a familiar environment (pictures, calls or visits from family members)

• Ensure hearing aids, glasses, and dentures are available

• Maintain normal sleep-wake cycle

  • Keep lights on in the day and avoid excessive naps

• Early PT, OT interventions, mobilization, move to bedside chair when able

• Remove medical support devices as able (foley catheters, restraints, telemetry)

• Ensure adequate bowel regimen and hydration

• Assess for pain and treat appropriately

• Medication reconciliation to reduce or eliminate total anticholinergic load, and to reduce or eliminate other deliriogenic medications as able

  • See Beers criteria

• See critical care section for prevention in the ICU (ABCDEF bundle)

• Note on pharmacologic management: There is no pharmacologic intervention known to prevent or treat delirium. Medications for agitation only treat certain behavioral symptoms of delirium, are typically ineffective/harmful for hypoactive delirium, and do not modify the underlying pathological process. Reserve medications for agitation impairing patient safety when non-pharmacologic interventions alone are unsuccessful. See agitation section for medication approach