Delirium: Assessment and Management in the Emergency Department

Posted on Oct 19, 2024 in Medicine & Health

Delirium

Definition

Delirium is characterized by:

  • Disturbance of consciousness: Reduced clarity of environmental awareness, with diminished ability to focus, sustain, or shift attention.
  • Change in cognition: Memory deficit, disorientation, language disturbance, or perceptual disturbance.
  • Presence of a general medical condition: This is usually assumed rather than specified.
  • Clinical subtypes: Hypoactive, hyperactive, and mixed.

Key Features

  • Recent onset of fluctuating awareness
  • Impairment of memory and attention
  • Disorganized thinking

Developing Delirium

Risk Factors

  • Age >65
  • Past or present cognitive impairment
  • Dementia
  • Current hip fracture
  • Severe illness, likely to deteriorate

Precipitating Factors

  • Disorientation
  • Dehydration
  • Constipation
  • Hypoxia
  • Infection
  • Immobility/reduced mobility
  • Pain
  • Polypharmacy
  • Poor nutrition
  • Sensory impairment (e.g., hearing or visual)
  • Poor sleep

High-risk patients should be identified in the ED, and appropriate prevention strategies implemented.

Assessment

ADEPT Tool

The ADEPT tool guides care for older adults with agitation or delirium: Assess, Diagnose, Evaluate, Prevent, and Treat.

ADEPT Tool

History

A detailed history is often difficult to obtain. Obtain information from carers, general practitioners, and others close to the patient. Document:

  • Onset and course of delirium
  • Previous intellectual function
  • Full drug history (including non-prescribed drugs and recent cessation)
  • Alcohol history
  • Functional status (activities of daily living)
  • Aids used (hearing aids, glasses, etc.)

Learning Bite: Corroborate history from reliable sources, as patients with delirium may provide inaccurate information.

Examination

Perform a full examination and a 4AT assessment. Distinguishing between delirium, dementia, and primary psychiatric illness can be challenging. Manage delirium first if differentiation is difficult.

Investigations

Investigations should target potential risk factors or causes identified in the history and examination.

Routine Investigations

At the bedside:

  • Oxygen saturation
  • Blood glucose (finger prick)
  • Electrocardiogram (ECG)
  • Urine dipstick +/- MSU
  • Chest x-ray

In the laboratory:

  • Full blood count (FBC)
  • U&E
  • Glucose

Specific Laboratory Tests (Consider based on assessment):

  • Arterial blood gases +/- carboxyhemoglobin
  • Liver function tests (LFTs)
  • Coagulation studies
  • Thyroid function tests (TFTs)
  • Blood cultures
  • Drug levels (e.g., theophylline, digoxin)
  • B12, folate, VDRL, autoimmune screen
  • D-dimer (only for suspected DVT/PE)
  • C-reactive protein (CRP)/ESR

Computerized Tomography (CT) Scanning

CT head scanning is not routine. Indications include:

  • Focal neurological signs
  • Confusion after head injury or fall
  • Evidence of raised intracranial pressure

Lumbar Puncture (LP)

Reserve LP for suspected meningitis or other CNS infections.

Management

Identify and treat the underlying cause.

Infection

Start prompt antibiotic treatment if infection is suspected (after collecting cultures). UTIs are often over-diagnosed.

Drug History

Review medications and withdraw as necessary. Anticholinergic drugs and polypharmacy can precipitate delirium. Consider indications, side effects, and anticholinergic burden.

Medications Implicated in Delirium:

  • Tricyclic antidepressants (e.g., amitriptyline)
  • Antimuscarinics (e.g., oxybutynin)
  • Antihistamines (e.g., cetirizine, loratadine, hydroxyzine)
  • H2 receptor antagonists (e.g., ranitidine)
  • Opioids (e.g., codeine)
  • Benzodiazepines (e.g., lorazepam)
  • Gabapentin
  • Theophylline
  • Hyoscine

Alcohol

Administer parenteral thiamine if alcohol abuse or withdrawal is suspected.

Biochemical Abnormalities

Normalize biochemical abnormalities cautiously.

Multifactorial Approach

  • Manage underlying causes
  • Communicate regularly with the patient
  • Reorient the patient regularly (involve family/carers)
  • Provide a suitable care environment
  • Educate caregivers

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Preventative and Nursing Measures

  • Appropriate lighting
  • Regular reorientation cues
  • Use of clocks
  • Ensure functioning hearing aids and spectacles
  • Communicate with relatives
  • Encourage family visits and familiar objects
  • Regular analgesia if in pain
  • Optimize fluid balance
  • Eliminate noise and distractions
  • Administer fluids/medications orally if possible

Avoid:

  • Physical restraint
  • Constipation
  • Catheters (if possible)
  • Anticholinergic drugs
  • Unnecessary transfers

Drug Therapy

Avoid drug therapy if possible. Consider sedation if necessary for:

  • Essential investigations or treatment
  • Preventing harm to self or others
  • Relieving distress in agitated or hallucinating patients

If Drug Treatment Is Necessary:

Haloperidol (0.5-1 mg orally or IM, titrate up to 5 mg) is the initial choice. Avoid in patients with reduced GCS or significant cardiac conditions. Avoid haloperidol in Parkinson’s or Lewy body dementia.

Newer antipsychotics are not recommended.

Side Effects:

Monitor for extrapyramidal symptoms and prolonged QT interval.

For alcohol withdrawal delirium or if haloperidol is contraindicated, use lorazepam (2 mg IM/IV, titrate to effect).

Safety Pearls and Pitfalls

  • Consider the diagnosis (especially hypoactive delirium)
  • Routinely assess mental state in elderly patients
  • Obtain corroborative history
  • Obtain a full drug history
  • Consider injury (especially head injury) and pain
  • Order appropriate investigations
  • Address environmental factors
  • Avoid unnecessary sedation