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Delirium

Introduction

In this guideline, delirium is defined as disturbed consciousness and inattention with cognitive impairment; acute onset and fluctuating course as a physiological consequence of disease or treatment. Delirium is often reversible. Other terms used to describe delirium include acute confusional state, agitation, and terminal restlessness, but the terms restlessness and terminal agitation should be used once reversibility excluded.

Assessment

  • Common (30 to 85% of hospice patients), often reversible but diagnosed late
  • Three types:
    • hyperactive – increased arousal and agitation
    • hypoactive – quiet, withdrawn and inactive: more common but often missed or misdiagnosed as depression
    • mixed pattern
  • Diagnosis depends mainly on careful clinical assessment; consider using Mini-mental state examination (MMSE) or Confusion assessment method (CAM) as a screening tool
  • Accurate history from someone who knows the patient is important.

 Causes may be complex and multifactorial and may include:

  • Drugs (including: opioids, anticholinergics, steroids, benzodiazepines, antidepressants, sedatives)
  • Drug withdrawal (including: alcohol, sedatives, antidepressants, nicotine)
  • Dehydration, constipation, urinary retention, uncontrolled pain
  • Liver or renal impairment, electrolyte disturbance (sodium, glucose), hypercalcaemia, infection, hypoxia, cerebral tumour or cerebrovascular disease
  • Visual impairment and deafness are risk factors.

Differential diagnosis: depression, dementia (increased risk of developing delirium).

Investigations

  • Check full blood count and biochemistry, including calcium
  • Check for infection (urine infection in the elderly)
  • Review all medication and stop any non-essential drugs
  • Assess for sensory impairment
  • Check for opioid toxicity (drowsiness, agitation, myoclonus, hypersensitivity to touch) reduce opioid dose by 1/3rd.  Consider switching to another opioid if delirium persists
  • Check for constipation, urinary retention or catheter problems.

Management

Treat underlying causes.

  • If terminal delirium, see Last days of life guideline.
  • Maintain hydration, oral nutrition and mobility.
  • If nicotine dependent, consider using replacement patches.

Non-pharmacological management

  • Explain cause and likely course to patient, relatives and carers
  • Address anxiety; patients with delirium are often frightened
  • Quiet area or side room; limit staff changes
  • Ensure glasses, hearing aids etc. are accessible 
  • Adequate lighting, minimise noise, provide a clock the patient can see
  • Gentle repeated reorientation and to avoid confrontation
  • Try to maintain normal sleep-wake cycle
  • Explain the organic cause of behaviour and symptoms.

 

Medication

Pharmacological management (if essential to control symptoms)

  • Review regularly and withdraw medication as soon as the patient recovers.

First choice: haloperidol

  • Dose: 500 micrograms to 3mg oral or subcutaneous (SC) once daily (start with low oral dose).  Repeat after 2 hours, if necessary.
  • Maintenance treatment may be needed if cause cannot be reversed; use lowest effective dose: 500 micrograms to 3mg oral or 2mg SC once daily. (No evidence of greater benefit with newer antipsychotic medication).

Second choice: benzodiazepines

  • Benzodiazepines do not improve cognition; may help anxiety, use with caution.
  • Used in alcohol withdrawal (often at higher doses), sedative and antidepressant withdrawal; preferred in Parkinson’s disease
  • Lorazepam 500 micrograms to 1mg oral or sublingually
  • Midazolam SC 2 to 5mg, 1 to 2 hourly or diazepam orally or rectally 5mg, 8 to 12 hourly.

If increased sedation is desirable and appropriate:

  • Add or increase benzodiazepine (midazolam SC infusion 10 to 30mg every 24 hours in a syringe pump or diazepam rectally 5 to 10 mg, 6 to 8hourly)
  • Change haloperidol to levomepromazine SC 12.5 to 25mg, once or twice daily by injection or as a subcutaneous infusion in a syringe pump.

Practice Points

  • Attention to the environment is essential.
  • Opioid toxicity is a common cause of delirium, particularly in the elderly
  • Corticosteroids can cause florid delirium
  • The Adults with Incapacity Act covers the medical treatment of patients with cognitive impairment. Completion of AWI form and care plan will be required
  • In the acute situation, emergency treatment can be given without an Incapacity certificate.

Patient and carer advice points

  • Encourage the patient to keep taking oral fluids if able
  • The presence of a close relative or friend can help reassure the patient.

Resources

Professional

British Geriatrics Society Guidelines  
Adults with Incapacity Act (Scotland) (2000)

HIS - Delirium Management Comprehensive Pathway

 

Patient

Mental Health Foundation

References