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 is excluded.

• 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  • hypoactive – quiet, withdrawn and inactive: more common but often missed or misdiagnosed as depression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, corticosteroids, 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.

Treat underlying causes.

• If terminal delirium, refer to 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, for example, glasses and hearing aids 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.

Pharmacological management (if essential to control symptoms)

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

• †QTFirst 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 2mg to 5mg, 1 to 2 hourly or diazepam orally or rectally 5mg, 8 to 12 hourly.

• If increased sedation is desirable and appropriate seek specialist advice

• Add or increase benzodiazepine (†midazolam SC infusion 10mg to 30mg every 24 hours in a syringe pump or diazepam rectally 5mg to 10 mg, 6 to 8hourly)
• Change QT†haloperidol to QT†levomepromazine. Use lower doses if not used previously and in frail elderly, for example, 2.5mg to 5mg SC as required 2 hourly.
• Higher doses may be needed for persistent distress or delirium for example, 10mg to 25mg SC as required 2 hourly. 
• Seek specialist advice for doses over 50mg.

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

British Geriatrics Society 2013. The prevention, diagnosis and management of delirium in older people.

Her Majesty’s Stationery Office (HMSO) 2013. Adults with Incapacity (Scotland) Act 2000. Available: http://www.legislation.gov.uk/asp/2000/4/contents [Accessed 10 December 2013].

NICE 2010. Delirium: prevention, diagnosis and management. Clinical guideline. Available: https://www.nice.org.uk/guidance/cg103/resources/delirium-prevention-diagnosis-and-management-pdf-35109327290821 [Accessed 11 December 2018]

Scottish Delirium Association 2016. Delirium Management Comprehensive Pathway. Available: http://www.scottishdeliriumassociation.com/sda-delirium-management-pathways.html [Accessed 11 December 2018].