Delirium is a common though easily missed condition associated with increased morbidity and mortality.

It describes a sudden onset (hours to days) deterioration in mental functioning triggered mainly by acute medical illness, surgery, trauma or drugs. It is usually reversible and should generally be managed in the acute hospital.

Many conditions can trigger delirium and there is often more than one contributory factor. The key to assessment and management is timely recognition of delirium and the identification and treatment of the underlying cause.

Risk factors include:

• acute illness
• age over 70 years
• dementia
• sensory impairment
• frailty
• polypharmacy
• pain
• alcohol misuse

• Acute cognitive deficits – disorientation, disorganised thinking, altered attention
• Altered level of arousal - drowsiness or agitation
• Hallucinations and/or delusions (in around 20%)
• Symptoms often fluctuating (tending to be worse at night)

• Delirium is a medical emergency and life-threatening causes should be considered first e.g. hypoxia, hypotension, hypoglycaemia, drug intoxication or withdrawal.
• Other causes include infection, pain, constipation, heart failure, urinary retention, metabolic. 

• A to E assessment 
• The 4AT tool is recommended by NICE for identifying delirium
• Collateral history is very important – ask about onset, duration, any recent physical illness, accident/head injury, drug (prescribed or not) and alcohol use. 
• Investigations guided by history and examination findings – bloods (U&E, LFT, FBC, glucose, CRP, CA PO4, TFTs), urinalysis/culture, blood/sputum/stool culture, ECG, consider ABG, CXR. CT brain if focal neurology, head injury, history of fall, taking anticoagulants or non-resolving confusion.

• Explain the condition to patient and/or their carer
• If the patient is unable to consent to treatment complete an AWI Section 47 (Consent to Treatment) Form and an Annex 5 form, detailing the treatment plan for the patient if they are going to need more than one treatment or intervention. "Fundamental Healthcare Procedures" on the Annex 5 form refers to interventions which promote or safeguard nutrition, hydration, hygiene, skin care and integrity, elimination, relief of pain and discomfort, mobility, communication, eyesight, hearing and simple oral hygiene. 
• Environmental – aim to nurse in a quiet, appropriately lit area with regular orientation
• Medication review and optimisation
• Treat the underlying cause e.g. antibiotics for infection, fluids, analgesia. See here for further details. 
• Manage agitation – de-escalation, consider medication if risks to patient or others
• Consider referral to liaison psychiatry if: severe agitation not responding to standard measures, there is doubt about diagnosis, if detention under the Mental Health Act is being considered. Psychiatric services may hold information about baseline cognition and mental health. 

SIGN quick reference guide for Delirium

SIGN Guidelines Delirium

4AT Assessment Tool

Scottish Delirium Association: Delirium Management Comprehensive Pathway

SIGN/HIS Delirium Information Booklet For Patients And Carers