Clinical Notes : Mental Health

82. Delirium

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Definition :

Delirium is an acute confusional state, usually with a fluctuating course, characterised by disturbed consciousness, cognitive function or perception

Risk factors :

  • Age>65 years

  • Pre-existing cognitive impairment or dementia

  • Severe illness

  • Current hip fracture

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Clinical Presentation :

Delirium should be suspected in the presence of:

  • An acute confusional state

  • A change in perception e.g. visual or auditory hallucinations

  • A change in physical function e.g. reduced mobility, agitation, sleep disturbance

  • A change in social behaviour e.g. withdrawal, lack of co-operation for reasonable requests, alterations in mood, change in communication/attitude

Often patients may be labelled as "not themselves," "generally unwell," or "generally deteriorating." Even where patients do not meet all the criteria for a diagnosis of delirium, they may benefit from the approach to diagnosis and management outlined below, bearing in mind the other diagnoses that may be relevant to presentations such as reduced mobility.

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Diagnosis :

In older people, especially those with pre-existing cognitive impairment, it is common to find several factors contributing to delirium.

PINCHES ME is a useful mnemonic for the review of possible causes for delirium :

  • P - Pain

  • I - Infection

  • N - Nutrition

  • C - Constipation

  • H - Hydration

  • E - Endocrine + Electrolyte

  • S - Stroke

  • M - Medication and Alcohol

  • E - Environmental

Management :

Once delirium has been identified and diagnosed, a multi-factorial assessment and management plan should be undertaken addressing the following features:

  • ​Treat infection if it's there, but only if it's there.

    • Whilst infection is a common cause of delirium, it is not the only cause and is not present in all cases.

    • Urinary tract infection, in particular, is commonly over diagnosed in this scenario.

  • ​Address hydration status.

    • Many (although not all) patients with delirium are dehydrated.

    • Severely dehydrated patients or those with hypotension or suspicion of acute kidney injury should be investigated and referred as appropriate.

    • Patients should have fluid intake and output monitored and recorded.

    • Patients should be encouraged to maintain adequate oral rehydration. This may be achieved by offering small sips of fluids e.g. 60mls with each interaction with the patient.

  • ​Address nutritional status.

    • Many patients with delirium may not eat as much as usual and will need nutritional assistance. Offer foods rich in calories and that are known to be favoured by the patient. Record and monitor weight, and consider referral to a dietitian.

    • Treat constipation.

    • Many older patients with delirium who do not eat or drink much may become constipated. Laxatives should be prescribed to constipated, taking into account patient preferences.

  • ​Treat pain.

    • Regular paracetamol is a part of most multi component interventions for delirium.

    • A weak opioid may be considered on a prn basis and analgesia titrated to pain, whilst being mindful of common side effects of opioid analgesia which could compound the delirium.

    • Consider the possibility of urinary retention.

    • This may be commonly missed in older people who may still pass urine, and indeed have urinary frequency and urgency in the presence of significant post void residual urine volumes. Urinary retention may contribute to agitation. If a catheter is required it should be used for as short a period as possible

  • ​Encourage mobility.

    • Patients should be encouraged to mobilise as much as possible.

  • ​Review medications.

    • Consider whether a medication has been stopped or started recently. Typical offending medications include:

      • Tricyclic antidepressants e.g. amitryptilline

      • Antimuscarinics e.g. oxybutynin

      • Antihistamines e.g. cetirizine, loratadine, hydroxyzine

      • 2 receptor antagonists e.g. ranitidine

      • Opioids e.g. codeine

      • Benzodiazepines e.g. lorazepam

      • Gabapentin

      • Theophylline

      • Hyoscine

    • However, longstanding medications may also play a role in development of delirium and a thorough medication review should take place, considering, in particular, the indications for the medication, potential side effects and anticholinergic burden (Rudolph JL, 2008).

  • ​Drug/alcohol withdrawal.

    • Should be considered as a potential cause of delirium.

  • ​Sleep disturbance.

    • As much as possible, patients should be encouraged to maintain a normal sleep/wake cycle.

    • The use of hypnotics to aid sleep is usually discouraged and these may contribute to delirium.

  • ​Educate and re-orientate.

    • Caregivers should be educated as to the diagnosis of delirium and how they can help.

    • In particular, re-orientation strategies should be employed.

  • ​Environment

    • The use of large, clearly visible clocks and calendars is recommended, and wherever possible patients should be looked after in a familiar environment by familiar relatives or staff.

    • Hearing aids and spectacles should be used. Rooms should be well lit during the daytime and unnecessary noise should be kept to a minimum.

  • ​Sedation

    • Sedatives should be avoided if at all possible, and if used, used at the lowest possible dose for as short a time as possible.

      • NICE guidance recommends uses of haloperidol as first line (off-licence uses).

        • A dose of 0.5mg can be given two hourly, up to a maximum of 5mg/24 hours.

        • A baseline ECG is recommended as haloperidol can sometimes cause prolongation of the QTc interval.

        • Haloperidol should be avoided if there is

          • a history of Parkinson's disease,

          • CNS depression or clinically significant cardiac disorders e.g.

          • recent acute myocardial infarction,

          • uncompensated heart failure,

          • arrhythmias treated with class IA and III antiarrhythmic medicinal products,

          • QTc interval prolongation,

          • history of ventricular arrhythmia or torsades de pointes, clinically significant bradycardia, second or third degree heart block and uncorrected hypokalaemia.

      • Lorazepam is recommended if there is a contraindication to haloperidol.

        • The recommended dose is 0.5mg 2 hourly up to a maximum of 3mg/24 hours.

      • If sedation is used then it should be reviewed and weaned as soon as possible ideally within 24-48 hours, and certainly no more than seven days.

In the OOH setting the assessment and management of acute delirium is often rendered difficult by the absence of :

  • detailed clinical notes bearing crucial information about co-morbidity

  • formulated acute care management plan (instructions for family or nursing home staff for emergencies)

  • formulated chronic care management plan (instructions for family or nursing home staff for coping with activities of daily living and for monitoring and management of individual features of dementia)

As a consequence, it is not uncommon for the OOH GP to be forced to refer the delirious patient to A+E for evaluation.

The disruption to daily routines and environment resulting from referral to A+E and admission to a hospital ward in itself can compound the delirium and delay its resolution.

Whenever a delirious patient is referred OOH to A+E, the patient's registered GP should be contacted and encouraged to update the family and/or the nursing home staff and records, so as to avoid repeated OOH referrals to A+E and facilitate home management and investigation where possible.


The Interactive Confusion Assessment Method 

Set of short videos illustrating the CAM
Miller School of Medicine, Miami



Inouye SK, Van Dyck CH, Alessi CA, Balkin S, Siegal AP, Horwitz RI. 

Clarifying confusion: The Confusion Assessment Method.  A new method for detection of delirium. 

Ann Intern Med. 1990; 113: 941‑8.



Inouye SK

Delirium in Older Persons.

New England Journal of Medicine 2006;354(11):1157-65.


Delirium in Adults


Published July 2014



Delirium : diagnosis, prevention and management.


Published July 2010



The prevention, diagnosis and management of delirium in older people.

Concise guidance to good practice series, No 6.  

London: College Royal of Physicians

June 2006.


Delirium, dementia, and depression in older adults: assessment and care

International Affairs and Best Practice Guidelines

Published July 2016


Barr J, Fraser GL, Puntillo K, et al

American College of Critical Care Medicine. Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit.

Crit Care Med. 2013 Jan;41(1):263-306.


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