Delirium - a junior doctor's practical guide

Without doubt, one of the most challenging requests you will receive as a junior doctor (particularly in the middle of the night, when the symptoms of this condition most frequently occur) is to review a “confused” or “bizarrely acting” patient. Your heart will sink, your mind will race and you may even wish you had trained as a vet. Don’t panic! More often than not, your patient will have delirium - an often alarming, but manageable problem.

This article is written by a junior doctor and future psychiatrist who has regularly experienced the stress of dealing with these complex calls. One who knows all too well how infectious this “confusion” can feel, at 2am on an elderly care ward, when I have found myself desperately dredging the dark recesses of my medical school knowledge, most of which (think Krebs cycle) is, in retrospect, of little immediate assistance.

The acute confusional state is a subject easily overlooked at medical school, by teachers and students alike. It is neither rare nor sexy enough for consultants to wax lyrical about, and may not strike you as the most exciting of topics. Nevertheless, a sound understanding is essential; you can be sure that you will need this grounding far more frequently than your knowledge of, say, the lifecycle of the anopheles mosquito.

This guide covers how to diagnose delirium, how to identify its precipitating factors and, most importantly for your chances of getting any sleep on call, it outlines how to treat it, safely and efficiently. Your hospital will have its own guidelines for delirium – familiarise yourself with them. Much of the following is based on the Guy’s and St Thomas’ Trust guidelines, written by Dr T Ernst, from which I learnt a great deal.

Overview

Delirium is a common neuropsychiatric condition. It presents in both medical and surgical settings and is known by various names, including organic brain syndrome, intensive care psychosis and acute confusional state.

Incidence

• Delirium is present in 10% of medical patients who are hospitalised¹
• A further 10-30% develop delirium after admission¹
• Postoperative delirium occurs in 15-53% or surgical patients and in 70-87% in intensive care²

The importance of delirium

• Patients with delirium have an increased length of stay, increased mortality and increased risk of institutional placement³
• Hospital mortality rates of patients with delirium (6-18%)³ are twice that of matched controls
• Up to 60% of individuals suffer persistent cognitive impairment following delirium and they are also three times more likely to develop dementia³

Recognising the patient with delirium

This can be tricky. Symptoms of delirium can mimic other psychiatric disorders, including depression, dementia, mania, or psychosis. There are, however, cardinal features of delirium that you must always look for. As defined in the American Psychiatric Associations Diagnostic and Statistical Manual⁴, delirium is characterised by:

1. Acute onset – Occurs abruptly, usually over a period of hours or days. It is therefore important to establish that the symptoms are a new phenomenon.
2. Fluctuating course – Symptoms tend to come and go or increase and decrease over a 24 hour period. Establish if there have been lucid intervals.
3. Inattention – There is difficulty in focusing, sustaining and shifting attention. The patient may struggle to maintain concentration or follow commands.
4. Disorganised thinking – This may be manifested by incoherent speech. Watch for rambling or irrelevant conversation or an illogical flow of ideas.
5. Altered level of consciousness – Clouding of consciousness is present, with reduced clarity of awareness of their environment.
6. Cognitive defects – Perform a mini-mental state examination (MMSE). There are typically global or multiple deficits in cognition, especially disorientation, memory and language deficits.
7. Perceptual deficits – Illusions or hallucinations occur in ~30% of patients
8. Psychomotor disturbances – Beware. Hyperactive features may present more readily but hypoactive features (lethargy and decreased motor activity) are more subtle and, as such, are easier to miss. These may be attributed to “being old”, but a collateral history might show these features to be new.
9. Altered sleep-wake cycle – Typically you may hear from relatives or nursing staff that there has been day time drowsiness with night time insomnia, fragmented sleep or complete night-day reversal. This also occurs in dementia.
10. Emotional disturbances – These are very common. They are manifested by intermittent and labile symptoms of fear, paranoia, anxiety, depression, irritability, apathy, anger or euphoria. The patient might try to hit or kiss you!

Any given patient will probably not have all of these features. You can use the CONFUSION ASSESSMENT METHOD (CAM) to screen for delirium. Put simply, the diagnosis can only be made if: numbers 1, 2 and 3 are present +/- numbers 4 or 5.

Collateral history

I cannot emphasise enough the importance of collateral history. You must speak to the GP, carers, next of kin, relatives, nursing staff, social worker, friends or anyone who will be able to tell you if the patient’s symptoms are a new phenomenon. You should check old notes for a previous MMSE score or a history of confusion. A history of alcohol or substance misuse must be pursued. You will also need to know if the patient has a history of potential risk factors, such as incontinence or constipation and if there are particular things that the patient normally needs to function (e.g. glasses, hearing aids, walking sticks).

Perform a full physical examination

This should go without saying. You must target: Glasgow Coma Scale, temperature, sources of infection (lung, urine, skin, abdomen). A neurological examination is vital as is a rectal examination. Remember the expression: “If you don’t put your finger in it, you’ll put your foot in it!”

What blood tests should I send?

Full blood count, c-reactive protein, urea and electrolytes, liver function tests, thyroid function tests, calcium, glucose, vitamin B12 levels and folate.

• What initial investigations should I perform?
• Chest X-ray
• Electrocardiogram
• Blood cultures if febrile
• Urinalysis
• Pulse oximetry

What is the likely cause of delirium?

Delirium is almost invariably multifactorial and it is often inappropriate to isolate a single precipitant as the cause¹. The following tables discuss predisposing and precipitating factors. These are taken from the Guy’s and St Thomas’ Trust ‘Delirium Guidelines’.

Risk factors

Causes

How to manage delirium

• Delirium is a medical emergency and diagnosis and treatment of the underlying cause (as above) should be the first port of call
• It is important to ensure that symptomatic and supportive care is provided until full recovery
• Importantly, pharmacological management should be reserved for patients whose symptoms threaten their own safety or the safety of others, or would result in the interruption of essential therapy²
• Remember: antipsychotic and sedative medications can be dangerous in excessive doses. Additionally, the overuse of benzodiazepines can result in dependence.

The following is a list of “dos” and “don’ts” to provide practical assistance:

Do:

• Consider the core principles of medical ethics (beneficence, non-maleficence, justice, autonomy)
• Use interventions that are the least restrictive
• Let the patient wander within a safe environment
• Be courteous and polite
• Document everything clearly, including an assessment of capacity
• Consider urgent psychiatric review if the patient is not responding to initial management

Don’t:

• Delay attending - delirium has a high mortality
• Use bed rails as restraints - patients will climb over these and fall
• Use side rooms, unless the patient remains under special nursing supervision – observation provides safety
• Catheterize or use intravenous lines unnecessarily
• Order unnecessary tests (e.g. CT scan/frequent blood tests) if not indicated
• Use medication, unless all non-invasive interventions have first failed.

The pharmaceutical option

All else has failed, and you need to calm the patient down. General rules:

• Use a low dose of one medication and only repeat if necessary
• Tailor the dose to age/body size/degree of agitation
• Remember that the elderly are more sensitive to drugs and need smaller doses
• Keep strict records of what has been given
• Review all medications every 24 hours
• Choose oral over parental or intramuscular routes wherever possible
• Always refer to the British National Formulary to check drug information

Which drug to use?

• Different Trusts have different policies on which drug they like to use as a first line. In my house officer year, the Trust I worked for used Haloperidol. Other hospitals use benzodiazepines (e.g. Lorazepam, 0.5-2mg orally) as first line.
• The best rule is, if you are not sure, check with a senior or a pharmacist – there is always someone to ask for advice.

If you have taken anything away it should be the following:

1. Delirium is common
2. Delirium is dangerous
3. Delirium has many different aetiologies
4. Delirium is often missed

Keep your eyes peeled and get treating. When you get it right, it’s incredibly rewarding. Good luck.

References

• Nayeem K, O’Keefe S. Delirium. Clinical Medicine 2003; 3 412-415
• Inouye SK. Delirium in Older Persons. The New England Journal of Medicine 2006; 354:1157-1165
• Potter J, George J. The prevention, diagnosis and management of delirium in older people: concise guidelines. Clinical Medicine 2006;6:303-308
• DSM-VI Diagnostic and Statistical Manual of Mental Disorders (1994) American Psychiatric Press Inc.

Special thanks to the elderly care physicians at St Thomas’ Hospital, London. Their tuition and hospital delirium guidelines have been invaluable.

Dr Rory Conn, FY2 in old age psychiatry, rconn@doctors.org.uk

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Page last updated on 22 May by E Baker-Glenn