How best to screen for delirium?
Description
Delirium is common among elderly emergency department patients, being present in around 12% according to one study.[1] Patients with delirium are at increased risk of mortality, falls, prolonged hospital stay and being discharged to a nursing home. Most concerning of all, ED physicians may miss the diagnosis in as much as 80% of cases.[2]
How can we improve this?
The AMTS is a common way to screen for and assess a patient's level of confusion, but it has several disadvantages. It is nearly 50 years old and is rather culturally-specific. It was originally developed for in-patient use and is not validated for assessing delirium. This brings us to our first point...
It is more important to identify delirium than dementia in the Emergency Department.
An AMTS of 7/10 is of questionable significance without a known baseline. Of course it is useful to know whether your patient has dementia, but it is vital to recognise delirium. Besides all the risks mentioned above, patients with delirium need specific management and support during their admission. There is also a reason that a patient is delirious, and failing to identify delirium often means we don't diagnose the underlying cause.
Today's paper is great, because it considers each of the delirium screening tools and offers some evidence as to which ones are best. It also contains a handy review of the major causes of delirium (yes, there's more than just 'infection').
The paper
The authors did a comprehensive search of every paper published in English on delirium during the last 23 years, finally arriving at 117 articles. These were read, compared and summarised with the aim of providing an evidence-based review of current delirium management in the ED.
What is delirium?
Delirium can be called an 'acute confusional state'. It's an episode of mental disorientation that is caused by a physical condition of some sort.[4]
More exactly, it is defined in DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) as follows:[5]
- Acute onset, fluctuating course (often worse at night)
and - Reduced ability to focus or sustain attention
and - Disorganised or incoherent thinking (rambling or illogical flow of ideas)
or - Altered level of consciousness (lethargic or hyperactive)
Screening tools
The authors discuss several different tools that have been developed to diagnose delirium. They vary in sensitivity, specificity and administration time. The paper suggests using a brief, sensitive triage tool, to be followed by a slightly more time-consuming, specific diagnostic tool.
Triage tools (very sensitive, don't miss any cases)
SQiD (single question in delirium):
"Is this person more confused than before?"
UB-2 (ultra-brief 2-item bedside test):
"Please tell me the day of the week"
"Please tell me the months of the year backward"
DTS (delirium triage screen):
Altered level of consciousness?
"Can you spell the word LUNCH backwards?"
Diagnostic tools (very specific, don't over-call delirium)
CAM (confusion assessment method):
This asks about each of the features from the DSM-5 definition above. The diagnosis of delirium by CAM requires the presence of features 1 and 2, and either 3 or 4. Most experts recommend that it is administered only by clinicians who have been specifically trained to do so.
4AT (4 A's test):
Assigns points to each of the following, more points meaning increased likelihood of delirium. It requires no special training, and can be accessed via MDcalc or the 4AT website.
1. Alertness (normal or abnormal)
2. AMT4 (location, age, date of birth, current year)
3. Attention (months backwards)
4. Acute change or fluctuating course
A recent study of 785 patients found the 4AT to have a specificity of 94%.[6] SIGN (the Scottish Intercollegiate Guidelines Network) recommend that the 4AT is used to identify patients with probable delirium in the ED.[6]
The bottom line
Rather than concluding that your patient is "a bit confused", actively consider whether they might have delirium. Use the 4AT in patients who are acutely confused, drowsy or agitated.
Causes of delirium
The authors make three important points about aetiology:
- Almost any illness can precipitate delirium
- Most cases of delirium have more than one cause
- Clinicians should not anchor on a UTI as the cause for delirium, as many older patients have pyuria as a baseline
A helpful mnemonic for remembering the common causes of delirium is 'PINCH-ME'...
To these I would add urinary retention (you can think of this as constipation/retention) and electrolytes (under E), as hypercalcaemia in particular is a common cause of delirium.
More FOAMed on this topic
EM3 - Delirium
NUEM - The Seriousness of Deliriousness
emDocs - Delirium
References
- Baten V, Busch H, Busche C, Schmid B, Heupel-Reuter M, Perlov E, et al. Validation of the Brief Confusion Assessment Method for Screening Delirium in Elderly Medical Patients in a German Emergency Department. Acad Emerg Med [Internet] 2018;25(11):1251–62. Available from: https://www.ncbi.nlm.nih.gov/pubmed/29738102
- Lewis L, Miller D, Morley J, Nork M, Lasater L. Unrecognized delirium in ED geriatric patients. Am J Emerg Med [Internet] 1995;13(2):142–5. Available from: https://www.ncbi.nlm.nih.gov/pubmed/7893295
- Lee S, Gottlieb M, Mulhausen P, Wilbur J, Reisinger H, Han J, et al. Recognition, prevention, and treatment of delirium in emergency department: An evidence-based narrative review. Am J Emerg Med [Internet] 2019;Available from: https://www.ncbi.nlm.nih.gov/pubmed/31759779
- Ahmed Y. Delirium [Internet]. Royal College of Psychiatrists.2019 [cited 2019 Dec];Available from: https://www.rcpsych.ac.uk/mental-health/problems-disorders/delirium
- American Psychiatric Association . Diagnostic and statistical manual of mental disorders. 5th ed. Washington DC; 2013.
- SIGN . Guideline 157: Risk Reduction and Management of Delirium [Internet]. Scottish Intercollegiate Guidelines Network.2019 [cited 2019 Dec];Available from: https://www.sign.ac.uk/assets/sign157.pdf
United States
