Emergency physicians treat their fair share of geriatric patients, and excel at treating conditions such as chest pain, abdominal pain, and fever. Unfortunately, we often overlook a common condition in the elderly that has recently been getting a lot more attention — delirium.
Approximately 20 million ED visits made in the United States are by patients over 65. (NCHS Data Brief Oct 2013;:1). Up to 20 percent of these patients are suffering from delirium (Emerg Med J 2013;30:263), yet detection by emergency physicians is extremely low. Hospitalists aren't much better at making the diagnosis. One study showed that 90 percent of all ED patients admitted to the hospital with unrecognized deliriumremained undiagnosed during their hospital stay. (Acad Emerg Med 2009;16:193.)
Patients with delirium have more serious illnesses, less chance of recovery, and overall worse outcomes, and a growing body of evidence demonstrates that simply treating the underlying process may not be enough. One study of patients with acute delirium found a 16 percent inpatient mortality rate; 40 percent required permanent institutionalization. (Int J Geriatr Psychiatry 2013;28:1015.)
A review article of inpatient outcomes found that patients with delirium may suffer prolonged cognitive impairment including inattention, disorientation, and memory impairment that could last for more than a year in addition to longer hospital stays, decreased function, and increased need for long-term care. (Age Ageing 2006;35:350.) Evidence even suggests that delirium may be linked to the body's inflammatory and stress response, with associated elevation inbiomarkers such as C-reactive protein. (J Crit Care 2013, in press.)
Patients with delirium who go undiagnosed at discharge may have trouble following instructions,and that may be associated with an increase in six-month mortality. (J Am Geriatr Soc 2003;51:443.)
Research continues on the cause, prevention, and management of delirium, but experts are also pushing for better identification of these patients. The clinical evaluation tools Confusion Assessment Method (CAM) and CAM-ICU have been validated for use in a variety of patient care settings. They are of questionable value in the ED, however, because of time constraints.
Han et al, however, produced the Delirium Triage Screen (DTS), a rule-out test, and the Brief Confusion Assessment Method (bCAM), a rule-in test as a rapid screening tool for delirium that can be easily used in the ED. They designed a prospective observational study to evaluate their rapid two-step surveillance tool, and compared it with the results of a full psychiatric evaluation for delirium.
Diagnosing Delirium in Older Emergency Department Patients: Validity and Reliability of the Delirium Triage Screen and the Brief Confusion Assessment Method
Han JH, Wilson A, et al
Ann Emerg Med
A convenience sample of patients was enrolled based on psychiatrist availability. Inclusion criteria included age 65 or older, in the ED for fewer than 12 hours at the time of enrollment, and not being in a hallway bed. A total of 365 of 953 eligible patients refused consent. Ninety patients were excluded for being unresponsive, having a language barrier, or being unable to respond to questions based on a pre-existing medical condition. An additional 92 patients had incomplete data collected. Patients included in the analysis were more likely to have more acute triage scores (ESI 2) and to be admitted to the hospital.
The DTS (rule-out component) was designed to take less than 20 seconds. If positive, the bCAM (rule-in component) was performed, which allowed for rapidly evaluating the cardinal features of delirium (altered mental status, fluctuating course, inattention, and disorganized thinking) in an average of 55 seconds. A 15-second time limit was placed on some answersto ensure brevity. Each patient then underwent a comprehensive psychiatric assessment by a blinded, experienced psychiatrist to establish a diagnosis of delirium by DSM-IV-TR criteria.
The DTS had an excellent sensitivity of 98% (95% CI 89.5%-99.5%) and a very low negative likelihood ratio of 0.04 (95% CI 0.01-0.25) when performed by an emergency physician or a trained research assistant,deeming it an effective rule-out test.The bCAM had an excellent specificity of 95.8% (95% CI 93.2% to 97.4%)when performed by a physician,making it a valuable rule-in test. Overall, the combination of tests had a sensitivity of 82% (95% CI 69.2% to 90.2%)and a specificity of 95.8% (95% CI 93.2% to 97.4%)when a physician performed both studies.
This tool is a great step in the right direction, but the study did have some limitations. Consultants were blinded to the results of each clinical tool being tested, but patient enrollment was based on consultantavailability, which might bias how patients were selected. More than a third of patients also refused consent, 10 percent were excluded for having incomplete data, and enrolled patients were more likely to have higher triage scores, all potential sources of selection bias.
The results of this study are encouragingdespite these limitations. With current statistics suggesting that the diagnosis of delirium is frequently missed, this bedside tool holds the promise to be an efficient clinical adjunct toscreen for delirium in elderly ED patients.
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* Read an abstract of the Annals of Emergency Medicine article featured in this column at http://1.usa.gov/1b08YiV.
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