So why do we need to talk about something that so blatantly slaps us across the face? Turns out it’s not always that easy. Review of several studies by Han et al. out of Vanderbilt University provides some clarity regarding the challenges and importance of this pathology in the ED. One study1 evaluated the relationship between the chief complaint of AMS as recorded by triage and delirium in patients presenting to the emergency department who were over the age of 65. The chief complaint of AMS or variants (such as “not acting right”, “confused”, etc) was compared to the presence of a diagnosis of delirium during the emergency department stay as performed by a psychiatrist utilizing DSM IV criteria. The good news is that the presence of such a chief complaint is 98.9% specific with a positive likelihood ratio of 33.82 based on their study, a good argument that an elderly patient with a chief complaint of AMS is very likely to be delirious. However, the presence of this chief complaint was only 38.0% sensitive for delirium, indicating that there are plenty more delirious 65+ year-olds making their way into the ED without a warning from triage that they may be so.

The poor sensitivity for detecting delirium doesn’t end at triage. Another cross sectional study2 investigating the recognition and risk factors of delirium in elderly ED patients cites a 57% to 83% miss rate by emergency physicians when it comes to diagnosis of delirium in this vulnerable patient population (with 76% being missed in their study). Furthermore, of the patients with unrecognized delirium that were admitted to the hospital, only 1 out of 16 (6.3%) had their delirium recognized by the admitting service on their initial history and physical exam.

To make matters worse, patient outcome for these elderly patients in the ED with delirium appears to have a significant mortality difference. In a prospective cohort study3 patients aged 65 or older were evaluated for delirium in the emergency department, this time utilizing the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) as opposed to psychiatry evaluation with DSM IV criteria diagnosis with the goal for evaluation of 6 month mortality. Diagnostic method was changed so as to be more applicable for ED practitioners, stating the CAM-ICU method to be more efficient for the fast-paced ED environment by requiring less than 2 minutes to complete as opposed to a more lengthly interview as performed by psychiatry. They found that patients diagnosed with delirium by CAM-ICU in the ED had a 6 month mortality of 37% as compared to 14.3% of those without delirium overall, with the proportion remaining similar amongst patients discharged from the ED (30.8% 6 month mortality in delirium positive discharged patients vs 11.8% for those without delirium.) This group followed up with another study4 to validate the CAM-ICU as compared to DSM IV criteria diagnosis via psychiatry. The CAM-ICU was found to have a suboptimal sensitivity for delirium in the range of 70%, but did have a good specificity of 98.6%.

What can we take away from all this?