Older patients who present to the emergency department frequently have acute or chronic alterations of their mental status, including their level of consciousness and cognition. Recognizing both acute and chronic changes in cognition are important for emergency physicians. Delirium is an acute change in attention, awareness, and cognition. Numerous life-threatening conditions can cause delirium; therefore, prompt recognition and treatment are critical. The authors discuss an organized approach that can lead to a prompt diagnosis within the time constraints of the emergency department.
Altered mental status or change in behavior in an older patient presenting to the emergency department frequently represents delirium.
Diagnosing delirium occurs at the bedside by the emergency physician and includes objective screening measures for level of consciousness and cognition followed by confirmatory testing.
Delirium is often caused by a potentially life-threatening underlying condition and carries a poor prognosis if unrecognized.
Determining the cause of delirium takes a thorough evaluation, including interviewing any available surrogates, reviewing medications, considering a broad differential, including infection, trauma, stroke, and performing comprehensive diagnostic testing.
Treatment of delirium includes treating the underlying cause as well as careful administration of antipsychotic drugs when nonpharmacologic treatments are insufficient.
Older patients who present to the emergency department (ED) frequently have acute or chronic alterations of their mental status, including their level of consciousness and cognition. Recognizing both acute and chronic changes in cognition are important for emergency physicians. Chronic changes in cognition due to dementia may affect the reliability of patients’ histories as well as their ability to follow discharge instructions. Failure to recognize this chronic impairment may therefore affect patient outcomes.
Most importantly for emergency physicians is to recognize acute changes in mental status. When older patients present with change in mental status as a chief complaint, it is nearly always caused by delirium. Delirium is characterized by an acute (hours to days) fluctuating change in attention, awareness, and cognition as defined by the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Older ED patients with delirium have an increased risk of mortality compared with nondelirious patients. The failure of ED physicians to diagnose delirium may also increase a patient’s mortality, as mortalities are more than twice as high in patients in whom delirium was not diagnosed in the ED, compared with those in whom delirium was diagnosed and nondelirious patients. Crucial to avoiding missed delirium is understanding the subtypes of delirium, which include hyperactive, mixed, and hypoactive states, with the most common being hypoactive. Hypoactive delirium can be misinterpreted as “fatigue” or “not acting like themselves” by caregivers, making this subtype of delirium most challenging to recognize.
Consequently, it is the task of the emergency physician to recognize both acute and chronic mental status changes. A structured approach to the rapid assessment of cognitive status is required. Emergency physicians must have a high index of suspicion for delirium, and once suspected, conduct a thorough evaluation to find the underlying cause.
Evaluation of Altered Mental Status and Delirium
Delirium risk assessment
The emergency physician needs to gather predisposing risk factors for the development of delirium while taking the history of an elderly patient ( Table 1 ). Predisposing risk factors lower the threshold for a patient to become delirious when faced with a precipitating cause ( Fig. 1 ). Furthermore, some predisposing risk factors can themselves cause delirium.
It is essential to include a review of the patient’s active medication list for polypharmacy and for drugs that are known to cause confusion listed on the updated Beers criteria. Notorious drug classes to screen for are anticholinergics, benzodiazepines, opiates, antidepressants, and muscle relaxants. A review of pharmacology in the geriatric patient can be found in the article by Welker KL, Mycyk MB: Pharmacology in the Geriatric Patient , in this issue.
Assessing level of consciousness (arousal)
A bedside examination should assess the patient’s level of consciousness using an objective bedside tool. These tools can assist in diagnosing delirium, and abnormal levels of consciousness are associated with mortality.
One of the simplest is the “AVPU” scale, which stands for alert, responsive to verbal stimuli, responsive to painful stimuli, or unresponsive. However, this scale does not evaluate the level of response to the stimuli, limiting its usefulness. For example, patients who respond to verbal stimuli by waking and interacting with the examiner differ substantially from those whose response to verbal stimuli is groaning. In addition the AVPU scale has a lower ability to predict mortality in hospitalized patients compared with the Glasgow Coma Score (GCS) and the Richmond Agitation and Sedation Scale (RASS).
The GCS was first described more than 40 years ago and is familiar to the emergency physician. GCS is tabulated from 3 scores for best eye opening, best verbal response, and best motor response ( Table 2 ). The advantage of GCS is familiarity due to the ubiquitous nature of the scale in the prehospital and hospital setting. There has been evidence that decreasing GCS in elderly trauma is associated with increased mortality, but this has not been widely studied in the nontraumatic elderly ED population.
|Eye opening response||1 = No response||2 = To pain||3 = To speech||4 = Spontaneous|
|Best verbal response||1 = No response||2 = Incomprehensible||3 = Inappropriate||4 = Confused||5 = Oriented|
|Best motor response||1 = No response||2 = Abnormal extension||3 = Abnormal flexion||4 = Withdraws from pain||5 = Localizes to pain||6 = Obeys commands|
The RASS measures the patient level of arousal on a scale ranging from −5 (Unarousable) to +4 (Combative). A score of zero represents an alert and calm patient. This simple tool takes less than 10 seconds to perform, and scores other than zero (alert and calm) have a high sensitivity for delirium. In the ED setting, Han and colleagues found that an RASS score of less than or equal to −1 or greater than or equal to 1 had a sensitivity of 84.0% and a specificity of 88%. An RASS of less than or equal to −2 or greater than or equal to 2 had a specificity of 99%, at the expense of a decreased sensitivity. The modified RASS provides an additional assessment of attention and provides additional anchors for scoring ( Table 3 ).