Delirium is an acute fluctuating disturbance of consciousness accompanied by inattention and changes in cognitive function.¹ Although its exact pathophysiology is poorly understood, delirium in the elderly has been associated with lengthy hospital stays, increased mortality, and substantial economic burden.

Unfortunately, emergency departments continue to do a poor job in recognizing this disease state despite its high prevalence in elderly patients who are admitted—close to 16 percent.² Health care costs associated with delirium are well over $38 billion annually and may be as high as $150 billion.³ Despite increasing research in the field, delirium is still missed by emergency physicians up to 83 percent of the time.^4,5 The good news is there are several areas where physicians can improve in not only the diagnosis but also in prevention.

Diagnosing Delirium
Delirium is found in all areas of medicine and must be dealt with in a multicomponent approach. For emergency physicians, this means prompt recognition as well as ensuring that admitting teams are clearly informed of the diagnosis.

Paramount to the diagnosis of delirium is first understanding who is most at risk. There should be a high index of suspicion in the geriatric population, particularly for severely ill patients and patients with a history of dementia, alcoholism, or hypertension.

Workups must begin with a full history focusing on the patient’s baseline mental status and timing of the confusion. Physicians should review all medications and look closely for precipitants such as anticholinergics and opioids. If a history is lacking upon arrival, assume the mental status change to be acute and proceed with a full workup.⁶ Vital signs, including a blood glucose level, as well as a detailed physical exam, especially the neuro exam, are critical starting points.

Look for signs of occult infection, abdominal processes, dry mucous membranes, focal neurological deficits, or any sign of acute illness. Based on history and physical examination, laboratory tests should be ordered along with imaging tests, as indicated (eg, chest X-ray, CT head). Selected patients may need a lumbar puncture to rule out meningitis/encephalitis, an EEG to rule out nonconvulsive status epilepticus, or an arterial blood gasses/venous blood gasses (ABG/VBG) test to rule out acidosis.

It’s important to differentiate delirium from common mimics such as psychotic illness and dementia.^6,7 In contrast to delirium, dementia occurs over a longer period of time, doesn’t fluctuate, and has an insidious onset. Dementia is the leading risk factor for delirium, but the two are distinct entities. Psychotic disorders are differentiated from delirium by their chronic courses with exacerbations as well as normal level of consciousness and otherwise lack of slurred speech.⁷

The 2014 ACEP Clinical Guidelines have suggested a two-part method for delirium screening in the emergency department that has shown some promise.⁸ The first is a sensitive tool called a Delirium Triage Screen that seeks to rule out delirium if there is normal mental status and no inattention demonstrated. The second part is a more specific tool called the Brief Confusion Assessment Method (bCAM). The algorithm is quick and easy to apply in an ED setting, and it has shown a sensitivity and specificity of 82 percent and 95 percent, respectively, for delirium detection.^9,10

Prevention
Prevention is equally as important as risk factor identification. Early interventions regarding disruptions in sleep, immobility, visual impairment, hearing impairment, dehydration, and cognitive impairment have been shown to reduce both the number of delirious episodes and their duration.¹¹

Melatonin levels are decreased in the elderly, a population at great risk for delirium. Delirium is multifactorial; melatonin may play a role in its pathogenesis.¹² In a randomized, controlled trial on sick, elderly patients, the melatonin agonist ramelteon was shown to reduce the risk of delirium significantly when compared to placebo (3 percent versus 32 percent).¹³

Currently, German societies recommend ramelteon’s use in the prevention of intensive care unit delirium.¹⁴ However, among other things, there are still uncertainties with regard to its long-term benefits and harms as well as optimal dosing. Further, in a 2016 Cochrane review of 529 patients, there were no data to suggest melatonin decreased the occurrence of delirium.¹⁵ There are multiple trials currently investigating melatonin in the hopes that it may become a therapy targeted at reducing delirium.

Critical Actions for Patients with Agitated Delirium
If you have a patient in your emergency department who shows signs of agitated delirium, there are several critical actions you should take to better diagnose and alleviate the condition:

• Urinary retention: Perform a quick bedside bladder ultrasound and straight catheter when appropriate. Avoid iatrogenic causes of delirium such as Foley placement.¹⁶
• Environment: Check to ensure the patient is neither too hot nor too cold. Assess for excessive tethering of wires and/or tubing.
• Constipation: Give stool softeners and disimpact if appropriate; review the patient’s medication list for constipation-causing meds.
• Pain: Assess for acute pain and provide adequate analgesia.
• Dehydration: See clinical exam and blood urea nitrogen to creatinine (BUN/Cr) levels to assess; give fluids when appropriate.
• Medications: Perform a thorough medication reconciliation; polypharmacy is frequently seen in the geriatric population.¹⁷
• Avoid benzodiazepines: In the absence of delirium tremens or benzodiazepine withdrawal, benzodiazepines should be avoided in this population.¹⁷
• Sedation: In sicker geriatric patients requiring sedative drips, some evidence suggests that the use of dexmedetomidine over propofol may reduce delirium.¹⁸
• Collateral information: Although challenging, diagnosing delirium in those with a history of dementia is crucial and may require phone calls to family for collateral information.¹⁷
• Differential: Keep a broad differential, and rule out life-threatening causes.

With the growth of our aging population, emergency departments will continue to see a geriatric population at risk for delirium. Prompt diagnosis has both clinical and financial benefits. Considering delirium first before dementia or psychosis is the best approach to avoid misdiagnosis and mislabeling the sick as psychotic.

Dr. Karounos is attending physician and director of research in the Department of Emergency Medicine for St. Joseph’s Regional Medical Center in Paterson, New Jersey. In addition to being the chief of geriatric emergency medicine for the medical center, she is chair of the ACEP Geriatric Emergency Medicine Section and serves on the New Jersey Chapter ACEP Board of Directors.

Dr. Bove is chief resident in emergency medicine at St. Joseph’s Regional Medical Center in Paterson, New Jersey.

References

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