Delirium

Delirium is an acute fluctuating change in mental state, usually due to reversible causes. In contrast with dementia, delirium is characterized by sudden changes typically associated with an acute illness or drug toxicity and is usually reversible. Delirium is common in older adults: 30% of older adults hospitalized on a medical unit become delirious, and 10% to 50% of older adults undergoing surgery experience delirium.

Delirium is often not treated because it is not recognized. Although commonly thought of as a hyperactive state, the less recognized hypoactive state is more common. Delirium is associated with increased mortality and morbidity. Among hospitalized patients, it is associated with up to a tenfold increase in mortality. Patients who develop delirium as inpatients are more likely to have poor functional outcomes and are at higher risk for death after discharge, as compared with inpatients who do not develop delirium.

Features of Delirium

Delirium is an acute confusional state characterized by a fluctuating course, inattention, cognitive dysfunction, and altered level of consciousness. Hyperactive delirium is characterized by an agitated state and accounts for only 25% of cases. Hypoactive delirium is characterized by withdrawn and depressed states and accounts for the majority of cases.

Screening

The Confusion Assessment Method (CAM) is a common tool used to identify the key features of delirium.

Risk Factors

The risk for delirium can be categorized as predisposing (baseline) and precipitating (acute) factors as follows:

• predisposing factors: older age, dementia, multiple comorbidities

• precipitating factors: surgery, pain, acute illness, constipation, urinary retention, infections, medication use (including anticholinergic drugs, benzodiazepines, and opioids), altered circadian rhythm, dehydration, and metabolic derangements

The more risk factors for delirium that are present, the more likely a patient is to develop it. A detailed evaluation is key to identifying these risk factors.

Evaluation

The evaluation of delirium should start with a thorough history and physical examination.

Delirium evaluation tools include the Confusion Assessment Method for the intensive care unit (CAM-ICU), the brief CAM (bCAM) for the emergency department, and the 3-minute diagnostic interview for delirium using CAM (3D-CAM). Evaluation for delirium should include ruling out dementia, depression, metabolic encephalopathy, and other psychiatric illnesses.

(Source: Delirium in Hospitalized Older Adults. N Engl J Med 2017.)

Management

The key to managing delirium is prevention, followed by prompt recognition, evaluation of the underlying risk factors, and implementation of nonpharmacologic interventions. Initial evaluation should begin with an assessment of precipitating factors.

All reversible or correctable contributing factors should then be addressed. This includes:

• carefully reviewing the patient’s medication list and eliminating or reducing the doses of drugs that are likely to contribute to delirium (especially sedatives and anticholinergic agents)

• optimizing sleep hygiene and eliminating unnecessary awakenings

• optimizing hydration and nutrition

• providing natural light during the day

• ensuring the patient is getting out of bed and is mobile

• frequently reorienting the patient to person, place, and time

Nonpharmacologic interventions are especially important for patients with delirium who experience agitation. Use of restraints should be minimized, as they have been associated with increased risk for injury.

Currently, no medications are approved for treatment of delirium. Antipsychotic agents are sometimes used (off-label) to manage agitation, but numerous studies and meta-analyses indicate that antipsychotics do not reduce the duration or severity of delirium. Limited data suggest that atypical antipsychotics would be preferred over haloperidol if needed, given the relatively safer profile, particularly in patients with Parkinson disease. Antipsychotic agents, trazodone, and valproic acid may be used to manage symptoms of agitation when a patient’s behavior poses harm to themselves or others. However, use of antipsychotics, trazodone, and valproic acid must be judicious with lowest effective dosing, timely discontinuation, and daily monitoring of risks and benefits.