Four principles of treating delirium can help protect medical/surgical patients at risk for morbidity and functional decline. These principals—which I call the “four Ps”—are prompt identification, protection, pragmatic intervention, and pharmacotherapy.
This article describes an up-to-date, “four-Ps” approach to treating delirium—including use of antipsychotics and supportive care—and offers evidence and case reports to address these clinical questions:
- What causes delirium?
- Does delirium worsen prognosis?
- Can delirium be prevented?
FOUR ‘Ps’ FOR TREATING DELIRIUM
When a patient’s mental status changes dramatically (Box 1),1 identifying potential delirium causes requires careful medical, psychiatric, and neurologic assessment. Assimilating this information is as essential to positive outcomes as are intensive nursing care and appropriate interventions.
Diagnostic criteria for delirium due to a general medical condition
- Disturbance of consciousness (i.e. reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention
- A change in cognition (such as memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a preexisting, established, or evolving dementia
- The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of a 24-hour period
- There is evidence from the history, physical examination, or laboratory findings that the disturbance is caused by the direct physiologic consequences of a general medical condition
Source: Reprinted with permission from the Diagnostic and statistical manual of mental disorders (4th ed., text rev). Copyright 2000. American Psychiatric Publishing.
Prompt identification. Delirium often goes unrecognized, delaying treatment. Easily administered rating scales—such as the Delirium Rating Scale (DRS)2 and the Confusion Assessment Method (CAM)3 —can help detect emerging symptoms.
Patient protection. Provide intensive nursing care—often one-to-one observation and containment—and, where possible, enlist the family in reassuring and calming the patient. Restraints may be needed to safeguard against injury and to prevent the patient from removing or dislocating monitoring equipment and IV access.
Pragmatic intervention. With medical colleagues, begin treating biochemical and physiologic abnormalities that are the most likely and most remediable contributors (Box 2).2,4-6 Review the patient’s medications and discontinue or replace any that may be causing delirium.
Pharmacotherapy. Based on clinical studies, antipsychotics appear to possess antidelirium properties and may be considered as one part of a patient’s treatment plan. Interpreting these studies is complicated, however, by delirium’s complexity, numerous causes, and presumed mechanisms, as well as the transience of some forms. For ethical reasons, no placebo-controlled studies of delirium treatment have been done.
EVIDENCE ON ANTIPSYCHOTICS
Haloperidol has been the drug of choice for managing delirium because it is less likely to cause hypotension and sedation than other neuroleptics. Optimum haloperidol dosing in delirium has not been established, but the usual range is 2 to 6 mg every 4 to 6 hours, depending on the patient’s age and delirium severity.
Instances of QTc interval prolongation have been reported with high-dose IV haloperidol (> 100 mg). This life-threatening effect—which can induce torsades de pointes dysrhythmia, ventricular tachycardias, and fibrillation—is very rare, quite variable, and unpredictable. It probably is a function of total dose and neuroleptic administration rate.
Atypical antipsychotics share haloperidol’s advantages over first-generation neuroleptics, with lower potential for dystonic reactions, parkinsonian side effects, and tardive dyskinesia. Preliminary evidence suggests that atypicals may be safe and effective in treating delirium, although no randomized controlled trials have been done and accurate dose-response curves have not been established. Low to modest dosages have been used in case series.
Risperidone. Two prospective, open-label trials—each with 10 patients—suggest that low-dose risperidone is effective for treating delirium:
- In one trial, risperidone given at an average dosage of 1.7 mg/d was effective in 80% of patients with delirium, and one patient responded to 0.5 mg/d. Some patients experienced sleepiness or mild drug-induced parkinsonism.7
- In the other trial, risperidone was started at 0.5 mg twice daily, with additional doses allowed on day 1 for cognitive and behavioral symptoms. This dosage was maintained until DRS scores declined to ≤12, then was reduced by 50% and continued until day 6. Mean maintenance dosage was 0.75 mg/d. Two patients discontinued risperidone because of sedation or hypotension.8
Delirium: Which patients are at highest risk?
At least 10% to 30% of hospitalized medically ill patients develop delirium, and rates approach 40% after age 65.4 Especially in older patients, delirium is a risk factor for:
- prolonged hospital stays
- increased morbidity and mortality
- increased functional decline and need for custodial care after hospital discharge.2
Risk factors. Prospectively identified risk factors for delirium include pre-existing dementia; age >65 years; serious medical illness; alcohol/sedative withdrawal; abnormal serum sodium, potassium, or blood glucose levels; vision or hearing impairment; hypoxia; malnutrition; and fever. Medication—particularly anticholinergic drugs—is one of the most common delirium triggers in susceptible patients.5
The most common underlying disorders that increase delirium risk in older patients are hip fracture, dementia, infections, and cerebrovascular events.6