Delirium is characterized by an altered level of consciousness, decreased attention span, acute onset, and fluctuating course. Approximately 15% of elderly patients admitted to the hospital have delirium as a presenting or associated symptom. Delirium will develop in another 15% of elderly patients during hospitalization.
In hospitalized patients, delirium is associated with a 10-fold increased risk of death, a 3- to 5-fold increased risk of nosocomial complications, a prolonged stay, and postacute nursing home placement.1 In addition, delirium during hospitalization predicts a poor functional recovery and an increased risk of death up to 2 years after discharge.2,3 Persistent delirium predicts an especially poor long-term outcome.4
The causes of delirium are often multifactorial. Predisposing and precipitating factors increase a patient's risk (Table 1).5-8 Predisposing factors are often difficult to change but are useful in identifying high-risk patients. Precipitating factors are often modifiable and offer the best opportunity for intervention.
Risk factors for delirium
Functional impairment in activities of
History of alcohol(Drug information on alcohol) abuse
Sensory impairment, especially visual
Acute cardiac events
Acute pulmonary events
Anemia (hemoglobin level < 10 g/dL)
Drug withdrawal (sedatives, alcohol)
Fluid or electrolyte disturbances
Infections (especially respiratory tract,
A number of medications may precipitate delirium (Table 2).9 Some experts believe that delirium is precipitated by the use of medications with a high anticholinergic burden. This condition may be exacerbated by the endogenous anticholinergic activity that occurs in persons with delirium.
Drugs that may precipitate delirium
Chloral hydrate(Drug information on chloral hydrate)
Lithium(Drug information on lithium)
Opioid analgesics (especially meperidine)
Clinical diagnosis may be difficult because delirium shares features with both dementia and depression (Table 3). A thorough history taking is especially important, with particular focus on previous cognitive difficulties, mood disorders, and a review of medications. Traditional screening devices used for depression and dementia, such as the Geriatric Depression Scale and Mini-Mental State Examination, may not yield accurate results in the setting of comorbid delirium. Tests of attention, such as the Digit Span Test, may be useful in identifying those who have a decreased attention span, a cardinal feature of delirium. Family members can often provide valuable information about a patient's baseline cognitive status.
Diagnostic criteria for delirium10
|Disturbance of consciousness with
reduced ability to focus, sustain, or
Change in cognition (eg, memory deficit, disorientation, language disturbance) or a perceptual disturbance not better accounted for by existing dementia
Development over a short time (hours to days) and fluctuation during the day
Evidence from history, physical examination, or laboratory results that the disturbance is a direct physiological consequence of a medical condition
The criteria from DSM-IV are the gold standard for the diagnosis of delirium (Table 4).10 Alternative criteria have been developed to help clinicians and nonclinical personnel diagnose and rate the severity of delirium. The Confusion Assessment Method is commonly used in inpatient settings and is based on DSM-III-R criteria (Table 5).11 The NEECHAM Confusion Scale is a nursing rating tool that screens for delirium, identifies patients at high risk, and assesses severity in medical inpatients.
Confusion Assessment Method11
|Requires features 1 and 2,
plus either 3 or 4:
Delirium can take several forms. Hyperactive delirium is the most easily recognized because patients with this form often fall or interfere with care. Hyperactive delirium is characterized by psychomotor agitation, verbal aggression, disorientation, visual hallucinations, and combativeness.
Two thirds of hospitalized patients with delirium are hypoactive and hypovigilant, however. Hypoactive delirium is characterized by somnolence and a decreased attention span. Although patients with this form are often overlooked, their delirium carries an equally poor prognosis.
A patient's cognition may fluctuate between the 2 subtypes of delirium. Therefore, it is important to remain vigilant for various signs of delirium and to obtain 24-hour reports on the patient's behavior from nursing staff and family members.Clinical approach
Elderly patients should be assessed for risk of delirium, and efforts toward mitigating or eliminating precipitating factors should be made—especially in those patients who show signs of or who are at high risk for delirium. Nonpharmacological interventions, such as environmental modification and nursing protocols that focus on distraction, redirection, and reorientation, are the recommended first steps in prevention and treatment. A multidisciplinary, multicomponent intervention may be useful in preventing delirium.12,13Treatment
Patients should be redirected and removed, if possible, from offending stimuli. Underlying disorders that precipitated the delirium should be treated. Recommended pharmacological agents for agitation and psychosis are listed in Table 6.4,14-16 Use benzodiazepines with caution, because they may produce agitation. Neuroleptics may cause QT prolongation, extrapyramidal adverse effects, and akathisia. In general, it is best to start with low doses and titrate as needed. Once a medication has been found effective, schedule doses for times of peak agitation (such as before medical procedures and at bedtime).
Agents prescribed for agitation and psychosis
|Haloperidol, 0.25 to 2 mg, PO/IV/IM bid
Lorazepam(Drug information on lorazepam), 0.5 to 2 mg, PO or IV, q4 - 8h
Olanzapine(Drug information on olanzapine), 2.5 to 10 mg/d, PO or IM
Quetiapine, 25 mg PO qd/qhs to 200 mg PO, divided, bid
Risperidone(Drug information on risperidone), 0.25 to 1 mg, PO bid
Use physical and pharmacological restraints only when all other options have been exhausted and the patient is interfering with care that is critical to his or her well-being (such as placement of an endotracheal tube or a central line). The use of physical restraints is associated with worsening delirium, injuries from falls, and debility. Most patients with delirium can be managed without restraints in a "delirium room."17 Pharmacological treatment of hypoactive delirium has not been extensively studied. Methylphenidate(Drug information on methylphenidate) may be useful for opiate-induced delirium in a hospice setting.18
This article previously appeared in Applied Neurology.