OBJECTIVES: To determine whether delirium is an independent predictor of adverse outcomes of hospitalization in older patients.

DESIGN: Cohort study

PATIENTS: A total of 225 people admitted as an emergency to an acute geriatric unit in a university teaching hospital

METHODS: Subjects were screened for delirium, defined by Diagnostic and Statistical Manual, 3rd Edition criteria, every 48 hours. Outcome measures included mortality, duration of hospital stay, hospital-acquired complications, and institutional placement. The influence of delirium on these outcomes was calculated after adjusting for age, illness severity on admission, burden of comorbidity, prior cognitive impairment, and level of disability.

RESULTS: Delirium was present on admission in 41 patients (18%) and developed after admission in a further 53 patients (24%). Patients with delirium were more likely than non-delirious patients to have chronic cognitive impairment, severe acute illness, multiple comorbid conditions, and functional disability. Nevertheless, in multivariate analyses adjusting for these factors, delirium was independently associated with prolonged hospital stay, functional decline during hospitalization, increased risk of developing a hospital-acquired complication, and with increased admission to long-term care.

CONCLUSION: Delirium is an independent predictor of adverse outcomes in older hospital patients.

The prognostic significance of delirium in older hospital patients.

Elderly people are more likely than younger patients to develop cognitive impairment as a result of taking medications. This reflects age- and disease-associated changes in brain neurochemistry and drug handling. Delirium (acute confusional state) is the cognitive disturbance most clearly associated with drug toxicity, but dementia has also been reported. The aetiology of cognitive impairment is commonly multifactorial, and it may be difficult to firmly establish a causal role for an individual medication. In studies of elderly hospital patients, drugs have been reported as the cause of delirium in 11 to 30% of cases. Medication toxicity occurs in 2 to 12% of patients presenting with suspected dementia. In some cases CNS toxicity occurs in a dose-dependent manner, often as a result of interference with neurotransmitter function. Drug-induced delirium can also occur as an idiosyncratic complication. Finally, delirium may occur secondary to iatrogenic complications of drug use. Almost any drug can cause delirium, especially in a vulnerable patient. Impaired cholinergic neurotransmission has been implicated in the pathogenesis of delirium and of Alzheimer’s disease. Anticholinergic medications are important causes of acute and chronic confusional states. Nevertheless, polypharmacy with anticholinergic compounds is common, especially in nursing home residents. Recent studies have suggested that the total burden of anticholinergic drugs may determine development of delirium rather than any single agent. Also, anticholinergic effects have been identified in many drugs other than those classically thought of as having major anticholinergic effects. Psychoactive drugs are important causes of delirium. Narcotic agents are among the most important causes of delirium in postoperative patients. Long-acting benzodiazepines are the commonest drugs to cause or exacerbate dementia. Delirium was a major complication of treatment with tricyclic antidepressants but seems less common with newer agents. Anticonvulsants can cause delirium and dementia. Drug-induced confusion with nonpsychoactive drugs is often idiosyncratic in nature, and the diagnosis is easily missed unless clinicians maintain a high index of suspicion. Histamine H2 receptor antagonists, cardiac medications such as digoxin and β-blockers, corticosteroids, non-steroidal anti-inflammatory agents and antibiotics can all cause acute, and, less commonly, chronic confusion. Drug-induced confusion can be prevented by avoiding polypharmacy and adhering to the saying ‘start low and go slow’. Special care is needed when prescribing for people with cognitive impairment. Early diagnosis of drug-induced confusion, and withdrawal of the offending agent or agents is essential.

Drug-Induced Cognitive Impairment in the Elderly

Objective: to examine the relative frequency and outcome of clinical subtypes of delirium in older hospital patients. Design: prospective observational study. Setting: acute geriatric unit in a teaching hospital. Subjects: 94 patients with delirium from a prospective study of 225 admissions. Measurements: clinical subtypes of delirium were determined according to predefined criteria. Characteristics examined in these subgroups included illness severity on admission, prior cognitive impairment, mortality, duration of hospital stay and hospital-acquired complications. Results: of the 94 patients, 20 (21%) had a hyperactive delirium, 27 (29%) had a hypoactive delirium, 40 (43%) had a mixed hypoactive‐hyperactive psychomotor pattern and seven (7%) had no psychomotor disturbance. There were significant differences between the four groups in illness severity (P < 0.05), length of hospital stay (P < 0.005) and frequency of falls (P < 0.05). Patients with hypoactive delirium were sicker on admission, had the longest hospital stay and were most likely to develop pressure sores. Patients with hyperactive delirium were most likely to fall in hospital. There were no differences in aetiological factors between the groups. Conclusion: outcomes of hospitalization differ in different clinical subtypes of delirium.

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Clinical significance of delirium subtypes in older people.

Objective
To study the phenomenology, clinical correlates, and response to treatment of delirium in critically ill children in the pediatric intensive care unit (PICU).

/pdf/pediatric-delirium-in-critical-illness-phenomenology-4isyx9mgp4.pdf

Pediatric delirium in critical illness: phenomenology, clinical correlates and treatment response in 40 cases in the pediatric intensive care unit.

Inflammation and Alzheimer's Disease: Relationships between Pathogenic Mechanisms and Clinical Expression

Many clinicians do not realize the costs associated with delirium. Francis and Kapoor found that patients who had had delirium had higher two-year mortality rates and greater loss of independence than control patients. The investigators also reported a trend toward decline in cognitive performance among patients who had had delirium. Levkoff and coworkers found that delirium was associated with no change in mortality, but that it was associated with prolonged hospital stays and an increased risk of institutional placement among community dwelling elderly. Poor outcomes might be avoided, in part, with early diagnosis and appropriate management of delirium.

C E Skotzko

Papers

Delirium: acute confusional state