Delirium: An evidence-based medicine (EBM) monograph for psychosomatic medicine practice, comissioned by the Academy of Psychosomatic Medicine (APM) and the European Association of Consultation Liaison Psychiatry and Psychosomatics (EACLPP)

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Introduction

This monograph summarizes current knowledge related to the diagnosis, epidemiology, etiology, and management of delirium. The monograph is based on the guideline ‘delirium’ of the National Institute of Clinical Excellence (NICE) [1], as well as on systematic reviews and pivotal trials. The quality of the evidence discussed in this monograph is graded as ‘high,’ ‘moderate,’ ‘low’ or ‘very low,’ following the ‘Grading of Recommendations Assessment, Development and Evaluation’ (GRADE) system, which was developed by the Cochrane Center (www.igh.org/Cochrane/GRADE). Readers are encouraged to consult the recommended readings for more detailed information (see: web-appendices).

Delirium is an acute neuropsychiatric disorder characterized by a disturbed level of consciousness with reduced ability to focus, sustain, or shift attention, and accompanied by changes in cognition, such as memory deficits, disorientation, speech and language disturbances, delusions and perceptual abnormalities. These changes in cognition are not better accounted for by a pre-existing or evolving dementia. In addition, sleep–wake cycle disturbance, increased or decreased motor activity, and emotional disturbances are often present. The disturbance typically develops over a short period of time and tends to fluctuate during the course of the day [2]. Clinically, a distinction between hyperactive and hypo-active delirium is often made on the basis of motor activity. Though this may be clinically useful, it has not found its way into the classification systems.

The gold standard for the diagnosis of delirium are the criteria of the 4th edition of the Diagnostic and Statistical Manual (DSM IV; codes 291.0 to 293.0 and 780.09) or the 10th edition of the International Classification of Disease (ICD 10; code F05) [2], [3] (Appendix B).

The occurrence of delirium depends on the setting.

  • In the general population, the reported prevalence is low and ranges from < 0.05 to 0.4%, with a higher prevalence in older people of 1.1% in those over 55 years [4], [5].

  • For hospital inpatients, a median prevalence of 21.4%, a median incidence of 15.2%, and a median occurrence rate of 22% is reported on general medical wards. In the NICE guideline the term ‘occurrence rate’ is used when there is overlap between prevalence and incidence data, such as may occur when in incidence studies prevalent delirium upon entering the study is not excluded.

  • The occurrence rate on general surgical wards is reported to be 44%; no data on prevalence and incidence rates in this setting are available [1].

  • Occurrence rates are higher on Intensive Care Units, with occurrence rates reported as high as 80%, depending on type of ICU [1].

  • In long term care, low quality evidence shows a median occurrence rate of 15.9% [6].

Delirium is currently seen as the resultant of a complex interaction of predisposing and precipitating factors [7].

High quality evidence identifies the following risk factors for incident delirium:

  • Older age

  • Cognitive impairment

  • Visual impairment [1]

Moderate quality evidence identifies the following risk factors for incident delirium:

  • lllness severity

  • Comorbidity

  • Infection

  • Fractures

  • Vascular surgery

  • Presence of a bladder catheter [1].

Moderate to low quality evidence identifies the following risk factors for persistence of delirium:

  • Cognitive impairment

  • Medical comorbidity

  • Vision impairment)

  • Use of physical restraints [1].

Low level evidence identifies the following risk factors for increased severity of delirium:

  • Number of room changes

  • Absence of clock or watch

  • Cognitive impairment

  • Not wearing glasses [1].

Low level of evidence shows no, or no clinically relevant, association for incidence or severity of with a variety of variables, such as sex, mobility, hearing impairment, incontinence, dehydration and polypharmacy [1]. Clinical experience however supports close attention for polypharmacy as a contributing cause of delirium.

Delirium has a number of negative prognostic implications.

High quality evidence exists for:

  • Increased length of hospital stay, particularly for ICU patients [1], [8], [9]

  • Increased and earlier post-discharge institutionalization [1]

Moderate to high quality evidence:

  • Increased mortality: the mortality of delirium patients during their hospital stay is 22 – 76%; the mortality in the first year after discharge is 35 – 40% [10].

Moderate quality evidence:

  • Delirium is a risk factor for cognitive decline and dementia after 3 years [1]

Low quality evidence:

  • Delirium predisposes for worse functional abilities and activities of daily living [1] No study reported on the consequences of delirium for health related quality of life [1]

Several studies have demonstrated significantly increased costs of health care for patients who develop delirium [8], [9]. One study estimated these costs to be at least 2.5 times greater per day for delirious patients compared to non-delirious patients [11].

Section snippets

Screening and Assessment

Most health care providers recognize that delirium is a serious, underdiagnosed problem, but only a minority routinely screen for delirium and few use a specific tool for assessment [12]. Failure to detect delirium has been associated with poorer outcomes, including increased mortality [13], while explicit recognition of delirium has been associated with lower mortality and shorter inpatient stays [14].

Assessment consists of establishing the diagnosis, assessing severity and assessing clinical

Treatment

Treatment of delirium consists foremost of treatment of the underlying medical condition. In addition, there is evidence that symptomatic treatment, including non-pharmacological and pharmacological treatment may be beneficial to the patient. (For a list or randomized pharmacological trials, see Appendix B).

Nonpharmacological prevention

Mono-component interventions: there is no evidence of the effect of subcutaneous versus intravenous fluids on the incidence, duration or severity of delirium, both in a hospital setting and in a long term care setting (low quality evidence) [1].

Multi-component interventions: low quality evidence shows that multi-component interventions based on targeting modifiable risk factors (such as cognitive impairment, sleep deprivation, immobility, vision impairment, hearing impairment, dehydration),

Organization of detection and management

The available evidence does not allow for recommendation of a specific model of organization of delirium detection and management. However, the NICE guideline as well as available reviews and position papers stress the importance of a systematic and proactive approach to delirium identification and treatment. The approach to delirium should include systematic screening for patients with delirium risk factors, and then systematically following them for potential incident delirium and administer

Conflict of interest statement

The authors reported no conflicts of interest.

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References (27)

  • SK Innouye

    Predisposing and precipitating factors for delirium in hospitalized older patients

    Dement Geriatr Cogn Disord

    (1999)
  • EB Mildrandt et al.

    Costs associated with delirium in mechanically ventilated patients

    Crit Care Med

    (2004)
  • J McCusker et al.

    Delirium predicts 12-month mortality

    Arch Intern Med

    (2002)
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    This monograph is published co-jointly by the Guideline and EBM Subcommittee of the Academy of Psychosomatic Medicine (APM) and the European Association for Consultation-Liaison Psychiatry and Psychosomatics (EACLPP). The EACLPP and APM have started a series of monographs covering seminal topics in the area of CL-psychiatry and Psychosomatic Medicine. The aim of these monographs is to provide an evidence based summary of these topics. Monographs are published simultaneoulsy on both associations' websites, together with appendices including recommended readings, diagnostic criteria, an annotated list of randomized clinical trials, assessment and scales, areas for future research, and CME multiple choice question(s). The web version of the monograph will be updated every two years.

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