INTRODUCTION
Delirium is a neurocognitive disorder with acute onset and a fluctuating clinical
course. It typically involves changes in attention, but is commonly associated with
deficits in other cognitive domains.1 Despite
its high prevalence among hospitalized older adults, which varies between 18-35%,
this condition is still underdiagnosed; it is estimated that around one-third of
cases go unrecognized. The incidence of delirium among older adults varies depending
on the hospital setting, reaching 80% in intensive care units and in terminal
patients, for example.2,3
This condition is associated with an increased risk of mortality in hospital and
within 12 months of discharge, in addition to a greater frequency of
institutionalization and dementia.4 Delirium
triggers a cascade of events that can lead to potentially progressive functional
decline, increased length of hospital stay, the need for additional care staff, as
well as increased morbidity and mortality, which lead to a significant increases in
health care costs.5
Although it can be due to a single cause, the etiology of delirium is predominantly
multifactorial. Its development involves a close relationship between the
individual’s vulnerability and precipitating factor(s). Factors associated with
vulnerability (or predisposing factors) are dementia and previous cognitive
impairment, visual impairment, a history of alcohol abuse, age > 70 years,
multiple comorbidities, and previous psychiatric or neurological diseases.6 Many of these components are immutable or
poorly modulated in clinical settings.
However, a number of potential precipitating factors are often preventable or
treatable. Thus, it is essential to know the most frequent causes of delirium to
ensure quality care for older patients.
Literature review on precipitating factors of delirium
Articles were selected after searching MEDLINE (via PubMed) and Embase using the
terms “Delirium AND” “risk factors” OR “precipitating factors”. Selected
articles included hospitalized patients and were comprehensive in relation to
the population; classic articles that initiated research on this topic were also
included according to informal criteria.
The use and abrupt withdrawal of psychoactive medications are commonly associated
with delirium, especially drugs with a high anticholinergic load or
hypnotic-sedative action.7 One or more
psychoactive drugs contributed to the development of at least 40% of delirium
cases, principally sedatives, anxiolytics, narcotics, H1 and H2 blockers, and
antipsychotics.8 In addition to drugs,
other frequent situations can be considered precipitating factors, such as pain,
physical restriction, and immobility, dehydration, the use of devices such as
feeding tubes, urinary catheters, infectious conditions, malnutrition, ischemic
heart disease, hypoxemia, surgical procedures, etc.9,10
In 1992, an article on the risk factors for delirium among hospitalized older
adults was published in the Journal of the American Medical
Association, which concluded that patient-related factors prior to
admission (ie, predisposing factors) affected the development of delirium more
than the reason for hospitalization or care-related issues. Nevertheless, an
increased risk of delirium was independently associated with symptomatic
infection (OR 1.92; CI 1.04-3.57), room temperature > 37.2° C (OR 2.09; CI
0.96-4.57), uncontrolled pain (OR 1.89; CI 1.09-3.29), and psychotropic drug use
(OR 2.5; CI 1.15-5.43).11
In 1996, Inouye et al. reported on precipitating factors for delirium in
hospitalized older adults, finding that the relative risk increased 4.4 times
when physical restraints were used, 4 times in malnourished patients, 2.9 times
in patients taking ≥ 3 medications, and 2.4 times in patients using urinary
catheters.7
Several studies have described precipitating factors for delirium, although they
were generally aimed at specific populations, such as post-operative and cancer
patients.12,13 Another publication on the topic in the general
population provides an extensive review of > 100 predisposing and
precipitating factors, classified as surgical, systemic disease/ organic
dysfunction, metabolic, pharmacological, iatrogenic/environ-mental, trauma, and
biomarker- and neurotransmitter-related.14
Given the high rate of complications related to this condition, greater training
is needed to recognize the syndrome and identify older adults at greater risk.
The main objective of this article was to describe the main factors that
precipitate delirium. It is essential to identify these factors to plan
preventive actions, as well as to quickly diagnose the immediate cause, thus
allowing implementation of measures to reverse or stabilize the condition,
minimizing inflammatory/infectious/metabolic damage to the brain, potentially
reducing delirium severity and length, which are linked to complications and
permanent damage associated with an acute confusional state.5
To date, no specific medication has shown robust effectiveness for reducing the
incidence, length, or severity of delirium. Psychotropic medications are
prescribed only for severe behavioral symptoms involving a risk of harming self
or others or removing invasive devices.10
Thus, the most important way to minimize patient complications is to correct the
precipitating cause of delirium, which is why early identification is so
essential.
DELIRIUM+ as a mnemonic device
To promote teaching and care focused on clinical reasoning and, thus, the
prevention, early detection, and management of delirium, we propose a mnemonic
device, DELIRIUM, based on its main causes. Although originally developed for
Portuguese, the acronym’s items, which are described below, translate well
enough for use in English. Subsequent to this proposal, a pilot study of the
clinical applicability of the instrument will be conducted.
Table 1 (supplementary material) describes the categories for each letter of the
acronym: Discomfort, Electrolytes/ metabolism, Locale/environment, Infections,
urinary/fecal Retention, clinical complications, Uremia, and Medications. The
details of each category, including precipitating factors, are presented in the
supplementary material.
A second acronym, MAIS (meaning ‘plus’; represented by the + symbol), was added
to promote delirium prevention and non-pharmacological management: Mobility,
Assistant/ companion, Interaction, and Sleep. Descriptions of each item are
provided in Table 2 (supplementary material).
Figure 1 is a visual presentation of the
DELIRIUM+ mnemonic device.
FIGURE 1
DELIRIUM+ mnemonic device.
Renato Gorga Bandeira de Mello
