Early detection of delirium: Prodromal features

Niamh A. O'Regan, James M. Fitzgerald, D. W. Molloy, David Meagher, Suzanne Timmons

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

Abstract

Delirium is a serious neuropsychiatric condition, with a point prevalence of 20% in the general inpatient population, rising to almost 50% in older patients. It is independently associated with a range of adverse outcomes, including prolonged length of hospital stay, increased dependency and increased mortality. Despite its significance, delirium is often underrecognised in the hospital setting, with up to two-thirds missed or misdiagnosed across treatment settings. This underdetection contributes significantly to poorer outcomes. Early identification and multifaceted intervention can reduce the degree and duration of delirium, but once a patient develops established delirium, even the best quality medical and nursing care can only modestly impact on long-term sequelae. Multicomponent systemised strategies to identify those at risk and minimise modifiable risk factors have been shown to halve delirium incidence, and hence improve outcomes. Hence, delirium prevention is key to attentuating its long-term impact. One of the most typical features of delirium is its acute onset, but there is growing evidence to suggest that delirium is preceded by a prodrome of varying duration. The proposed symptoms have differed from one report to the next, some being part of the delirium cluster, both cognitive and non-cognitive, and others more somatic in nature. Lipowski described a prodromal period characterised by poor concentration, restlessness, irritability, fatigue, malaise, hypersensitivity to stimuli, sleep-wake cycle abnormalities and perceptual phenomena and suggested that a longer prodrome heralded a delirium secondary to systemic illness or metabolic abnormalities, rather than that caused by more mechanical or surgical aetiology. Over the last thirty years or so, studies in differing patient populations, and designed for other purposes, have described a variety of other potential prodromal features including headaches and general uneasiness; inattention and other cognitive features; changes in activity levels; frequent calls for assistance; perceptual disturbances; mood changes; language and thought disorder and disruption in sleepwake pattern. Additionally, recent prospective studies have shown that patients who go on to develop delirium tend to have subsyndromal features in the days or weeks before full diagnostic criteria are met. Greater recognition of the symptoms that characterise emerging delirium can facilitate proactive detection and prompt intervention; so that, in effect, we may be able to treat delirium pre-emptively. Further work is required to accurately define these early indicators and to ascertain whether intervening at this prodromal stage can lead to a meaningful improvement in outcomes.

Original languageEnglish
Title of host publicationDelirium
Subtitle of host publicationDiagnosis, Management and Prevention
PublisherNova Science Publishers, Inc.
Pages35-67
Number of pages33
ISBN (Electronic)9781631174728
ISBN (Print)9781631174711
Publication statusPublished - 1 Apr 2014

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