Delirium: A Marker of Vulnerability in Older People

Abstract

Delirium is an acute neuropsychiatric syndrome and one of the most common presenting symptoms of acute medical illnesses in older people. Delirium can be triggered by a single cause, but in most cases, it is multifactorial as it depends on the interaction between predisposing and precipitating factors. Delirium is highly prevalent in older patients across various settings of care and correlates with an increased risk of adverse clinical outcomes. Several pathophysiological mechanisms may contribute to its onset, including neurotransmitter imbalance, neuroinflammation, altered brain metabolism, and impaired neuronal network connectivity. Several screening and diagnostic tools for delirium exist, but they are unfortunately underutilized. Additionally, the diagnosis of delirium superimposed on dementia poses a formidable challenge - especially if dementia is severe. Non-pharmacological approaches for the prevention and multidomain interventions for the treatment of delirium are recommended, given that there is currently no robust evidence of drugs that can prevent or resolve delirium. This article aims to review the current understanding about delirium in older people. To achieve this goal, we will describe the epidemiology and outcomes of the syndrome, the pathophysiological mechanisms that are supposed to be involved, the most commonly used tools for screening and diagnosis, and prevention strategies and treatments recommended. This review is intended as a brief guide for clinicians in hospital wards to improve their knowledge and practice. At the end of the article, we propose an approach to improve the quality of care provided to older patients throughout a systematic detection of delirium.

Keywords: Atypical symptoms; confusion; delirium; elderly; frailty.

FIGURE 1

Conceptual framework of predisposing and precipitating factors leading to delirium after an acute stressor, and hesitating in poor health-related outcomes.

FIGURE 2

Proposed approach to select the screening tools for delirium according to the presence of dementia and the patient’s level of arousal. CAM, Confusion Assessment Method; DSM, Diagnostic and Statistical Manual of Mental Disorders; ICD, International Classification of Diseases; OSLA, Observational Scale of Level of Arousal; m-RASS, modified Richmond Agitation and Sedation Scale; HABAM, hierarchical assessment of balance and mobility; TCT, Trunk Control Test.

FIGURE 3

Proposed pharmacological approach for the agitated delirium (Delirium: diagnosis, prevention, and management. NICE clinical guideline n. 103, 2010). * The single study supporting this indication was restricted to patients with advanced cancer in end-of-life care. Please note that this treatment option should be considered for refractory symptoms only (after antipsychotics have failed).