Delirium: A Marker of Vulnerability in Older People PDF

# Delirium: A Marker of Vulnerability in Older People ## Introduction - Delirium is an acute neuropsychiatric syndrome. - It is 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 multifact...

# Delirium: A Marker of Vulnerability in Older People ## Introduction - Delirium is an acute neuropsychiatric syndrome. - It is 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 - it depends on the interaction between predisposing and precipitating factors. ## Definition and Causes of Delirium - The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) defines delirium as a neuropsychiatric syndrome with disturbances in attention and awareness. - The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), (American Psychiatric Association, 2013) defines delirium as a neuropsychiatric syndrome that encompasses different signs and symptoms, especially disturbances in attention and awareness. - Delirium represents the altered reaction of the CNS and its functioning when dealing with acute medical conditions, intoxication or withdrawal of medications, surgery, and electrolyte or metabolic imbalances (American Psychiatric Association, 2013). - Delirium is triggered by a single cause, but in most cases it is multifactorial, resulting from the interaction between predisposing and precipitating factors. - The higher the burden of the predisposing factors, the lower the magnitude of the precipitating factors required to cause delirium. ## Epidemiology - Delirium is common in older people. - A recent systematic review and meta-analysis identified 33 studies that evaluated delirium occurrence in medical inpatients over time. - The overall prevalence of delirium was 23%. - Delirium is a common surgical complication among older adults, with an incidence of 15-25% after major elective surgery and 50% after high-risk procedures, such as hip-fracture repair and cardiac surgery. - Delirium occurrence might be even higher in the ICU (31% prevalence). - In mechanically ventilated patients, delirium occurrence can range from 60 to 80%. - Delirium prevalence is about 14-18% in post-acute care setting and rehabilitation facilities, and in nursing homes, it can rage from 1.4 to 70%. - Delirium is thought to be less frequent in the community (1-3%), but studies are limited by methods to detect it and the selection criteria. - Delirium onset usually leads the patient to be referred to an emergency room, a setting in which this syndrome is present in 8 to 17% of older patients and up to 40% in nursing home residents. ## Outcomes - Patients with delirium show an increased risk of developing poor clinical outcomes, including increased likelihood of nursing home placement and death. - A two-fold increase in 2-year mortality risk when delirium is experienced during hospitalization when adjusted for age, gender, chronic diseases and, dementia. - Delirium has also been shown in patients with SARS-CoV-2 infection, with its duration determining the risk of death. - Delirium may also increase the likelihood of developing cognitive impairment or progress to dementia. ## Pathophysiology - The pathophysiology of delirium still remains speculative and it may represent a diverse range of pathobiology processes rather than a single entity. - Delirium has historically been viewed as a disorder of several neurotransmitters, including acetylcholine, melatonin, dopamine, norepinephrine, glutamate, 5-hydroxytryptamine or serotonin, histamine, and/or gamma-aminobutyric acid. - Delirium is the result of the combination of disorders in the neurotransmission, a failure in integrating and processing sensory signals and motor effectors, and a breakdown in cerebral network connectivity. - Several patient-specific factors interact to develop delirium, including neuroinflammation, "oxidative stress," "neuroendocrine dysfunction" and "circadian rhythm or melatonin dysregulation." - A peripheral infection or surgery may activate inflammatory cytokines and other mediators in the blood that can cross the blood brain barrier or reach the brain parenchyma through other routes, such as the vague nerve, and here activate the microglia cells and astrocytes. ## Diagnosis of Delirium - Clinical features of delirium include inattention, disorganized thought, altered consciousness, and other multiple cognitive domains. - Hallucinations, delusions, incoherent speech, inappropriate behavior, emotional lability, and alterations of the sleep-wake cycle can also be present. - There are at least three psychomotor subtypes of delirium: hypoactive, hyperactive, and mixed. - There is a non-hyperactive-non-hypoactive subtype of delirium characterized by normal level of psychomotor activity and no fluctuations between hyperactive and hypoactive subtypes, but it remains unclear which of these motor subtypes may underlie different causes of delirium. ## Diagnostic Criteria and Screening Tools - Delirium is essentially a clinical diagnosis. - The gold standard for the diagnosis are the DSM-5th edition and the International Statistical Classification of Diseases and Related Health Problems, 10th revision criteria. - Two of the most commonly used tools for detection are the Confusion Assessment Methods (CAM) and the 4AT test. - The Confusion Assessment Methods (CAM) has been developed by Inouye et al. (1990), including an algorithm based on four core features of delirium: acute change or fluctuating course, inattention, and either or both disorganized thinking, and alteration of consciousness. - The 4AT test, a relatively new tool proposed by Maclullich and colleagues, encompasses 4 items: alertness, the Abbreviated Mental Test - 4 (AMT4), attention (tested with months of the year backwards, MOTYB), and acute change in mental status or its fluctuation. ## Barriers to Delirium Recognition - Delirium has been recognized for at least two millennia as a dangerous condition, but it still remains underdiagnosed. - One explanation is that medical culture does not regard delirium as an important topic. - Another reason is that delirium has received various clinical labels such as "acute confusion," "acute organic brain syndrome," "brain failure," "intensive care psychosis," "toxic encephalopathy," which impede the communication among clinicians and healthcare professionals. ## The Challenging Diagnosis of Delirium Superimposed on Dementia - Delirium superimposed on dementia is a common condition in older people. - It is a real diagnostic challenge for clinicians, given the relative lack of tools specifically designed for its recognition. - The DSM-5 does not provide specific indications on how to diagnose delirium when overlapping on pre-existing dementia. - The CAM has shown only moderate sensitivity (77%) in detecting DSD. - Other tools, such as the 4AT, have never been specifically tested in DSD patients. - People with dementia may already have impairments in cognitive functions, especially in attention, which is a key feature of delirium. - In patients with severe dementia, attention may be impaired, limiting the ability of the attentional tests to discriminate between delirium and dementia. ## Prevention - There is robust evidence that non-pharmacological approaches are the best to prevent delirium in hospitalized patients. - In 1999, Inouye and colleagues described the hospital Elder Life Program (HELP), a model of care tailored for older patients and specifically oriented to prevent delirium during hospital stay. - HELP has been shown to significantly decrease delirium incidence and duration. - Non-pharmacological approaches recommended by reviews and guidelines include orientation strategies (e.g., orientation boards, calendars, clocks), promotion of patient's hydration, sleep, mobilization, and use of assistive devices such as eyeglasses and hearing aids, if needed. ## Pharmacological Approaches - The idea to prevent delirium using pharmacological interventions is fascinating, but, at present, is poorly supported by the literature. - Antipsychotics have been investigated, given their efficacy in psychiatric diseases, but antipsychotics are ineffective and are potentially harmful in treating delirium. - Benzodiazepines are similarly ineffective and should be avoided, except in alcohol or benzodiazepine withdrawal-related delirium. ## Treatment - There are several guidelines from scientific and academic societies that offer guidance and practical recommendations in the management of delirium in older patients. - The first step is to identify acute and life-threatening causal factors, including hypotension, low tissue oxygenation, drug overdose or withdrawal, and hypoglycemia. - Once life-threatening conditions have been corrected, the second step is the identification of the underlying causes of delirium. - The third step is the adoption of non-pharmacological treatments, including avoiding unnecessary tubes, catheters and physical restraints, approaching patients at the bedside with recognizable faces, adopting tools to facilitate orientation, and promoting sleep hygiene and optimizing nutritional and fluid intake. - Environmental factors, such as unfamiliar environment, excessive noise and ward moves, may be precipitating factors of delirium and should be avoided.. ## Pharmacological Approaches - Delirium presenting with severe agitation requires immediate non-verbal and verbal de-escalation techniques. - If this approach fails, or if agitation is severe and stressful for the patient and/or can endanger the provision of life-sustaining therapies, a pharmacological approach should be considered. - Pharmacological agents result in sedation and may perpetuate delirium. - It is crucial to keep in mind that any changes in medications, including over-the-counter and herbal medications, or changes in dosage of medication or abrupt withdrawal of medication could result in delirium. Benzodiazepines, opiates, tricyclic antidepressants, anticholinergic medications, antihistamines and tramadol should be avoided or reduced if possible. - Constipation and urinary retention are common causes of severe agitation in people with moderate to severe dementia. ## Future Perspectives and Summary - The medical community still does not recognize delirium as it should. - Delirium is a frequent atypical presentation of diseases in the geriatric population. - Delirium and its duration are associated with negative outcomes. - Delirium detection (and thus treatment) may be regarded as a clinical priority. - The tracking for the presence of delirium should be undertaken at least daily in acute hospital wards. - If, after treatment, delirium resolves, this may be an indirect sign that a patient is clinically improving. - Prolonged/persistent delirium may also be present despite the extensive diagnostic approach and therapeutic measures. - We propose to look at delirium as a marker of clinical instability and as a “litmus test” of the effectiveness of the care provided.