Delirium: Acute Confusional States in Palliative Medicine

Delirium is among the most prevalent and challenging clinical problems. Its assessment and management must be individualized based on both a biomedical understanding of the disease and its comorbidities, and a more nuanced understanding of prognosis, risks and benefits of treatment. Every intervention must be informed by a critical understanding of the changing goals of care. These complexities are critically explored in this volume. Given the diversity of clinical presentations associated with neurological and psychiatric disorders in the medically ill, considerable efforts have been made during the past decade to derive meaningful diagnostic criteria for delirium. Consensus on diagnostic criteria are needed as a foundation for future investigations focused on the epidemiology, etiologies, and treatments of this disorder. Even distinctions that appear simple in some populations, such as the difference between delirium and dementia, can become clouded when an underlying disease is progressing and the patient is exposed to complex therapies for the disease itself and for its consequences. If an acute confusional state that is expected to be transitory never clears, should it still be called a delirium? If one or two of the elements that together characterize delirium—for example, changes in alertness, psychomotor activity, cognition, perception, mood, or sleep-wake cycle—occur in isolation, is this delirium? The development of validated measures to identify delirium, and grade its severity, have been an important advance. They highlight the need for additional studies that will clarify the phenomenology of delirium, establish evidence-based criteria for diagnosis, and rationalize the type of clinical assessment that is needed to define a treatment strategy. Studies that separately assess consciousness, cognition, perception, and mood potentially could define subpopulations that may benefit from more targeted interventions. Ultimately, treatable pathophysiologies linked to a particular phenomenology might be elucidated. Even the most sophisticated research, however, will never obviate the clinical challenge in managing delirium in populations with advanced illness. Death is commonly preceded by a period of somnolence or confusion, which may be as brief as hours or as long as months. Although the decline might be attributable to specific biomedical causes, it is not considered pathologic if it is perceived to be part of the normal dying process. If this is the case, interventions are limited to those necessary to ensure comfort and reassure the family. Efforts to assess and reverse the underlying causes, which are essential in other clinical settings, would be inappropriate then. Thus, the clinical problem of delirium resonates with a broad range of profound challenges in palliative care. Clinicians are notoriously poor prognosticators, yet some understanding of the time left is needed to inform judgments about the evaluation and management of delirium. If there is a chance for meaningful survival, and the goals of care are consistent with this, the delirious patient may undergo a very aggressive evaluation and complex interventions designed to reduce contributing causes and reverse the disorder. If the patient is perceived to be imminently dying, however, the overriding concern may be the control of agitation or fear. No effort is made to identify or treat potential causes. Ethical considerations are prominent in this decision making and are under intense discussion among specialists in palliative care. Should the delirious patient at the end of life empirically receive hydration, a simple intervention that would reverse one potential contributing factor? Or does the belief that death is imminent preclude this intervention? If the delirious patient is agitated, what are the ethical considerations in using sedative doses of drugs until death occurs? These are complex issues, and require case-by-case reasoning. The management of delirium requires excellent communication, a fundamental aspect of the broader effort to provide palliative care. If an understanding of the patient’s and family’s expectations and values is obtained before the patient loses capacity for decision making, the subsequent course may be less conflicted. If the patient has a surrogate for decision making, communication with this person, and the rest of the family, is key once the patient is unable to express desires. The scientific and clinical characterization of delirium is yet rudimentary, but clinicians must do the best they can. The critical evaluation of the existing literature that is combined in this volume with the Authors’ personal experience and a number of practical examples can provide a good foundation for the challenges faced at the bedside.