Delirium: Opportunity for Comfort in Palliative Care

Jacqueline F. Close, PhD, RN, GCNS-BC, FNGNA; Carol O. Long, PhD, RN, FPCN

Disclosures

Journal of Hospice and Palliative Nursing. 2012;14(6):386-394. 

In This Article

Background

Prevalence and Incidence

The risk of developing delirium is positively associated with age, frailty, and the number of chronic and acute medical problems. In studies on delirium in hospital settings, the prevalence and incidence rates of delirium differ in the published literature. Delirium has been reported to be present in 14% to 24% of new admissions to the hospital. The incidence of new cases of delirium has been shown to be from 6% to 56% in hospitalized patients.[7] In a 2003 study by Agnostini and Inouye,[8] 15% to 53% of older postoperative adults were diagnosed with delirium. In another study of patients in an intensive care unit, 70% to 87% of patients were diagnosed with delirium.[9] Delirium also has been found in 51% to 85% of post–acute care admissions.[10] Patients with dementia or any cognitive impairment have a very high incidence of delirium superimposed on dementia, ranging from 22% to 89%.[11]

Delirium is the most common complication experienced by patients with advanced illness, occurring in up to 85% of patients in the last weeks of life.[12] Delirium is also very common in hospitalized patients, occurring in 26% to 44% of patients with late-stage cancer and up to 88% of patients with terminal illness.[13] Fang et al[14] speculate that the prevalence of delirium in cancer patients is from 11% to 35%, and in terminal cancer patients, the prevalence may be as high as 85%. In palliative care units, the probability of developing delirium can be as high as 88%.[15]

"Terminal restlessness," "nearing or near death awareness," and "terminal anguish" characterize delirium as "a clinical spectrum of unsettled behaviors in the final days of life."[16] (p345) Despite the fact that delirium is common in older, very ill patients and as part of the dying process, nurses can provide significant interventions to reduce distress and provide comfort to the patient and family. Delirium in people who are terminally ill includes the detection and elimination of the underlying cause (when possible) and nonpharmacologic and pharmacologic treatments. Patient and family education and reassurance are paramount to easing anxiety and providing for a therapeutic environment.

Risk Factors

There are numerous risk factors for developing delirium. These include predisposing risk factors and precipitating risk factors.

Predisposing risk factors for delirium are risk factors present before the patient becomes ill that may affect a patient's vulnerability for developing delirium. Some of these predisposing risk factors include advancing age, preexisting cognitive impairment, severity of illness, depression, vision or hearing impairment, and functional impairment.[17] Other literature describes all of the same predisposing risk factors but also includes male sex, depression, alcohol abuse, abnormal serum sodium level, and vision and hearing impairment.[17–19] Inouye[7] lists the top predisposing factors for developing delirium as (1) baseline cognitive impairment or dementia, (2) severe underlying illness and comorbidity, (3) functional impairment, and (4) advanced age.

Precipitating risk factors precede the development of delirium and are any noxious insults or events that happen during an illness regardless of the setting. These risk factors may include medication errors, immobilization, dehydration, malnutrition, iatrogenic events, medical illnesses, infections, metabolic abnormalities, alcohol or drug withdrawal, environmental or psychosocial factors, and the use of indwelling bladder catheters or physical restraints.[7] Sleep deprivation, fecal impaction, and urinary retention are frequent causes for delirium at the end of life.

Delirium is very common in patients with advanced cancer and may involve multiple physiological causes such as infection, end-stage organ failure, and adverse medication events, and in some cases, it is caused by paraneoplastic syndromes.[20] In patients with cancer, delirium may develop from structural or metabolic problems and complicates the assessment and management of pain, dyspnea, nausea, anxiety, and other symptoms.[20,21]

The onset of delirium is acute in most cases, and the cardinal clinical symptoms include difficulty sustaining attention, a fluctuating course, cognitive changes, and altered level of consciousness.[22] The patient is unable to maintain attention for any period of time, and he/she may be disoriented to time and place. Perception disorders, hallucinations, identification mistakes, and distortion in the size of objects are frequently noted.

Subtypes of Delirium

Delirium can manifest itself in three different subtypes: hyperactive, hypoactive, and mixed delirium. Mixed delirium includes elements of hyperactive delirium and hypoactive delirium.

Hyperactive delirium is characterized by agitation, hypervigilance, restlessness, emotional instability, hallucinations, and delusions. Patients with hyperactive delirium exhibit behaviors most commonly recognized as delirium, and these behaviors include psychomotor hyperactivity and excitability. These patients are easily identified by several associated behaviors, such as fast or loud speech, irritability, combativeness, impatience, swearing, singing, laughing, uncooperativeness, euphoria, anger, wandering, distractibility, and nightmares.[23]

Hypoactive delirium is characterized by withdrawal, flat affect, apathy, lethargy, reduced alertness, and decreased responsiveness. The patient may be somnolent and exhibit reduced psychomotor activity such as unawareness, decreased alertness, sparse or slow speech, slowed movements, staring, and apathy. This is the "quiet" patient for whom the diagnosis is often missed.[23] Patients with hypoactive delirium are often misdiagnosed as demented or depressed, and at the end of life, hypoactive delirium not only can be mistaken for depression but is also difficult to differentiate from opioid sedation.[24]

In palliative care settings, hypoactive delirium can be misdiagnosed as depression or fatigue, particularly if a formal assessment is not completed. Using valid and reliable screening tools for palliative care patients can assist in diagnosing and differentiating delirium, especially when hypoactive delirium might otherwise go unrecognized.[25]

The third type of delirium is mixed delirium and involves fluctuations between hyperactive and hypoactive behaviors. Mixed delirium is very difficult to diagnose because of the changing presentation of the patient, who alternates between a hyperalert and a hypoalert state. An astute assessment and evaluation will capture the mixed type of delirium, but this may go unnoticed because of the fluctuations between the two states.

Regardless of the type of delirium the patient is experiencing, it is imperative that delirium is prevented, if possible, recognized, assessed, documented, and treated to lessen the negative outcomes resulting from this syndrome. The associated poor outcomes of delirium are very distressing to the patient and family members as well as healthcare professionals, and nursing support is vital to both the patient and family to lessen fears and anxiety.

Challenges

Delirium has a negative impact on patient outcomes. It is associated with emotional distress, as people with delirium are often anxious, angry, or depressed. Pain is much more difficult to treat in patients with delirium, and patients with hyperactive delirium are at risk for falls and other types of injuries.[2] In addition, outcomes of patients diagnosed with delirium during hospitalization include an increased incidence of functional decline, new nursing home placement, and even death.[26] Studies indicate that delirium was associated with increased mortality at hospital discharge and at 12 months postdischarge.[27] Delirium was also associated with poor functional status among patients with and without dementia.[28] Healthcare costs of patients with delirium are more than 2½ times the costs of patients without delirium, and the added financial burden can run from $16,303 to $64,421 per person.[29]

Clinical Assessment

The identification of delirium remains a clinical diagnosis, based on bedside observation of the patient and information from families and caregivers. According to Inouye et al,[4] the diagnosis of delirium should be based on careful bedside monitoring of the four key features of delirium, which include (1) acute onset and fluctuating course, (2) inattention, (3) disorganized thinking, and (4) altered level of consciousness. Many healthcare providers consider delirium a common and serious problem, yet few monitor for this condition, and most admit that it is underdiagnosed.[30] Fluctuating symptoms make delirium hard to detect, especially when primary care providers spend only brief intervals of time with patients. Nurses, on the other hand, spend more time at the bedside and could therefore assess for and treat symptoms of delirium across healthcare settings.

Pathophysiology

The pathophysiology of delirium is not completely understood, and the proposed causes for delirium are numerous (Table 1). It has been suggested in the literature that delirium may be a disturbance in cerebral oxygenation, a disturbance in neurotransmission, a disturbance in cytokine production, or a disturbance in plasma esterase activity.[31,32] Patients receiving palliative and end-of-life care are particularly vulnerable for developing delirium.

Delirium can be caused by many different metabolic or ischemic insults to the brain, such as hypoxemia, hypercapnia, hypoglycemia, or any major organ dysfunction. Trauma, infection, surgery, or any other physical insult to the body can lead to increased production of proinflammatory cytokines that, in susceptible patients, induces delirium.[32] Peripherally secreted cytokines can intensify responses in the microglia (phagocytes that clean up waste products from the nervous system) that in turn cause severe inflammation of the brain.[32] Proinflammatory cytokine levels have been shown to be elevated in patients with delirium.[33]

The Predictive Model of Delirium explains delirium as the relationship between the vulnerability (predisposing risk factors) of the hospitalized older adult and noxious insults during (precipitating factors) hospitalization. This relationship can contribute to the development of delirium.[7] This model considers the development of delirium related to baseline patient vulnerability and precipitating factors or noxious insults occurring during hospitalization. Noxious insults are untoward negative incidents occurring to a patient while the patient is hospitalized, such as a urinary tract infection directly related to the presence of an indwelling urinary catheter or a patient fall sustained during an episode of hyperactive delirium. Highly vulnerable patients (those who have several risk factors) may experience an episode of delirium with few noxious insults. On the other hand, patients with low vulnerability (few risk factors) may need to experience several noxious insults to trigger an episode of delirium.[7]

Assessment and Measurement Tools

Screening Instruments Screening instruments identify the presence of cognitive impairment but do not diagnose delirium.[34] The Mini-Mental State Examination is used to evaluate cognitive changes and assesses orientation, instantaneous recall, short-term memory, attention, constructional capacities, and use of language.[35] The NEECHAM Confusion Scale is used for a rapid assessment as well as monitoring of acute confusion in hospitalized older individuals.[36] The Delirium Observation Screening Scale is an assessment tool designed to assist nurses in the early recognition of delirium during regular care and is based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), criteria for delirium.[37] The Nursing Delirium Screening Scale is an observational five-item instrument designed to be completed in 1 minute and is a simple, yet accurate, continuous, "around-the-clock symptom monitoring."[38] (p373) The tool of choice should be the one best suited for the patient population being screened.

Diagnostic Instruments Diagnostic instruments are an adjunct to clinical and cognitive evaluation and help in diagnosing delirium.[39] The Confusion Assessment Method (CAM) is a diagnostic tool designed for use by a nonpsychiatrically trained interviewer to identify and recognize delirium quickly and accurately both at the bedside and in research settings.[5] The CAM is used as the primary tool to screen residents in nursing homes.[40] The Delirium Rating Scale-Revised-98 is used both as a diagnostic and severity-based instrument based on the DSM-IV and common symptoms found in delirious patients. This is used to rate the severity of delirium over time and differentiates patients with delirium from patients with dementia, schizophrenia, and depression.[41,42]

Severity of Symptom Instruments These scales are used to rate the severity of the symptoms of delirium. The Memorial Delirium Assessment Scale (MDAS) is a brief, reliable tool for assessing delirium severity among medically ill, adult patients and can be accurately scored by multiple raters. The MDAS is highly correlated with existing measures of delirium and cognitive impairment.[42] The Bedside Confusion Scale (BCS) is used for continuous observation of an alteration in attention, with or without a change in level of consciousness. The BCS is designed for the palliative medicine population, requires minimal training, and takes approximately 2 minutes to complete.[43] The Delirium Index measures the severity of symptoms of delirium and is based on observation of the patient, without additional information from informants.[44] (For additional details on the psychometric properties of each instrument, consult the detailed reference list at the end of this article). Table 2 describes the assessment tools used in screening, diagnosing, and determining the severity of delirium.

Delirium is very common at the end of life, but if assessed and identified early, interventions may be put in place to lessen the symptoms and ensure the patient's comfort along with patient and family well-being. The most important approach to treatment of delirium is to reverse underlying causes if possible, and in palliative care, the goals of treatment for delirium are balanced with a caring approach, providing a safe environment, and avoiding uncomfortable interventions. Addressing only one of the factors contributing to the delirium is not likely to help improve the delirium. However, a multifactorial intervention strategy that addresses as many predisposing and precipitating factors as possible supports positive nursing care.

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