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Delirium in the Elderly: a review
Suzanne Wass,1 Penelope J. Webster,2 Balakrishnan R. Nair3 Delirium is a common disorder, often under diagnosed and mismanaged. It is becoming more prevalent, because of the ageing Accepted: 25 May 2008From the Department of 1Geriatic Medicine, Calvary Mater Hospital, NSW population. In this clinical review, we summarise the definition, Australia,2 Geriatic Medicine, John Hunter Hospital, NSW, Australia,3 Continuing diagnosis and management of delirium.
Medical Professional Development, School of Medine and Public Health, niversity of Keywords: Delirium, Dementia, Depression.
New Castle, and Continuing Professional Development, Hunter New England Health, NSW, Australia.
Address correspondence and reprint to: Prof. Balakrishnan R. Nair, MBBS, FRACP, FRCP Clinical Professor of Medicine, Associate Dean Continuing Medical Professional Development, School of Medicine and Public Health, Director of Continuing Professional Development, Hunter New England Health, NSW, Australia Email: [email protected] Delirium is a common syndrome affecting many elderly prevalence of delirium in the community is 1.1% amongst the patients not only admitted into acute medical wards but also in the general population aged over 55 years,6 and up to 14% in those community. The syndrome of delirium can be defined as acute brain over 85 years.7 The incidence amongst nursing home residents failure associated with autonomic dysfunction, motor dysfunction and homeostatic failure. It is complex and often multi-factorial, and The consequences of delirium are considerable for the patient hence continues to be under diagnosed and poorly managed. Despite and the health services. In the US delirium is estimated to increase medical progress, delirium remains a major challenge for health care health costs by US$2500 per patient, totalling US$6.9 billion workers with the increasing burden of an ageing population.
per year.8 If we consider that less than half of patients have fully recovered at point of discharge, this incurs additional costs in Definition and terminology
the form of increased residential care, rehabilitation and home services.9, 2 The Diagnostic and Statistical Manual of Mental Disorders Even when detected early and managed appropriately, delirium can lead to significant mortality and morbidity in frail, elderly patients. Adverse outcomes can include the following: “a disturbance of consciousness that is accompanied by a change in cognition that cannot be better accounted for by a pre-existing or evolving dementia”. • Prolonged hospital stay (on average 8 days longer)10 Delirium develops over a short period of time (hours to • Increased mortality whilst in hospital (up to 75%) in the days) and fluctuates throughout the course of the day. It is months following Discharge (40% 1 year mortality)1, 11, 12, 13 characterised by a reduction in clarity of awareness, inability to • Increased risk of developing complications such as hospital focus, distractibility and change in cognition. Other terminology acquired infection; pressure ulcers, incontinence and falls used to describe delirium includes ‘acute confusional state’, ‘acute brain syndrome’, ‘acute organic reaction’, ‘acute brain failure’ and • Poor physical and cognitive recovery at 6 and 12 months,15 with lower scores on the Mini Mental State Examination occurrence and consequences of delirium
(MMSE) at discharge compared to controls 16 The available data for the incidence and prevalence of delirium is • Increased risk of placement in a residential home1, 13 varied. It appears that 15% to 30% of elderly patients will have • Increased risk of developing dementia even in patients with no delirium on admission to hospital and up to 56% will develop delirium during their stay.4 Incidence of delirium is highest amongst certain subgroups including those with cancer, AIDS The odds of a poor outcome are increased by the frailty of and terminal illness and after surgical procedures such as hip the patient and delays in diagnosis,15 highlighting the crucial replacement and cardiac surgery. It is more common in certain importance of early detection and proactive management.
ward environments like ICU and palliative care units.5 The point Oman Medical Journal 2008, Volume 23, Issue 3, July 2008
Delirium in the Elderly . Wass et al. Classification
table 1: Clinical Features of Delirium
The DSM-IV-TR classifies delirium according to aetiology, as Essential features
Variable features
1. Delirium due to a general medical condition 2. Substance Intoxication Delirium (drugs of abuse) Disorganised thinking and speech Emotional disturbance 4. Substance Induced Delirium (medications or toxins) 6. Delirium not otherwise specified.
Examination signs
autonomic Dysfunction
Clinically delirium can be divided into the following three i. Hyperactive Delirium (30%). Patients are agitated and hyper
alert with repetitive behaviours, wandering, hallucinations and aggression. Although recognised earlier, there is association with increased use of benzodiazepines, over sedation, use of ii. Hypoactive Delirium (25%). Patients are quiet and
withdrawn which is often missed on a busy medical ward leading to increased length of stay, increased and more severe Adapted from Inouye SK. Delirium in Older Persons. NEJM; iii. Mixed Delirium. Fluctuating pattern seen in 45% of cases.3, 10,
risk and precipitating factors
Most elderly patients will have multiple risk factors making them Clinical features
more susceptible to delirium (see Table 2). Vulnerability is also increased when multiple precipitating factors are present, or if the The DSM-IV-TR stipulates that, as well as matching the definition, precipitating insult is particularly severe. It is impossible to list all patients must have the following clinical features: of the conditions and stressors that may precipitate delirium, but 1. Disturbance of consciousness. A reduced ability to focus, the most common (and most relevant to an elderly population) are listed in Table 3. Delirium is often the only sign of an underlying serious medical illness in an elderly patient and, therefore, 2. A change in cognition or perceptual disturbance including particular attention should be made to identifying and correcting disorientation and language disturbance.
3. The above features develop over hours to days and fluctuate table 2: Common Risk Factors for Delirium
non Correctable
There are many other features that can be associated with delirium and these are described in Table 1. It is also worth remembering that frank delirium can be preceded by a period Mild Cognitive Impairment, Dementia, Parkinson>s Disease of prodromal illness (normally 1-3 days), where the patient may appear impatient, anxious, restless, distracted, develop urinary incontinence or start refusing investigations. In hindsight, family members are able to give a history of this prodromal period but it is very difficult to detect clinically. Elderly patients with delirium often do not look ill apart from the behavioural changes.
Oman Medical Journal 2008, Volume 23, Issue 3, July 2008
Delirium in the Elderly . Wass et al. Correctable
the acute decline in cognition that needs to be taken into account during cognitive screening assessments. Studies show that 30% Hearing impairment or visual impairment indicates a threefold to 67% of patients with delirium go undetected.18, 24 Detection can be improved by implementing cognitive testing and screening Malnutrition, dehydration, low albumin. Associated with a instruments, accompanied by educational programmes for staff.25 The MMSE is the most widely used instrument to test cognitive Social Isolation, sleep deprivation, new environment, moves function. Although it is used in the setting of delirium, it was not designed for this purpose. To detect delirium, it is necessary to know the patients baseline function and engage the patient in New addition of three or more medications repeat testing throughout their illness. This may be effective in certain high-risk situations (i.e. post hip fracture) but further evaluation is needed.26 A drop of >2 points from baseline indicates delirium, whilst an improvement of 3 points or more indicates potentially Correctable
The Australian Society for Geriatric Medicine, The American Uraemia, blood urea >10 is an independent risk factor.22 Psychiatric Association and The British Geriatrics Society all recommend the Confusion Assessment Method (CAM), a Prolonged hospital stay, increased risk after 9 days.5 screening tool specifically designed to detect delirium (see Table 4). This has reported sensitivity of >94%, specificity of >90% and is easy to use in a clinical setting. Again the patient should be reassessed throughout their hospital stay to monitor progress.14 table 3: Precipitating Factors
precipitating factors
table 4: Confusion assessment Method (CAM)
Confusion assessment Method (CaM)
1. acute onset and fluctuating course
• Is there evidence of change in cognition from baseline? Electrolyte disturbance (sodium, calcium, magnesium, phosphate) Endocrine disturbance (Blood sugar, thyroid) 2. inattention
Nutritional deficiencies (thiamine, B12, folate) • Does the patient have difficulty focusing attention? Pulmonary disorders (particularly in the setting of hypoxemia) 3. Disorganised thinking
• Does the patient have disorganised thinking, rambling Post surgery, especially cardiac, orthopaedic or with ICU stay 4. altered level of consciousness
• Alert, hyper alert, lethargic or drowsy, stupor, coma All patients must have 1 and 2 with either 3 or 4 to diagnose Adapted from Harrisions Online, Chapter 26. Confusion and Delirium, McGraw-Hill Companies. Accessed February 2009.
recognising patients with delirium
When a patient with confusion is admitted to hospital, they The third assessment tool worth noting is the Delirium Rating should be presumed to have delirium until proven otherwise. A Scale (DRS). It covers a range of symptoms relating to delirium, collaborative history from family or carers is essential to establish not only useful for diagnostic purposes, but for assessing severity Oman Medical Journal 2008, Volume 23, Issue 3, July 2008
Delirium in the Elderly . Wass et al. and distinguishing delirium from other disorders. Although It is important to differentiate between delirium, dementia accurate, it is more complex than the CAM, requires specialist and depression. Lewy Body Dementia, with its hallucinations and trained Psychiatrists or Geriatricians and has mainly been used fluctuations is a classic example, whilst 42% of patients referred to psychiatric services for depression actually have delirium.28 Table 5 summarises the main differences.
table 5: Differentiating between Delirium, Dementia and Depression
Delirium
Dementia
Depression
Consciousness
attention
Thinking
perception
MMSE: Mini Mental State examinationAdapted from Milsen K et al. Nurs Clin N Am. 2006; 41: 1-22 prevention of delirium
that the approach to prevention needs to be multifactorial. The landmark study conducted by Inouye in 1999,29 and other Prevention can be divided into primary, secondary and tertiary. prevention studies,30, 31, 32 have demonstrated that delirium can Primary prevention strategies are aimed at reducing the incidence be prevented or at least moderated by addressing modifiable risk of delirium. Given that delirium is a complex medical problem factors. This reflects a humanistic, compassionate approach to resulting from one or more variables involving body systems in management based on high quality nursing and medical care (see addition to environmental factors, as delineated above, it follows table 6: Delirium Prevention Strategies
Environmental strategies
Clinical practice strategies
orientation to time
Ensure function is optimised
• room with an unobstructed view to the outside world • lighting appropriate to the time of day • provision of a clock and calendar suitable for an individual’s • encourage independence in activities of daily living • dentures and dental appliances well fitted and in place• encourage and assist if necessary to ensure adequate hydration • monitor and regulate bowel function • promote relaxation and sufficient sleep Oman Medical Journal 2008, Volume 23, Issue 3, July 2008
Delirium in the Elderly . Wass et al. orientation to place
facilitate communication
• avoid frequent room changes and keep room changes to a • hearing aids • encourage family and carer’s to bring in personal and familiar • interpreters and communication aids • dentures and dental appliances well fitted and in place orientation to people
Ensure culturally sensitive approach
• encourage family and carer involvement by facilitating • awareness and respect of cultural and religious sensitivities • Orientate to personnel providing name and role Maximise comfort
• single room to minimise disturbance of personnel attending • Manage reduce discomfort and pain using nonpharmacological to other patients at any time of the night and day • reduce incident noise especially, unpredictable sounds e.g. • minimise invasive procedures e.g. indwelling catheters; IV buzzers, alarmed medication delivery devices, televisions, • address issues exacerbating emotional distress • Reduce exposure to activity/stimulation e.g. Unavoidable disturbance if nursed in an acute environment where the likelihood of resuscitation, urgent intervention is likely • Facilitate undisturbed sleep at night• Avoid sleep deprivation provide routine
Minimise perception of threat
• train personnel to use calm, confident manner keeping voice • Meal times at regular intervals and times • activities such as personal care at regular times Caution with medication
• review and minimise medication• avoid psychoactive drugs• avoid anticholinergic drugs• take careful drug and substance history and anticipate withdrawal syndromes from alcohol, nicotine, benzodiazepines, narcotics Anticipate, prevent, identify and treat medically reversible problems• screen high risk patients with a validated instrument e.g. • thorough physical examination• dehydration• malnutrition• electrolyte abnormalities• hypoalbuminaemia• anaemia• renal impairment• urinary retention• depression Oman Medical Journal 2008, Volume 23, Issue 3, July 2008
Delirium in the Elderly . Wass et al. Secondary prevention requires optimal clinical management table 7: Investigation of the delirious patient
at the time of delirium and will be addressed below in the Tertiary prevention strategies require identification of previous episodes of delirium by taking a careful history to recognise high- risk individuals. A randomised placebo-controlled trial using low dose haloperidol in elderly hip-surgery patients at risk of delirium showed that although there was no difference in the incidence of delirium, the severity and duration of delirium, and length of investigation of the delirious patient
Delirium is generally at least partially reversible if the cause of the delirium can be identified and treated promptly. Investigation Targeted investigations as Electrocardiogram of a patient presenting with an acute confusional state should informed by the history Post void residual bladder scan • Thorough history including: alterations to sleep-wake cycle, nutrition, and recent misadventure including falls. It is Further investigations to Thyroid function and thyroid be considered if no cause antibody tests essential to access corroborative history from carers, family, witnesses, access information including previous investigations from doctors involved in the care of the patient, allied health professionals, aged care assessment team members to establish the sequence of events, identify likely precipitating factors, the level of function and cognition prior to the presentation and if there have been any previous episodes of suspected delirium in • Review of medications including: medications taken prior to presentation, new medications commenced or medications ANA: Antinuclear Antibody; ENA: Extractable Nuclear ceased, adherence to treatment. In addition it is important to establish a substance use history including nicotine, ethanol, benzodiazepines, and other centrally acting drugs to identify Current research is aimed at determining a biochemical marker for delirium. In a recent study C-reactive protein was found to be useful not only to predict incidence of delirium but also recovery • Thorough physical examination including: vital signs, postural from it. These results need to be interpreted with caution pending blood pressure measurement, pulse oximetry, urine analysis, further investigation. C-reactive protein is well known to be a blood sugar level, palpation of the bladder for urinary retention marker of inflammation, however it “actual y captures only one specific and body weight. The physical examination may need to be aspect of inflammation, which is not necessarily the most relevant for targeted and opportunistic in the context of a patient exhibiting delirium and does not reflect all aspects of inflammation”.36 severe behavioural or emotional disturbance.
• Initially, investigations should be targeted at identifying Management
or ruling out common causes of delirium in addition to non-pharmacological management of delirium
investigations targeted at issues arising from history and Non-pharmacological strategies similar to the interventions examination. (Table 7) If the cause of delirium is not identified listed for prevention should be implemented whenever possible. by this approach it may be necessary to conduct additional Logically, if delirium is a multi-factorial problem, it follows that investigations aimed at identifying less common causes.
multidisciplinary interventions are likely to provide most success Oman Medical Journal 2008, Volume 23, Issue 3, July 2008
Delirium in the Elderly . Wass et al. in management. Bergmann et al,37 have proposed a model or care In patients with co-existing medical conditions where use of for management of delirious patients in the acute setting with dopamine antagonists are contraindicated, such as Lewy Body a standardised approach involving “ four key steps: assessment of dementia and Parkinson’s Disease, low doses of risperidone can be delirium symptoms in new admissions, evaluation and treatment of tried with careful monitoring. reversible causes of delirium, prevention and management of common Benzodiazepines are well recognised as appropriate treatment complications of delirium, and restoration of cognitive and self-care for alcohol or drug withdrawal. In practice, benzodiazepines with function in delirious patients”. A randomised trial involving a a short half-life and no active metabolites, for example, lorazepam, multidisciplinary intervention encompassing: a standardised oxazepam, or midazolam may be of benefit for patients with excessive nursing intervention protocol, review by a geriatric specialist anxiety symptoms, with severe agitation not responding to anti- consultant and follow-up by an intervention nurse who liaised psychotics, or when antipsychotic medication is contraindicated.14 with all team members compared with usual care, conducted Benzodiazepine use can be associated with a worsening of by Cole et al38 failed to demonstrate that multidisciplinary care confusion and sedation. A Cochrane Review pertaining to the use was more beneficial compared with usual care. A Cochrane of benzodiazepines for delirium is pending.47 Systematic Review is currently pending.39 In the setting of delirium prognosis
multicomponent intervention directed at prevention of delirium is likely to have much greater impact than stratagems aimed at Studies have shown that nearly half of patients with delirium are discharged from the acute hospital setting with persistent symptoms and of these, 20-40% still have delirium at 12 months.48 pharmacological Management of Delirium
Longer term outcomes in these patients are consistently worse Administration of pharmacological agents should be reserved than in those patients who fully recover by point of discharge, and for patients with severe agitation or behavioural disturbance it is unknown whether these patients will ever recover.
who are at risk of interrupting essential medical care and risk of It is essential to use a multidisciplinary team approach to causing harm to them self or others. This strategy outweighs risk discharge to ensure adequate support for patients and their carers. associated with administration of the medication when symptoms Ideally, there should be close communication between the hospital team, primary care and the patients’ family or caregivers. Education There are numerous guidelines available providing advice should be provided on what to expect with regards to the patient’s on approach to pharmacological management of delirium.2, 5, 11, function and prognosis. The patient should have regular review 14, 21, 25, 26 Many institutions have developed their own protocols, every few days in the community and minimum follow up should procedures and guidelines adapted to local conditions.
Consensus opinion based on evidence from the literature practical Key points
supports the use of antipsychotics for the treatment of delirium. Traditionally low dose haloperidol has been considered the drug • Every elderly patient admitted with confusion should be of choice as haloperidol is available in oral and parenteral dose presumed to have delirium until proven otherwise.
forms, and has a lower incidence of adverse effects including • Improve early detection using the CAM and serial cognitive anticholinergic side effects, postural hypotension, and sedation • Implement clinical guidelines, practice changes and education when compared with other traditional antipsychotic agents.26 programmes for all medical, nursing and allied health staff.49, 50 A recent Cochrane review conducted a literature review and • Education and support of families and carers is essential metanalysis “comparing the efficacy and incidence of adverse effects • Ensure close follow up in the community and good of haloperidol with risperidone, olanzapine and quetiapine in the communication between hospital staff and primary care.
treatment of delirium”.41 The authors concluded that there was no evidence that the atypical antipsychotics offered any advantage references
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Oman Medical Journal 2008, Volume 23, Issue 3, July 2008

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