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Delirium in the Elderly

Author: Steve Fordham / Editor: Clifford J Mann / Reviewer: Liz Florey / Codes: CAP8 / Published: 07/08/2017 / Review Date: 07/08/2020

Introduction

Delirium (acute confusional state) is common in hospital medicine. In the elderly, the prevalence of delirium ranges from 11%-42% [1].

Patients with delirium have:

  • Increased length of hospital stay
  • Higher risk of complications in both medical and surgical settings
  • Higher mortality, both in hospital and up to 6 months following discharge [2].

It is estimated that a third of cases are preventable [3]. In addition the detection and documentation of delirium by emergency physicians is poor, with reported sensitivity rates as low as 35% [4]. It is an essential skill for emergency physicians to be able to identify, rationally assess and implement effective initial treatment strategies in confused elderly patients.

Clinical assessment

Clinical presentation

The diagnosis of delirium is clinical. The DSM-IV criteria for defining delirium are [5]:

  • Disturbance of consciousness (i.e. reduced clarity of awareness of the environment) with reduced ability to focus, sustain or shift attention.
  • A change in cognition (such as memory deficit, disorientation, language disturbance) or the development of a perceptual disturbance that is not better accounted for by a pre-existing, established, or evolving dementia.
  • The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day.

Three clinical subtypes are recognised (see Fig 1). It is important to be aware of the hypoactive subtype as this is less likely to be recognised despite patients having a more severe illness [6].

delirium_subtypes
Fig 1: Delirium subtypes

Learning Bite

The key features of delirium are:

  • Recent onset of fluctuating awareness
  • Impairment of memory and attention
  • Disorganised thinking

Risk Stratification

A number of risk factors exist for developing delirium and for precipitating delirium in hospitalised patients (see Figs 2 and 3) [7].

delirium_risk_factors
Fig 2: Risk factors for developing delirium

delirium_precipitating_factors

Fig 3: Precipitating factors for delirium

The mnemonic SMASHED is a useful aide memoir when assessing the possible causes or precipitants of acute confusion:

S Substrates: hyperglycaemia, hypoglycaemia, thiamine
Sepsis
M Meningitis and other CNS infections
Mental Illness, functional psychoses
A Alcohol intoxication or withdrawal
S Seizures: Seizure activity, post-ictal states
Stimulants: anticholinergics, hallucinogens, cocaine
H Hyper: hyperthyroidism, hyperthermia, hypercarbia
Hypo: hypothyroidism, hypothermia, hypoxia, hypotension
E Electrolytes: hypernatraemia, hyponatraemia, hypercalcaemia
Encephalopathy: hepatic, uraemic, hypertensive, others
D Drugs of any sort

History

A detailed history is often difficult to obtain in delirious patients; effort should always be made to obtain information from carers, general practitioners and others close to the patient.
In addition to standard questions useful points to remember and document are:

  • Onset and course of delirium
  • Previous intellectual function (e.g. ability to manage household affairs, pay bills, compliance with medication, use of telephone and transport)
  • Full drug history (including non prescribed drugs and recent drug cessation)
  • Alcohol history
  • Functional status (Activities of daily living)
  • Aids used (hearing/glasses etc)

Learning Bite

Many patients with delirium are unable to provide an accurate history. Wherever possible, corroboration should be sought from the carer, general practitioner or any source with good knowledge of them.

Examination

A full examination should be performed to search for evidence of underlying causes of the confusion. Neurologic and mental status examinations should be performed.

  • The Abbreviated Mental Test (AMT) [8] Score and the Confusion Assessment Method (CAM) [9] are the quickest and most widely used methods of assessment suitable for emergency department use.
  • By themselves these tools cannot distinguish between delirium and other causes of cognitive impairment.

Abbreviated Mental Test Score AMT (Less than 8/10 is abnormal)

  1. Age
  2. Time (to nearest hour)
  3. Address for recall at end of test (42 West Street)
  4. Year
  5. Name of Hospital
  6. Recognition of 2 people (e.g. doctor/nurse)
  7. Date of Birth
  8. Year of First World War
  9. Name of present Monarch
  10. Count backwards 20-1 (this also tests attention)

Confusion Assessment Method (CAM) Diagnostic Tool

1. Acute onset and fluctuating course

and

2. Inattention (e.g. 20-1 test, with reduced ability to maintain or shift attention)

and either 3.

Disorganised thinking, illogical or unclear ideas

or

4. Alteration in consciousness (usually lethargic or stuporous)

Disorganised thinking is defined as rambling or irrelevant conversation, unclear or illogical flow of ideas, or unpredictable switching from subject to subject.

Investigation Strategies

Investigations

Investigations should be directed towards potential risk factors or causes of the delirium found from the history and examination. The following should be routine in any confused patient (Fig 4):

delirium_investigations
Fig 4: Investigations

Other specific laboratory tests to consider, depending on initial assessment findings:

  • Arterial blood gases +/-carboxyhaemoglobin
  • LFT
  • Coag
  • TFT
  • Blood cultures
  • Drug levels (e.g. theophylline, digoxin)
  • B12, Folate, VDRL, autoimmune screen
  • D-Dimer (only as part of focussed DVT/pulmonary embolism work up)
  • CRP/ESR

CT Scanning

There is no evidence for the use of routine CT head in the initial investigation of acute delirium.

Learning Bite

Indications for CT in the investigation of acute delirium are:

  • Focal Neurological signs
  • Confusion after head injury / fall
  • Evidence of raised intracranial pressure

Lumbar Puncture

Lumbar puncture should be reserved for patients in whom meningitis or another CNS infective cause is suspected. There is no evidence for routine use.

Management

The most important task in the management of delirium is the identification and treatment of the underlying cause.

  • Infection is one of the most common causes of delirium. It is essential if infection is suspected to commence prompt antibiotic treatment directed at likely organisms, following the collection of appropriate cultures.
  • Biochemical abnormalities should be corrected, but in a prudent fashion. These changes do not always occur acutely (e.g. Sodium) and normalisation should proceed cautiously.
  • If alcohol abuse or withdrawal is suspected remember parenteral thiamine.

Drug history should be reviewed and medications withdrawn as necessary. Anticholinergic drugs are particularly implicated in precipitating acute confusional states (see Fig 5).

delirium_drugs
Fig 5: Drugs with anticholinergic activity commonly used in older people [10]

Many drugs commonly used in the elderly have anticholinergic activity and can cause confusion. Take a full drug history and have a low index of suspicion for iatrogenic causes.

Preventative and nursing measures

Research evidence on the effectiveness of interventions to prevent delirium is lacking [11].

Despite this, some strategies that are simple to implement in the emergency department include:

  • Appropriate lighting levels for time of day
  • Regular and repeated cues to improve personal orientation
  • Use of clocks to improve orientation
  • Hearing aids and spectacles in good working order
  • Communication with relatives as to the cause and treatment measures for delirium.
  • Encourage family to visit (may help calm patient) and to bring in familiar objects from home.

Medical treatment considerations to minimise confusion include:

  • Regular analgesia if in pain
  • Optimise fluid balance to prevent dehydration
  • Elimination of unexpected and irritating noise or other unfamiliar distractions (e.g. pump alarms give fluids/meds orally if possible)

Learning Bite

Avoid:

  • Use of physical restraint
  • Constipation
  • Catheters where possible
  • Anticholinergic drugs
  • Unnecessary intra/inter ward transfers

Drug therapy

Drug therapy in the management of delirium should be avoided if possible. Sedation may be required in the following situations [7]:

  • In order to carry out essential investigations or treatment
  • To prevent the patients endangering themselves or others
  • To relieve distress in a highly agitated or hallucinating patient.

If drug treatment is necessary haloperidol is the current initial medication of choice. An appropriate starting dose would be 0.5-1mg (orally,IM) with regular reassessment and titration up to a maximum of 5-10mg.

There is no evidence to support the use of newer antipsychotic medications (e.g. olanzapine, risperidone) in the management of delirium [12].

Side effects include extrapyramidal symptoms, and haloperidol should be not be used for this reason in patients with Parkinsons or Lewy Body Dementia. Regular ECG monitoring should be performed to ensure that the QT interval does not become prolonged.

For delirium due to alcohol withdrawal, or those not suitable for haloperidol, a benzodiazepine would be suitable. Lorazepam, at an initial dose of 2mg (IM/IV), with regular reassessment and titration to effect is preferred. Evidence of effectiveness over other medications is lacking [13].

Learning Bite

If drug treatment is necessary first line therapy is titrated Haloperidol 0.5-10mg (IM/PO). In those who have:

  • Parkinsons
  • Lewy body dementia
  • Prolonged QT
  • Extrapyramidal side effects
  • Delirium due to alcohol withdrawal

Titrated Lorazepam 2mg (IV/IM) is the drug of choice.

Safety pearls and Pitfalls

Pitfalls

  • Failure to consider the diagnosis, particularly the hypoactive subtype
  • Failure to routinely assess the mental state of all elderly in the emergency department
  • Failure to obtain a corroborate history from relatives, carers or friends. This is particularly important when trying to distinguish between delirium and dementia
  • Failure to obtain a full drug history
  • Failure to appreciate that injury (particularly head injury) and pain are important causes of acute confusion
  • Requesting insufficient or inappropriate investigations. A full set of all blood tests/x-rays/CT scans is not needed in the initial management of many patients
  • Failure to appreciate that environmental factors are vitally important in the prevention and treatment of delirium
  • Avoid sedating patients unless absolutely indicated

MedicoLegal and other considerations

Key learning points

  1. The key features of delirium are: recent onset of fluctuating awareness, impairment of memory and attention, and disorganised thinking. [DSM IV, strong recommendation]
  2. High Risk patients should be identified in the Emergency Department and appropriate prevention strategies implemented. [Moderate Quality, Strong recommendation]
  3. Many patients with delirium are unable to provide an accurate history. Wherever possible, corroboration should be sought from the carer, general practitioner or any source with good knowledge of the patient. [Low quality, Strong recommendation]
  4. Many drugs commonly used in the elderly have anticholinergic activity and can cause confusion. Take a full drug history and have a low index of suspicion for iatrogenic causes. [Low quality, strong recommendation]
  5. The Abbreviated Mental Test (AMT) Score and the Confusion Assessment Method (CAM) are the quickest and most widely used methods of assessment suitable for emergency department use. [Low quality, weak recommendation]
  6. Indications for CT in the investigation of acute delirium are: [Low quality, weak recommendation]
    • Focal Neurological signs
    • Confusion after head injury
    • Confusion developing after a fall
    • Evidence of raised intracranial pressure
  7. The most important action in the management of delirium is the identification and treatment of the underlying causes. [Low quality, strong recommendation]
  8. Avoid: [Low quality, Strong recommendation]
    • Use of physical restraint
    • Constipation
    • Catheters where possible
    • Anticholinergic drugs
    • Unnecessary intra/inter ward transfers
  9. If drug treatment is necessary, first line therapy is titrated Haloperidol 0.5-10mg (IM/PO). In those who have: [Low Quality, Weak recommendation]
    • Parkinsons
    • Lewy body dementia
    • Prolonged QT
    • Extrapyrimidal side effects
    • Delirium due to alcohol withdrawal

    Titrated lorazepam 2mg (IV/IM) is the drug of choice.

References

  1. Siddiqui N, Home AO, House AO, Holmes JD. Occurrence and outcome of delirium in medical patients; a systematic literature review. Age Aging 2006;35:350-64.
  2. American Psychiatric Association. Practice guideline for the treatment of patients with delirium. Am J Psychiatry 1999;156(5 suppl):1-20.
  3. Inouye SK, Bogardus ST Jr, Charpentier PA et al. A multicomponent intervention to prevent delirium in hospitalized older patients. N Engl J Med 1999;340:669-76
  4. Hustey HM, Meldon SW. The prevalence and documentation of impaired mental status in elderly emergency department patients. Ann Emerg Med 2002;39:248-53.
  5. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th Ed (DSM IV). Washington, DC, APA, 1994.
  6. OKeeffe ST, Lavan JN. Clinical significance of delirium subtypes in older people. Age Ageing 1999;28:115-9.
  7. British Geriatrics Society and Royal College of Physicians. Guidelines for the prevention, diagnosis and management of delirium in older people. Concise Guidance to good practice series, No.6. London:RCP 2006.
  8. Jitapunkul S, Pillay I, Ebrahim S. The abbreviated mental test: its use and validity. Age Ageing 1991;20:332-6
  9. Inouye SK, van Dyk C, Alessi CA et al. Clarifying confusion: the confusion assessment method. A new method for detection of delirium. Ann Intern Med 1990;113:941-8.
  10. Young J, Inouye SK. Delirium in older people 2007. BMJ;334:842-846.
  11. Siddiqi N, Holt R, Britton AM, Holmes J. Interventions for preventing delirium in hospitalised patients. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.:CD005563.
  12. Lonergan E, Britton AM, Luxenberg J. Antipsychotics for delirium. Cochrane Database of Systematic Reviews 2007, Issue 2. Art. No.:CD005594.
  13. Lonergan E, Luxenberg J, Areosa Sastre A, Wyller TB. Benzodiazepines for delirium. Cochrane Database of Systematic Reviews 2009, Issue 1. Art. No.:CD006739.
  14. Meagher D, Delerium: optimizing management 2001. BMJ;322:144-9.

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3 Comments

  1. jalalbl says:

    I like this module, really what we see in ED , infrequent patients admissions with history of confusion largely related to delirium

    Delirium

  2. Kalakoti says:

    Comprehensive module for ED.

  3. Kais Mokabar Mustafa says:

    good useful module

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