Introduction
Epidemiology
Examination
Medical treatment
Conclusion
References

Introduction

Managing confusion is challenging because of several factors that are prevalent in the elderly. These include living alone, lack of detailed history on presentation, cognitive impairment, complex comorbidities, several constraints on proper evaluation and assessment and it requires team work for complete assessment and management. Biological ageing is characterised by the progressive loss of adaptability, with decreasing functional reserves and diminution of the ability to recover from a physiological injury. At the same time, ageing can lead to a multiplicity of diseases and to polypharmacy, along with changes in the patient’s physical and personal environment. 

Epidemiology

The incidence of delirium (acute confusional state) increases progressively after the fourth decade of life.1 An estimated 15 to 26% of elderly patients with delirium die, usually as a result of the pathologic process responsible for the delirium.2 Elderly patients with delirium may have underlying dementia (cognitive impairment). In fact, dementia is a known risk factor for delirium. As many as 22% of community-dwelling elderly persons with dementia have coexisting delirium.3 20% of patients aged 65 are delirious on admission to the hospital.4 The reported prevalence of delirium among elderly hospitalised patients ranges from 14% to 56%. Its prevalence in nursing homes is 58%.4

Dementia is the most prevalent organic mental syndrome in older persons. The risk of dementing illness increases with age. The prevalence of dementia increases from 10 to 15% at the age of 75 years to between 25 and 35% in persons 85 years of age and older.5 If present population trends continue, the prevalence of severe dementia is expected to triple by the year 2040.5

Definitions

Delirium (acute confusional state) is characterised by a disturbance of consciousness and a change in cognition that develop over a short period of time. The disorder has a tendency to fluctuate during the course of the day.

Delirium is common, has multiple causes and causes distress to numerous patients and their relatives.

The diagnosis requires all four criteria in the DSM IV definition.1 Delirium is often not recognised and a high index of suspicion is required. Delirium is diagnosed on clinical grounds: The entity is characterised by its typical manifestations, acute onset, and fluctuating course. The aetiology is then sought. The features of delirium in the individual patient, the past medical history, and the patient’s pre-existing cognitive deficits (if known) can point the way to whatever further diagnostic testing may be indicated.

Screening tools for delirium are useful as many times delirium is unrecognised clinically.6 These include:

  1. Confusion Assessment Method (CAM) is the most widely used tool, but relies on understanding of inattention, and needs specific training
  2. Single question in delirium (SQiD): “Do you think (name) has been more confused lately?” has shown promise in oncology patients
  3. 4AT test - tests alertness, attention, AMT4 and acute history. It has a sensitivity 89.7%, specificity 84.7%, and is brief and simple. No understanding of inattention is needed.

Subtypes

  • Hyperactive delirium – restless, agitated, delusional, risk of harm
  • Hypoactive delirium – lethargic, monosyllabic, often overlooked
  • Mixed type.

 

Delirium and dementia may coexist. In this situation, treatment of the delirium often improves the patient's cognitive and/or functional abilities.

Dementia can be classified as reversible or irreversible. Potentially reversible causes include thyroid dysfunction, deficiencies of vitamins such as B12 and folate, infections, subdural haematoma, metabolic abnormalities such as uremia, and normal-pressure hydrocephalus. The major irreversible causes of dementia include vascular dementia, central nervous system (CNS) trauma, Parkinson's disease, Pick's disease and human immunodeficiency virus (HIV) infection. Rarer irreversible causes include Creutzfeldt-Jakob disease and Huntington's disease.

Diagnostic approach

To differentiate delirium from dementia the physician should pay close attention to the timeline of events, as well as the patient's functional status and comorbid conditions.

History

If it is not possible to obtain a history from the patient, a collateral history should be sought from a relative / carer. Pick up the phone if necessary! It is vital to know what is ‘normal’ for this patient.

The family plays a key role in the diagnosis by providing a detailed history of changes in the patient's mental status. However, family members, including the patient's spouse and adult children, will have individual interpretations of the severity and impact of the patient's cognitive symptoms. 

The ‘poor historian’ maybe the assessing doctor.

In addition to standard questions in the history, the following information should be specifically sought:

  1. Previous intellectual function
  2. Change in functional status (eg. mobility, transfers, toileting/bathing, aids used)
  3. Speed of onset and course of confusion
  4. Previous episodes of acute or chronic confusion
  5. Sensory deficits – hearing, sight, speech
  6. Symptoms suggestive of underlying cause (eg. infection)
  7. Associated chronic medical problems
  8. Previous precipitants of confusion
  9. Pre-admission social circumstances – formal or informal care package
  10. Full drug history including non-prescribed drugs, why drug is prescribed, any recent changes, adherence, adherence aids used, any drugs omitted (antiparkinsonian, antiepileptics)
  11. Alcohol history

Examination

The physical examination may be helpful in distinguishing between neurologic and psychiatric disorders in an elderly patient who presents with confusion. Close attention should be given to the patient's underlying illnesses. Unless otherwise indicated by the history, the physician should focus the physical examination on the cardiovascular, neurologic and psychiatric systems. The physical examination may be normal.

The physical evaluation should include an assessment of the patient's level of arousal and orientation. Patients who lack alertness or have a clouded consciousness are more likely to have delirium than dementia. Focal neurologic changes are signs of an underlying neurologic disorder. Unfortunately, focal changes are not associated exclusively with delirium or dementia.

A full examination should be carried out including in particular the following areas:

  1. Neurological examination (however, if they can comply with a full neuro, delirium is unlikely!)
  2. Conscious level (Glasgow Coma Scale)
  3. Evidence of pyrexia
  4. Evidence of alcohol abuse or withdrawal
  5. Cognitive function using a standardised tool (eg AMTS). Cognitive tests may need to be repeated over time.

Investigations

The following investigations are almost always indicated in patients with acute confusion in order to identify the underlying cause:

  1. Full Blood Count, CRP
  2. Calcium
  3. Urea and electrolytes
  4. Liver function tests
  5. Glucose
  6. Thyroid function tests
  7. Chest Xray
  8. ECG
  9. Blood cultures
  10. Urinalysis / MSU

Other investigations may be indicated according to the findings from the history and examination:

  1. CT scan (eg. if focal neurologic signs, confusion developing after head injury or fall, raised intracranial pressure signs)
  2. Serum B12 and folate
  3. Arterial blood gases
  4. Specific cultures (MSU, sputum)
  5. Lumbar Puncture (if meningism or headache and fever)

Medical treatment

  1. Where possible withdraw or reduce any drugs causing confusion
  2. Correct biochemical derangements
  3. If there is a high likelihood of infection (eg. abnormal urinalysis or chest xray), treat promptly with appropriate antibiotics
  4. Relieve exacerbating symptoms (pain, urinary retention, constipation, thirst)
  5. Avoid major tranquillisers where possible
  6. Monitor AMTS
  7. Communicate with the relatives

Preventive measures against delirium

  • Adequate fluid intake
  • Adequate nutrition
  • Adequate mobilisation and physical exercise
  • Adequate medication (eg. for pain); check the appropriateness of drug combinations and dosages
  • Avoid withdrawal phenomena due to rapid cessation of substances on which the patient may be dependent
  • Monitor closely in the perioperative period
  • Avoid excessive sensory stimulation

Management in hospital

  1. Good lighting levels
  2. Repeated orientation (clocks, calendars, newspapers, familiar objects)
  3. Repeated reassurance, ideally by the same person
  4. Sensory aids where necessary (glasses, hearing aids)
  5. Avoidance of physical, emotional or chemical restraints
  6. Minimal distractions, calm environment (consider side room)
  7. Approach and handle gently
  8. Avoid multiple ward transfers
  9. Maintenance / restoration of normal sleep patterns
  10. Encouraging visits from familiar friends / family (and ‘distraction therapists’)

Sedation

Sedation should be avoided if at all possible. They cause worsening of confusion and increase risk of falls. However, it may be necessary in the following circumstances:

  1. In order to carry out essential investigations/treatment
  2. To prevent patients endangering themselves or others
  3. To relieve distress in highly agitated or hallucinating patients 

Wandering is not an indication for drug treatment. Decision to treat should be multidisciplinary. Document appropriately in the notes. In Parkinsonian patients, Lewy Body dementia, Haloperidol is contraindicated. Review medication every 24 hours. Start with low doses. Discontinue sedation as soon as possible. Avoid polypharmacy.  If in doubt, doctor should ask for advice from pharmacy.

Once the diagnosis of delirium, depression or reversible dementia has been made, the underlying disorder(s) should be treated. If the problem is caused by one or more specific medications, the patient should be switched to other drugs that are less likely to cause confusion in the elderly. Depression should be treated appropriately. Treatment of delirium improves cognitive functioning even in patients with underlying dementia.

If an irreversible dementia is diagnosed, attention is focused on decreasing morbidity during the clinical course of the disease. The risks and benefits of medications for dementia are decided by specialist team and should be discussed with the patient and caregivers.

Conclusion

The term ‘confusion’ is loosely used by professionals and the assessing doctor should use more specific terminology. Acute confusion is called delirium. Vulnerability plus precipitant leads to delirium, which is secondary acute brain injury and is associated with high mortality. Delirium is common both in primary and secondary care, many times poorly recognised and poorly managed in the elderly. Early diagnosis and skilled management improves prognosis.

 

Authors

Dr Saloni Gupta, Specialist Registrar, Birmingham and Solihull Mental Health Trust

Dr Abhaya Gupta, Consultant Geriatrian, Hywel Dda University Health Board

 

References

    1. Diagnostic and statistical manual of mental disorders. 4th ed. Washington, D.C.: American Psychiatric Association, 1994:124–55,339–50.
    2. Van Hemert AM, van der Mast RC, Hengeveld MW, Vorstenbosch M. Excess mortality in general hospital patients with delirium: a 5-year follow-up of 519 patients seen in psychiatric consultation. J Psychosom Res. 1994;38:339–46.
    3. Mellissa K Andrew, Susan H Freter, K Rockwood. Prevalence and outcomes of delirium in community and non-acute care settings in people without dementia: a report from the Canadian Study of Health and Aging. BMC Med.2006;4.15.
    4. Cole MG, Primeau FJ. Prognosis of delirium in elderly hospital patients. Can Med Assoc J. 1993;149:41–6.
    5. Prince M, Bryce R,Albenese E et al. The global prevalence of dementia: A systematic review and metaanalysis. Alzheimers and dementia. Jan 2013;9;1:63-75.
    6. Jayita De, Anne Wand. Delirium Screening: A Systematic Review of Delirium Screening Tools in Hospitalized Patients. The Gerontologist, Volume 55, Issue 6, 1 December 2015, Pages 1079–1099.