Authors: Helen Mansfield / Editor: Michael John Stewart / Reviewer: Jennifer Lockwood, Amanda King / Codes: ELC2, ELC4, ELP1, ELP9, SLO1, SLO7 / Published: 08/01/2021

Dementia is a progressive illness impairing the mental function of many men and women across the UK, with an incidence of 180,000 new cases each year in England and Wales

Different modalities of cognitive function can be affected, including memory, language, orientation, behaviour, attention, visual-spatial functions, executive functions and motor control.

Dementia is more common in the ageing population and, therefore, it is an important consideration when seeing older patients in the ED.

Patients may present with problems secondary to dementia, whether or not the diagnosis has been made previously. Alternatively, patients may be known to suffer from dementia and present with concomitant health problems.

Patients’ complex needs present a challenge to carers and services, which can compromise patient autonomy, and the well being of carers.

Learning bite:

It is important that emergency physicians are aware of the different types of dementia, the disease process, clinical spectra, initial diagnostic tools and possible treatments to facilitate patient-centred care for sufferers of dementia, and their carers.

There are currently thought to be four main types of dementia.

The categories have developed over time as different clinical spectra have been linked with distinct pathological processes. They are:

  • Alzheimer’s disease (AD)
  • Vascular dementia (VD)
  • Dementia with Lewy bodies (DLB)
  • Frontotemporal dementia (FTD)

Several working groups have developed criteria for the four subtypes, which are recognised by the National Institute for Health and Clinical Excellence (NICE).

Type of dementia Diagnostic criteria
Alzheimer’s disease
  • Preferred criteria: NINCDS/ADRDA
  • Alternatives include ICD-10 and DSM-IV
Vascular dementia
  • Preferred criteria: NINDS-AIREN
  • Alternatives include ICD-10 and DSM-IV
Dementia with Lewy bodies
  • International Consensus criteria for dementia with Lewy bodies
Frontotemporal dementia
  • Lund-Manchester criteria
  • NINDS criteria for frontotemporal dementia
  • DSM-IV: Diagnostic and Statistical Manual of Mental Disorders, fourth edition
  • ICD-10: International Classification of Diseases, 10th revision
  • NINCDS/ADRDA: National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer’s Disease and Related Disorders Association
  • NINDS–AIREN: Neuroepidemiology Branch of the National Institute of Neurological Disorders and Stroke–Association Internationale pour la Recherche et l’Enseignement en Neurosciences

Definite diagnoses require histopathology acquired from autopsy or biopsy.

Probable and possible diagnoses can be made using the various clinical criteria.

Many patients will have a mixed dementia with features suggestive of several subtypes. They should be treated according to the most predominant type.

Risk factors

The known risk factors for dementia include:

  • Age
  • Female gender
  • Excess alcohol intake
  • Head injury causing loss of consciousness at some point in the patient’s past
  • Depression
  • Learning difficulties
  • Diabetes
  • Obesity
  • Hypertension
  • Hypercholesterolaemia
  • Smoking

Learning Bite

There are modifiable and non-modifiable risk factors for dementia. Reduction of these factors has not been shown to reduce dementia rates.

Features of Dementia

The risk factors overlap for the different dementia subtypes, as do the different pathological processes occurring within the brain. However, certain features are found to predominate in each group.

A description of these features and how they contribute to the disease process is provided:

Neurofibrillary tangles

Neurofibrillary tangles are clumps of tau protein.

Tau proteins are required for normal axonal microtubule stability.

Clumping of these proteins, following hyperphosphorylation, causes neurones to fail and die.

Amyloid plaques

Amyloid plaques are deposits of beta amyloid.

The mechanism through which they cause cell death is not fully understood, but may be due to disrupting cell architecture.

Head injury has been shown to increase the amyloid levels within cerebrospinal fluid (CSF), which in turn may be the mechanism by which head injury can predispose to dementia.

An autosomal dominant genotype affecting amyloid precursor proteins has been associated with early-onset AD.

Synaptic loss

Synaptic loss causes death of the neurons.

As progressive connections are lost, widespread atrophy can ensue.

Lewy bodies

Lewy bodies are intracytoplasmic inclusion bodies made of neurofilaments.

They cause cellular dysfunction by displacing cellular contents.

They were first identified by Frederick Lewy in the substantia nigra of patients with Parkinson’s disease, and this finding reflects the overlap of clinical features between Parkinson’s disease and Lewy body dementia.

Cerebrovascular disease

Cerebrovascular disease may be secondary to well known risk factors such as diabetes, hypertension, hypercholesterolaemia and smoking.

Vascular dementia may follow both embolic and haemorrhagic events, multiple lesions or single infarcts.

Pathophysiological features of dementia subtypes are compared Table 1:

Table 1


The clinical presentation of dementia patients has helped categorise the four main subtypes: AD, VD, DLB and FTD. These are now discussed in more detail.

For clarity the descriptions each relate to a single subtype, but in clinical practice a mixed pattern is often seen.

Probable Alzheimer’s disease

Characteristics of AD

Progressive cognitive impairment and memory loss established by clinical and neuropsychological testing with all of the following:

  • Impairment of two, or more, areas of cognition
  • Onset between the ages of 40 and 90 years
  • No other disease capable of producing a dementia syndrome or delirium
  • This is the commonest form of dementia

A possible diagnosis of AD may be made if the presentation or progression is atypical, but no other dementia syndromes or disease states are present.

How AD affects the patient

Initially, people may seem slightly more forgetful than otherwise expected for their age. However, as the disease progresses, sufferers may get lost in familiar settings and lose the ability to perform tasks they previously enjoyed such as cooking and playing cards.

They may become repetitive, telling the same story time and time again, neglectful of their personal hygiene or have difficulties making decisions.

As their impairment becomes more severe, they may struggle to recognise family members and have difficulty communicating as their speech deteriorates.

Sudden onset of functional impairment, focal neurological signs, seizures or gait changes are unlikely to be due to Alzheimer’s disease.

Learning Bite

The hallmark of Alzheimer’s disease is a gradual but relentless impairment of memory function.

Probable vascular dementia

Characteristics of VD

Cognitive decline and memory loss established by clinical and neuropsychological testing combined with:

  • Impairment sufficient to affect activities of daily living
  • Impairment of two or more areas of cognition
  • No other disease capable of producing a dementia syndrome or delirium


Cerebrovascular disease defined as either:

  • Presence of focal neurological signs
  • Evidence of cerebrovascular disease on brain imaging, CT or MRI


A relationship between the above components defined as either:

  • Onset of dementia within three months following a recognised stroke
  • Abrupt deterioration in cognitive functions or fluctuating, stepwise progression of cognitive deficits

How VD affects the patient

Classically, people with VD will suffer with cognitive impairments within three months of an acute neurological event.

Deteriorations in function may be abrupt and stepwise, affecting their memory, attention and intellect. They commonly have mood and behavioural changes, which may make them aggressive and difficult to care for at home.

The effects of dementia on their activities of daily living are separate to but compound the impairment caused by their focal neurological deficit(s).

Progressive memory loss and changes in speech or motor function are rarely seen in VD without evidence of corresponding lesions on imaging.

Learning Bite: Typically, patients with VD develop symptoms within three months of an acute neurological event i.e. stroke. Deterioration is stepwise and abrupt. Mood swings are common.

Probable dementia with Lewy Bodies

Characteristics of DLB

Progressive cognitive decline with:

  • Impairment sufficient to affect activities of daily living
  • Prominent deficits of attention, frontal-subcortical skills and visuospatial function
  • No other disease capable of producing a dementia syndrome or delirium


Two of the following:

  • Fluctuating cognition with pronounced variations in attention and alertness
  • Recurrent, visual hallucinations that are typically well formed and detailed
  • Spontaneous motor features of parkinsonism

How DLB affects the patient

Sufferers of DLB may present with varying levels of alertness such as excessive daytime drowsiness and long daytime naps. Their cognitive level may swing abruptly from being relatively good to poor.

Parkinsonian features are common in the early stages of the disease, in contrast to AD where they may only occur later in the dementia syndrome.

Other features of DLB include repeated falls, syncope, transient loss of consciousness, neuroleptic sensitivity, systematised delusions and hallucinations in other modalities.

Focal neurological deficits, or evidence of cerebrovascular disease on brain imaging, make a diagnosis of DLB unlikely.

Learning Bite: Patients with DLB classically suffer with excessive somnolence, abrupt swings in cognitive function and features of Parkinson’s disease.

Probable frontotemporal dementia

Characteristics of FTD

Progressive, gradual cognitive decline with:

  • Early and progressive change in personality or language
  • Impairment sufficient to affect activities of daily living
  • No other disease capable of producing a dementia syndrome or delirium
  • No disturbance better accounted for by a psychiatric diagnosis

How FTD affects the patient

People in the early stages of FTD may have difficulties with social and personal conduct, which may seem impulsive or inappropriate, often with frustrated outbursts.

Their actions may cause harm such as shop lifting or jumping from a moving car, and can be sexual in nature.

Later, they may become repetitive or compulsive over certain acts with little insight into their problems.

Their expression of language may be affected early on, progressing to affect reading and writing, although their understanding is often preserved.

Sufferers may become virtually mute.

Learning Bite: Patients with FTD frequently exhibit problems with their behaviour and spoken communication.

Validation of Studies

Table 1: Sensitivities and specificities of clinical criteria for dementia subtypes
















Validation studies of the clinical criteria have been undertaken for all dementia subtypes, except FTD. They are limited by the fact that the gold standard diagnostic tests are performed at autopsy, so they consist of cohort studies once a definitive diagnosis is reached after death. This table outlines the sensitivity and specificity found to date.

Learning Bite: Probable diagnosis of dementia can be made using clinical criteria, but definitive diagnosis currently requires autopsy samples.


The ED may be the first port of call for patients with changes in behaviour associated with dementia. The ED is frequently attended by dementia sufferers who have had either:

  • An acute deterioration in their condition
  • A fall, or collapse either at home, or elsewhere, such as a residential/nursing home

It is easy, in a busy ED, to fail to fully address the issues. Simply taking a full history may require several phone calls to carers and GPs, and examination may require the help of multiple people including relatives/loved ones.

Using a systematic approach to history taking, examination and investigation of these patients will hopefully minimise errors and help identify reversible co-morbidities.

Common errors

The assessment of patients with dementia is challenging for many reasons, and errors can be made. For example:

  • It can be difficult to separate dementia from delirium and depression. All may affect a patient concomitantly
  • The impairments caused by dementia may make patient interaction more difficult
  • Symptoms and signs can be more difficult to elicit
  • It can be difficult to assess levels of distress and pain

Patient’s history

The patient may be able to give the history themselves, but it is important to obtain a collateral history to compensate for any lack of insight.

Carers and relatives may be the only source of information if the patient is unable to communicate clearly.

Important features in the history will include:

  • The acute symptoms and preceding events
  • Rate and pattern of decline
  • Areas of impairment i.e. memory, speech, motor, behaviour, decision making etc.
  • The presence of other symptoms i.e. hallucinations, delusions and depression
  • Previous medical history particularly of CVD, Parkinson’s disease and risk factors including hypertension, hypercholesterolaemia, diabetes, smoking and mental illness
  • A careful drug and alcohol history
  • A clear social history addressing how they and the carer are managing

Learning Bite: A full and collaborative history is required when assessing patients with dementia to optimise patient care.

Patient Confidentiality

atients with dementia are entitled to the same confidentiality, and autonomy, as all other patients.

They are entitled to the safeguards and professional duties required by the Mental Capacity Act.

Carers of patients with dementia must be considered when making management plans.

Dementia, Delirium and Depression

Table 1: Classical differentiating features of delirium, dementia and depression





Onset Hours to days Months to years Weeks to months
Pattern Fluctuant throughout the day

Progressive over time

Often worse at night


Often worse in the morning

Areas of impairment Global At least two areas affected Specific impairments within several areas of function
Alertness Often impaired Often normal Often normal
Affect Often agitated but can be hypoactive Dependent on subtype or severity Flattened
Course Reversible Irreversible over time Reversible

As already discussed, there can be considerable overlap between dementia, delirium and depression.

Delirium is an acute, reversible organic mental syndrome characterised by reduced ability to maintain attention to external stimuli and disorganised thinking.

Depression is a mental state of depressed mood characterised by feelings of sadness, despair and discouragement.

This table describes the classical differentiating features of each.

Examining the Patient

The emergency physician can use three components of examination to help evaluate patients with cognitive impairment.

Mental state
Mental state examinations can be used to help elucidate any patterns more consistent with mental illness.
Physical examination
Physical examination can be useful to the emergency physician in several ways:
  • It can identify reversible causes of delirium such as sepsis or injury
  • An unkempt patient may reveal difficulties with the social care of the patient
  • The patient’s interaction during the examination may indicate their degree of impairment and there may be clues which indicate a dementia subtype

For these reasons the physical examination should include:

  • A full set of observations
  • Careful examination of all systems:
    • Cardiovascular – could there be heart failure or infarction?
    • Respiratory – could there be a covert pneumonia?
    • Neurological – is there any focal neurology, Parkinsonism or signs of head injury?
    • Gastrointestinal – could the patient be constipated?
    • Genitourinary – could there be a UTI or retention?
    • Dermatological – are there any pressure sores or cellulitis?
  • A general examination to identify any injuries causing the patient distress
Clinical Cognitive Assessments

The format for each assessment is a series of questions that test attention, concentration, orientation, immediate and delayed memory, higher cortical function including praxis, perception and language and other executive function to varying extents.

They can be used as part of the initial assessment and also to reassess impairment over time.

The instruments look to show cognitive change for an individual and so the rule in/rule out threshold can be affected by pre-morbid intelligence and education.

All four require the test to be administered in the patient’s first language and most require reading and writing skills, so they may not be applicable to all patients.

A comparison of the features of each assessment is presented on the next page.

Example assessments

NICE recognises the following clinical cognitive assessments, and links to these examples can be found on the Web Resources page of this session:

  • Mini Mental State Examination (MMSE)
  • 6-item Cognitive Impairment Test (6-CIT)
  • The General Practitioner Assessment of Cognition (GPCOG) (Athens user name required)
  • 7-minute screen

In addition, a Test Your Memory (TYM) screening test for Alzheimer’s disease has been developed since the NICE guidance was published. A link to this can also be found on the Web Resources page of this session.

Comparison of Clinical Cognitive Assessments

Table 1: Comparison of the features of clinical cognitive assessments
Features of the test Test
  MMSE 6-CIT GPCOG 7-minute screen Mini-cog TYM
Time taken (minutes) 7 3-4 <4 7 3 5
Positive LR 6.3 7.3 4.8 4.7 13 6.6
Negative LR 0.19 0.15 0.22 0.09 0.25 0.07
Persons underaking the assesment Doctor and patient Doctor and patient Doctor, patient and carer Doctor and patient Doctor and patient Self-administered by the patient
Reading and writing skills Yes No Yes Yes Yes Yes
Best possible score 30/30 0/28 15/15   8/8 50/50
Score suggestive of dementia 23/30 8/28 11/15 Each score is summed with a log regression formula to convert to risk of dementia 5/8 42/50



Delirium caused by organic factors can complicate and mimic dementia. It is important to identify and treat any reversible disease process to relieve distress and improve functional level.

Investigations can aid diagnosis, especially when history and examination findings are limited. NICE advises the following tests when assessing a patient with cognitive impairment at initial presentation:

  • Routine haematology
  • Biochemistry including urea and electrolytes, calcium, glucose and LFT
  • Thyroid function test (TFT)
  • Serum vitamin B12 and folate
  • Midstream urine (MSU)

A chest x-ray, lumbar puncture, syphilis and HIV serology may be indicated by clinical findings, but should not be considered routinely. Neuroimaging can be performed electively as part of specialist assessment for patients with suspected dementia without clinical findings suggestive of acute intracranial pathology.

More information can be found in the Learning Zone session: Acute Delirium in the Elderly.

Learning Bite: Investigations are indicated to help diagnose any possible reversible element of a patient’s cognitive decline.


The management of patients with dementia should be a patient-centred, multi-disciplinary approach, utilising pharmaceuticals and supportive strategies to minimise distress and maximise the activities of patient and carer.

Treatments can aim to improve the cognitive impairment and the behavioural changes associated with dementia.

The emergency physician should have an understanding of these interventions in order to pragmatically evaluate such patients during acute medical or social crises.

Pharmacological Strategies

There has been controversy about the cost effectiveness of antidementia drugs. Current NICE guidance advises the use of specific drugs; but with some caveats.

Specific drugs

For moderate AD, current NICE guidance advises the use of:

  • Acetylcholinesterase inhibitors
  • Donepezil
  • Galantamine
  • Rivastigmine

However, there are caveats:

  • It must be prescribed by a specialist
  • MMSE score of 10-20 is required unless:
    • >20 with significant impairment of social functioning
    • <10 with a poor pre-morbid level of cognition
    • The patient has learning difficulties
    • The patient is not English speaking
  • Review of the patient and response to treatment must occur every six months
  • The carer’s view of response to treatment must be taken into consideration

Current evidence suggests they are not helpful in the management of VD, DLB or FTD.


Memantine is a drug prescribed in the past for moderate to severe dementia.

It is now advised to be started only as part of well designed trials.

Antidepressants and antipsychotics

Dementia patients may also be on antidepressants and antipsychotics to try to help control the behavioural aspects of their disease.

These should only be given to patients with severe symptoms as they are associated with an increased risk of death.

Urgent situations

In an urgent situation, where the behaviour of a patient with dementia may cause danger to themselves or others, sedative and antipsychotic medication may be appropriate.

NICE advises the following strategy:

  • Lorazepam or haloperidol are the drugs of choice
  • IM injection is the preferred route of delivery
  • The lowest effective dose should be used
  • A single agent should be used except where rapid tranquilisation is required

Patients and carers should be given the opportunity to discuss the events surrounding involuntary sedation, and the reasons why it was necessary.

Learning Bite

Acetylcholinesterase inhibitors can be helpful for reducing cognitive impairment in moderate Alzheimer’s disease. There is no evidence to support their use for other dementia subtypes at present.

Non-pharmacological Interventions

For those with mild to moderate dementia, involvement with a structured group stimulation programme, where patients engage with exercises requiring cognitive processing, may help their cognitive impairment.

This is supported by quantitative and qualitative evidence.

Behavioural changes are shown to benefit from a number of interventions including:

  • Aromatherapy and massage
  • Multisensory stimulation
  • Music and dance
  • Animal-assisted therapy

Support strategies

The aim of reaching an early diagnosis of dementia for patients is to facilitate the initiation of interventions which may help slow the progression of their disease and to help patients and carers access help and support early on.

There are a number of agencies which provide this practical and emotional support. They disseminate information regarding the symptoms and signs of dementia, its progression and available treatments, as well as giving financial and legal advice.

There are also a number of support groups specific for each dementia subtype, such as The Lewy Body Dementia Association and The Association for Frontotemporal Dementias.

All of these agencies have user-friendly websites and many have local branches with support groups and advisors who can be contacted by phone or post, for those without access to the internet.

Useful Resources

Alzheimer’s Society
The Alzheimer’s Society has a number of helpful leaflets aimed at patients and carers and these can be printed from its website.
Specific advice on driving can be found on this website.
NHS Choices website
Carers UK website
Citizens Advice Bureau
Not all patients or carers are able to get help themselves, and therefore a proactive approach must be adopted so that appropriate care packages can be put in place.

Links to these websites can be found on the Web Resources page of this session.

Learning Bite

Non-pharmacological interventions can benefit both cognitive and behavioural aspects of dementia.

It is important to be aware of the services and charities available in your local area as well as national programmes.

Failure to recognise early features suggestive of dementia can lead to:

  • Lack of investigation to exclude potentially reversible pathologies
  • Delayed assessment by specialist services
  • Delay to implementing helpful pharmacological and non-pharmacological therapies

Delay to engaging patients and carers with appropriate support networks can result in:

  • Missing the opportunity to make legal and financial decisions while the patient maintains capacity
  • A lack of vigilance required when caring for a patient such as assessing their fitness to drive and to perform certain tasks at work

These pitfalls can be avoided by raising awareness of the features and implications of dementia amongst emergency care providers.

  1. Mini Mental State Examination
  2. 6-item Cognitive Impairment Test (6-CIT)
  3. The General Practitioner Assessment of Cognition (GPCOG)
  4. Test Your Memory
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