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At the heart of general practice since 1960

SARS and avian flu

A recent European survey found Britain

had the longest average time between early signs of dementia being noticed and eventual diagnosis –

Dr Claire Royston advises what investigations should be carried out

The past 10 years have seen a big shift in thinking on dementia care. The old view of dementia as a state many older patients find themselves in that necessitates them being 'taken care of', is being replaced by the more satisfying concept of a multidimensional illness requiring a precise clinical formulation with the potential to reduce associated disablement.

A more active approach to investigating possible dementia is the cornerstone of this change. The arrival of drugs with the potential for symptomatic treatment in the early stage of Alzheimer's has added further momentum.

In the UK the proportion of people over the age of 60 will increase from 20.8 per cent to 26 per cent by 2041. Within this increase there will be a disproportionately large increase in people over the age of 85 – this group of individuals is predicted to rise from 6 per cent of the over-60s to around 11 per cent by 2041, or more than one million people1.

The trends for families to become nuclear and to move around the country will reduce the number of families able to contribute to the care of elderly and dependent relatives.

What is dementia?

The diagnosis of dementia, and importantly its differentiation from conditions such as depression or delirium, is based on a detailed clinical history from the patient and a collateral informant, together with the results of a physical and mental status examination.

The key points of the ICD-102 definition of dementia are:

•A syndrome due to disease of the brain, usually of a chronic and progressive nature

•Results in disturbances of multiple higher cognitive functions

•Consciousness not clouded

•Accompanied by deterioration in emotional control, social behaviour or motivation

•Interferes with personal activities of daily living

•Changes an individual's role performance.

Two aspects of the definition are worthy of specific comment: first, dementia is not synonymous with short-term memory difficulties; second, the diagnosis no longer has an age component, so that the term senile dementia, which was historically applied to those developing a dementia over the age of 65, is a redundant term.

The identification of the syndrome of dementia does not have any aetiological implications. More than 70 diseases may underlie a dementia; however, three specific aetiological types of dementia are probably responsible for between 70 and 80 per cent of all cases of dementia. These are Alzheimer's disease, vascular dementia, and dementia with Lewy bodies.

When to investigate

The traditional practice has been for old-age psychiatry services to work mainly with patients in the middle-to-late stages of dementia. The provision of respite day care or for more extended periods was an important component of these services, together with the implementation and management of long-term continuing care during the later stages of illness.

The closure of large mental asylums and the development of community-based multidisciplinary teams in old-age psychiatry services have resulted in a reduction of resources.

There has also been a major shift in thinking as to the most pertinent role for psychiatrically trained health care professionals, given that patients in the later stages of illness mainly need social care interventions and support.

The remit of memory clinics is very variable, with some seeing only patients at the very earliest stages of dementia while others focus on the multi-disciplinary assessment of patients at any stage of a dementing process.

Where clinics exist there is a developing role for GPs in screening patients in order to identify those with a possible dementia and to initiate both an investigation and referral to specialist services at an early stage.

It is important to consider the meaning of dementia from the patient's and family's perspective, and the social stigma surrounding the condition, which tends to discourage them from presenting to the GP

until crises occur relatively late in the illness.

The individual patient initiates a relatively small number of referrals. When they do occur, the concerns they present to the GP are subjective complaints of poor memory, such as 'I go shopping and can't remember what I went for', or 'I've always had a good memory for appointments and birthdays, but now I have to write things down or I forget'.

More often patients present to the GP with less specific complaints such as 'not feeling myself', 'I feel more worried about making decisions', or they describe symptoms suggestive of a depression or anxiety disorder.

Many patients come to the attention of the GP as a consequence of their family's concerns. Typical worries are that the patient is becoming forgetful: 'She keeps losing her keys and phoning me;' and the recognition of repetitive speech patterns: 'She keeps on asking me the same question over and over again.'

Families often become concerned about changes in behaviour and self-care, for example hiding dirty clothes or 'She is no longer getting washed and changed properly'. Or concern about the patient's safety at home: 'She keeps leaving the gas cooker on and burning pans.'

There is growing interest in simple cognitive screening tests for use in general practice; the tests most commonly used are the mini-mental state examination (MMSE)3 and abbreviated mental test score (AMTS)4.

As with all tests there are issues relating to the sensitivity and specificity, and as a consequence it is difficult to specify appropriate cut-off points without identifying a large number of false-positives. Although attractive in their simplicity, these tests should be thought of as an adjunct to be used either with evidence for an early dementia obtained from a clinical history, or with evidence of a significant change in role performance.

In a climate in which there is little cash for developments in health care services, we should ask ourselves: 'Why is it important to make an early diagnosis?'

Early identification can:

•Provide opportunities for specific drug therapies that are of potential symptomatic value, for example, acetylcholinesterase inhibitors

in Alzheimer's disease

•Enable patients to engage in psychological interventions, for example, memory retraining

•Allow patients and carers to plan for the future

•Help patient's autonomy, for example, by setting up power of attorney or compiling a living will

•Prompt families to access support groups at an early stage, for example, Alzheimer's Association groups.

How to investigate

Investigating a patient with suspected dementia is a three-stage process, and the GP is most likely to be involved in the first stage. To avoid duplication or omission of investigations it is important to develop effective communication from primary to secondary care, and for timely reporting of assessments from specialist services back to the GP.

Stage 1 – Exclude The aim of the initial stage of investigation is to exclude potentially reversible causes of dementia, or additional physical or psychiatric problems that may be superimposed on a primary

dementia and exacerbate the condition.

Depressive illness and delirium are two common co-morbid conditions that must be positively excluded. A detailed history and physical and mental examinations are the key investigations.

Information is needed on the presenting symptoms in terms of onset, duration and progression. Clinical features helpful in differentiating a primary dementia from depression and a delirium are detailed in table 1.

A patient with dementia often has difficulty providing a reliable and comprehensive history, and it is therefore mandatory to obtain a collateral history from a close informant such as a spouse, or home carer.

The physical examination needs to be detailed and should include a neurological screen. Once again, the emphasis is on identifying any potentially reversible physical problems that may be either of aetiological significance or acting as aggravating factors.

A review of the current drug regime is particularly important, and basic information concerning non-specific exacerbating factors, such as poor hearing or sight, are also key elements of the examination.

There are differing views of the laboratory tests that should be undertaken as part of the screening process. The Royal College of Psychiatry5 suggests the following should form a starting point, with further tests depending on the clinical picture and physical examination:

•Full blood count

•ESR

•Serum B12 and folate

•Thyroid function tests

•Urea and electrolytes

•Serum calcium

•Liver function tests

•Random blood glucose

•Syphilis serology

•Basic urinalysis.

There is a debate concerning CT and MRI in the investigation of patients with dementia. Again, with reference to the RCP guidelines5, it is suggested that a CT scan should be performed 'if practicable, unless the patient has a history of more than a year and there is a typical clinical picture – age should not be a bar'.

More specific guidelines have been developed. For example, Burns6 suggests the following indicators for CT scanning:

•Clinical suspicion of underlying tumour

•Presence of unexplained focal neurological signs

•Development of seizure activity

•Recent head injury

•Suspicion of normal pressure hydrocephalus

•Evidence of cerebral infarction.

Due to the variation that exists in old age psychiatry services across the country, and the differing models of memory clinic in operation, it is very difficult to make generalisations about which elements of stage 1 should be undertaken by the GP.

For a patient being assessed the priority must be that all elements of stage 1 are undertaken, with no unnecessary duplication. The most effective and convenient way to ensure this occurs is for primary care organisations to raise this as a specific issue with their local service providers.

Stage 2 – Identify The next stage is to make a positive diagnosis of a dementia syndrome and identify the specific aetiological sub-type. In addition to investigations already completed, a neuropsychological assessment contributes significantly.

It is also important to make a specific assessment of the occurrence and consequences of the behavioural and psychological symptoms. A specific diagnosis of the type of dementia is desirable from many perspectives, including the patient's prognosis and appropriate treatment.

Anticholinesterase inhibitors are specifically licensed for the treatment of patients with Alzheimer's disease.

Patients with dementia with Lewy bodies are more sensitive to the side-effects of neuroleptic medication, and the treatments may be associated with an excess mortality in these patients7.

There is a clear priority to tightly manage a patient's blood pressure if the diagnosis is vascular dementia.

Stage 3 – Describe The goal here is to develop a description of important psychosocial factors that are key to understanding the impact of dementia on the patient in terms of day-to-day care and quality of life.

Further investigation is required at this stage in order to determine the nature and degree of functional disability and, equally important, to facilitate abilities that remain intact. Information relating to medicolegal issues will also be relevant to implementing the support and care of the patient, and knowledge of the patient's social circumstances and support will be important in identifying areas of potential vulnerability.

The future

From the perspective of the GP, there is an ever-increasing pressure to screen older people to detect dementia in its earliest stages, and actively to contribute to the investigation process.

Priority must be given to research to develop screening tools and programmes to help early referral to specialist services.

Furthermore, as the majority of patients with dementia will continue to be managed by primary care, we need improved systems to promote rapid communication between primary and secondary care services.

Success in developing an integrated care pathway for investigating patients who present with possible early dementia will reduce the number of patients and families presenting to services in crisis at a late stage in the illness, and it is reasonable to hope that this will reduce premature institutionalisation.

Alzheimer's disease

Mrs A came to the surgery accompanied by her husband, who had been worried about his wife for the last six months. Mrs A said she was a bit 'forgetful' but that this wasn't really causing her any problems.

Mr A described his wife as becoming progressively more muddled and forgetful over the last six months, and was constantly asking him the same question over and over again. She was reluctant to go out and meet friends, and 'got in a state' when she tried to make a meal, so that he had taken over the cooking.

Initial assessment revealed a very poor short-term memory (she could not recall three objects after five minutes), and many answers to questions were confabulatory in content – that is, they were made up.

Vascular dementia

Mrs B had been attending surgery over the last two years as part of the management of her hypertension. Her daughter brought her to see the GP as an emergency, as she had come for her weekly visit and found her mother very confused, uncharacteristically unkempt, and because she had clearly had a recent fall and bruised her face.

She described several similar episodes during the previous six months. Mrs B was unable to give a clear account of what had occurred over the preceding week. She was very upset and tearful on several occasions during the consultation. During this initial assessment she had great difficulty in concentrating on the questions and her short-term memory was poor.

Dementia with Lewy bodies

Mrs C came to see the GP with her husband, who had been worried about her for the last nine months, and this had 'come to a head' recently. Mrs C was adamant she could see men in the garden at night and, according to her husband, had become very frightened and upset because he said there was no one there.

She also said she had heard a cat in the house and had insisted her husband 'get it out' as it was bringing soil in. Mr C said he didn't know what to expect anymore, as some days his wife would be her normal self and on others quite muddled in her thinking.

The initial assessment revealed some problems with short-term memory, and on physical examination some parkinsonism features were noted.

References

1 Mann A. Epidaemiology. In: Psychiatry in the Elderly. Eds. Jaboby and Oppenheimer.

2nd Edition. Oxford: Oxford University Press, 1997:

Chapter 4, pp63-78

2 The ICD-10 Classification of Mental and Behavioural Disorders. Geneva: World Health Organisation, 1992

3 Folstein MF et al. Mini-Mental State: A practical method for grading the cognitive state of patients for the clinician.

J Psychiatr Res 1975;12:189-98

4 Hodkinson HM. Evaluation of

a mental test score for

assessment of mental impairment in the elderly. Age Ageing 1972;1:233-28

5 Royal College of Psychiatry

council report CR49. London: RCP, 1995

6 Burns A. Computed tomography in Alzheimer's disease.

Lancet 1993;341:601-62

7 McKeith IG et al. Lewy body dementia – diagnosis and treatment. Br J Psychiatry 1995;167:709-17

Claire Royston is clinical director, mental health older people services, Bedfordshire and Luton Community NHS Trust

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