1. Epidemiology and aetiology
Dementia increases in prevalence with age, and is a progressive disease process with a community-wide impact, and an unremitting course.
About 5 per cent of people aged 65 and over have some form of dementia, with the prevalence rising to about 20 per cent by 80 years and nearer one in three by 90 years.
A recent report from the Alzheimer's Society estimated that there are currently 700,000 people with dementia in the UK and that this number will grow to over one million by the year 2025.
The NICE/Social Care Institute for Excellence dementia jointly published guidelines in 2006 to equip GPs with a series of recommendations that will enhance clinical awareness and management. In addition, their broad scope should inform inter-agency working, commissioning and training.
The guidelines recommend that general population screening for dementia should not be undertaken. However, for middle-aged and older people, vascular and other modifiable risk factors for dementia - for example, smoking, excessive drinking of alcohol, obesity, diabetes, hypertension and raised cholesterol - should be reviewed and treated.
Types of Dementia
The aetiology of the dementia syndromes remains unclear, with different brain structures being affected in different ways.
For the purposes of everyday general practice we should think about the main types of dementia syndrome in clinical rather than pathophysiological terms, as follows.
Alzheimer's disease, the most common form, is characterised by progressive loss of cognitive then physical function, often over a long course.
Vascular dementia, the second most common form, is associated with hypertension and generalised vascular disease, and is characterised by step-wise changes in cognitive and functional ability and a shorter course than Alzheimer's disease.
Dementia with Lewy bodies shares some features with Parkinson's disease and is characterised by the experience of visual hallucinations. There are also rare types of dementia, including frontal lobe dementias and new variant Creutzfeldt-Jakob's disease.
Mixed patterns of dementia types also occur.
2. Making a diagnosis
Dementia is often insidious in onset and difficult to diagnose in the early stages. There is no classic presentation, since one in three patients with dementia will also have features of a concurrent mental illness. Some of the common early changes that occur in dementia syndromes are shown in the table below.
A clinical diagnosis of dementia requires evidence of memory loss and impairment of one other aspect of cognition, such as an impaired ability to perform goal-directed tasks or an inability to sustain attention, sufficient to cause the individual or their family significant problems.
If a dementia syndrome is suspected a comprehensive assessment should be carried out, staged over several consultations if necessary. This should include history taking from the patient and an informant; cognitive and mental state examination using a brief instrument; a basic dementia screen of FBC, calcium, glucose, and renal and liver function, thyroid function tests, serum vitamin B12 and folate levels (to identify tractable co-morbidities); and a review of medication to identify drugs, including OTC products, that may adversely affect cognitive functioning.
Cognitive testing should be undertaken using a standardised instrument. The mini mental state examination is frequently used, but a number of alternatives exist. None of these tests is diagnostic and scores should be interpreted in the clinical context.
Memory assessment services are increasingly the single point of referral for patients with possible dementia. These are likely to offer a range of assessment, diagnostic, therapeutic and rehabilitation activities.
Communicating or receiving a diagnosis of dementia is challenging and often distressing. GPs should make time available to discuss the diagnosis and its implications with the patient and with family members, with consent. Patients and family are likely to need ongoing support to cope with the diagnosis and the later stages of the dementia.
Any advice and information given should be recorded. The Mental Capacity Act 2005 in England and Wales offers new opportunities for patients who wish to plan ahead for care, health decisions and finances. A range of new helpful leaflets for patients and families is available from the Ministry of Justice.
EARLY CHANGES IN DEMENTIA SYNDROMES
- Shallowness of mood, frustration
- Lack of emotional responsiveness and
- consideration of others
- Depression and/or anxiety
- Short-term memory deficit with particular difficulty in registration and recall of new information
- Thinking becomes concrete with a reduced range of concerns
- Perseveration of thoughts and actions, accompanied by repetitive speech
- Social withdrawal
- Emotional and physical disinhibition
- Difficulty in carrying out purposeful tasks: domestic tasks, dressing
- Socially inappropriate behaviour, self-neglect
- Disorientation progressively for time, place and eventually for person
- Usually later in the disease process
Management of dementia syndromes requires systematic follow-up of patients and their carers, and rests on three approaches: using symptom-modifying medication, solving problems caused by challenging behavioural and psychological symptoms, and liaising with social care services.
The recent NICE review of the cholinesterase inhibitors donepezil, rivastigmine and galantamine concluded that they do seem to work as symptom-modifiers, at least for 12 months or so, in a large minority of patients with Alzheimer's disease.
They do not improve memory but do seem to improve social interaction, and make life more enjoyable for both the patient and those around them.
Psychological and behavioural symptoms occurring in the middle stages of the disease process can be difficult to understand. We recommend using the PAID acronym (see box above).
Dementia is a long-term condition and social care - generally the local council's adult services department -will help support patients with this condition. Knowledge of local services including the voluntary sector - for people with dementia and their carers - is beneficial in providing tailored care, as the dementia becomes more disabling.
- Physical problems, like pain, are triggering behaviour changes
- Activities of others are annoying or frightening the person with dementia
- Intrinsic features of dementia are appearing, like walking ('wandering') and stroking
- Depression underlies the behaviour change, or there are delusions - psychotic symptoms
- Alzheimer's Society. The rising cost of dementia in the UK, London: Alzheimer's Society, 2007.
- NICE/SCIE. Dementia: Supporting people with dementia and their carers in health and social care. London: NICE, 2006 www.nice.org.uk/guidance/cg42
- Ministry of Justice www.justice.gov. uk/whatwedo/mentalcapacity.htm.
- Contributed by Professor Steve Iliffe, professor of primary care at University College London and Professor Jill Manthorpe professor of social work at King's College, London.