Dementia

This is a syndrome where the patient has multiple cognitive deficits and memory loss (enough to impair occupational or social functioning); with either associated deterioration in language (aphasia), perception and comprehension (apraxia); impaired ability to recognise objects (agnosia); and/or a disturbance in executive functioning (inability to think abstractly and plan, initiate, sequence, monitor and stop complex behaviour). Deterioration must represent a progressive decline from a previous higher level of functioning, and consciousness should not be clouded (cf acute confusional state, delirium). Memory loss is typically for recent events and long-term memory can be remarkably intact.

Incidence

There are an estimated 163,000 new cases of dementia identified each year.¹ It increases with age, 6.7% per 1,000 person years at age 65-69, to 68.5 per 1,000 person years at age 85 and above.¹

Prevalence

Very rare below 55 years. 3% prevalence by 70 years and doubles every 5.1 years thereafter.
According to UK figures provided by the Alzheimer's Society, prevalence is 1:1000 in patients aged 40-65; 1:50 in 65-70 year olds, 1:20 in 70-80 year olds and 1:5 in the 80 age group.²

In contrast to acute confusional state, (which is usually is of recent onset and may have a reversible cause), the history should go back at least several months, and usually several years.

Typically the patient has become increasingly forgetful, and has carried out the normal tasks of daily living (eg cooking, shopping) with increasing difficulty. Sometimes the patient appears to have changed personality eg by becoming uncharacteristically rude and aggressive or be antisocial (eg. sexually disinhibited or shoplifting). They may have hallucinations or delusions, but these are unusual and may suggest a more acute confusional state or Lewy body disease. For objective evidence, carry out a test of cognitive functioning (see below).

The diagnosis of dementia should only be made after:

• Comprehensive history and physical examination. The key to diagnosis is a good history of progressive impairment of memory and other cognitive functioning (usually requiring the help of a spouse, relative or friend).
  Make specific notes on the following:⁶
  • Attention and concentration ability
  • Orientation - Time, place, person
  • Memory - both short and long term
  • Praxis - can they get dressed, lay a table etc.
  • Language function (usually evident during questioning)
  • Executive function - problem solving etc.
• Conduct a formal cognitive and mental state examination. It is important to do formal testing rather than just chatting to the patient as even quite demented people can be remarkably plausible. NICE⁶ suggests using either:
  • Mini-mental state examination (MMSE) (supplemented with informant questionnaire on cognitive decline)⁷ is a good assessment tool for dementia.⁸
  • 6 item cognitive impairment test (6-CIT)⁹ - useful as a screening tool in primary care.⁹
  • General Practitioner Assessment of Cognition (GPCOG)¹⁰
  • 7 Minute Screen^11,12
• Other reversible organic causes have been excluded

• Ensure no treatable cause has been missed by arranging FBC, ESR or CRP, MSU, U+E, LFT, Glucose, Ca²⁺ , TFT, B12 and folate (red cell folate). Don't always believe low-normal B12s: cellular deficiency may co-exist - if in doubt one should treat (homocysteine metabolites may be a better test). ¹⁴
• Consider blood cultures, CXR and CT/MRI scan, psychometric testing as appropriate to confirm diagnosis.
• VDRL/TPHA should not be performed routinely - but only if risk factors are present.
• CSF examination should be used if Creutzfeldt-Jakob disease or other forms of rapidly progressive dementia are suspected.¹⁵

• Patients with mild cognitive impairment (MCI) should be referred to memory assessment clinics. MCI is defined as a decline in cognitive function greater than expected taking account of the subject's age and education which is not interfering with activities of daily living (ADL).
• Genetic clinical genotype analysis should only be requested where an inherited cause is suspected.⁶

• Refer to a specialist with expertise in differential diagnosis - so that the subtype of dementia can be identified using the appropriate criteria and investigations.
• Nominate a key worker, and agree a mental health care management plan with the principal carer. Record in the patient's record.
  Care plans should address patient's activities of daily living (ADL), particularly trying to maximise their independence. The aim to keep the patient in as familiar and unchanging an environment as possible, building in exercise and occupational therapy, and some flexibility to cope with fluctuating abilities.
• Identify and involve all carers as much as possible, and ensure they understand both the diagnosis and prognosis (prepare the spouse for the day when the patient no longer recognizes loved ones).
• Try to involve the psychiatric social worker and carer support workers early. They can help with the initial risk assessment, arrange appropriate financial support (allowances etc.); arrange day care, day centre attendance, relief admissions etc..
• Behavioural and psychotic symptoms may need assessment by psychogeriatrician, who may also assess whether drug treatment is appropriate to prevent deterioration.
• Driving is a very complex task and people who are demented must not drive. There may be lack of insight and reluctance to loose mobility and freedom.
• Give any specific treatment (eg if hypothyroid or B12/folate are low), and treat concurrent illnesses (these may contribute significantly to confusion).

Drug treatment of dementia

Donepezil, galantamine and rivastigmine are recommended as options for moderate Alzheimer's disease only. Although this is considered to be patients within the MMSE range 10-20, the decision to offer acetylcholinesterase inhibitors should be based on an assessment that should be much broader than the MMSE results.

• It may be appropriate in those with an MMSE score >20, who have moderate dementia as judged by significant impairments in functional ability and personal and social function compared with premorbid ability.
• It may also be appropriate in those with an MMSE score <10 because of a low premorbid attainment or ability or linguistic difficulties, who have moderate dementia as judged by an assessment tool sensitive to their level of competence.
• Do not rely on MMSE results in patients with learning disabilities or where the MMSE was applied in a language in which the patient is not fluent.

NICE recommends:¹⁶

• Treatment is started by a doctor who specialises in the care of people with dementia.
• Patients who are started on the drug are checked every 6 months, usually by a specialist team.
• The check-up includes a Mini Mental State Examination (MMSE) and assessment of the patient's behaviour and ability to cope with daily life .
• The views of carers on the patient's condition are discussed at the start of drug treatment and at check-ups.
• The drug is stopped if the patient's MMSE score falls below 10 points, or if the drug isn't working.
• The least expensive of these three drugs is prescribed first. However, if this is not suitable for the patient another drug could be chosen.
• Memantine is not recommended as an option for people with moderately severe to severe Alzheimer's disease unless it is being used as part of a clinical trial (research).
• For people with vascular dementia, acetylcholinesterase inhibitors and memantine should not be prescribed for the treatment of cognitive decline, except as part of properly constructed clinical studies.

Patients and relatives with a suspected genetic cause for dementia should be offered genetic counselling by the regional genetic services.
The focus for prevention should be the modification of behaviour in middle aged and older people (reducing smoking, alcohol consumption, obesity and treating other cerebrovascular disease risk factors such as hypertension and hypercholesterolaemia).⁶