The main differential diagnosis of dementia is depression, especially major depression, which is termed pseudodementia. The mode of onset is one way in which it may be possible to distinguish between depression and dementia. Dementia has a slow and surreptitious onset that is not clear-cut, while depression has a more definable and clear-cut onset that may be precipitated by a specific incident. Patients often have a past history of depression. Those with dementia have no insight; those with depression have insight, readily give up tasks, complain bitterly and become distressed by their inability to perform normal enjoyable tasks. It is vital to determine the cause of dementia.
In response to cognitive testing, the typical response of the depressed patient is ‘don’t know’, while making an attempt with a near-miss typifies the patient with dementia (see TABLE 8.4).
Table 8.4Comparison of dementia and pseudodementia (commonly severe depression) ||Download (.pdf) Table 8.4 Comparison of dementia and pseudodementia (commonly severe depression)
| ||Dementia ||Pseudodementia |
|Onset ||Insidious ||Clear-cut, often acute |
|Course over 24 hours ||Worse in evening or at night ||Worse in morning |
|Insight ||Nil ||Present |
|Orientation ||Poor ||Reasonable |
|Memory loss ||Recent > remote ||Recent = remote |
|Responses to mistakes ||Agitated ||Gives up easily |
|Response to cognitive testing (questions) || |
Slow and reluctant but understands words (if cooperative)
It is vital to detect depression in the elderly as they are prone to suicide: ‘Nothing to look back on with pride and nothing to look forward to.’ The middle-aged and elderly may not complain of depression, which can be masked. They may present with somatic symptoms or delusions.
Note that depression occurs commonly in people with dementia, especially in the early stages.
Dementia (chronic organic brain syndrome)13
The incidence of dementia increases with age, affecting about 1 person in 10 over 65 years and 1 in 5 over 80 years. It doubles every 5 years from age 65 and is uncommon under 60 years. The important causes of dementia are:
Note: Mixed dementia should be considered.
Other causes of dementia:
normal pressure hydrocephalus
In Alzheimer disease, there is insidious onset with initial forgetfulness progressing to severe memory loss (see FIG. 8.5). In frontal dementias the earliest manifestations are personality change and alteration of behaviour, including social dysfunction. Dementia with Lewy bodies is characterised by any two of visual hallucinations, spontaneous motor Parkinsonism and fluctuations in the mental state. Vascular dementia usually starts suddenly and is accompanied by focal neurological signs with evidence of cerebrovascular disease.
Symptom progression in Alzheimer disease
BADL = basic activities of daily living.
Source: Modified from Feldman et al. Clinical Diagnosis and Management of Alzheimer’s Disease (1st edn), 1998
The characteristic feature of dementia is impairment of memory. Abstract thinking, judgment, verbal fluency and the ability to perform complex tasks also become impaired. Personality may change, impulse control may be lost and personal care deteriorate.
Risk factors for dementia include:
Differential diagnosis of dementia includes:
normal cognitive impairment of ageing
acquired brain injury
various medical conditions (e.g. anaemia, thyroid/endocrine disorders)
The DSM-IV (TR) criteria for dementia are presented in TABLE 8.5 and clinical clues suggesting dementia in TABLE 8.6.
Table 8.5DSM-IV (TR) criteria for dementia of Alzheimer type (modified) ||Download (.pdf) Table 8.5 DSM-IV (TR) criteria for dementia of Alzheimer type (modified)
|Diagnosis of dementia requires evidence of: |
|A1 ||Clear evidence of decline in memory and learning |
|A2 || |
At least one of the following cognitive disturbances:
|B ||Disturbance significantly interferes with social and work functions |
|C ||Gradual onset and continuing cognitive decline |
|D ||Not due to known organic causes (e.g. drugs, cerebrovascular disorders) |
|E ||Not due to delirium |
|F ||Not due to another axis 1 disorder (e.g. major depression) |
Table 8.6Clinical clues suggesting dementia ||Download (.pdf) Table 8.6 Clinical clues suggesting dementia
|1 Patient presentations |
|New psychological problems in old age |
|Ill-defined and muddled complaints |
|Uncharacteristic behaviour |
|Relapse of physical disorders |
|Recurrent episodes of confusion |
|2 Problems noted by carers |
|‘Not themselves’—change in personality (e.g. humourless) |
|Domestic accidents, especially with cooking and heating |
|Unsafe driving |
|False accusations |
|Emotional, irritable outbursts |
|Tendency to wander |
|Misplacing or losing items (e.g. keys, money, tablets, glasses) |
|Muddled on awakening at night |
|3 Mental state observations |
|Vague, rambling or disorganised conversation |
|Difficulty dating or sequencing past events |
|Repeating stock phrases or comments |
|Playing down obvious, perhaps serious, problems |
|Deflecting or evading memory testing |
The many guises of dementia can be considered in terms of four major symptom groups:14
Deficit presentations—due to loss of cognitive abilities, including:
confusion and restlessness
apathy (usually a late change)
self-neglect with no insight
poor powers of reasoning and understanding
Unsociable presentations—based on personality change, including:
Dysphoric presentations—based on disturbed mood and personal distress, including:
Disruptive presentations—causing distress and disturbance to others, including:
aggressive, sometimes violent, behaviour
agitation with restlessness
The problem occasionally results in marked emotional and physical instability. It is sad and difficult for relatives to watch their loved ones develop aggressive and antisocial behaviour, such as poor table manners, poor personal cleanliness, rudeness and a lack of interest in others. Sometimes severe problems, such as violent behaviour, sexual promiscuity and incontinence, will eventuate.
There is always the likelihood of accidents with household items such as fire, gas, kitchen knives and hot water. Accidents at the toilet, in the bath and crossing roads may be a problem, especially if combined with failing sight and hearing. Such people should not drive motor vehicles.
Without proper supervision they are likely to eat poorly, neglect their bodies and develop medical problems, such as skin ulcers and infections. They can also suffer from malnutrition and incontinence of urine or faeces. The median time to death after diagnosis is 3 years.
Management of suspected dementia
Exclude reversible or arrestable causes of dementia:
full medical history (including drug and alcohol intake)
mental state examination: select from several tools, e.g. Montreal Cognitive Assessment
investigations (see Laboratory investigations, above, and CHAPTER 45)
Refer to a specialist to confirm the diagnosis and provide ongoing shared care. There is currently no cure for dementia—the best that can be offered to the patient is tender, loving care.
Dementia is a terminal disease.
Education, support and advice should be given to both patient and family. Legal issues should
be discussed such as enduring power of attorney, enduring guardianship and advanced care planning. Multidisciplinary evaluation and assistance are needed. Regular home visits by caring, sympathetic people are important. Such people include relatives, friends, GPs, district nurses, home help, members of a dementia self-help group, religious ministers and meals on wheels. People with dementia tend to manage much better in the familiar surroundings of their own home and this assists in preventing behaviour disturbance. Encourage the person to exercise, eat well and stay socially connected.
Special attention should be paid to organising memory aids, such as lists, routines and medication, and to hygiene, diet and warmth. Adequate nutrition, including vitamin supplements if necessary, has been shown to help. Provide ongoing support to carers.
Driving is a problem, especially as many are reluctant to give up their licence. Those with mild dementia are more likely to cause road accidents. In some states it is compulsory for doctors to report patients who are unfit to drive. If uncertainties arise or a patient is recalcitrant, refer to the local Road Traffic Authority. In Sweden it is recommended that those with moderate to severe dementia should not drive.
The behavioural and neuropsychiatric problems are a major management issue. Depression can occur early in dementia and requires intervention. Demented patients are vulnerable to superimposed delirium, which is often due to:
urinary tract infection
other febrile illness
Delirium should be suspected if a stable patient becomes acutely disturbed.
Dementia and Parkinson disease
A feature of Lewy body dementia, Parkinson disease is a very difficult yet common problem. One problem is that medication affects the mental processes. Lewy body dementia is extremely sensitive to the typical antipsychotics—typical agents should not be prescribed.16 Quetiapine is the agent of choice. The choice of drugs is critical to care, so referral to an experienced team which can provide a good neuropsychiatric assessment is advisable. The best option appears to be the administration of:
levodopa to maximum dose
quetiapine at night
Demented patients often do not require any psychotropic medication. Antidepressant drugs can be prescribed for depression. Citalopram is effective in treating agitation but tricyclic antidepressants (TCAs) tend to aggravate confusion.16 Benzodiazepines are effective for short term use in agitated behaviours. The cholinesterase inhibitors donepezil, galantamine and rivastigmine appear to delay progression of dementia to a modest extent only. There appears to be no differences between the available agents. Beware of drugs that aggravate such as anticholinergics, opiates, TCAs, frusemide, prednisolone and salbutamol.16
Available drugs for Alzheimer disease
donepezil 5 mg (o) nocte for 4 weeks, increase to 10 mg nocte as tolerated
galantamine prolonged release 8 mg (o) daily for 4 weeks, increase to 16 mg daily or 24 mg if tolerated
rivastigmine 1.5 mg (o) bd for 2 weeks, increase gradually up to 6 mg bd as tolerated
rivastigmine 4.6 mg transdermal daily for 4 weeks, then 9.5 mg daily as tolerated
Aspartate (NMDA) antagonist
Based on double-blind randomised trials of the two drugs donepezil and rivastigmine and using Cochrane data,15,17 the following points emerge:
only modest improvement overall
greatest improvement with higher doses
higher doses less well tolerated
long-term efficacy unknown
clinical effectiveness in severe disease has not been demonstrated18
The newer agent memantine appears to have similar outcomes and can be used in combination.
Using evidence-based medicine criteria on numbers needed to treat (see CHAPTER 13), the evidence shows that 13 patients must be treated with rivastigmine 6–12 mg/day for 6 months for one patient to display clinically meaningful improvement.18,19
To control psychotic symptoms or disturbed behaviour probably due to psychosis:20
olanzapine 2.5–10 mg (o) daily
risperidone 0.25–2 mg (o) bd, increasing to maximum of 2 mg daily
To control symptoms of anxiety and agitation use:
oxazepam 7.5 mg (o) one to three times daily
Benzodiazepines should be used only for short periods (maximum 2 weeks) as they tend to exacerbate cognitive impairment in dementia.
As yet there is insufficient evidence for the efficacy of complementary medicines such as Ginkgo biloba,21 vitamin E22 and other antioxidants in treating (alleviating symptoms in) dementia, despite some epidemiological evidence, especially in the case of vitamin E. However, we should encourage our patients in preventive healthy lifestyle strategies, such as optimal nutrition rich in essential vitamins and exercise. Deficiencies of folate, vitamin B12 and vitamin D should be treated.