Progressive deterioration of intellect, behaviour and personality as a consequence of diffuse disease of the cerebral hemispheres, maximally affecting the cerebral cortex and hippocampus.
Distinguish from delirium which is an acute disturbance of cerebral function with impaired conscious level, hallucinations and autonomic overactivity as a consequence of toxic, metabolic or infective conditions.
Dementia may occur at any age but is more common in the elderly, accounting for 40% of long-term psychiatric in-patients over the age of 65 years. A recent study shows an annual incidence rate of 187/100 000 persons. Dementia is a symptom of disease rather than a single disease entity. When occurring under the age of 65 years it is labelled 'presenile' dementia. This term is artificial and does not suggest a specific aetiology.
The rate of progression depends upon the underlying cause.
ACUTE SUBACUTE CHRONIC
WEEKS MONTHS YEARS
The duration of history helps establish the cause of dementia; Alzheimer's disease is slowly progressive over years, whereas encephalitis may be rapid over weeks. Dementia due to cerebrovascular disease appears to occur 'stroke by stroke'.
All dementias show a tendency to be accelerated by change of environment, intercurrent infection or surgical procedures.
Development of symptoms
Introspective. Unsure of self.
Difficulty in coping with work and ordinary routine -(retained insight).
Mutism, incontinence and DEATH
Loss of insight, behavioural changes, loss of inhibition.
Long-term care. Cannot be left unattended.
This initial phase of dementia may be inseparable from the pseudodementia of depressive illness.
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