Old age onset psychiatric disorder: Dementia

 Dementia is old age onset psychiatric disorder commonly after  the age of 65. Dementia is a syndrome due to diseases of brain usually chronic and progressive on nature in which there is disturbance of multiple cognitive function including memory, thinking, orientations, comprehension, calculation learning capacity, language and judgment. The consciousness  is not clouded. Dementia produce decline in intellectual functioning and usually some interference with personal activities of daily living such as washing, dressing, personal hygiene, excretory and toilet activities.

Dementia is an acquired  global impairment of intellect capacity, memory and personality, but without impairment of consciousness  that the patient has impaired ability to learn new information or to recall previously learned information, associated with one or more of the following cognitive disturbance: aphasia, apraxia, agnosia and disturbance of executive functioning(planning, organizing, sequencing and abstracting) associated social and occupational functioning, with a course characterized by gradual onset and continuing cognitive decline .

Dementia is the major cause of long term disability in old age. The point prevalence of dementia in those over 65 days range from 3-8% and is 15% those over 80, with relative excess of dementia at Alzheimer type among woman and of vascular dementia among man . The incidence of dementia in a Liver pool community study confirmed by three year follow up was 9.2\1000 cases per year, broken down into Alzheimer’s type (6.3/1000), vascular(1.9/1000) and alcohol related (1.0/1000). Rates approximately trebled with every ten year of age. The distension between dementia occurring before the age of 65 and that occurring after  was based on the assumption that the cases was different. Although the expression and course of diseases ways vary with age the major findings demented patients of all age are broadly similar.

           

  Prevalence- 5-8% over 65

                     15-20% over 75

                     25-50%over 85

Two principal patterns of intellectual impairment have been described in dementia. The

First reflecting cortical dysfunction occurs in the majority the second subcortical dementia is less common but there is considerable overlap in clinical presentation. The cortical pattern of intellectual decline includes loss of language, learning, perception, calculation and praxis skill and manifests as aphasia, amnesia, agnosia, acalculia and apraxia. The subcortical pattern result from disorders motivation, mood, attention and arousal, reveled by psychomotor slowing, memory loss, affective disorders, and impaired problem solving. The cortical dementia produce neuropathlogical changes involving primarily, but not exclusively association cortex and medical temporal lobes Alzheimer’s diseases and selected strokes. Mixed subcortical and cortical pattern occur in multiple sclerosis, stroke, severe head injury, Creutzfeidt- Jacob diseases and neoplastic cases.

Marsden (1985) reported 708 patient data shows:

Alzheimer’s diseases             39%

Multiinfract dementia           13%

Alchol dementia                   8%

 Metabolic                            4%

 Hydrocephalus                    4%

 Tumor                                  3%

  Huntgotns diseases              2%

  Infections                            1%

 Toxic condition                    1%

  Post traumatic                    1%

  Parkinsion diseases              0.1%

  Subdural haemetama            0.1%

  Post anoxic                          0.2%

  Pseudodementia                 9%

  Other                                    2%

Causes :

Causes of dementia are found  about 15% patient below the age of 65, but in fewer than 5% of those of 65 presenting with intellectual impaitment. About half of treatable patients have psedodementia the other have treatable tumor, haemartoma, hydrocephalus, metabolic or infective disorders. There are few studies of causes dementia in third world countries. The prevalence of dementia in shanghai in people over the age of  55 is 4-6% .

Alzheimer’s diseases(AD)

Alzheimer’s disease  is associated with decline in both memory and thinking sufficient to impair activities of daily living. Which is insidious onset slow deteroration and have minium duration of symptoms and imparliment of six months. Three phase of the disease include in earliest stages the patient complaints of forgetfulness and difficulty in naming and word findings. This may be accompanied by disorder of visuospatiol skills. Some degrees of depression in reaction to the cognative impairment or some considerable degree of performance anxiety or both may commonly accompany such features. In second stage that impairment become more serve and is accompanied by other focal features such as apraxia, agnosia, and comprehension difficulties and failure to mental calculation. The loss of sense of personal identify occurs in the later stages of disorders. Alzheimer’s diseases currently represent a major burden for society (Lal et al, 1999).

The cardinal neuropathlogical feathers of Alzheimer’s diseases are presence of neurotic plaque and neurofibrillary tangles at post partum on cortical biopsy. Both can occur in normal aging but the tangles are most commonly confirmed to the hippocampi inn dementia. The quality of plaques and tangles has been shown to relate to ante-martem measure of degree of cognitive impairment.In addition there is gurnulovaclur degeneration in the hippocampi, aluminum and amyloid deposition, hyaline degradation  and synaptic connections .

      

Parkinson’s  disease

It  is slowly progressing dementia characterized by tremor ,rigidity, bradykinasia  and postural instability. Twenty to sixty percent are associated  with  dementia on later life. Parkinson’s dementia is also associated with  cognitive slowing, executive dysfunction, impairment of memory. Parkinsonism is also associated with high prevalence of depression.

    Lewy body dementia

Lewy body dementia covers 7-26% of whole dementia feature includes earlier onset , prominent vaculation feature of parkinsonism, rapid evolution  of dementia associated with psychiatric symptoms. It is better to respond with antipsychoties,  histopathology shows lewy  inclusion bodies in the cortex .

Vascular Dementia

Arteriosclerosis was regarded major cause  of senile dementia Tomlinson  et al (1970) demonstrated that at least 50-100 ml of brain tissue had in infracted vascular dementia occurred. The advance of CT and MRI scanning has revealed all increasing frequency of ischemic abnormality in the deep while matter in-patient with dementia. Multiinfract dementia is characterized by abrupt episodes of hemiperasis, sensory changes, dysphasia and focal symptoms from stroke with fluctuating course and stepwise  deterioration in intellectual functioning cognitive deficit and often patchy depend upon sites of lesion. Post CVA 8% people dementia.

Huntiongton’s disease

It is autosomal disorder dominant disorder of choreform movement and subcortical dementia, haws a prevalence of about 4-9 cases per 100,000 in UK . Two third of living Huntington’s  disease present with chorea. Chorea consist of  muscles jerks, randomly distributed in space and time , brief in duration and unpredictable in appearance. Eye movements are also abnormal. Dysarthria and dysphasia worsen as the disease progressively increased.

Creutzfeidt-Jacob disease(Prion disease)

It is slow virus disease causing dementia. It is degenerative disease of with long incubation periods are manifested as the disease usually progress swiftly, without remission  and death within months.

Other causes of Dementia

Endocrine disorder, hypothyroidism, hypercalcaemia, hypoglycemia

Brain Tumor

Subdural haematoma

Head injury

Vitamin deficiency vitamin B12,folic acid, niacin

Infection-HIV

Toxic- effect of Alchol

Brain tumor may present with dementia, particularly slowly growing deep midline tumor of the corpus callesum  or frontal lobes ,frontal meninges are important to defect, as they are benign and potentially curable. Chronic subdural haematoma is another treatable causes of dementia , in which head injury may have been previously . Hydrocephalus is usually due to tumors particularly in the posterior fossa , obstructing the cerebral aqueduct and by CSF flow.

Treatment of dementia:

• Evaluation of psychiatric, neurological and general medica l evaluation of nature and cause of cognitive and non- cognitive symptoms.
• Follow up routinely every 6 months ,if complex condition more frequent check up and admission.
• Evaluation of  suicidal risk and potential for violence .
• Education to family member and patient

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• Long term follow up.