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ALZHEIMER'S DISEASE AND DEMENTIA
Dementia is a clinical syndrome characterized by impairment of multiple higher cortical functions that include memory, orientation, thinking, comprehension, calculation, capacity for learning, language, judgment,  executive function and visuo-spatial function. It is usually accompanied or preceded by deterioration in emotional control, social behavior or motivation.
Alzheimer's disease is the most common cause of dementia. Sporadic cases usually present after >60 year while familial types are rare and present in <60 year of age (early-onset dementia).
Short-term memory loss is the most common early symptom. Other spheres of cognitive impairment manifest after several years.

Diagnosis

  • In order for a diagnosis of dementia to be made, cognitive impairment should be severe enough to represent a significant decline from previous level of occupational and social functioning

Diagnostic Guidelines

  • Diagnosis of subtype of dementia is done by using international standard criteria
  • Clinical assessment is the basis of diagnosis
    • Neuropsychological testing is used when dementia is not clinically obvious

Alzheimer’s Disease

  • Diagnosis of Alzheimer’s disease should be made when typical degenerative syndrome is present
    • Definitive diagnosis is only confirmed on microscopic exam of the brain (usually at autopsy)
    • MRI findings of hippocampal atrophy may help in the diagnosis of Alzheimer’s disease in a patient with typical clinical presentation
    • Amyloid positron emission tomography (PET) scan and cerebrospinal fluid amyloid and tau levels may help in the diagnosis of Alzheimer's disease

Vascular Dementia

  • Diagnosed by history, focal neurological signs and symptoms and/or imaging studies

Dementia with Lewy Bodies

  • Histopathologically, Lewy inclusion bodies are present in the cerebral cortex
  • May be diagnosed based on history, physical, neurological examination and functional neuroimaging studies usually MRI

Assessment

Clinical Assessment

Should include, but is not limited to, the following:

  • Careful evaluation of medical, psychiatric, neurological, medication and social history
  • Detailed review of cognitive and behavioral symptoms from patient and caregiver

Physical Examination

  • Exclude treatable causes which may be contributing to dementia

Laboratory Tests

Diagnostic Tests

  • Complete blood count (CBC), serum electrolytes, liver function test, renal function tests, glucose, thyroid function, vitamin B12 and folate levels, and syphilis serology (if syphilis is suspected)
  • Neuroimaging (MRI, CT scan)
  • Neuropsychological testing

Cognitive and Mental State Examination

  • Montreal Cognitive Asssessment, 7-Minute Screen, Memory Impairment Screen, Mini-Mental State Exam, or Abbreviated Mental Test
  • Score interpretations should also consider other factors that may affect the performance (eg educational level, social class, cultural background, literacy, language or other communication difficulties)
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