Different Types of Dementia

Question 1

What is the pathophysiology of Alzheimer’s disease?

Answer 1

• Degeneration of cholinergic neurons in the nucleus basalis of Myener leading to deficiency of acetyl choline. There are also microscopic and macroscopic changes:
  
  • Microscopic: neurofibrillary tangle and b-amyloid plaque formation
  • Macroscopic: cortical atrophy. Widened sulci and enlarged ventricles

Question 2

What causes Vascular Dementia?

Answer 2

• Vascular dementia occurs as result of cerebrovascular disease either due to stroke, multi-infarcts or chronic changes in small vessels

Question 3

What causes Lewy Body Dementia?

Answer 3

• In Lewy body dementia, there is abnormal deposition of protein within neurons of brainstem, substantia nigra and neocortex.
• Outside the brainstem, LBs are associated with more profound cholinergic loss than AD.
• Within the brainstem they are associated with dopaminergic loss and parkinsonian-like symptoms

Question 4

What causes Fronto-Temporal Dementia?

Answer 4

• There is specific degeneration (atrophy) of the frontal and temporal lobes of the brain.
• One type is Pick’s disease where protein tangles (Pick’s bodies) are seen histologically

Question 5

What are stages of Alzheimer’s disease?

Answer 5

• Early Stages: memory lapses (most common presenting symptom), difficulty finding words, forgetting names of people/places
• Disease Progression: apraxia, confusion, language problems, difficulty with executive thinking, visuospatial abilities, agnosia
• Later Stages: disorientation to time and place, wandering, apathy, incontinence, eating problems, depression, agitation, hallucinations

Question 6

What is the ICD-10 Criteria for Alzheimer’s disease?

Answer 6

1. The general criteria for dementia A–D must executive functions:
2. No evidence for any other possible cause of dementia or systemic disorder.
   
   1. Early onset Alzheimer’s disease
      
      1. General criteria for Alzheimer’s met and age of onset is <65
      2. At least one of the following must be met: (1) relatively rapid onset and progression; (2) in addition to memory impairment there is aphasia, agraphia (↓ ability to communicate through writing), alexia (↓ ability to read), acalculia (↓ ability to perform mathematical tasks) or apraxia
   2. Late onset Alzheimer’s disease
      
      1. General criteria for Alzheimer’s met and age of onset is >65
      2. At least one of the following must be met: (1) slow, gradual onset and progression; (2) predominance of memory impairment over intellectual impairment.

Question 7

What are the characterisitics of Vascular Dementia?

Answer 7

• Usually presents in the late sixties or early seventies.
• Stepwise rather than continuous deteriorations

Question 8

What are symptoms of Vascular Dementia?

Answer 8

• Memory loss
• Emotional changes (depression, apathy)
• Personality changes (earlier than memory loss)
• Confusion
• Neurological symptoms or signs (e.g. spastic weakness, increase tendon reflexes)

Question 9

What are examination sign of Vascular Dementia?

Answer 9

Examination

• Focal neurology (often upper motor neurone signs)
• Signs of cardiovascular disease elsewhere

Question 10

What are features of Dementia with Lewy bodies?

Answer 10

• Day to day fluctuations in cognitive performance
• Recurrent visual hallucinations
• Motor signs of Parkinsonism (tremor, rigidity, bradykinesia)
• Recurrent falls, syncope, depression
• Severe sensitivity to neuroleptic drugs

Question 11

What is the difference between Parkinson’s disease with dementia and DLB?

Answer 11

• People with Parkinson’s disease who develop dementia after 12 months are diagnosed as Parkinson’s disease with dementia
• DLB is where dementia and Parkinsonian features within 12 months of one another

Question 12

What are signs and symptoms of Fronto-temporal dementia (including Pick’s disease)?

Answer 12

• Usually occurs at 50-60 years insidiously. Family history positive in 50% of cases
• Early personality change: disinhibition, apathy, restlessness, worsening of social behaviours, repetitive behaviour, language problems,
• Memory is preserved in early stages whereas insight is lost early

Question 13

What are characterisitcs, symptoms and signs of Huntingtons disease?

Answer 13

• Autosomal dominant therefore strong family history.
• Abnormal choreiform movement of face hands and shoulder and gait abnormalities. Dementia presents later

Question 14

What are features of CJD?

Answer 14

• Onset usually before 65
• Rapid progression with death within 2 years
• Disintegration of virtually all higher cerebral function
• Dementia associated with neurological signs (pyramidal, extrapyramidal, cerebellar)

Question 15

What are features of Normal Pressure Hydrocephalus?

Answer 15

• Average age of onset is after 70. Triad of dementia with prominent frontal lobe dysfunction, urinary incontinence and gait disturbance (wide gait).