Pathology of Parkinson’s Disease & Atypical Parkinson’s Disease Flashcards
What are examples of dopaminergic nigro-striatal pathway disruption?
- Vascular
- Drug-induced
- Toxic
- Inflammatory
What are the large group due to misfolded protein accumulation?
- Idiopathic PD
- PSP
- CBD
- MSA
What are examples of small proportion that has a known genetic cause?
- Familial PD
- HD
- Wilson disease
- MAPT
What happens to a section from the midbrain?
there is black substance, the substantia nigra - it has disappeared with people with Parkinson’s disease
What is the discovery timeline for Parkinson’s disease?
1817 - James Parkinson described Parkinson’s disease?
1865 - William Rutherford Sanders proposed and 1870’s Jean-Martin-Charcot actively introduced the term Parkinson’s disease
Where do the Braak stages start?
In the medulla especially in the 10th cranial nerve nuclei
• There is growing evidence that it is coming from the gut – the nerve comes and goes away from the gut
• In the brain, it spreads further to the pons, into the Locus coeruleus
• Spreads further into the substantia nigra – the patient starts to present with parkinsonism
• It spreads further into the hippocampal region – memory becomes impaired
• Spreads further to the various neocortical areas
• It finally affects the sensory cortex in the parietal lobe
What is the typical pathology of Parkinson’s disease?
- Black substance disappeared
- Locus Coeruleus have disappeared
- Other important nuclei are putamen, subthalamic nuclei should look normal
- The cerebellar cortex, white matter should look matter
Deviation from Braak stage
• There is no strong relationship between density of Lewy body pathology and severity of PD clinical symptoms
- 40% of elderly (85+) individuals have Lewy body pathology
- 67% caudo-rostral pattern
- 32% amygdala-dominant pattern (AD pathology and ApoE4 associated)
• Amygdala-dominant Lewy body pathology is seen in ~40% of AD patients
Atypical distribution of Lewy body pathology:
- It is not following Braak stage from 1-6
- It is not amygdala dominant
- It has midbrain and frontal cortex involvement
Clinical-pathological correlation in PD:
- Where the disease is motor-predominant, Parkinson’s disease starts quite early
- The patients live quite a long time
- There is another aggressive form – disease starts at an older stage – patients die with the disease much quicker
Pathological: radiological correlation of MSA
- In MSA, there is Hot cross bun signs
- Looking at the pons
- Differences in the height of the pontine base
- In histological slice, pattern, the way the pontine base atrophies [transverse fibres atrophied]
Increased likelihood of MSA if development of:
- Autonomic dysfunction within the first 3 years of symptom onset
- Severe orthostatic hypotension
- Urinary incontinence with requirement of urinary catheter
Tauopathies
Tauopathies can be either 3-repeat Tau or 4-repeat Tau or a mixture of 3-repeat and 4-repeat Tau
How are Tauopathies differentiated?
differentiated based where they dominant inclusions is located – the shape of those inclusions either neurons or astrocytes infers different shapes and forms that define what the underlying disease is
Where is Tauopathies described in?
oligodendroglia cells
