Parkinson’s Disease Flashcards
What is the difference between incidence and prevalence?
Prevalence:
- how many people there are with a condition at a given time
Incidence:
- probability of occurrence of a particular medical condition
Why is the prevalence of people with Parkinson’s disease higher than the incidence?
People with Parkinson’s tend to live for a long time
Prevalance and incidence are increasing as the population is getting older
What is the definition of Parkinsonism?
A clinical syndrome comprising:
Bradykinesia
and at least one of:
- Tremor
- Rigidity
- Postural instability
What is bradykinesia?
Slowness of movement
What is the definition of Parkinson’s disease?
- The most common cause of Parkinsonism
- it is due to specific pathology in the brainstem and basal ganglia - Lewy bodies and neuronal degeneration
- it involves certain clinical features - asymmetry, sustained response to levodopa etc.
Why is it important to know the clinical features of Parkinson’s disease?
Certain clinical features at the time of diagnosis help to distinguish from other causes of Parkinsonism
What are the 4 categories of causes of Parkinsonism?
- Neurodegenerative conditions
- Drug-induced
- Vascular
- Metabolic
What neurodegenerative conditions can cause parkinsonism?
What is a term for these conditions?
- Parkinson’s disease (PD)
- dementia with Lewy bodies (DLB)
- progressive supranuclear palsy (PSP)
- multiple system atrophy (MSA)
The bottom three conditions are known as Parkinson’s Plus
They all have the features of Parkinsonism but the processes that happen in the brain and the rapidity of decline is faster than PD
What can cause drug-induced parkinsonism?
Parkinsonism is caused by a lack of available dopamine
this can occur due to degeneration of neurones or dopamine-blocking drugs
these are dopamine agonists (anti-psychotics, anti-emetics)
What are the vascular causes of parkinsonism?
Tiny blood vessels around the basal ganglia being damaged can induce parkinsonism
What is the main metabolic cause of parkinsonism?
Wilson’s disease
What are the risk factors for Parkinson’s disease?
Advancing age:
- 1% 60 years, 4% 80 years
- 5% cases are diagnosed < 40 years old
- male > female 3:2
- caucasians > Asians and africans
- rural living and farmers
- family history
What environmental risk factors lead to increased risk of Parkinson’s disease?
- Pesticide exposure
- prior head injury
- rural living
- beta-blocker use
- agricultural occupation
- well water drinking
What are the environmental risk factors that decrease risk of Parkinson’s disease?
- Tobacco smoking
- coffee drinking
- NSAID use
- calcium channel blocker use
- alcohol consumption
Why may calcium blockers decrease risk of Parkinson’s disease?
Substantia nigra cells exposed to increased calcium ion flux because of maintained autonomous electrical activity
What are the 2 pathological hallmarks of Parkinson’s disease?
- Early degeneration and death of dopaminergic neurones within the substantia nigra pars compacta of the basal ganglia
- a-syn - Lewy body (cell body) and Lewy neurite (axons)
This is the accumulation of abnormal protein that is wrapped in Lewy body
What is the abnormal protein that accumulates in Parkinson’s disease?
A - synuclein protein
this is a soluble protein that becomes insoluble and triggers a cascade of reactions that leads to the death of the dopamine releasing neurones
What is meant by “prodrome”?
Period before diagnosis
changes in the brain are happening but the patient hasn’t yet development movement symptoms
What are examples of things which may occur during the prodrome phase?
This can go back to 20 years prior to diagnosis or more
includes constipation, REM sleep behaviour disorder, lack of sense of smell and being tired during the day
What is meant by the “easy” stage of Parkinson’s disease?
The first 10 years after diagnosis
drugs can be used to replace dopamine that will treat both the motor and non-motor symptoms during this period
What is meant by the “hard” stage of Parkinson’s disease?
The more complicated symptoms of Parkinson’s start to arise
- psychosis and hallucinations
- dementia
- swallowing problems
- problems with blood pressure control
60-70% of dopamine cells are lost before the tremor and stiffness of movement arises
How is the progression of Parkinson’s disease linked to pathology?
The a-synuclein protein deposition begins in the bottom part of the brain (medulla)
the deposition then progressively moves up the brainstem and through the brain over time
the protein deposition may originate outside of the brain altogether, explaining the symptoms in the prodromal phase