Neurodegeneration Two -Parkinsons Flashcards
What is parkinsons in broad terms?
Parkinsons disease is a degenerative disease of the nervous system
What is primarily affected in parkinsons?
Selective death of neurons, particularly dopaminergic neurons in the Substantia niagra
(progressive disease)
What is the incidence of PD?
3% over 80
Typically 13 years till death
Smoking reduces risk by 50%
What are the clinical cardinal symptoms of PD?
(often asymmetric at onset)
- Rest tremor
- Bradykinesia or akinesia
- Rigidity
- Abnormal postural reflexes
What are extra symptoms of pd?
Abnormal gate
falling
trouble with speech
impassive face
How is PD diagnosed?
Normally on symptoms, imaging rules outs other PD like diseases (imaging+lab tests usually not done)
- Must have 2+ cardinal symptoms
- Progressive course
- Response to levodopa (90% do)
- No alternative cause for symp
- High confidence of diagnostic accuracy (parkinsonism, rest tremour, asymmetry and response to levodopa)
Whats the differential diagnosis (what else could it be)?
EXAM
- Essential tremor: tremor wrose with posture, action, temporary improvement with alcohol, family history
- Drug induced parkinsonism
- Multiple cerebral infarcts, weakness, dementia
- Alzhiemers disease
- Parkinsons plus syndromes
- Hydrocephalus
What cells are selectively lost in PD?
Pigmented, melanin containing dopaminergic neurons of the SNpc, which project in the striatum
What happens when theres a loss of the dopaminergic neurons from the SNpc?
Loss of dopamine in striatum.
No regulation of stratial cells therefore tonic activation of fibers projecting elsewhere thus causing symptoms
What else is found in PD in the pathology?
Lewy bodies = neural inclusion bodies
Extensive pathology involving:
- Cholingergic neurons in nucleus basalis of meynert
- Noradrenalin neurons locus coerules
- Seratonin neurons midline raphe
and neurons in the cerebral cortex, brainstem, spinal cord, PNS
What is the cause of PD?
Unknown
May be:
Infection
genetic
Environmental toxins
How does infection play a role in PD?
Viruses can cause disease that are very similar to PD
How does genetics play a role in PD?
May have small role. But not obvious
What role does environmental toxins play in PD?
MPTP is a drug analgue that causes PD as it selectively kills dopaminergic neurons in the SNpc
What is the pathophysiology of PD?
- Mechanism of neuronal death is unknown in PD
- Neurotoxicity from free radical generation, excitatory neurotransmitters, mitochondrial dysfunction, loss of neurotrophic support and immune factors may all have a role.
