L3. Parkinson's disease Flashcards
what does the incidence of PD increase with
age
3 main features of PD
resting tremor
muscle ridigity
bradykinesia
what is the most common 1st sxs of PD
bradykinesia
4 other clinical feautures of PD
- postural instability
- depression
- autonomic NS dysfunction
- decreased cognitive impairment
give a few examples of autonomic dysfunction
impaired GI motility, bladder dysfunction, sialorrhoea, excessive head and neck sweating, orthostatic hypertension
give a few examples of decreased cognitive impairment
impaired visual-spatial perception and attendtion, slowness in motor tasks, impaired concentration, dementation
which part of the brain is involved in PD
substantia nigra
normal function of substantia nigra
allows smooth movements - regulation of posture and muscle tone
what is present in the substantia nigra in PD
lewy bodies and lewy neurites
what neurones are located in the substantia nigra?
dopamine
what is degraded in PD
substantia nigra
3 pathophysiological causes of PD
- loss of >80% dopamine
- loss of dopamine receptors in nigrostriatal pathway
- increase in acetylcholine in striatum
describe 4 steps in dopamine stimulation in a healthy individual
- DA stimulates basal ganglia
- basal ganglia has dampening effect on reticular formation - reducing unneccesary movements.Ach reduced
- rReticular formation sends motor info to spinal cord
- controlled smooth movement
describe 4 steps in dopamine stimulation in a person with PD
- lack of DA - basal ganglia not stimulated
- increase in ACh - inhibits smooth movement and dampening effect of RF
- info not sent to RG and therefore not sent to spinal cord
- increased muscle tension and tremor
what is parkinsonism
umbrella term used to describe conditions which have similar sxs to PD
what is the cause of PD
idiopathic
what 3 drugs can cause PD like sxs?
anti-psychotic drugs block DA receptors
MPTP
rotenone (pesticide)
what 5 things can cause secondary parkinsonism?
- drugs
- toxins
- neoplasms/strokes
- other neuronal system degenerations
- genetics
which 4 drugs can cause secondary parkinsonism?
- antipsychotics
- anti-emetics
- methyl-dopa (Anti-hypertensive)
- reserpine
what 2 toxins can cause secondary parkinsonism?
MPTP
carbon monoxide poisoning
strokes in what region of the brain can cause secondary parkinsonism?
nigrostriatal pathway
other neuronal system degenerations which can cause secondary parkinsonism?
- wilson’s disease - copper in brain
- progressive supranuclear palsy
- multiple-system atrophy
what is the only technique to differentiate PD and parkinsonism?
DAT scan (DA transporter scan)
what does the DAT scan image?
presynaptic DA transporter