Movement disorders Flashcards
triad of parkinsonism?
‘RAT’
- rigidity (cogwheel)
- akinesia
- tremor
what is akinesia
can be in the form of slowness of movement (bradykinesia) or difficulty initiating movement with small amplitude of movements (hypokinesia)
describe the tremor in parkinsonism
4-6Hz resting tremor, pill rolling. Exacerbated by concentrating e.g. counting back from 100
what is Parkinson’s disease?
a progressive neurodegenerative disease characterised by levodopa-responsive parkinsonism
histopathology of PD?
intracytoplasmic, eosinophilic, alpha synuclein containing inclusions known as lewy bodies
lewy bodies specifically target where in the brain in PD?
the pars compacta of the substantia nigra: causes disturbance in the dopaminergic pathway
how is PD diagnosed?
clinically
PD
1) onset gradual or sudden?
2) symmetrical or asymmetrical?
3) related to age?
gradual onset
often starts asymmetrical
typically in >55s, risk increases with age
clinical features of PD?
triad of parkinsonism (RAT)
stooped posture, postural instability, slow shuffling gait
micrographia
masked facies
non-motor symptoms (constipation, REM sleep behaviour disorder, depression, dementia)
most effective treatment of PD?
levodopa
how does response to levodopa change over time
honeymoon period: initially consistent response throughout the day
progressive decline in response causing akinesia
and possibly overshoot from akinesia to dyskinesia
Levodopa
1) MOA
2) side effects
3) combined with which other drug? why?
1) dopamine precursor that can cross the BBB
2) hypotension, nausea, dyskinesia
3) peripheral dopa-decaboxylase inhibitor (carbidopa) to prevent peripheral metabolism of levodopa
Monoamine oxidase B inhibitors
1) MOA
2) side effects
3) examples?
4) used when in PD?
1) inhibit monoamine oxidase B enzyme, which catabolises dopamine to homovanillic acid
2) hypertensive crisis when consuming tyramine-containing foods e.g. cheese
3) rasagiline, selegiline
4) can be used as an add-on or even as monotherapy in early mild PD
Dopamine agonists
1) MOA
2) side effects
3) examples?
4) used when in PD?
1) directly stimulate dopamine receptors
2) hypotension, nausea, ankle swelling, hallucinations
3) pramipexole
4) can be used as initial treatment in younger pts (<70) due to high risk of dyskinesia in younger patients on levodopa
causes of drug induced parkinsonism?
chlorpramazine haloperidole lithium valproic acid metoclopramide
treatment of drug induced parkinsonism?
cessation of the agent
change from typical (1st gen) to atypical antipsychotic
symptomatic treatment with anticholinergics e.g. benztropine, procyclidine
Lewy body dementia vs parkinson’s disease dementia?
PD dementia: onset of dementia >1 year after onset of parkinsonism
LBD: onset of dementia before or at same time as parkinsonism
3 core features of lewy body dementia?
dementia
parkinsonism
visual hallucinations
features of multiple system atrophy?
parkinsonism (poor response to levodopa) autonomic dysfunction (postural hypotension, ED, urinary urgency) +/- cerebellar dysfunction
MRI of multiple system atrophy?
putaminal atrophy and ‘hot cross bun’ appearance on axial section of pons
features of progressive supranuclear palsy?
- axial akinesia and rigidity
- loss of balance and unexplained falls
- forgetfulness
- dysarthria
- loss of eye movements (supranuclear gaze palsy, esp on vertical plane)
MRI of progressive supranuclear palsy?
midbrain atrophy with a hummingbird sign on sagittal view
what causes vascular parkinsonism?
multiple small strokes or infarcts