Case 7 - Parkinson's Lecure Flashcards
what is the normal onset age of PD
usually occur 60
what is the youngest onset less than
40 and in 5% of patients
what are the core clinical features
bradykinesia, rigidity
resting tremor ± postural
where are Lewy bodies most found
the substantia nigra
what is the main component of Lewy bodies
alpha-synuclein
how does it spread through brain regions
caudo-rostral spread
what are the recessive genes In parkinsons
SNCA, LRRK2
what are the environmental factors involved with PD
toxins e.g MPTP, paraquat
possibility of spread of toxic
how is parkinsons diagnosed
bradykinesia + tremor and/or rigidity
absence of red flags and at least one of:
clear response to dopaminergic therapy
levodopa induced dyskinesia
rest tremor
olfactory loss
what are the red flags for idiopathic PD diagnosis
absent tremor, symmetrical onset
early gait abnormality and falls
pyramidal tract signs
poor levodopa response
supranuclear gaze palsy (PSP)
dysautonomia, ataxia, stridor (MSA)
apraxia, myoclonus, alien limb (CBS)
early dementia (DLB, PSP, CBS)
what are the possible pre motor features
REM sleep behaviour disorder almost all will develop PD
anosmia
constipation
depression
pain
what is bradykinesieaa and the path
increased inhibitory output to central pattern generators in brainstem
increased inhibitory output to thalamus and motor cortex
abnormal 20Hz oscillations in the basal ganglia circuit
what is rigidity
increased muscle tone
more obvious during slow movements
pathology of peripheral rigidity
reduced inhibition from type Ib fibres
overactive type II fibres
increased activity due to peripheral stimulation
pathology of central rigidity
altered activity in GABA and ACh interneurones
altered inhibition of indirect pathway
increased responsiveness of STN/GPi firing to peripheral stimulation
tremor is absent in what percent of PD patients
30%
features if tremor
less response to dopaminergic drugs
not just basal ganglia output
thalamo-cortical-cerebellar loops
modified by basal ganglia activity
dopaminergic therapy diagram
levodopa benefits
better motor improvement in short term
reduced freezing of hair
levodopa disadvantages
more dyskinesia, possibly in long term
benefits of dopamine agonists
less dyskensia and longer latency to dyskinesia
disadvantages of dopamine agonists
nausea, postural hypotension, somnolence
impulse control disorders
withdrawal problems
what are motor complications in PD
wearing-off and motor fluctuations
L-dopa induced dyskinesia
what are the mechanisms of motor complications
pulsatile dopaminergic stimulation
abnormal handling of dopamine by 5-HT neurones
abnormal synaptic plasticity
what is amantadine
NMDA receptor antagonist
reduces dyskinesia by around 40%
recent study shows effects persistent following long term treatment
NMDA and AMPA receptor antagonists
what can abrupt withdrawal of medications lead to
nueroleptic malignant syndrome
what is a SPECT scan
single photons registered by rotating gamma camera
low cost, poor resolution
long tracer half life
what is a PET scan
two y-rays emitted at 180 degrees detected by static ring of detectors
higher cost, better resolution
18F-flurodopa PET
