Case 7 - Parkinson's Lecure Flashcards

1
Q

what is the normal onset age of PD

A

usually occur 60

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2
Q

what is the youngest onset less than

A

40 and in 5% of patients

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3
Q

what are the core clinical features

A

bradykinesia, rigidity
resting tremor ± postural

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4
Q

where are Lewy bodies most found

A

the substantia nigra

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5
Q

what is the main component of Lewy bodies

A

alpha-synuclein

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6
Q

how does it spread through brain regions

A

caudo-rostral spread

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7
Q

what are the recessive genes In parkinsons

A

SNCA, LRRK2

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8
Q

what are the environmental factors involved with PD

A

toxins e.g MPTP, paraquat
possibility of spread of toxic

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9
Q

how is parkinsons diagnosed

A

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

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10
Q

what are the red flags for idiopathic PD diagnosis

A

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)

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11
Q

what are the possible pre motor features

A

REM sleep behaviour disorder almost all will develop PD
anosmia
constipation
depression
pain

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12
Q

what is bradykinesieaa and the path

A

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

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13
Q

what is rigidity

A

increased muscle tone
more obvious during slow movements

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14
Q

pathology of peripheral rigidity

A

reduced inhibition from type Ib fibres
overactive type II fibres
increased activity due to peripheral stimulation

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15
Q

pathology of central rigidity

A

altered activity in GABA and ACh interneurones
altered inhibition of indirect pathway
increased responsiveness of STN/GPi firing to peripheral stimulation

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16
Q

tremor is absent in what percent of PD patients

A

30%

17
Q

features if tremor

A

less response to dopaminergic drugs
not just basal ganglia output
thalamo-cortical-cerebellar loops
modified by basal ganglia activity

18
Q

dopaminergic therapy diagram

A
19
Q

levodopa benefits

A

better motor improvement in short term
reduced freezing of hair

20
Q

levodopa disadvantages

A

more dyskinesia, possibly in long term

21
Q

benefits of dopamine agonists

A

less dyskensia and longer latency to dyskinesia

22
Q

disadvantages of dopamine agonists

A

nausea, postural hypotension, somnolence
impulse control disorders
withdrawal problems

23
Q

what are motor complications in PD

A

wearing-off and motor fluctuations
L-dopa induced dyskinesia

24
Q

what are the mechanisms of motor complications

A

pulsatile dopaminergic stimulation
abnormal handling of dopamine by 5-HT neurones
abnormal synaptic plasticity

25
Q

what is amantadine

A

NMDA receptor antagonist
reduces dyskinesia by around 40%
recent study shows effects persistent following long term treatment
NMDA and AMPA receptor antagonists

26
Q

what can abrupt withdrawal of medications lead to

A

nueroleptic malignant syndrome

27
Q

what is a SPECT scan

A

single photons registered by rotating gamma camera
low cost, poor resolution
long tracer half life

28
Q

what is a PET scan

A

two y-rays emitted at 180 degrees detected by static ring of detectors
higher cost, better resolution
18F-flurodopa PET