Parkinson's Disease

Question 1

what are the 3 characteristic features of Parkinsonism?

Answer 1

akinesia (can be bradykinesia or hypokinesia)
tremor (4-6 Hz resting tremor described as a pill rolling tremor)
rigidity (lead-pipe or cogwheel)

Question 2

how can akinesia be tested for?

Answer 2

ask patient to repeatedly oppose middle finger and thumb

will cause fatiguing and decrementing amplitude of the repeated movement

Question 3

how can a resting tremor be tested for?

Answer 3

ask the patient to count backwards from 100

resting tremor will become more apparent as it is induced by concentration

Question 4

how is rigidity be tested for?

Answer 4

flex and extend the patient’s relaxed wrist and elbow joint

Question 5

what is parkinson’s disease?

Answer 5

progressive neurodegenerative movement disorder characterized by levodopa responsive parkinsonism

Question 6

histology of parkinson’s disease?

Answer 6

neuronal loss

presence of intracytoplasmic, eosinophilic alpha synuclein containing inclusions called Lewy Bodies

Question 7

what do lewy bodies do?

Answer 7

target the pars compacta of the substantia nigra causing disturbance in the dopaminergic pathway

Question 8

how is parkinson’s disease diagnosed?

Answer 8

clinically
characteristic features
starts asymmetrically
older patients

Question 9

clinical features of parkinson’s disease?

Answer 9

parkinson's triad = cardinal features
flexed posture and postural instability (later features)
shuffling gait
micrographia (small handwriting)
masked facies (loss of facial expressions)
non-motor symptoms
- constipation
- REM sleep disorder
- depression
- dementia

Question 10

most effective medication for parkinsons?

Answer 10

levodopa

Question 11

mode of action of levodopa?

Answer 11

dopamine precursor that can cross the blood-brain barrier

Question 12

side effects of levodopa?

Answer 12

hypotension
nausea
dyskinesia
over time patients may start to notice levodopa becoming less effective

Question 13

what is given alongside levodopa to prevent peripheral metabolism of levodopa?

Answer 13

peripheral dopa-decarboxylase inhibitors (carbidopa)

Question 14

how do monoamine oxidase B inhibitors (rasagiline and selegiline)?

Answer 14

inhibits monoamine oxidase B which is responsible for catabolising dopamine to homovanillic acid

Question 15

side effects of monoamine oxidase inhibitors?

Answer 15

hypertensive crisis when consuming tyramine containing foods (such as cheese, red wine etc)

Question 16

how are monoamine oxidase inhibitors used?

Answer 16

can be used as add on or even as monotherapy in early mild parkinsons

Question 17

how do dopamine agonists work (e.g pramipexole)?

Answer 17

stimulate dopamine receptors directly

Question 18

side effects of dopamine agonists?

Answer 18

hypotension
nausea
ankle swelling
hallucinations

Question 19

how are dopamine agonists used in parkinsons?

Answer 19

can be used as an initial treatment in younger patients (<70) due to the high risk of dyskinesia in younger patients using levodopa

Question 20

features of drug induced parkinsonism?

Answer 20

onset of parkinsonian features
often symmetrical developing a few weeks after starting or raising dose of some medication or after withdrawing from anti-parkinsonian agent

Question 21

examples of drugs associated with drug induced parkinsonism?

Answer 21

chlorpromazine
haloperidol
lithium
valproic acid
metoclopramide

Question 22

how is drug induced parkinsonism managed?

Answer 22

cessation of the causitive drug
- cant just stop typical antipsychotic so should be switched to an atypical due to lower risk of extra pyramidal side effects
anticholinergics such as benztropine and procyclidine can be used for symptomatic relief

Question 23

how can lewy body dementia and parksinson’s dementia be differentiated?

Answer 23

dementia >1 year after onset of parkinsons = parkinsons dementia
dementia before or at same time as parkinsons onset = lewy body

Question 24

3 core features of lewy body dementia?

Answer 24

progressive disabling cognitive impairment (dementia)
recurrent visual hallucinations
features of parkinsonism

Question 25

characteristics of multiple system atrophy?

Answer 25

parkinsonism (but with poor response to levodopa)
autonomic dysfunction (causing postural hypotension, ED and urinary urgency)
and/or cerebellar dysfunction

Question 26

what is seen on MRI in multiple system atrophy?

Answer 26

putaminal atrophy

hot cross bun appearance of pons in an axial section

Question 27

what is progressive supranuclear palsy?

Answer 27

degenerative disease that causes axial akinesia and rigidity, loss of balance and unexplained falls, forgetfulness, dysarthria and loss of eye movements (supranuclear gaze palsy on vertical plane mainly)

Question 28

what is seen on MRI in progressive supranuclear gaze palsy?

Answer 28

midbrain atrophy with a hummingbird sign seen on sagittal view

Question 29

what causes vascular parkinsonism?

Answer 29

multiple small stroked or infarcts

Question 30

features of vascular parkinsonsim?

Answer 30

generally more problems with gait than tremor
more problems in lower body
very slow progression compared to other parkinsonism
poor response to levodopa

Question 31

how can vascular dementia be differentiated from other parkinsonian syndromes?

Answer 31

SPECT