Parkinsons

Question 1

what is the cause of parkinsons?

Answer 1

• unknown
• genetics
• environmental factors
• oxidative stress

Question 2

what are the genes associated with Parkinsons?

Answer 2

SNCA, Parkin, PINK-1, DJ-1 and LRRK = codes proteins including alpha-synuclein

Question 3

what part of the brain is affected in Parkinsons disease?

Answer 3

substantia nigra

Question 4

what is the underlying mechanism of Parkinsons disease?

Answer 4

Loss of nigrostriatal dopaminergic neurons

Question 5

what is the consequence of loss of striatal dopaminergic output in Parkinsons?

Answer 5

decreased activity of the direct pathway and increased activity of the indirect pathway cause increased inhibitory activity from the globus pallidus internus (GPi)/substantia nigra zona reticulata to the thalamus, and therefore reduced output to the cortex.

Question 6

what are the clinical features of parkinsons?

Answer 6

resting tremor
rigidity
bradykinesia
Postural Instability
Shuffling gait 
difficulty initiating lower limb movement

Question 7

what are the additional clinical features of Parkinson’s?

Answer 7

• eye movements – loss of ocular convergence and upward gaze
• sweat and greasy skin
• depression
• dementia
• autonomic features – postural hypotension, constipation
• REM sleep behaviour disorder – act out dreams

Question 8

how is parkinsons diagnosed?

Answer 8

• dopaminergic agent trial
• MRI brain
• functional neuroimaging (dopamine transporter imaging such as FP-CIT or beta-CIT SPECT, or fluorodopa PET)

Question 9

what is the management of Parkinson’s?

Answer 9

MAO-B inhibitor, dopaminergic agent, amantadine, or trihexyphenidyl
Physical activity

Question 10

what is the additional management if there is nausea and/or vomiting on carbidopa/levodopa in Parkinson’s?

Answer 10

additional carbidopa or domperidone

Question 11

what is the additional management if there is nausea and/or vomiting on dopamine agonist in Parkinson’s?

Answer 11

domperidone

Question 12

what is the additional management if there is a refractory tremor in Parkinson’s?

Answer 12

pharmacotherapy or deep brain stimulation, intrajejunal infusion of levodopa/carbidopa

Question 13

what is the additional management with wearing off (motor fluctuations) on dopamine agonists (not taking carbidopa/levodopa) in Parkinson’s?

Answer 13

carbidopa/levodopa

Question 14

what is the additional management with wearing off (motor fluctuations) taking carbidopa/levodopa in Parkinson’s?

Answer 14

COMT inhibitor, dopamine agonist, MAO-B inhibitor, or switch to extended-release carbidopa/levodopa

Question 15

what is the additional management if there is a dyskinesias in Parkinson’s?

Answer 15

reduce dopaminergic medications (if tolerated) or add amantadine

Question 16

what is the additional management if there is unpredictable off-times, motor fluctuations, or freezing in Parkinson’s?

Answer 16

apomorphine or as-needed doses of carbidopa/levodopa

Question 17

what is the additional management if there is dysphagia in Parkinson’s?

Answer 17

dissolvable selegiline or carbidopa/levodopa or transdermal rotigotine

Question 18

what is the TRAPS acronym in parkinson’s mean?

Answer 18

Tremor
Rigidity
Akinesia
Postural Instability 
Shuffling Gait

Question 19

what MAO-B inhibitor is commonly used in Parkinson treatment?

Answer 19

Selegiline (also rasagiline)

Question 20

what is mechanism of action of selegiline?

Answer 20

enzyme metabolises dopamine