Parkinson's Disease

Question 1

Causative process of Parkinson’s disease symptoms?

Answer 1

Symptoms are caused by a lack of dopamine in the basal ganglia, secondary to loss of midbrain substantia nigra pars compacta neurons

Question 2

How do models show the pathophysiology of Parkinson’s disease relative to dopamine loss?

Answer 2

Models of basal ganglia function suggest:
- basal ganglia take inputs concerning “motor plans” from the motor and cognitive frontal cortex
- dopamine then acts as a gate to allow those motor plans to be executed
Hence a loss of dopamine will contribute to a slowing of this process (bradykinesia)

Question 3

Classical clinical features in Parkinson’s Disease?

Answer 3

• Bradykinesia
• Postural instability
• Rigidity
• Tremor ~3-4Hz

Question 4

When does postural instability appear in the disease course and what may it be seen as?

Answer 4

Appears late in disease

May be seen as a lack of ability to voluntarily adjust position in response to postural disturbance

Question 5

2 types of Parkinsonian rigidity?

Answer 5

1 - “lead-pipe” - stiff throughout range of motion (classical)

2 - “cogwheel” - essentially “lead-pipe” with tremor superimposed

Question 6

Features of tremor in Parkinson’s Disease?

Answer 6

• most common feature
• usually unilateral
• about 3-4Hz in frequency
• may take the form of the classic “pill-rolling” tremor (trying to roll a pill or another small object between thumb/index finger)

Question 7

Drug commonly used to treat Parkinson’s?

Answer 7

Levodopa (L-DOPA)

Question 8

What is “Parkinson-plus” syndrome?

Answer 8

Multiple system atrophy

- Parkinson’s symptom constellation but includes postural hypotension