Parkinson's

Question 1

What is the classic triad of Parkinson’s disease?

Answer 1

Akinesia
Rigidity
Tremor

Question 2

What is the pathology of Parkinson’s?

Answer 2

Destruction of dopaminergic neurones
Projecting from substantia Nigra (midbrain) to striatum of basal ganglia (caudate nucleus and putamen)
Leads to imbalance in favour of cholinergic and other neutotransmitter mechanisms

Question 3

When do symptoms appear in PD?

Answer 3

When about 60-80% of nigrostriate dopaminergic neurones have been lost

Question 4

Describe akinesia in PD

Answer 4

Bradykinesia - slowing down, particularly with complex motor tasks
Lack of spontaneous movement:
Poverty of facial expression
Difficulty changing position
Quiet and monotonous speech
Abnormal gait and stance

Question 5

What is the gait like in PD?

Answer 5

Flexed / stooped posture
Initiation of walking and turning are difficult
Shuffling gait

Question 6

Describe rigidity in PD

Answer 6

Lead-pipe rigidity. Constant throughout ROM

Cogwheel rigidity is a consequence of tremor superimposed on background of lead pipe rigidity

Question 7

Describe the tremor of Parkinson’s disease

Answer 7

Mainly affects hands
Pill rolling
Present at rest
Exacerbated by anxiety or stress
Improves on action, may disappear

Question 8

How may cranial nerves be affected in Parkinson’s?

Answer 8

Mild impairment of upgaze
Eyelids may be tremulous
Glabellar tap sign: repeated taps to forehead. In normal people, reflex blinking rapidly fatigues but this doesn’t happen in PD

Question 9

What are the non-motor symptoms of PD?

Answer 9

Depression
Hallucinations - visual
Psychosis
Dementia
Sleep disorders: insomnia
Autonomic: constipation, bladder disturbance, erectile dysfunction, postural hypotension
Anosmia

Question 10

How is Parkinson’s diagnosed?

Answer 10

Clinical

Response to treatment used to distinguish between PD and other akinetic-rigid syndromes

Question 11

How does Levodopa work?

Answer 11

Natural substrate for dopamine synthesis

L-dopa can cross the blood brain barrier

Question 12

How is Levodopa given?

Answer 12

In combination with a DOPA de carboxylate inhibitor
To prevent peripheral breakdown of L-dopa
Also reduces side effects
E.g. Co-careldopa (sinemet)

Question 13

What are the side effects or co-careldopa?

Answer 13

Postural hypotension
Confusion
Hallucinations
Delusions

Question 14

What is Madopar?

Answer 14

Co-beneldopa

L-dopa + DOPA de carboxylase inhibitor

Question 15

What are the complications of long-term L-dopa therapy?

Answer 15

Motor fluctuations - wearing off
On-off
Dyskinesias - involuntary movements occurring in association with drug treatment

Question 16

How can long-term complications of L-dopa be minimised?

Answer 16

Frequent small doses
Controlled release preparations
Combined use with MAO-B inhibitors or COMT inhibitors
Continuous administration e.g. Transdermal patches

Question 17

How does L-dopa use change with time?

Answer 17

Increases as the effects decrease

This means more side-effects

Question 18

What are Rotigotine and Ropinirole?

Answer 18

Dopamine agonists

Question 19

What are the side effects of dopamine agonists?

Answer 19

Drowsiness
Nausea
Hallucinations
Compulsive behaviour

Question 20

What is apomorphine and how is it used?

Answer 20

Potent DA agonist
Used as continuous SC infusion
Or as rescue pen for sudden freezing

Question 21

Name an MAO-B inhibitor

Answer 21

Selegeline

Rasagiline

Question 22

What classes of drugs can cause Parkinsonism?

Answer 22

Neuroleptics
Metoclopramide
Prochlorperazine