Parkinson's Disease

Question 1

What is Parkinson’s disease?

Answer 1

Progressive reduction in dopamine in the basal ganglia leading to movement disorders. These are typically astmmetrical

Question 2

What is the pathophysiology of Parkinson’s disease?

Answer 2

Degeneration of dopaminergic neurons in the substantia nigra due to accumulation of alpha synuclein. The normal function of the basal ganglia is coordinating movements such as walking, voluntary movements.

Question 3

What are the clinical features of Parkinson’s disease?

Answer 3

Triad:
1. Bradykinesia,
2. Asymmetric ‘pill-rolling’ tremor,
3. Led pipe rigidity
Others:
Shuffling gait,
Autonomic dysfunction - constipation, erectile dysfunction, postural hypotension and urinary
Hypomimic faces,
Micrographia,
Drooling of saliva,
Depression,
Hallucinations and delusions

Question 4

What factors exclude a diagnosis of Parkinson’s disease?

Answer 4

Cerebellar signs
Vertical gaze palsy,
Possible drug induced parkinsonism,
Absence of L-dopa response,
Cortical sensory loss,
Normal scan

Question 5

What are some causes of parkinsonism?

Answer 5

Parkinson’s disease,
Drug induced,
Progressive supranuclear palsy,
Multiple system atrophy,
Lewy body dementia
Wilson’s disease

Question 6

Describe features of drug induced parkinsonism

Answer 6

Motor symptoms develop rapidly and are bilateral. Rigidity and resting tremors are uncommon

Question 7

What is the difference between a Parkinson’s tremor and a benign essential tremor?

Answer 7

Parkinson’s - Asymmetrical, worse at rest and improves with intentional movement.
Benign essential tremor - bilateral, improves at rest, worse with movement and improves with alcohol

Question 8

What are the features of multiple system atrophy?

Answer 8

• Parkinsonism,
• Autonomic disturbance (erectile dysfunction is often an early sign, postural hypotension and atonic bladder)
• Cerebellar signs
• Will have a poor response to levodopa

Question 9

What are the features of progressive supranuclear palsy?

Answer 9

• Postural instibility and falls (early gait instability),
• Impairment of verticle gaze (vertical gaze palsy)
• Parkinsonism
• Cognitive imparment (primarily frontal lobe)
• Poor response to levadopa

Question 10

What are the investigations for Parkinson’s disease?

Answer 10

Primarily clinical diagnosis but can do SPECT (single photon emission computed tomography)

Question 11

Name some examples of L-DOPA drugs and their side effects

Answer 11

• L-dopa with carbidopa/benserazide
• Side effects include dyskinesia (main side effect) nausea, vomiting, postural hypotension, confusion and hallucinations.
• Dyskinesia at peak dose (dystonic, chorea and athetosis)

tends to be first line as most affective for motor symp and others

Question 12

Name some examples of dopamine agonists and their side effects

Answer 12

Ropinirole or Apomorphine (potent and normally given subcut)
Side effects: Dopaminergic side effects, daytime somnolence or impulse control disorders
Often used in early disease in those without functional impairment or in late disease when there is dyskinesia

Question 13

Name some examples of MOA-B inhibitors

Answer 13

Selegiline or Rasagiline.
These inhibit monoaminde oxidase B enzymes which breakdown dopamine
Can be used as monotherapy but genreally used in combination with levodopa in late disease. Generally well tolerated

Question 14

Name an example of COMT inhibitors

Answer 14

Entacapone
Results in longer L-dopa half life so used in combination. Can cause diarrhoea

Question 15

What are some red flag symptoms which indicare atypical parkinsons disease

Answer 15

Rapid progression of gait impairment,
Symmetrical disease,
Severe autonomic failure
Respiratory dysfunction

Question 16

What is classed as a failure to respond to levodopa?

Answer 16

Failure to respond to 1-1.5g of levodopa daily

Question 17

What drugs can be used for its anti dyskinertic effects?

Answer 17

Amantadine (NMDA receptor antagonist)

Question 18

What are treatment options for advanced parkinson’s?

Answer 18

Apomorphine pen injections/subcutaneous pump.
Intrajejunal duodopa infection,
Deep brain stimulation - Electrical stimulation of the subthalamic nucleus. It is targeted, adjustable and non-destructive

Question 19

What should be added if patient is still experiancing symptoms on levodopa?

Answer 19

Addition of dopamine agonist, MAO-B inhibitor ot COMT inhibitor

Question 20

What are some side effects of levodopa?

Answer 20

Dry mouth, anorexia, palpitations, postural hypotension or psychosis.
Never acutely stop levodopa
May become less effective over time with reduced end of dose effect

Question 21

What are some important factors about dopamine receptor agonists?

Answer 21

Some of them such as bromocriptine have been associated with pulmonary and cardiac fibrosis so ddo ECHO, and chest x ray before starting.
Can also cause impulse control disorder

Question 22

What is used to treat drug induced parkinson’s?

Answer 22

Antimuscarinics

Question 23

What is the management for Parkinson’s Disease

Answer 23

1. Hold off for as long as possible as medication efficacy weans over time and they have lots of side effects.
2. If motor problems then give L-dopa with carbidopa
3. If motor symptoms are not affecting patients QOL then use dopamine agonists or COMT inhibitors