Wk 29 - Parkinson's disease 1

Question 1

What is PD?

Answer 1

• Degeneration of dopamine secreting nerve cells

- Severe attack of tremors that affect 1 hand + spread to leg on same side

Question 2

What are the motor symptoms of PD?

Answer 2

• Tremor
• Rigidity
• Akinesia: slowness of movement
• Postural instability

Question 3

What are the non-motor symptoms of PD?

Answer 3

• Anxiety + depression
• Excessive daytime sleepiness
• Constipation
• Sexual dysfunction
• Postural hypo
• Weight loss
• Pain

Question 4

What are the risk factors of PD?

Answer 4

• Non-smoker + low caffeine drinkers
• Genetic mutation: autosomal dominant mutation in gene LRRK-2
• Mutation in parkin gene
• Neuroleptic drugs
• Antiemetics: prochlorperazine + metoclopramide

Question 5

Where is dopamine produced?

Answer 5

Substantial nigra w/in Basal ganglia

Question 6

What is the role of the basal ganglia?

Answer 6

Controls motor skills + movement sequences

Question 7

What does dopamine promote?

Answer 7

• Function of basal ganglia
• Maintaining attention
• Switching focus of attention
• Mood
• Visual perception

Question 8

What occurs during progressive degeneration of dopamine producing neurons?

Answer 8

• Formation of lewy bodies

- Lewy bodies deposited in dopamine prod neurons tf produce little/no dopamine

Question 9

Clinical signs of PD are evident when what percentage of dopamine producing neurones are lost?

Answer 9

80%

Question 10

Outline the causes of PD

Answer 10

• Dopaminergic neurons in substantia nigra + corpus striatum destroyed
• 80% dopaminergic neurons damaged
• Striatum rich in excitatory cholinergic neurons that counteract action of dopamine - dopamine-acetylcholine balance

Question 11

What is the Nigrostriatal dopaminergic tract responsible for?

Answer 11

Motor control (part of extrapyramidal system)

Question 12

What is the first step of diagnosing PD?

Answer 12

Bradykinesia plus one:

• Rest tremor
• Rigidity
• Postural instability

Question 13

What is the second step of diagnosing PD?

Answer 13

History of:

• Repeated strokes
• Neuroleptic medications use
• Head injury
• Definite encephalitis

Presence of atypical ft:

• Early falls
• Supranuclear gaze palsy
• Ataxia + cerebellar features
• Early autonomic ft
• Early cognitive decline
• Poor response to L-dopa

Question 14

What is the third step of diagnosing PD?

Answer 14

At least 3:
- Unilateral onset

• Rest tremor
• Evidence of progression
• Persistent asymmetry
• Excellent response to L-dopa
• L-dopa induced dyskinesias
• L-dopa response for 5+ years
• Clinical course of 10+ years

Question 15

What happens when diagnosis PD?

Answer 15

• Diagnosis based on TRAP
• PD suspected: refer to neurologist
• Referral: 6 wks (normal) + 2 wks (severe)
• MRI + CT scan
• 8F-dopa PET scanning/DAT scanning available at specialist centres

Question 16

What are the clinical features of physiological tremor?

Answer 16

• Anxiety disorder
• Signs of thyrotoxicosis
• Fine tremor

Question 17

What are the clinical features of essential tremor?

Answer 17

• +ve Fx

- Alcohol responsive

Question 18

What are the clinical features of dystonic tremor?

Answer 18

• Asymmetrical
• Jerky tremor
• Focal

Question 19

What are the clinical features of cerebellar disorders?

Answer 19

• Intention tremor (not rest)
• Broad-based gait
• Nystagmus, dysarthria,

Question 20

What are the clinical features of vascular parkinsonism?

Answer 20

• Often lower > upper body

- Multiple cerebrovascular risk factors

Question 21

What are the clinical features of drug induced parkinsonism?

Answer 21

• Frequently symmetrical (not always)

- Haloperidol, antiemetics, valproate

Question 22

What are the clinical features of atypical parkinsonism?

Answer 22

• Early backward falls
• Eye movement problems
• Cognitive decline