[MND] Parkinson's Disease

Question 1

Parkinson’s Disease can be defined as a

Answer 1

Chronic progressive neurodegenerative disease of the central nervous system resulting from death of the dopamine-generating cells in the substantial nigra (midbrain)

Question 2

Causes?

Answer 2

Cause is unknown (idiopathic) but there are theories of viral and/or genetic predisposition or combinations of ageing, environmental toxins, genetics and programmed cell death

Question 3

What are the risk factors for Parkinson’s Disease?

Answer 3

Age (middle to late), male>female, family history, post menopause, agriculture (pesticides, herbicides), and possibly head trauma

Question 4

Epidemiology

Answer 4

NZ 1 in 500
10,000 people in NZD have
Believed 1% of people above 60 have Parkinson’s
Mean age onset is 58/59

Question 5

Pathophysiology

Answer 5

• Interruption between the pathways of the substantial nigra to striatum
• Degeneration of Neuromelanin containing cells in substantial nigra (>70% of cells lost) leads to reduced dopamine which results in neurotransmitter imbalance, resulting in disruption of the output of the BG to thalamus/cortex

Question 6

Lesion location

Answer 6

Basal ganglia, primarily the pars compacta of the substantia nigra (midbrain)

Question 7

Progression

Answer 7

• Chronic Progressive

Question 8

Facial expressions? (clinical features)

Answer 8

Expressionless, stoney, mask-like

Question 9

Postural features (clinical features)?

Answer 9

Stooped, postural instability, abnormal reflexes, gait disturbances

Question 10

Symptoms of PD is evident when ___ to ____ of dopamine is lost

Answer 10

70-80%

Question 11

Diagnosis

Answer 11

• Medical history and neurological exam
• Based mainly on symptoms (i.e. movement and non-movement symptoms)
• Response to Levadopa
  MRI and CTs of PD patients are usually normal

Question 12

Explain what ‘Dopamine Precursors’; ‘Levadopa’; and ‘Dopamine Agonists’ are?

Answer 12

Medication for PD

• Dopamine Precursors boost production in substantia nigra, but may become ineffective and lead to dyskinesia
• Levadopa (i.e. sinamet), can improve bradykinesia and rigidity
• Dopamine agonists increase uptake of receptors in striatum

Question 13

Prognosis

Answer 13

• Rate of motor decline is greater in those with less impairment at the time of diagnosis; cognitive impairment more frequent in those over 70 years
• Little effect on life expectancy
• Can affect employment
• ## Autonomic disturbances 10~ years post onset

Question 14

Hoehn & Yahr Scale is

Answer 14

A outcome measure for PD, classification of disabilities (5 stages of progression), takes into account cognitive difficulties

Question 15

Cognitively, there can be

Answer 15

impaired memory

Question 16

Basal Ganglia disorders cause deficits in

Answer 16

the generation of internal (automatic) behaviour