Parkinson's

Question 1

Signs and symptoms

Answer 1

Shuffling gait
Stooped posture
Monotonic speech
Masked face
Freezing, struggles to start/stop moving

Question 2

Compensations by rewiring can help up to

Answer 2

80% neurones in movement pathway lost

Question 3

Dopamine pathways (5)

Answer 3

Motor function
Reward
Psychosis
Prolactin secretion
Nausea/vomiting

Question 4

Enzyme that metabolises dopamine

Answer 4

COMT, polymorphisms determine how much dopamine is active, links to risk behaviour

Question 5

Carbidopa, benserazide use

Answer 5

Used for pheochromocytoma and as adjunct with L-DOPA so L-DOPA is used in CNS

Question 6

Carbidopa, benserazide MOA

Answer 6

Inhibits DOPA decarboxylase, prevents L-DOPA -> dopamine, doesn’t cross BBB so only in body hence used as adjunct to L-DOPA

Question 7

D2R antagonist MOA

Answer 7

Domperidone blocks D2 receptors in periphery, reduces SE from dopaminergic drugs

Question 8

D2R antagonist use

Answer 8

Mainly anti-emetic, used as adjunct to L-DOPA/D2 agonist to prevent SE from dopamine

Question 9

Muscarinic antagonist MOA

Answer 9

Procyclidine, orphenadrine, benzhexol block muscarinic receptors in striatum

Question 10

Muscarinic antagonist use

Answer 10

Only used in drug-induced PD (DA antagonists used in antipsychotics) as increases susceptibility to dementia in elderly patients

Question 11

Muscarinic antagonist SE

Answer 11

Dry mouth, urinary retention, constipation

Question 12

MAO-B inhibitors MOA

Answer 12

Selegiline, rasagiline inhibit dopamine specific breakdown enzyme in brain, potentiates L-DOPA

Question 13

MAO-B inhibitor use

Answer 13

Adjunct to L-DOPA as can reduce dose needed by up to 1/3, also has anti-parkinsonian action when used alone and delays need for Levodopa

Question 14

D2 agonist MOA

Answer 14

Ropinirole (monotherapy in younger), Bromocriptine, pergolide act on D2 receptors

Question 15

D2 agonist SE

Answer 15

Restrictive valvular heart disease
Nausea
Psychiatric symptoms
Postural hypotension
Behaviour changes (gambling/hypersexuality)
Daytime somnolence (strong desire for sleep)

Question 16

D2 agonist use

Answer 16

Used with domperidone to prevent nausea, used mostly in young patients or in late disease to buffer L-DOPA fluctuation but usually apomorphine for this instead

Question 17

Amantidine MOA

Answer 17

Initially made as antiviral but blocks NMDA receptors and works well for small % of patients without SE
Possibly works due to effect on glutamate in globus pallidus and thalamus

Question 18

Deep brain stimulation use

Answer 18

STN stimulation works well in some who haven’t responded to other treatments, very expensive so used last ditch

Question 19

Other motor problems and treatments

Answer 19

Huntingdons Chorea - tetrabenazine depletes DA
Restless legs - ropinirole (possibly decreases DA sensitivity)
Tourettes - haloperidol (DA antagonist), pimozide