13.2 neurology

Question 1

what are the clinical features of Parkinson’s?

Answer 1

pill rolling tremor
lead pipe rigidity
bradykinesia
postural instability

Question 2

what are some clinical features of Parkinsonism?

Answer 2

• tremor is pill rolling
• lead pipe rigidity
• bradykinesia
• postural instability

Question 3

what are some non motor manifestations of Parkinsonism?

Answer 3

• mood changes
• pain
• cognitive change
• urinary symptoms
• sleep disorder
• sweating

Question 4

what are some other causes of Parkinson’s other than idiopathic?

Answer 4

• drug induced
• vascular
• progressive supra nuclear
• multiple system atrophy
• corticobasal degeneration

Question 5

what is a DAT scan?

Answer 5

dopamine active transporter scan

abnormal in parkinsons disease

Question 6

what is the pathology of idiopathic Parkinson’s disease?

Answer 6

• neurodegeneration
• levy bodies
• long of pigment of substantial nigra
• reduced dopamine

Question 7

how is the basal ganglia circuitry affected in Parkinson’s?

Answer 7

1) loss of dopaminergic neurones in substantial nigra results in reduced inhibition in neostriatum
2) loss of inhibition in neostriatum allows increased production of acetyl choline (excitatory) to motor cortex and spinal cord
3) chain of abnormal signalling leads to impaired mobility

Question 8

where is levodopa converted to dopamine once it crosses the blood brain barrier?

Answer 8

converted to dopamine by substantia nigra in brainstem

HOWEVER in Parkinson’s = fewer cells of substantia nigra = less reliable effect of levodopa = motor fluctuations

Question 9

what enzyme converts levodopa to dopamine in peripheral tissue?

Answer 9

dopamine decarboxylase

Question 10

what are the ADRs of L-Dopa?

Answer 10

• nausea and anorexia (acts on vomiting centres)
• hypotension (central and peripheral)
• psychosis
• tachycardia

Question 11

what are the disadvantages of L-Dopa usage?

Answer 11

• precursor (needs enzyme conversion)
• long term use can lead to loss of efficacy and involuntary movements, as well as motor complications e.g dystonia and freezing

Question 12

why must levodopa be used instead of dopamine?

Answer 12

dopamine cannot cross the blood brain barrier

Question 13

name some dopamine receptor agonists

Answer 13

amantadine
apomorphine
ropinirole
rotigotine

Question 14

what are the advantages of dopamine receptor agonists?

Answer 14

• direct acting
• less dyskinesias/motor complications
• possible neuroprotection

Question 15

what are the disadvantages of dopamine receptor agonists?

Answer 15

• less efficacy than L-Dopa
• impulse control disorders e.g hyper sexuality, pathological gambling, compulsive shopping
• more psychiatric (dose limiting)
• expensive

Question 16

what are the ADRs of dopamine receptor agonists?

Answer 16

ADRs include

• sedation
• hallucination
• confusion
• nausea
• hypotension
• as well as can get impulse control disorders e.g hyper sexuality, pathological gambling, compulsive shopping

Question 17

give an example fan catechol-o-methyl transferase inhibitor (COMT) and state what it does

Answer 17

entacapone

reduces peripheral breakdown of L-Dopa to 3-O methyldopa as well as prolonging the motor response to L-Dopa

Question 18

if you prescribe entacapone, what would you prescribe that with?

Answer 18

give with Levodopa and carbidopa as alone it has no therapeutic effect

Question 19

name two anticholinergic drugs

Answer 19

orphenadrine

procyclidine

Question 20

what are the advantages and disadvantages of anticholingeric drug use in IPD?

Answer 20

advantages are

• treat tremor
• not acting via dopamine receptors

disadvantages

• no effect on bradykinesia
• side effects e.g confusion and drowsiness