Parkinson's disease

Question 1

What is Parkinson’s disease?

Answer 1

Parkinson’s disease is a progressive neurodegenerative condition caused by degeneration of dopaminergic neurons in the substantia nigra of basal ganglia

Question 2

There is pigment loss in the brain of Parkinson patients; why is this?

Answer 2

Pigment loss correlates with dopaminergic cell loss

Question 3

What are the signs and symptoms of Parkinson’s?

Answer 3

Classic triad of features: bradykinesia, tremor, and rigidity.

are characteristically asymmetrical

Question 4

Describe the changes in the brain of Parkinson’s patients?

Answer 4

Prominent dopaminergic neuron loss in the substantia nigra pars compacta (SNpc) with a-synuclein-containing Lewy bodies

Question 5

What is the mainstay of management in PD?

Answer 5

Symptomatic drug treatment with drugs that increase dopamine concentration or directly stimulate dopamine receptors

Question 6

What is bradykinesia?

Answer 6

Impairment of voluntary movements, slowing and freezing on the spot e.g slow shuffling steps, reduced arm swinging and difficult initiating movements

Question 7

What is the tremor in PD?

Answer 7

Resting 3-5 Hz tremor worse when stressed or tired,
and improves with voluntary movement

‘pill-rolling’, i.e. in the thumb and index finger

Question 8

What kind of rigidity is present in PD?

Answer 8

Cogwheel

Question 9

Apart from the classic triad, what are signs are present in PD?

Answer 9

Mask-like facies (reduced expressions), flexed posture, micrographia, drooling of saliva

psychiatric features: depression is the most common feature, dementia, psychosis and sleep disturbances may also occur

impaired olfaction (ansmonia), REM sleep behaviour disorder, Fatigue, autonomic dysfunction:, postural hypotension

Question 10

What is the difference between drug-induced PD and classic PD?

Answer 10

In drug induced; motor symptoms are generally rapid onset and bilateral

rigidity and rest tremor are uncommon

Question 11

Multiple system atrophy is a cause of Parkinsonism which can be difficult to differentiate from idiopathic Parkinson’s disease. How can they be differentiated?

Answer 11

Key features to help you differentiate are the presence of unilateral symptoms, and more severe/early onset autonomic dysfunction (postural hypotension/erectile dysfunction) in MSA.

Question 12

What is the first line treatment for PD if motor symptoms are affecting QOL?

Answer 12

Levodopa

Question 13

What is the first line treatment for PD if motor symptoms are NOT affecting QOL?

Answer 13

Dopamine agonist (non-ergot derived), levodopa or monoamine oxidase B (MAO B) inhibitor.

Question 14

Out of Levodopa, MAOB and dopamine agonists, which group of drug has the least adverse effects?

Answer 14

Levodopa

Question 15

Out of Levodopa, MAOB and dopamine agonists, which group of drug has the most motor complications?

Answer 15

Levodopa

Question 16

What drug can be given in PD if daytime sleepiness occurs and other strategies have failed?

Answer 16

Modafinil

Question 17

If orthostatic hypotension develops in PD then a medication review looking at potential causes should be done. If symptoms persist what drug should be given?

Answer 17

Midodrine - acts on peripheral alpha-adrenergic receptors to increase arterial resistance

Question 18

What drug is given in PD for troublesome saliva drooling?

Answer 18

Glycopyrronium bromide

Question 19

Levodopa is co-prescribed with another drug, what is this drug and why?

Answer 19

Decarboxylase inhibitor (e.g. carbidopa or benserazide) to prevent peripheral metabolism of levodopa to dopamine before reaching the brain (prevents breakdown of levodopa to dopamine in peripheries by inhibition of dopa decarboxylase enzyme)

Question 20

What are the side effects of Levodopa in PD?

Answer 20

dyskinesia, ‘on-off’ effect, dry mouth, anorexia, palpitations, postural hypotension, psychosis, drowsiness

Question 21

What is important to know about Levodopa in PD??

Answer 21

It is important not to acutely stop levodopa. If a patient with Parkinson’s disease cannot take levodopa orally, they can be given a dopamine agonist patch as rescue medication to prevent acute dystonia.

Question 22

Give examples of dopamine receptor agonists in PD?

Answer 22

bromocriptine, ropinirole, cabergoline, apomorphine

Question 23

What has to be done before prescribing Dopamine receptor agonists in PD?

Answer 23

Associated with pulmonary, retroperitoneal, and cardiac fibrosis - echocardiogram, ESR, creatinine and chest x-ray should be done

Question 24

What are the side effects of dopamine receptor agonists used in PD?

Answer 24

Cause impulse control disorders, excessive daytime somnolence, hallucinations in older patients, nasal congestion and postural hypotension.

if patient has dementia, don’t prescribe

Question 25

Give examples of MAO-B (Monoamine Oxidase-B) inhibitors used in PD

Answer 25

selegiline/rasagilline

Question 26

What is the mechanism of action of MAO-Bs in PD?

Answer 26

Inhibits the breakdown of dopamine secreted by the dopaminergic neurons in synaptic cleft

acts on dopamine concentrations and dopamine secretory vesicles.

Question 27

What is the mechanism of amantidine in PD?

Answer 27

Mechanism is not fully understood, probably increases dopamine release, and inhibits its uptake at dopaminergic synapses

Question 28

What are anti-muscarinic drugs used for in PD?

Answer 28

Now used more to treat drug-induced parkinsonism rather than idiopathic Parkinson’s disease

Help tremor and rigidity

Question 29

Give examples of anti-muscarinic drugs used for in PD

Answer 29

procyclidine, benzotropine, trihexyphenidyl (benzhexol)