Parkinson's disease Flashcards
What is Parkinson’s disease?
Parkinson’s disease is a progressive neurodegenerative condition caused by degeneration of dopaminergic neurons in the substantia nigra of basal ganglia
There is pigment loss in the brain of Parkinson patients; why is this?
Pigment loss correlates with dopaminergic cell loss
What are the signs and symptoms of Parkinson’s?
Classic triad of features: bradykinesia, tremor, and rigidity.
are characteristically asymmetrical
Describe the changes in the brain of Parkinson’s patients?
Prominent dopaminergic neuron loss in the substantia nigra pars compacta (SNpc) with a-synuclein-containing Lewy bodies
What is the mainstay of management in PD?
Symptomatic drug treatment with drugs that increase dopamine concentration or directly stimulate dopamine receptors
What is bradykinesia?
Impairment of voluntary movements, slowing and freezing on the spot e.g slow shuffling steps, reduced arm swinging and difficult initiating movements
What is the tremor in PD?
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
What kind of rigidity is present in PD?
Cogwheel
Apart from the classic triad, what are signs are present in PD?
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
What is the difference between drug-induced PD and classic PD?
In drug induced; motor symptoms are generally rapid onset and bilateral
rigidity and rest tremor are uncommon
Multiple system atrophy is a cause of Parkinsonism which can be difficult to differentiate from idiopathic Parkinson’s disease. How can they be differentiated?
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.
What is the first line treatment for PD if motor symptoms are affecting QOL?
Levodopa
What is the first line treatment for PD if motor symptoms are NOT affecting QOL?
Dopamine agonist (non-ergot derived), levodopa or monoamine oxidase B (MAO B) inhibitor.
Out of Levodopa, MAOB and dopamine agonists, which group of drug has the least adverse effects?
Levodopa
Out of Levodopa, MAOB and dopamine agonists, which group of drug has the most motor complications?
Levodopa
What drug can be given in PD if daytime sleepiness occurs and other strategies have failed?
Modafinil
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?
Midodrine - acts on peripheral alpha-adrenergic receptors to increase arterial resistance
What drug is given in PD for troublesome saliva drooling?
Glycopyrronium bromide
Levodopa is co-prescribed with another drug, what is this drug and why?
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)
What are the side effects of Levodopa in PD?
dyskinesia, ‘on-off’ effect, dry mouth, anorexia, palpitations, postural hypotension, psychosis, drowsiness
What is important to know about Levodopa in PD??
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.
Give examples of dopamine receptor agonists in PD?
bromocriptine, ropinirole, cabergoline, apomorphine
What has to be done before prescribing Dopamine receptor agonists in PD?
Associated with pulmonary, retroperitoneal, and cardiac fibrosis - echocardiogram, ESR, creatinine and chest x-ray should be done
What are the side effects of dopamine receptor agonists used in PD?
Cause impulse control disorders, excessive daytime somnolence, hallucinations in older patients, nasal congestion and postural hypotension.
if patient has dementia, don’t prescribe
Give examples of MAO-B (Monoamine Oxidase-B) inhibitors used in PD
selegiline/rasagilline
What is the mechanism of action of MAO-Bs in PD?
Inhibits the breakdown of dopamine secreted by the dopaminergic neurons in synaptic cleft
acts on dopamine concentrations and dopamine secretory vesicles.
What is the mechanism of amantidine in PD?
Mechanism is not fully understood, probably increases dopamine release, and inhibits its uptake at dopaminergic synapses
What are anti-muscarinic drugs used for in PD?
Now used more to treat drug-induced parkinsonism rather than idiopathic Parkinson’s disease
Help tremor and rigidity
Give examples of anti-muscarinic drugs used for in PD
procyclidine, benzotropine, trihexyphenidyl (benzhexol)
