Parkisons disease and Parkinsonism Flashcards
What is parkisons disease?
Progressive neurodegenerative disorder caused by degeneration of dopaminergic neurons in substantia nigra
What are the triad of symptoms in Parkinsons disease?
Bradykinesia, tremor and rigidity
(also get postural instability)
Motor symptoms usually asymmetrical
Describe the bradykinesia associated with Parkisons
Poverty of movement also seen
Short shuffling steps with reduced arm swinging
Difficulty initiating movement
What are the non-motor features of Parkisons disease?
Mood changes- depression most commonly, dementia, psychosis
REM sleep behaviour disorder
Sweating
Drooling of saliva
Micrographia
Mask like face
Olfactory loss
autonomic failure e.g. postural hypotension
Describe the Parkisonian tremor?
Most marked at rest, 3-5Hz
Worse when stressed or tired, improves with voluntary movement
Typically ‘pill-rolling’
Describe the rigidity in Parkisons disease?
Lead pipe
Cogwheel, due to superimposed tremor
How do you diagnose Parkisons Disease?
1) Based on clinical features:
Bradykinesia + at least one of muscular rigidity, 4-6Hz rest tremor, postural instability (not caused by primary visual, vestibular, cerebellar or propiocepetive dysfunction)
2) Exclude other causes of parkisoniasm
3) 3 or more of the following needed (plus step 1)
Unilateral onset
Rest tremor present
Progressive disorder
Persistent asymmetry
Excellent response to Levodopa
Clin course of 10 years or more
Levodopa response for 5 years or more
NOTE: structural neuro imaging in normal
Outline the pathology of Parkinsons disease?
Neurodegneration
Lewy body in the substania nigra with alpha synuclein
Loss of pigment in the substania nigra- 50% of pigment loss–> symptoms, increased turnover
Reduced Dopamine
What medication is first line in Parkisons if the patients motor symptoms are affecting their QOL?
Co-careldopa (Levodopa + peripheral dopamine decarboxylase)
Why do we give LevpDopa instead of dopamine?
Dopamine cannot cross the blood brain barrier
MOA of levodopa?
Taken up by dopaminergic cells in substantia nigra and converted to dopamine.
If their are less dopaminergic cells–> less reliable affect of Levodopa
What do we need to prescribe along with levodopa?
A peripheral DOPA decarboxylase inhibitor (so it doesn’t get broken down before it reached the BBB) e.g co-careldopa (Brand name: sinemet) or Co-beneldopa (madopar)
Benefits of prescribing co-careldopa/co-beneldopa instead of just LevoDopa?
Reduced dose required
Reduced side effects
Increase L-DOPA reaching brain
Advantages of Co-careldopa?
Highly efficacious
Low side effects
Side effects of Levodopa?
Dry mouth
psychosis
tachycardia
nausea/anorexia
hypotension
Note side effects are reduced as L-dopa administered as co-careldopa