Parkinson's Disease Flashcards
What is Parkinson’s Disease?
a progressive degenerative disease caused by death of dopaminergic neurons primarily in the substantia nigra pars compacta
What does PD actually begin with?
loss of noradrenergic input into the dorsal motor nucleus of X
loss of noradrenergic neurons of the locus coeruleus
What is seen in the SNc with normal aging?
a loss of dopaminergic neurons (50% decrease ages 20-60)
Besides the SNc, what is another area that experiences a decline in DA?
mesolimbic system.
What is the mesolimbic system?
it includes projections from the ventral tegmental area to the amygdyla,
nucleus accumbens,
prefrontal cortex,
and hippocampus via medial forebrain bundle (MFB)
With continued development of Parkinson’s, there is a continued decline and loss of connections within the PFC, limbic cortex, and hippocampus. what symptoms does this cause?
loss of cognitive skills
memory loss
higher associative cognitive functioning
What are cardinal signs of Parkinsons?
- resting tremor
- bradykinesia
- rigidity
- postural instability
What is resting tremor characterized by?
4-6 Hz resting “pill rolling” tremor which begins in peripheral extremities but progresses proximally
What are the 3 components of bradykinesia?
Hypokinesia
Bradykinesia
Akinesia
Hypokinesia?
paucity of movement
Bradykinesia?
slow movement
Akinesia
problem initiating movement
What is rigidity?
increased muscle tone and resistance to movement
What are the two types of rigidity common in PD?
Lead pipe- continuous rigidity making joints stiff
Cog-wheel- interposition of rigidity and breaking of rigidity when limbs are passively moved
What is postural instability in PD?
slowing of postural reflexes.
posture and rigidity make pt more unstable and increased risk of falling
What are the gait abnormalities associated with PD?
slow shuffle
no arm swing
retropulsion (stepping backward)
festinating gait (rapid short steps)
2 other S/S with PD?
Dysarthria and dysphagia
What are 6 nonmotor impairments common in PD?
- cognitive decline (up to 80%)
- postural hypotension
- hallucinations
- autonomic changes
- fatigue and sleepiness
- pain
in most cases there is no known cause of the degeneration of DA neurons, but some cases might have what involved?
environmental or genetic causes
What are a few pharmacological management approaches to PD?
- replacement therapy
- dopamine agonists
- blocking enzymatic breakdown of DA
- anticholinergic interventions
What is used in replacement therapy for PD?
Levodopa (L-Dopa)
Levorotatory 3, 4 dihydroxyphenylanaline
(metabolic precursor to DA because it cannot cross BBB)
Why is L-Dopa rapidly metabolized peripherally? how can we fix this?
because there are a large # of DA neurons in the gut area.
typically co administered with carbidopa
what is carbidopa?
blocker of DOPA decarboxylase
What is the combination of carbidopa and L-Dopa called?
SinemetTM