SECRETS Neurology - Parkinson's Flashcards
sx
resting tremor (pill-rolling)
bradykinesia
cogwheel rigidity
masked facies
stooped posture
festinating gait
damaged area
degradation of dopaminergic, neuromelanin-containing neurons in substantia nigra
direct pathway
inhibit inhibitory globus pallidus internus & substanstia nigra pars reticularis –> activate thalamus
indirect pathway
inhibit thalamus
nigrostriatal tract
substantia nigra –> basal ganglia
activate direct pathway = activate thalamus
inactivate indirect pathway = activate thalamus
pathophysiology
damage dopamine inputs to nigrostriatal tract –> net decrease in motor activity
Unopposed ACh –> activate indirect pathway –> tremor
L-dopa
cross BBB to increase CNS dopamine levels
uneffective in parkinsonism
Carbidopa
dopa decarboxylase inhibitor
cannot cross BBB
prevents metabolism of L-dopa in periphery
minimize side effects of peripheral dopamine
administer with L-dopa
peripheral dopamine ADR
orthostatic hypotension nausea/vomiting confusion hallucinations arrhythmias dyskinesia
bromocriptine
pergolide
dopamine receptor agonists
increase central dopaminergic activity
selegiline
selective MAO-Bi
inhibit dopamine degradattion
MAO-A vs MAO-B
A = degrade serotonin and NE B = degrade dopamine
benztropine
anticholinergic
cross BBB
inhibit ACh to restore dopa/ACh balance
tx bradykinesia/akinesia
Amantadine
tx Influenza A
anticholinergic & antiglutamatergic effects
increase dopamine output from intact nerve terminals
MPTP
analog of opioid meperidine
causes irreversible parkinsonism by destroying neurons in substantia nigra
