parkinson's Flashcards
what
progressive reduction of dopamine in basal ganglia leading to disorders of movement
symptoms characteristically asymetrical
classic triad
resting tremor
rigidity
bradykinesia
basal ganglia
responsible for coordinating habitual movements, controlling voluntary movements and learning specific movement patterns
pathophysiology
substansia nigra produces dopamina
dopamine is essential for basal ganglia function
parkinsons - graduall but progressive fall in dopamine production
typical patient
older man ~70yrs
stooped posture
forward tilt
reduced arm swing
shufflig gait
features
unilateral tremor
cogwheel rigidity
bradykinesia
depression sleep disturbance, insomnia asomina postural instability cog impairment, memory problems
features - unilateral tremor
frequency 4-6hz
pill rolling tremor
worse at rest
features - cogwheel rigidity
resitance to passive movement - inc tone
features - bradykinesia
handwriting gets smaller and smaller
shuffling gait
difficulty initiating movements
hypomimia
Parkinson’s tremor vs benign essential tremor: symmetry
P = assymetrical
BET = symmetrical
Parkinson’s tremor vs benign essential tremor: frequency
P = 4-6Hz
BET= 5-8Hz
Parkinson’s tremor vs benign essential tremor: when resting
P = worse at rest
BET = improves at rest
Parkinson’s tremor vs benign essential tremor: effect of intentional movement
P = improves with intentional movement
BET = worse w intentional movement
Parkinson’s tremor vs benign essential tremor: effect of alcohol
P = no change w alcohol
BET = improves w alcohol
parkinson’s plus syndromes - multiple system atrophy
neurones of multiple brain systems degenerate
affects basal ganglia plus other areas
basal ganglia destruction –> parkinson presentation
other areas destructin –>autonomal dysfunction + cerebellar dysfunction
parkinson’s plus syndromes - Lewy Body dementia
type of dementia assoc w features of parkinsonism
progressive cog decline visual hallucinations delusions disorders of REM sleep fluctuating consciosness
Mangement - levodopa
synthetic dopamine
given orally
usually combined with another drug that stops levodopa being broken down in body before enters brain
Levodopa - what is it usually given in combination with
peripheral decarboxylase inhibitors
ex carbidopa, benseradize
levodopa - example of combination drugs
co-benyldopa (levodopa + benserazide)
co-careldopa (levodopa + carcbidopa)
when is levodopa used
it is most effective treatment for symptoms but becomes less effectve overtime
often reserved when other treatments are not managing to control symptoms
dopamine side effects
dyskinesias
- dystonia
- chorea
- athetosis
COMT inhibitors
inhibitors of catechol-o-methyltransferase
metabolises levodopa in body and brain
taken with levodopa (+ decarboxylase inhibitor) to slow breakdown of levodopa in brain
extends effective duration of levodopa
COMT inhibitor example
entacapone
dopamine agonists
mimic dopamine in basal ganglia and stimulates dopamine receptors
usually used to delay use of levadopa and then used in combination of levodopa to reduce dose of levadopa needed
dopamine agonists S/E
pulmonary fibrosis with prolonged use
dopamine agonists examples
bromocryptine
pergolide
carbergoline
Monoamine Oxidase-B Inhibitors
blocks monoamine-oxidase B enzyme from breaking down dopamine
increase circulating dopamine
used to delay use of levodopa and then in combo with levodopa to reduce reuquired dose
Monoamine Oxidase-B Inhibitors examples
selegiline
rasagiline
