parkinsons Flashcards
(29 cards)
parkinsons
progressive reduction of dopamine in the basal ganglia - leading to disorders of movement
-> loss of dopaminergic neurons froms the pars compacta region of substantia nigra
(can see this in brain (coloured) as releases melanin)
types of parkinsons
idiopathic
familial
other (non-degenerative)
- drug induced
- post-encephalic
- toxins
- trauma
risk factors for parkinsons
advancing age - greatest
fam history (esp early onset <40yrs)
males
environmental - pesticide exposure, prior head injury, RUral living, beta blocker use
genetic
- LRRK2 (AD)
- PARKIN
- Alpha-synuclein - AD, Lewy bodies
what harmful act can DECREASE risk of parkinsons?
smoking
basal ganglia
is responsible for coordinating habitual movements – walking, looking around
o Controlling voluntary movements + learning specific movement patterns
substantia nigra
produces neurotransmitter called dopamine
-> Dopamine is essential for correct functioning of the basal ganglia
pathophysio of parkinsons
reactive gliosis happens in response to dopaminergic neuron loss -> astrocyte formation
starts at brain stem + ascends up to brain
- advanced = cortical involvement
- pre-motor symptoms = just brain
what would be seen if mid brain was cut into sections in Parkinsons and substantia nigra visible
reveal loss of normal black pigment in substantia nigra + locus ceruleus (melanin reduction)
parkinsons triad
bradykinesia - slow + diminshing movements
rigidity - increased muscle tone, resistance to passive movement, “cogwheel” as you passively flex arm (gives way to small little jerks)
tremor - at rest, unilateral pill rolling
parkinsons motor features
handwriting getting smaller, shuffling gait
difficulty initiating movements - standing still to walking
diffuculty turning - having to take lots of wee steps
reduced facial movement/expressions = hypomimia
tremor worse at rest + if distracted, 4-6Hz (4-6 times a second)
reduced arm swinging
stooped posture, forward tilt
eyes move horizontally v slowly
non-motor symptoms of parkinsons
anosmia
REM sleep disorder behaviour - act out dreams, speak, move
depression, constipation
friendly hallucinations
dementia - must have parkinsons for at least 1yr prior to onset, presentation similar to DLB
parkinsons diagnostic criteria
UK PDS brain bank criteria
- Bradykinesia + at least one of –
a. Muscle rigidity
b. 4-6hz rest tremor
c. Postural instability not causes alternate primary cause - Exclusion
a. History of stroke - Supporting criteria – 3 or more
a. Unilateral onset
b. Rest tremor
c. Progressive syndrome
d. Asymmetry
e. Excellent response to L-dopa
f. Development of L-dopa dyskinesia
g. Sustained L-dopa response > 5yrs
what can be said about tremor dominant parkinsons
tremor-dominant subtype being associated with slower rate of progression and less functional disability
neurohistological hallmark of parkinsons
Lewy Bodies
(pigment loss correlates with dopaminergic loss)
imaging for parkinsons
SPECT/DaT scan
normal = comma shaped
abnormal = “period” shaped
key medications for parkinsons
levodopa (with Peripheral decarboxylase inhibitors – carbidopa / benserazide)
dopamine agonists - bromocriptine, pergolide, cabergoline
SSRIs for depression
Osmotic laxatives for constipation
key medications for parkinsons
levodopa (with Peripheral decarboxylase inhibitors – carbidopa / benserazide)
dopamine agonists - bromocriptine, pergolide, cabergoline
SSRIs for depression
Osmotic laxatives for constipation
key medications for parkinsons
levodopa (with Peripheral decarboxylase inhibitors – carbidopa / benserazide)
dopamine agonists - bromocriptine, pergolide, cabergoline
SSRIs for depression
Osmotic laxatives for constipation
levodopa
Synthetic dopamine to boost dopamine levels
Usually combined with drug that stops it being broken down before reaches brain
* Peripheral decarboxylase inhibitors – carbidopa / benserazide
Most effective Mx for symptoms but becomes less effective over time
side effects of levodopa
- Postural hypotension – give midodrine if bad
- Dry mouth, anorexia, palpitations
- End of dose wearing off – worse symptoms at end of dosage interval
- Greatest symptomatic benefit but longterm is assoc with motor complications
- When dose too high, can develop dyskinesias (abnormal movement assoc with excessive motor activity) examples –
o Dystonia – where excessive muscle contraction leads to abnormal postures or exaggerated movements
o Chorea – abnormal involuntary movements that can be jerking + random
o Athetosis – involuntary twisting or writhing movements usually in fingers, hands or feet
side effects of levodopa
- Postural hypotension – give midodrine if bad
- Dry mouth, anorexia, palpitations
- End of dose wearing off – worse symptoms at end of dosage interval
- Greatest symptomatic benefit but longterm is assoc with motor complications
- When dose too high, can develop dyskinesias (abnormal movement assoc with excessive motor activity) examples –
o Dystonia – where excessive muscle contraction leads to abnormal postures or exaggerated movements
o Chorea – abnormal involuntary movements that can be jerking + random
o Athetosis – involuntary twisting or writhing movements usually in fingers, hands or feet
4 main parkinson plus syndromes
progressive supranuclear palsy
multiple system atrophy
cortico-basal degeneration
Lewy body dementia
all present with parkinsonism (resting tremor, rigitidy + bradykinesia) plus additional symptoms
progressive supranuclear palsy
parkinsonism + vertical gaze palsy - dysfunction of muslce involved in looking upwards
impairment of vertical gaze - down worse than up
-> may complain of difficulty reading or descending stairs
bradykinesia prominent - broadbased stiff gait, falls
tend to present with a more symmetric + tremor negative parkinsonism
multiple system atrophy
rare condition where neurons of multiple system in brain degenerate
affects basal ganglia + other areas
- degen of basal ganglia -> parkinsonism
- degen in others -> autonomic + cerebellar dysfunction
autonomic dysfunction
- postural hypotension, constipation
- sexual dysfunction, abnormal sweating
cerebellar dysfucntion -> ataxia