Parkinsons Disease Flashcards
What neurotransmitter is involved in PD and explain
Loss of dopaminergic neurons in the substantia nigra of basal ganglia
symptoms asymmetrical or symmetrical?
asymmetrical - 1 side more affected than the other
triad of features
resting tremor
bradykinesia
cogwheel rigidity
what are the basal ganglia?
group of structures in middle of brain that are responsible for coordinating habitual movements eg walking or looking around and control voluntary movements and learning movement patterns
what part of basal ganglia produce dopamine?
substantia nigra
what is dopamine essential for?
correct functioning of basal ganglia
typical PD patient
older aged man around the age of 70
frequency of tremor
4-6 times a second
how is the tremor often described?
pill rolling tremor
what makes the tremor worse and better?
pronounced when at rest and improves with voluntary movement
worse if patient distracted
what is rigidity?
resistance to passive movement of a joint
How does bradykinesia present?
shuffling gait
handwriting smaller and smaller
reduced facial movements - hypomimia
difficult initiating movement
other conditions which can affect PD patients
depression sleep disturbance and insomnia anosmia postural instability cognition and memory problems
PD tremor vs benign essential tremor
PD = asymmetrical, worse at rest, improves with intentional movement, other PD features, no change with alcohol BET = symmetrical, improves at rest, improves with alcohol, worse with intentional movement`
Parkinson’s plus syndromes
dementia with lewy bodies
multiple system atrophy
progressive supranuclear palsy
multiple system atrophy
neurones atrophy in multiple areas including basal ganglia
PD and autonomic dysfunction
cerebellar dysfunction
Dementia with lewy bodies features
visual hallucinations
delusions
disorders of REM sleep
fluctuating consciousness
How is PD diagnosed?
clinically
UK PD society brain bank clinical diagnosis criteria
4 main classes of drugs used
levodopa
COMT inhibitors
MAOB inhibitors
dopamine agonists
what is levodopa?
synthetic dopamine given orally
what is levodopa combined with?
peripheral decarboxylase inhibitors eg carbidopa to prevent levodopa being broken down in body before it enters BBB
side effect of dopamine
dyskinesias eg dystonia, chorea and athetosis
dystonia
excessive muscle contraction leads to abnormal postures or exaggerated movements
chorea
abnormal involuntary movements that can be jerking
athetosis
involuntary twisting or writhing movements in fingers, hands or feet
when is levodopa used?
most effective but less effective over time
reserved for when patient not managing
COMT enzyme role
metabolises levodopa in body and brain
example of COMT inhibitor
entacapone
side effect of long term dopamine agonist use
pulmonary fibrosis
What do monoamine oxidase enzymes do?
break down neurotransmitters eg dopamine, serotonin and adrenaline
does monoamine oxidase B act on all neurotransmitters?
no - just dopamine
