Parkinson's Flashcards
What are the deposits in parkinson’s?
Lewy body proteins which are made up tangles of alpha sinuclein
3 main feature that happen in the brain in Parkinson’s
- lewy body protein deposits of alpha-synuclein
- loss of dopaminergic neurons form pars compacta of substantia nigra of the midbrain
- degeneration also occurs in other basal ganglia nuclei
How is Parkinson’s diagnosed?
- clinical diagnosis by recognizing physical signs and symptoms
- DAT imaging to assess extent of neuron loss
Name two genes associated with early onset Parkinson’s
PARK 1 gene - codes for alpha synuclein protein
- inherited AD
- rare but major lewy body protein
- PARK 2 - codes for Parkin protein
- Autosomal recessive
- responsible for most cases of juvenile PD
What does PARK 1 gene code for and inheritance?
for alpha synuclein protein
- inherited AD
- rare but major lewy body protein
What does PARK 2 gene code for and inheritance?
PARK 2 - codes for Parkin protein
- Autosomal recessive
Genes responsible for juvenile PD
PARK 2
Triad of parkinsons
bradykinesia, tremor and rigidity
Facial features seen in Parkinson’s
facial immobility : mask like
-Serpentine stare - reduced frequency of spontaneous blinking
2 features of bradykinesia
- slowing down of movements - progressive fatiguing and reduced amplitude
- Short shuffling steps with reduced arm movements
Features of tremor
- Unilateral
- Resting
- Pin rolling between thumb and index
Features of rigidity
- lead pipe - stiffness seen passive limb movements
2. cogwheel rigidity - stiffness occurs with tremor
Features of posture
- stooped posture is characteristic
Features of speech and swallowing
- quiet, indistinct flat voice
- drooling
- swallowing difficulty - increased risk of aspirayion pneumonia
Cognitive and psychiatric changes
- Dementia can develop
- Visual hallucinations and psychosis
- Depression and anxiety are common
Drug-induced parkinsonism
- motor symptoms are generally rapid onset and bilateral
- rigidity and rest tremor are uncommon
Levodopa ( mechanism of action )
- a precursor of dopamine which is used as a dopamine supplement
- precursor needs to be used because dopamine itself cannot cross the blood-brain barrier
- Administered alongside ‘decarboxylase inhibitor’ ( carbidopa) to inhibit decaboxylase enzyme from converting Ldopa into dopaine peripherally
MOAB inibitors ( mechanism of actions )
- inhibits monoamine oxidase enzyme which breaks down dopamine
Drawback of Levodopa
Effectiveness reduces over time
Name a MAO
Selegiline
Dopamine receptor agonists
- Used as primary Tx before Levodopa
Example of Dopamine receptor agonist
Ropinirole
Catechol-O-Methyl Transferase inhibitor - mechanism of action
COMT is an enzyme which transfers methyl group onto dopamine and inactivates it
- this enzyme is inhibited and so more dopamine is avaliable
Catechol-O-Methyl Transferase inhibitor - indication
- Tx patients when effectiveness of Levodopa is staring to wear off
- Increase duration effect of Levodopa
