Parkinson's Disease Flashcards
What is Parkinson’s disease?
Neurochemical Disorder
Substantia nigra loses dopamine producing ability
Inhibition of cholinergic system (decrease in dopamine = increase in acetylcholine)
Up to ___% loss of dopamine occurs before Parkinsonian symptoms appear.
80%
What are 4 causes of Parkinson’s disease?
- Idiopathic: risk factors and family history (MOST COMMON)
- Encephalitis
- Toxic encephalopathy
- Other degenerative diseases of the BG
What are the 4 most common clinical manifestations of PD? (TRAP)
- Tremor (resting due to excessive cholinergic activity)
- Rigidity (non velocity dependent increase in muscle resistance to stretch)
- Akinsiea/bradykinesia (caused by loss of dopamine)
- Postural instability
How does a tremor typically first present in patient’s with Parkinson’s disease?
- Starts unilaterally
2. First in seen in fingers (pill rolling)
5 characteristics of a tremor
- Is present at rest, and often disappears with limb movement
- increases with exertion or tension
- Decreases or disappears with sleep
- Has a frequency of 4-7 Hz
- Typically spreads over time
What is an early sign of rigidity? Does it appear bilaterally or unilaterally first?
Appears unilaterally before bilaterally
Early sign: loss of arm swing in gait
What are 2 characteristics of bradykinesia? What movements are most affected by bradykinesia?
- Characterized by an inability to perform purposeful movements
- Difficulty producing accurate, quick/ smooth
movements leading to over/undershooting of
movement - Sequential/simultaneous movements most affected
What is akinesia? What causes this? What can make this worse?
- Difficulty with movement initiation
- Caused by co-contraction of agonist and antagonist resulting in no movement
- Increased frequency in tight/enclosed spaces
True or False: Bradykinesia and Akinesia are mediated by the same mechanism.
FALSE
Both are motor planning deficits, but are mediated
by separate mechanisms and do not correlate with
each other
What posture is most commonly seen in patients with PD?
Flexor bound posture
What are 3 reasons patients with PD have an increased risk for falls?
- Delayed equilibrium reactions
- Lack of anticipatory postural control
- Inability to adequately respond to perturbations
What are 4 gait impairments associated with PD?
- Festinating, shuffling gait and retropulsion
- ↓ heel strike and loss of heel toe progression
- ↓ step length
- Loss of trunk rotation (impairs bed mobility)
____ occurs in > 50% of individuals with PD
DEPRESSION
What is the difference between primary and secondary depression in PD?
Primary: Due to loss of dopamine neurons
Secondary: Reactive or due to sensory deprivation
List 4 other symptoms of PD.
- Low, whispering monotone voice
- Masked face
- Lack of autonomic regulation leads to ↑ salivation and sebaceous secretions
- Micrographia (progressively small handwriting)
What are 4 side effects of dopaminergic drugs? What is a disadvantage of using these drugs?
- orthostatic hypotension
- “on/off” times
- dyskinesia
- hallucinations
Disadvantage: Less effective overtime (need more and more of the drug to achieve the same effects)
What are the effects of dopamine agonists? What are 3 side effects?
- Brain thinks there is more dopamine
- Delays need for Sinemet
Side effects: drowsiness, edema, obsessive problems
What are the effects of anticholinergics? What are 4 side effects?
- Restores acetylcholine/ dopamine balance
- Control tremor early on
Side effects: dry mouth, sedation, confusion, urinary
retention
What are the effects of MAO-B inhibitors? What are 2 side effects?
- Slow the breakdown of dopamine
- Decrease free radical production from dopamine
metabolism - Reduce on/off time fluctuations
Side effects: orthostatic hypotension, insomnia
What are the effects of COMT inhibitors?
Blocks this enzyme that inactivates dopamine,
prolongs effective Sinemet time
What are the effects of antivirals? What are 3 side effects?
- Helps rigidity and bradykinesia
- Low doses smooth fluctuations
- High does suppress dyskinesias
Side effects: edema, skin blotches, insomnia
What is the on/off phenomenon? What causes this phenomenon?
Short duration therapeutic response followed by rapid
reduction in that response
Due in fact that PD medications are toxic to the
receptor site
What is meant by a ‘narrowing therapeutic window’ relative to drug therapy in PD?
Patient needs to fall out of the effects of the drug before we can give them more of the drug, because the additive effects are toxic
What are botox injections used to manage in PD?
Manage hypertonia
Have been used to manage severe equinovarus or
claw deformities caused by rigidity
What surgical approach is used to treat PD?
Deep brain stimulation
