Degenerative Diseases Flashcards
How many people in the US have Parkinson’s? What happens to incidence with age?
~1.5 million people with PD in the US
Incidence increases with age
10% onset before 40 y.o.
PD is what kind of disease? What causes it?
Is a neurochemical disorder
Substantia nigra loses dopamine producing ability. Up to 80% loss before symptoms!
Leads to a disinhibition of the cholinergic system
Etiology
Mostly idiopathic (family history + risk factor)
Can also be due to encephalitis, toxic encephalopathy, other degenerative basal ganglia diseases
PD - TRAPPED
T- tremor
R- rigidity
A- Akinesia/Bradykinesia
P- Postural instability
What causes the tremor and rigidity?
Excessive cholinergic activity
What causes the a/bradykinesia?
Loss of dopamine
What is the most common presenting problem in PD patients? How does it start?
Tremor
Starts unilaterally
Typically first seen in fingers: “pill rolling”
Characteristics of PD tremor include: (5)
Is present at rest, and often disappears with limb movement
Increases with exertion or tension
Decreasesor disappears with sleep
Has a frequency of 4-7 Hz
Typically spreads over time
What is rigidity? Name two types of rigidity.
A non-velocity dependent increased resistance to PROM
Lead pipe vs. Cog wheel
Characteristics of Rigidity: (2)
Appears unilaterally before bilaterally
An early sign: loss of arm swing in gait
What is Bradykinesia?
Paucity of movement
Characteristics of Bradykinesia: (3)
Characterized by an inability to perform purposeful movements
Difficulty producing accurate, quick or smooth movements leading to over or undershooting of
movement
Sequential or simultaneous movements most
affected
What is akinesia?
Difficulty with movement initiation
Initiation occurs with co-contraction of agonist and antagonist
What’s the difference between bradykinesia and akinesia?
Both are motor planning deficits, but are mediated by separate mechanisms and do not correlate with each other
What is akinesia associated with?
Associated with the assumption of fixed
postures
a.k.a. “freezing”
Increased frequency in tight/enclosed spaced
Characteristics of PD Postural Instability and Fall Risk
Flexor bound posture (Often considered diagnostic)
INCREASED FALLS RISK! (Delayed equilibrium reactions, lack of anticipatory postural control, inability to adequately respond to perturbations)
Characteristics of PD Gait
Festinating, shuffling gait and
retropulsion
Decreased heel strike and loss of heel, toe progression
Decreased step length
Loss of trunk rotation
Also impairs bed mobility
PD Gait happens as a result of:
Combination of rigidity and bradykinesia
Intellectual changes and dementia occurs in how many PD patients?
Occur in > 50% of individuals with PD
PD Depression
1°: due to loss of dopamine neurons
2°: either reactive or due to sensory deprivation
Other PD symptoms: (4)
Low, whispering monotone voice
Masked face
Lack of autonomic regulation leads to ↑ salivation and sebaceous secretions
Micrographia (Related to bradykinesia, 2° to inappropriate rate and scale of movements)
Medical Management
Dopaminergics Dopamine Agonists Anticholinergics MAO-B Inhibitors COMT Inhibitors Antiviral
What are the side effects of dopaminergics?
Side effects include orthostatic hypotension, “on/off”
times, dyskinesia, hallucinations
Less effective over time
What do dopamine agonists do?
Brain thinks there is more dopamine
Delays need for Sinemet, increaseduse for YOPD
Side effects: drowsiness, edema, obsessive problems
What domapine agonist is used for severe off times?
Apokyn. You need an anti-nausea medication with this.
What do anticholinergics do? What are the side effects?
Control tremor early on
Side effects: dry mouth, sedation, confusion, urinary retention
What do MAO-B inhibitors do? What are the side effects?
Slow the breakdown of dopamine
Decreases free radical production from dopamine
metabolism
Reduce on/off time fluctuations
Side effects: orthostatic hypotension, insomnia
What do COMT Inhibitors do? What are the side effects?
Blocks this enzyme that inactivates dopamine,
prolongs effective Sinemet time
Side effects similar to Sinemet
