Parkinson's Disease Flashcards
A slowly progressive neurodegenerative disorder that affects movement, muscle control, & balance
- Part of dz process develops as cells are destroyed in certain parts of the brain
- Cells release essential neurotransmitters (dopamine) that help control movement & coordination
Primary is idiopathic
Secondary may be seen w/parkinsonian sx’s as a s/e of antipsychotic drugs or tumors
Normally, the ___ ___ neurons produce the neurotransmitter dopamine which acts to inhibit neurons from firing
substantia nigra
___ is a neurotransmitter that excites neurons & fires to stimulate motor neurons
The 2 neurotransmitters work together to maintain a balance in neuronal excitation & the person has control over movement & balance
Acetylcholine (Ach)
In PD, the substantia nigra neurons die & no longer produce dopamine
Acetylcholine’s effects on neuronal excitation goes unopposed
There’s no longer the balance of dopamine to slow impulses
Therefore, purposeful movement, coordination, & balance are impaired
Pts w/PD have difficulty controlling & initiating movement
Dopamine is also responsible for assisting the body to respond to stress & prepare it for the fight-or-flight response
Also appears to be important for efficient info processing, & deficiencies may also be responsible for problems in memory & concentration that occur in many pts
Approx 80% of the 20,000 dopamine-producing neurons in the substantia nigra have died by the time PD motor sx’s have developed
Etiology & Risk: Genetic
- Specific genetic factors appear to play a strong role in early-onset PD, an uncommon form of the dz
- Recent research suggests that multiple genetic factors may also be involved in some cases of late-onset PD; have been @ least 5-10 genetic locations id’d
Environmental
- May trigger the condition in genetically-susceptible people
- Some evidence implicates pesticides & herbicides
- Higher incidence in those living in rural areas; those who drink private well water or are agricultural workers
Dopaminergic neurons produce a protein called ____ that’s normally degraded by enzymes
If not degraded, build-up of this protein in the dopaminergic neurons causes toxic fibrils called Lewy bodies
Too many Lewy bodies are assoc w/neuron death in the substantia nigra
Pesticides & herbicides may interfere w/enzymes that degrade this protein
alpha-synuclein
Age
- > 40 & more than likely 60 & over are @ higher risk
Low estrogen
- @ neuronal synapses, estrogen inc the conc of neurotransmitters such as serotonin, dopamine, & norepinephrine
- It affects their release, re-uptake, & enzymatic inactivation; also inc the # of receptors for these neurotransmitters
Repeated head trauma
- Greater than 2 episodes of LOC
Stages of PD
- Stages I-V
Stage ___
→ Complete dependence
V
Stage ___
→ Postural instability
→ Inc gait disturbances
III
Stage ___
→ Akinesia
→ Rigidity
IV
Stage ___
→ Bilateral limb involvement
→ Mask-like face
→ Slow, shuffling gait
II
Stage ___
→ Unilateral limb involvement
→ Minimal weakness
→ Hand & arm trembling
I
Assessment: Motor Symptoms
► on-off phenomenon
► resting tremor
► pill rolling
► micrographia
► cogwheel rigidity - resistance to passive movement
► bradykinesia/akinesia
► postural instability - a dec or change in motor & muscle movements that leads to unsteadiness & hesitation in movement & gait when the individual starts or stops walking
► loss of balance
