Week 10 - Parkinson's Disease Flashcards
what is parkinson’s disease
- a progressive & neurodegenerative & movement disorder that involves degeneration of dopaminergic neurons in the substantia nigra
what two nt does parkinson’s disease effect? how?
- causes an imbalance in nt dopamine & ach secreted in the basal nuclei
= excessive Ach, dopamine deficiency
what is the fnxn of dopamine (3)
- trunk support
- voluntary motion
- posture
what are movement programs from the motor cortex typically inhibited by
- GABA secreted from the basal nuclei onto the thalamus
what effect does ach have on GABA? dopamine?
- ach = excitatory hormone = increased secretion of GABA
- dopamine = inhibitory = decreased secretion of GABA
what effect does excessive ach have
- excessive ach stimulated inhibition of the motor cortex = inhibition of movements
( why we get the rigidity, slowed movement, etc.
what is the most common cause of PD
- most common cause is idiopathic
what are other causes of PD (4)
- encephalitis
- severe carbon monoxide poisoning
- MPTP
- neurleptic drug toxicity
what are risk factors of PD (4)
- 60 years or older
- FHx
- history of head trauma
- exposure to herbicides & pesticides
what are the 4 main symptoms of PD
- tremor
- rigidity
- bradykinesia
- postural instability
what other symptom may occur w PD
- intellectual deterioration
what causes the tremor during PD to be more pronounced (4)
- more pronounced at rest
- enhanced by stress, concentration, or anxiety
is the tremor uni or bilateral
- usually begins in only one side of the body initially
- but can progress & be bilateral
what is the tremor during PD often described as
“pill rolling”
- looks like ur trying to roll a pill between the thumb & index finger
what affects does the tremor during PD have (2)
- affect handwriting
- affect ADLs
what is rigidity
- increased resistance to passive movement
what can rigidity during PD look like?
“cogwheel rigidity”
- watch video in notes as it is hard to explain
what can rigidity during PD cause
- muscle soreness/fatigue due to the constant state of rigidity
what is bradykinesia
- slow voluntary movements
what other effect can PD have on motor function (6)
can cause reduction in autonomic extrapyramidial movements –> does not execute involuntary movements such as:
- blinking
- swinging arms while walking
- swallowing saliva = drooling
- facial expressions
- postural adjustments
what is meant by “masked face” during PD
- way to describe the lack of facial expressions that occur w PD
what kind of posture is seen w PD
- stooped or flexed posture
what is postural instability
- flexed posture with “shuffling” steps
what can postural instability lead to (2)
- instability
- falls
what is postural instability complicated by
- slowed voluntary movements
describe the onset of PD
- insidious & gradual
define akinesia
- the loss of the ability to move muscle voluntarily
- absence of movement
define bradykinesia
- slowness of movement
define dyskinesia
- abnormal involuntary movement
what happens as PD progresses (6)
complications increase such as:
- motor symptoms
- weakness
- akinesia
- neuro problems
- neuropyschiatric problems (depression, anxiety)
what changes in mental status might you see during assessment of PD (5)
- depression
- mood swings
- flat affect
- sleep disturbances
- dementia (memory loss & confusion)
what changes in sensation might you see during assessment of PD
- paresthesia
- loss of smell
what changes in balance/corrdination might you see during assessment of PD (5)
- bradykinesia
- shuffling gait
- stooped posture
- difficulty initiating movements
- unable to stop themselves from going forward & backwards
what changes in movement might you see during assessment of a pt with PD (7)
- tremors (pill rolling)
- rigidity (cogwheel)
- jerky quality
- muscle fatigure & soreness
- difficulty executing involuntary movements
- drooling
- masked face
which cranial nerves might be effected by PD
- CN1
- CN 2,3,4,6
- CN 5, 7
- CN 8
- CN 9,10,12
- CN 11
- all of them
what might the change in CN 1 cause
- loss of smell
what might the change in CN 2,3,4,6 cause (2)
- visual changes
- difficulty w eye closure & blinking
what changes in CN 5 and 7 might you see (2)
- blank, expressionless face
- difficulty chewing
what changes in CN 8 might you see (2)
- hearing loss
- balance issue
what changes in CN 9,10, 12 might you see (2)
-issues with speech & swallowing
what changes in CN 11 might you see
- issues w movement of head & shoulders
_____ occurs in 40% of PD pts
- dementia
is there a diagnostic test for PD
- no specific diagnostic test
describe how diagnosis of PD is completed
based of manifestations & history
- must have 2/3 classic triad
what is the PD traid
- tremor
- rigid
- bradykinesia
what can confirm the diagnosis of PD
- positive response to antiparkinson meds
what is a type of surgical care for PD
- deep brains stimulation
describe how deep brain stimulation works
- involves placing an electrode in the thalamus, globus, pallidus, or subthalamic nucleus
- connected to a generator in the upper chest
- device is programmed to delivery specific current to targeted brain location
what is the goal of treatment for PD
- restoring the balance between ach and dopamine
what 3 classes of meds are used for PD
- dopaminergic agents
- dopamine agonists
- MAO inhibitors
what are 2 types of dopaminergic agents for PD
- levodopa
- levodopa/carbidopa
what is the MOA of levodopa
- crosses the BB and is converted to dopamine in the brain = increased lvls of dopamine
what is a challenge w levodopa (2)
- only a small part reaches the brain
- bc most is metabolized in the body
= difficult to achieve optimal dosages - also loses effectiveness over time
what is the most effective drug for parkinsons
- levodopa
what are 4 adverse effects of levodopa
- dyskinesias
- postural hypotension
- NV
- psychosis
what is dyskinesia
- abnormal, involuntary, erratic movements of the face, arms, legs, or trunk
how does levodopa cause dyskinesias
thru the on-off phenoneom:
- too little dopamine = parkinson’s disease symptoms worsen
- but too much due to the med = dyskinesia
how can we prevent the NV associated levodopa? what is a con to this?
- give w food
- but it will decrease absorption
what needs to be done if levodopa causes psychosis
- dose will need to be reduced
what med is often given in combo w levodopa
- carbidopa
what is the MOA of carbidopa
- no therapeutic effect on its own
- but it stops metabolism of levodopa in the body = increased amt of dopamine available to the brain
list adverse effects of levodopa/carbidopa
- decreased CVS effects (hypotension)
- decreased NV side effect of levodopa
- increased dyskinesias
how does levodopa/carbidopa decrease the CVS and NV side effect associated w levodopa on its own
- by decreasing the lvl of dopamine in the body
how does levodopa/carbidopa increase the dyskinesias compared to levodopa on its own
- by increasing the amt of dopamine in the brain
what is a type of dopamine agonist used for PD
- pramipexole
what is the MOA of pramipexole
- directly activates dopamine receptors
describe the use of pramipexole
- for mild to mod PD symptoms
what are the effects of pramipexole
- improved motor performance
- stabilized motor control in later disease when used w levodopa
list s/e of pramipexole (6)
- NV
- dizziness
- daytime somnolence
- insomnia
- hallucinations
describe dyskinesia during pramipexole
- does not cause dyskinesia
what is one s/e associated w pramipexole if used with levodopa
- high likelihood of postural hypotension (more than 50%
what is an MAO-B inhibitor used for PD
- selegiline (deprenyl)
what is the MOA of selegiline
- inhibits the enzyme monoamine oxidase B, which breaks down dopamine = more dopamine in brain
describe the relation between selegiline and levodopa
- prolongs the effects of levodopa bc it prevents the dopamine it is converted into from being inactivated so quickly
what is a pro to selegiline
- may delay disease progression
what are 2 side effects of selegiline
- insomnia
- postural hypotension
what are 3 types of dyskinesia
- akinesia
- akathisia
- dystonia
what is akinesia
- loss of voluntary motor function
what is akathisia
- having the urge to move, restlessness ex: - rocking while standing - lifting feet as if marching on spot - crossing & uncrossing legs while sitting
what is dystonia
- abnormal muscle tone leading to impaired or abnormal movements of head, neck, and tongue
