Parkinsons disease Flashcards
what are the 3 main types of movement disorders
PD is a movement disorder comprising of tremors, rigidity, slow movement (bradykinesia)
3 important categories:
-Parkinsonism (slow movement)
-tremor (rhythmic movement) - excessive movement
-dystonia (frequent pattern movement) - excessive movement
what does the onset of these movement disorders normally look like?
Onset is usually unilateral (one side of body is more effected) then moves to other side and becomes a bilateral impact
You can see in this patient one side of her body is slower than the other- decrement
What are the risk factors for PD?
Combination of genetic predisposition and environmental factors (More important than genetics as demonstrated via studies that suggested in congruent twin studies the risk of both having it was low emphasising importance for environmental factors)
High risk to PD is those exposed to pesticides
Prior head injury can be a factor for PD but not strong risk factor
Things that decrease risk to PD
-decrease smoking/drinking
-reduced caffeine intake
However due to pathology of PD, it’s unlikely for them to have habitual formation with these factors as they have decreases dopaminergic neurones and that important for reward system to function which is associated with habitual formation.
2 important at-risk causative genes for PD
-GBA
-LRRK2
PD –> genetic causes only accounts for 5-10%
What are the neuropathological hallmarks of PD?
There’s neurodegeneration in all parts of a PD brain but crucially the degeneration of dopaminergic neurones in substantia nigra.
If we examine surviving neurones- there’s an accumulation of Lewy body aggregates that contain alpha-synuclein, these are found in other areas of brain like brain stem.
-the quantity and location of these aggregates have been used to stage pathology and severity of PD
What is the way in which the progression of PD is catgeorised? and how many stages are there and what do the first 3 and last 3 refer to? Where does the onset of PD begin and what are some of the challenges of using this staging in PD?
Braak staging - this uses alpha synuclein aggregation and localisation to stage the disease.
6 stages
The first three refer to the presymptomatic phase?
4,5,6 refer to symptomatic phase.
-Onset of PD begins at dorsal motor X nucleus - medulla oblongata
-and olfactory bulb located at the bottom of cerebral hemishphere near the front (forntal lobe)thus disease spreads from this region, reaching substantia nigra- causing onset of motor symptoms.
But now this is challenges raising the idea if alpha synuclein is a causative or protective aggregate of PD
what are the cardinal motor signs of PD?
Bradykinesia
Resting tremor
Rigidity
postural instability (this occurs later on)
what is the main mechanism of disease in PD?
-protein degradation
-mitochondrial function
-synaptic and endosomal vesicle and protein recycling
-inflammation and ageing (SASP?)
-
why is the progression of going caudal to rostral challenged?
Also, the onset of the disease starting at brain stem then going up to affect other regions (rostral-caudal) has been challenged as there have been patients with aggregation in cortex and not in brain stem where it is thought to have been started.
what is the difference between functional tremor and tremor in PD
We see resting tremor a lot during walking triggering it.
It causes a metal stress triggering the tremor
Re-emergent tremor occurs when holding posture like holding arm straight out but re appears but in fucntional tremor, when doing an activity it helps reduce frequency and amplitutde of the tremors
what is the core feature of parkinsonism? and what is anohter term for this
When taking about bradykinesia we refer to slow amplitude in movement= hypokinesia
(Reduced velocity, amplitude and decrement-reduced)
Akinesia - poverty of expected spontaneous movements.
what arethe features of bradykinesia on motor function?
reduced facial expression - hypomania
-soft voice as it affects their phonation - hypophonia
-short step gait
-shuffling gait
-small handwriting- micrographia
-reduced dexterity
describe gait dysfunction in PD and what does freezing gait mean?
Gait dysfunction is characterised by reduced velocity, cadence-rhythm, stride length, arm swing and asymmetry on stride length
As disease progresses and becomes bilateral it will affect both sides reducing velocity in these tasks.
Freezing of gait is a motor block in muscles when walking taking very short steps and feet are glued to grown
Freezing of gait shown when walking, passing narrow passage, turning around, dual tasking like talking whilst walking so they are asked not to speak to not impact their walking
What is the weird anomaly seen in individuals in terms of their speed of walking?
When they run their movement becomes much faster. Walking faster is easier for PD patient then walking slower
what is the clinical diagnostic criteria for PD? and name 3 atypical symptoms?
To diagnose requires presence of the four cardinal features especially bradykinesia
So requires presence of bradykinesia plus one of the other 4
Demonstrated sustained response to levodopa-good and sustained over time
Need to exclude atypical signs that are associated to other disease with Parkinson’s like symptoms-atypical symptoms such as:
-postural instability in the first 3 years.
-early freezing
-early hallucinations and demntia
what are some of the exclusion criteria used for PD?
Need to have absence of all absolute exclusion criteria that suggest alternative diagnosis such as no observable response to high dose of levodopa.
2 supportive criteria (resting tremor of limb and goes response to dopaminergic therapy)
Absence of red flag with same to first-to be sure not another diagnosis (such as absence of progressive motor symptoms)
