pain in movement disorders Flashcards
what is Parkinson’s disease?
it is a neurodegenerative disease characterised by slowness of movement (bradykinesia), rigidity, and tremor (present at rest)
what is dystonia?
is a movement disorder that causes excessive muscles contractions or spasms involuntarily and it often involves quick muscle contractions, frequent twisting, repetitive movement, and abnormal neck and head posture
what are the most parkinson disease and dystonia symptoms caused by (refer to neurology)?
most of symptoms seen in PD and dystonia is caused by abnormal firing rate in basal ganglia
What are the key brain-component regions within the basal ganglia?
putamen, caudate, substantia nigra, subthalamic nucleus, and globus pallidus, which are in a connected network that is abnormally firing in individuals with movement disorders.
describe the dopaminergic nigrostriatal system and how this is affected in parkinson’s disease and dystonia
its a network connecting the substantia nigra to striatum, which is mediated by delivery and release of dopamine
In Parkinson’s disease, there is neurodegeneration of these neurons, leading to a reduction in domain levels. A reduced abundance of domaines leads to abnormal firing rates, which result in tremors and other symptoms.
In dystonia, there is no neurodegeneration; however, there is an abnormal firing rate in the basal ganglia.
describe the 5 body distributions of dystonia?
focal: affect one body part
segmental: 2 contiguous body parts (that are connected)
multi-focal: different body parts that aren’t contiguous
hemi dystonia: ipsilateral side of body
generalised dystonia: several parts of body
What are some of the types of dystonia you can have based on the body part it affects?
cervical dystonia
trunkal dystonia
lower limb dystonia
upper limb dystonia
generalised dystonia
What are the key clinical characteristics to consider when diagnosing dystonia?
age of onset (infancy, childhood, adolescence, early adulthood, late adulthood)
body distribution (focal, segmental, multi-focal, hemi dystonia, generalised dystonia)
temporal pattern
(paroxysmal-episodic, static/fixed)
associated features
(other neurological conditions or disorders)
dystonia can be a symptom of what type of disease?
neurodegenerative disease (PD), genetic disease, or diseases in general
What is it called when dystonia is a disease rather than a symptom of other diseases?
idiopathic dystonia
what is the main pathways causing idiopathic dystonia?
dysfunction or abnormalities in basal ganglia—sensory motor network
which type of dystonia are more often associated with pain?
idiopathic cervical dystonia
which type of pain is cervical dystonia?
pain in neck and shoulder muscle due to excessive muscle contractions can lead to abnormal posture to one sideand muscular related pain from the overuse of muscles- causes discomfort and stiffness.
they can also expereince neuropathic pain due to nerve compression caused by excessive abdnoraml muscle contractiosn that is reported as a shooting and burning sensation.
why is pain bad in dystoniaand in general?
poor quality of life affects ability to function adequately
what is the other non-common feature associated with cervical dystonia?
headaches
What are the common conditions that can develop in idiopathic CD patients with reference to pain?
radiculopathy, which is injury or damage to nerve roots in the area where they leave the spine
dont k if this is corect beacuse idiopathic is a primary dytonia where there isnt an identifiable cause
What are the different ways to determine the severity of pain?
Pain scaling questionnaires
temporal discrimination threshold (TDT), which is used to assess sensory processing. It works by for example, applying pressure and having the patient hold a button. When that pressure becomes a painful stimulus, the button is pressed, which indicates their threshold for pain. This is usually done several times to produce reliable outcomes.
Is the mechanism for functional dystonia the same as or different from idopathic dystonia?
different
what are the mechanisms of pain inn dystonia?
-prolonged muscle contractions
-alteration in noiciceptive processing and sesnitivity of painful stimuli (high density of deep pain receptors in neck)
Is the transmission of pain or descending control abnormal in CD and is there a possible theory that pain is prolonged?
the ascending pain transmission is normal, but the declining pain control is abnormal in CD patients, so there could be involvement of subthalamic nucleus and ventrolateral thalamus as they are responsible for pain modulation so there is a possible theory of dysfunction in those areas
What is abnormal in the case of functional dystonia in terms of experiencing pain?
the emotional or cognitive component of pain is abnormal or impaired
as pain tolerance is increased in functional dystonia but not in idiopathic dystonia, suggesting impairment in the emotional and cognitive components of pain.
what are the treatment of pain in dystonia
botulinum toxin (Botox) is effective for pain in cervical dystonia
The effects of it wear off and treatment needs to be repeated after a few months. not long term
for more severe cases, patients can undergo surgery like deep brain stimulation
describe botulinum toxin
its a zinc protease produced by gram positive anaerobic clostridium botulinum
it has a light chain (which is the recognition receptor) and a heavy chain (the active part of toxin that medicates the mech of action)
how many serotypes of BT is there and what are the common ones?
7 (A-G)
common is A, sometimes B
what does the clinical effects of botulinum toxin depend on?
depends on dosage; the higher the dosage, the stronger the palsy (paralysis due to no muscle contraction)
we use a small dosage to avoid any significant side effects but they usually subside within a few weeks
What are some non-motor symptoms, emotional signs and axial motor signs of Parkinson’s disease and what is the most common and second most common neurodegenerative disease?
non motor symptoms: digestive problems / gastrointestinal (constipation/ decreased bowel movement), sleep, pain, fatigue
emotional signs:
-depression
-anxiety
-psychosis
axial motor signs:
-speech
-gait
-posture
-balance
-PD most common
-Alzheimer’s second common
what is the neuropathological features of PD
neural degeneration of dopaminergic neurons in substantia nigra
aggregation of a-synuclein that accumulates to form lewy bodies (some think this is pathogenic while others suggest it could be a protective mechanism)- good biomarker for PD
What are the main motor signs of Parkinson’s disease?
bradykinesia (slow movement)
tremor
rigidity
postural instability (occurs later on)
what is a treatment for PD
levodopa, which replaces dopamine due to neurodegeneration of dopaminergic neurons in substantia nigra
What type of dystonia is most likely to occur if you have Parkinson’s disease?
lower limb dystonia (can be associated with lower limb pain as a result) the foot inverts inwards
What is the peripheral mechanism for low pain tolerance in PD?
there is seen to be a reduced density of meisner’s corpuscles (which is responsible for transmitting sensations of fine touch) due to neurodegeneration of skin nociceptors
