Parkinsons Flashcards
prevalence of parkinson’s
one of the most common neurodegenerative conditions- 1:500, prevalence increases with age (1:50>80), men 1.5X more likely to develop condition
etiology of parkinsons
genetic cause- 15%, environmental factors- pesticides, herbicides, industrial pollutants
cause still unknown
definition of parkinsons
is a chronic, progressive neurodegenerative disorder resulting from the degeneration of dopamine producing neurons in the substantia of the basal ganglia, it is characterised by tremor and disturbance to voluntary movement, posture balance
role of basal ganglia
regulating planning, initiating and termination of movement, regulate muscle tone required for specific body movements, control subconscious or stereotyped contractions of skeletal muscles, act on inhibit antagonist or unnecessary movements, stores movement memories, dopamine is a excitatory neurotransmitter
dopamine
substantia nigra is the main source of dopamine, basal ganglia part of a series of parallel loops involving the thalamus and cerebral cortex.
classic model for dopamine
direct pathways- promotes movements, indirect pathways- inhibits movement, dopamine excites the direct pathway and inhibits the indirect pathway- leads to movement (inhibits inhibition)
what happens in parkinson’s disease
neurodegeneration in the substantia nigra in the basal ganglia leading to a lack of dopamine, lack of dopamine leads to- lack of excitement of the direct pawaht, lack of inhibition of the indirect pathway= lack of movement
primary clinical features/ cardinal signs- bradykinesia
slow movement, akinesia- no movement, paucity or slowness of movement- with a slower initiation of movement and a progressive reduction in the speed and amplitude of repetitive action, in PD, the decreased production of dopamine leads to an increased inhibitory effect of the thalamus so that there sia suppression of movement in the cortex
primary clinical features/ cardinal signs- Resting tremor
lack of dopamine leads to a release of inhibition of tremor, resting tremor (pill rolling) occurs when the muscle is relaxed, such as when the hands are resting on the lap. with this disorder, a person’s hands, arms, or legs may shake when they are at rest. of the tremor only affects the hand or fingers. the tremor is inhibited during movement
primary clinical features/ cardinal signs- rigidity
not getting movement, no stimulation of direct pathway, no inhibition of indirect pathway
lack of dopamine- stiff or inflexible muscles, resistance to passive movement, lead pip rigidity- resistance all the way through movement, or corg wheel rigidity give a bit then get resistance
secondary clinical features- movements
difficulty initiating and terminating movement, freezing when walking, lack of spontaneous movement and initiating movement, festinating gait pattern, slow shuffling gait, loss of stereotyped movements such as arm swing during gait
secondary clinical features- other
difficulty with motor task- turning i nbed, sit to stand, dressing, shaving
monotone speech, micrographia, problems with swallowing, sleep disorders- due to rigidity/ tightness, depression
postural instability
develops later in the disease, characteristic fixed posture, flexed hips and knees, unable to access balance reactions
Hoehn and Yahr- stage 0-2.5
0- no signs of disease, 1- unilateral involvement with minimal functional ability, 1.5- unilateral involvement also involving neck and spine, 2- bilateral disease but no impairment or balance, 2.5- mild to moderate bilateral symptoms with recovery when the pull test is given (the doctor stands behind the person and asks them to maintain their balance when pulled backwards)
Hoehn and Yahr- stage 3-5
3- bilateral mild to moderate disease, some postural instability, physically independent
4- severe disability, but still able to walk, or stand unassisted
5- needing a wheelchair or bedridden, unless assisted
medical management- dopamine replacement
levodopa (e.g. Sinemat)- aims to replace the lost dopamine but dopamine cannot cross the blood/brain barrier so Sinemet and madopar all contain drugs that facilitate the. crossing of the brain
medical management- dopamine copycats/ protectors
copycats- known as dopamine agonists- e.g. apomorphine, pergolide,
protectors- monamine oxidase B (MAO- B) inhibitors (e.g. selegiline) and COMT- inhibitors (e.g. entacapone)- these protect the current levels of dopamine by blocking enzymes that break it down
medical management-anticholinergics
(e.g. arpiocline- mostly younger patients). correct imbalance between D/acetylcholine: imbalance can cause increase muscle tension and tremor and also increase salivation and urgency
problems with medicaiton
get to point where they don’t work anymore- need to keep increasing the amount of medication but- effects reduce over time- increase dosage- side effects (dyskinesia is- strange movements)
surgery
deep brain stimulation for tremor
medical management- surgery- pallidotomy
is a neurosurgical procedure whereby a tiny electrical probe is placed in the globus pallidus, which is then heated to 80° for 60 secs, to destroy a small area of brain cells
medical management- surgery- thalamtomy
destroys the thalamus
medical management- surgery- stem cell research
research working with laboratory rats show it is possible to make dopamine cells from embryonic stem cells and transplants them into brain ,replacing the cell lost to the disease
life expectancy
parkinson’s is not itself a killer it will contribute to death of person with PD, immobility and mental disability can cause and/or exacerbate other illness that can contribute to death (pneumonia), quality of life is dramatically affected for both patient/ client and family
