Parkinson's Disease (Shaking Palsy) - Clinical Presentation and Pathophysiology

hello in this video we're going to talk about Parkinson's disease which is a neurodegenerative disease about 0.3 percent of the population over the age of 40 has this disease it's about 7.5 million people worldwide so let's look at the firstly signs and symptoms of Parkinson's and here I'm drawing a patient who shows who presents with tremors shaking and he presents like this due to a condition called Parkinson's disease that affects the brain the Cardinal features of Parkinson's disease therefore these include tremors rigidity bradykinesia postural instability there are other features which affect the cranial facial areas which include hypomania which is basically decrease in facial expression dysphasia hypotonia reduction in basically the tone of the voice volume Vizier's include visual problems such as blurred vision and eyelid opening apraxia other features also include gait you can have shuffling fascinations and freezing so all these signs and symptoms are a result of problems that occur within the brain particularly in an area of the brain known as the basal ganglia so let's just quickly revise are some important anatomical structures of the brain so here we have the fornix which is an important part of the limbic system we have the hippocampus which is for memory the amygdala for emotions but we will mainly concentrate on this yellow structure here which is known as the basal ganglia or the basal nucleus medially to the basal ganglia is the thalamus which essentially is a connection between the cortex and the brainstem spinal cord so again Parkinson's disease as a result of problems that occur within the basal ganglia or the basal nucleus because this area is responsible for muscle tone as well as the ease of movement so to it helps in a smooth movement and learn to movement patterns so let's just take a cross-section a coronal section of the brain here and look at the basal ganglia in a bit more details and its components so here we're looking at a section of the brain here in green is the thalamus just to orientate where we are all these structures in yellow here they are part of the basal ganglia so basal ganglia is made up of the caudate nucleus caudate putamen putamen the Globus pallidus of which we have an external and internal part we also is made up of the nucleus accumbens which I have not drawn here and we also have the sub thalmic sub thalamic nucleus and the substantia which is consists of two parts and just to complete this image we already have the M the amygdala here as well as the hippocampus so we will mainly focus again on the basal ganglia which is disrupted in Parkinson's disease so what does the basal ganglia do so let's just have a quick general overview of what it does so here again we have the brain and this yellow structure is a basal ganglia essentially what happens is the cortex when it wants to in when it when it wants to initiate a movement it will send signals first to the basal ganglia and the basal ganglia will send signals back to the cortex particularly the motor cortex and then when the signals are sent back to the motor cortex the motor cortex can then you know initiate these signals send the signals down the spinal cord and then you know out through the ventral horn of the spinal cord to that skeletal muscle to initiate a smooth controlled movement okay now let's look at that in a bit more detail so again the cerebral cortex is in it wants to initiate a voluntary movement it will it will first send signals to the basal ganglia and the basal ganglia will help in the subconscious control of sub skeletons muscle tone as well as a coordination of learned movement patterns this information will then be sent back to the cerebral cortex through a loop it will be sent to the thalamus first and then thalamus will send this info to the cerebral cortex the cerebral cortex will then send the movement signals the smooth controlled movement signals down the spinal cord to the skeletal muscle and thus we have a normal movement pattern two important parts in this diagram the input from the cerebral cortex to the basal ganglia and the output from the basal ganglia to the thalamus back to the cortex in Parkinson's disease the output number two there's a problem in the output and thus we do not have a normal controlled movement pattern it is not smooth so now let us go back to the big diagram and learn about the interconnection that occur within the basal ganglia and how and the disruption that occurs and how this results in Parkinson's disease so in this diagram we're going to look at all the components of the basal ganglia so to start the code a nucleus and codec putamen is also known as the codec striatum so here the rectangular structure I'm drawing is the codec striatum this is the cortex and all these other structures here are part of the basal ganglia we have this substantial pars compacta the Globus pallidus internal the substantia pars reticulata Globus pallidus external the subthalamic nucleus and the thalamus now I'm going to start drawing the interconnections that occur within this region but firstly I want to I want you to learn three main points the input from the cortex to the basal ganglia is to the striatum to the codec striatum first so the input is is to the codec striatum the output from the basal ganglia occurs in the Globus pallidus internal that's the point - so the Globus pallidus internal is the output from the basal ganglia to the thalamus and then the thalamus will then send this information to the cortex back to the cortex in that loop and this is 0.3 the cortex will then send this information to the skeletal muscle down the spinal cord - - you know to cause a smooth movement pattern coordinated movement pattern so those are the three main points the input to the basal ganglia the output from the basal ganglia and then the output from the from the cortex again to the muscle now within the basal ganglia there's a lot of interconnections happening between the glutamatergic neurons which are the excitatory neurons as well as the GABAergic neurons which are your inhibitory neurons but the most important thing in in this diagram are is within a substantial pars compacta because here we have dopaminergic neurons that arise and these dopaminergic neurons they release dopamine in to the caudate striatum so dopamine can bind onto two types of receptor d1 dopamine 1 or dopamine 2 and depending on which receptor binds to it is either excitatory or inhibitory so if dopamine binds on to d1 receptor it is excitatory if so it will stimulate that neuron if dopamine binds to the DD 2 receptors dopamine will inhibit that neuron so if we were to follow it step by step the dopaminergic neurons releases dopamine dopamine binds on to the d1 receptor which is excitatory so it will stimulate the gabaergic neuron here and it will directly inhibit this gaba gaba Nurik neuron allowing the thalamus to send signals to the cortex so thus the cortex can you know send signals to skeletal muscle for a controlled movement pattern so that is what occurs normally but unfortunately in Parkinson's disease there is there's not much dopamine that dopaminergic neurons die so in Parkinson's disease you have a reduced dopamine in the substantia and the pathogenesis probably involves apoptosis or necrosis of dopaminergic neurons and it is it is a result of the death of these neurons can be due to protein misfolding aggregation and toxicity it can be due to defective proteolysis it can be due to mitochondrial dysfunction or oxidative stress these are all theories regardless of the cause the result is that we have reduced dopamine in the in this area in the basal ganglia okay now let's go back to the diagram and look at what happens if we have reduced dopamine if we have reduced dopamine dopamine does not bind on to the d2 receptor which normally inhibits this gabaergic neuron thus the gabaergic neuron here is now overactive and secretes gaba which inhibits the second gabaergic neuron because this gabaergic neuron is now inhibited it cannot inhibit the glutamatergic neuron in the subthalamic nucleus and so the subthalamic nucleus glutaminergic neurons will secrete glutamate which will stimulate this gabaergic neuron in the Globus pallidus internal similarly because we have no dopamine the dopamine does not bind onto the d1 receptor and so the gabaergic neuron that normally inhibits the Globus pallidus internal neuron is not stimulated and as a result we have a overactive gabaergic neuron from the Globus pallidus in China to the thalamus so we have excessive inhibitory input to the thalamus thalamus inhibition causes suppression arm of the thalamocortical spinal pathway and because of this the signals that the basal ganglia should have sent back to the cortex doesn't doesn't really happen and so as a result when the when you want to initiate a movement it's not smooth coordinated controlled and really and thus your result in it doesn't result in the clinical manifestations of Parkinson's disease I hope that all made sense now let's look at the pathology of Parkinson's disease so let us zoom into the substantia area here which is which can be which is basically located on the midbrain here's a cross-section of the midbrain and let's compare Parkinson's disease substantial Niagra to the one of a normal patient what we see in Parkinson's disease is we see demyelination neuronal loss and gliosis within the substantia another pathological hallmarks is the presence of Lewy bodies within the soma of the neuron so here we have the some of the neuron and this blue structure here our Lewy bodies and Lewy bodies are round Easterner philic intracytoplasmic occlusions in the nucleus are in the nuclei of the neuron the Lewy bodies are made up of mainly alpha so nuclear proteins ubiquitin as well as there's other proteins but mainly alpha synuclein now let's talk about the risk factors as well as a protective factors of Parkinson's disease so the risk factors of Parkinson's disease include family risk factors there are genetic risk factors which include GBA CN CA lurk - Park - and pink one as well as there's shown that pesticides can cause Parkinson's disease protective factors include smoking coffee vigorous exercising as well as the use of non-steroidal anti-inflammatory drugs so that concludes this video on Parkinson's disease we looked at the signs and symptoms we looked at the some neuroanatomy of the basal ganglia we looked at the function of the basal ganglia as well as what occurs in Parkinson's disease and then we looked at the the path of is as well as the pathology and the risk factors and protective factors thank you for watching I hope you enjoyed this video

Channel: Armando Hasudungan

Views: 769,484

Keywords: Disease (Cause Of Death), Parkinson's Disease (Disease Or Medical Condition), neurodegenerative disease, basal ganglia, anatomy brain, anatomy basal ganglia, clinical presentation, manifestation, risk factors, management, antiparkinsonism, treatment, medicine, substantia nigra, animation, lecture, shaking palsy, overview

Id: Hu5KVfFnrh0

Length: 13min 53sec (833 seconds)

Published: Fri Mar 18 2016