Stroke Syndromes (older version, with sound) - CRASH! Medical Review Series

hello everybody so we are going to talk here about stroke syndromes on the other set of slides I talked about diagnosing a stroke managing stroke post emergency management of stroke and different things to decide as well as as well as outpatient care here we're going to talk about we're going to talk more about how to determine where the stroke is in as much as the circulation based on the symptoms the patient has so this is going to be more intense on the neuroanatomy we're not going to talk so much about treatment or diagnosis but more so clinical appearance so let's go going so just to recap some of the fundamentals there's about a hundred thousand people every year in the US who have strokes many of them are recurrent strokes about ninety percent of those 800,000 are ischemic strokes the other ten percent are hemorrhagic strokes generally due to ablate of bleeding aneurysm usually a berry aneurysm remember that there is a mnemonic for who the people that are predisposed to bury aneurysms and that's shame Sh AMD s for smoking H for hypertension a4a dealt polyposis kidney disease m 4 mar fans and e for ehlers-danlos so although we tend to stereotype stroke as a disease of the elderly and it generally is about one in five strokes eighteen percent are in children and in young adults so we cannot exclude stroke just because of age some of the things on the differential diagnosis for stroke include include the post ekdahl state which is after a seizure you can have something called Todd's paralysis where for instance you may not be able to read you may not be able to see you may not be able to move a certain limb that can happen and so that can bit be confused with a stroke only differences these are people who've had a seizure it can be confused with migraine headache auras that can that can cause changes in the visual field it can be confused with vertigo or meniere's disease multiple sclerosis conversion disorder malingering cerebral infection and brain tumor so those are some things to keep in mind of course stroke is deadly some of these most of these other ones are not deadly at least acutely so it's very important whenever a patient has acute neurologic signs acute focal neurologic signs that stroke is at the forefront of your mind and that you can rule it out these are just some risk factors in the United States for stroke and the percentage of people that have them so hypertension hyperlipidemia are two of the big ones that most people have then there's other risk factors such as a previous stroke a previous myocardial infarction both of those sort of go towards hyperlipidemia diabetes atrial fibrillation and so on and so forth so the most prevalent symptoms of stroke include facial drooping one-sided arm or leg weakness verbal deficits which could be slurring dysarthria aphasia verbal agnosia where meaning that verbal agnosia being you can hear speech but you can't understand it and then altered level of consciousness most patients will have at least altered level of consciousness however we're going to see that there are lots of different places where you can get strokes in your brain and not all of them have these signs so it's important to know the different syndromes of strokes not all of them are the stereotypical facial drooping one sided arm and leg weakness or arm or leg weakness verbal deficits some of them don't have any of them so as I mentioned other symptoms can be present as well a taxi visual field deficit sim balance vertigo and so forth and of course that's just going to depend on where it is in the cerebral or cerebellar circulation provided that the patient is stable to out rule stroke the best initial diagnostic step is going to be a non-contrast CT of the head you really can't go wrong by doing that as long as you have a stable patient if a patient has acute focal neurologic deficits a CT is going to be useful no matter what because another possibility could be injury and in that case then of course we're going to want to have a CT then so a non-contrast CT of the head is the best initial diagnostic step in patient or were suspecting stroke of course we always have to stabilize the patient first so don't be thinking that I'm saying this is always the best first step this is the best initial diagnostic stuff okay a stroke and TI a so let's just quickly gloss over how we diagnose and treat it we're not going to spend the bulk of the time on this lecture talking about that so history hypertension hypercholesterolemia Appa 'they are sort of at the periphery so hypertension is the number one risk factor for stroke and symptoms of stroke is mentioned is altered level of consciousness facial drooping one-sided armor leg weakness usually it's on one side of the body or the other you could have verbal deficits or gate disturbances certainly you're not going to have all of these you may just have one or a couple of them it all just depends on where the stroke is you should always consider stroke in a patient with acute onset focal neurologic deficits regardless of the age the initial diagnostic step is always going to be a non-contrast CT this has to be done for two reasons one because we're looking for a stroke two because we need to know what kind of stroke is if there is one so the CT is going to help us differentiate between an ischemic stroke or hemorrhagic stroke and that's going to be really as far as how we manage the stroke we also need to have routine labs particularly including glucose and inrs and that's because if the patient has an ischemic stroke one of the possible ways we can treat them is TPA alteplase and in order to use TPA one it has to be an ischemic stroke obviously and two they need to have normal inrs and three they need to have a glucose of greater than 50 any glucose less than 80 we're going to treat with supplemental glucose but we need to make sure that the patient is you glycemic because that is a necessary condition in order to treat the patient with with alteplase with tissue plasminogen activator TPA and that is our the most preferable treatment for any patient with this key mix stroke and then of course we should always have an EKG on any patient with a stroke as well because we're looking for atrial fibrillation if the patient has atrial fibrillation then our management is going to be different the acute management will be the same but the long-term management will be to treat the patient for atrial fibrillation many many patients with with stroke have atrial fibrillation so EKG is certainly worth getting emergency treatment is going to include supplemental oxygen around you just your ABCs right there blood pressure control we tend to use labetalol of course if we're going to do TPA as you know if you watched the previous the first stroke lecture we need to get their blood pressure below systolic 180 any patient though we should get their blood pressure below systolic 220 and then as mentioned treat hypoglycemia if their glucose is less than 80 and treat fever if they are febrile now while the initial diagnostic step is always a non-contrast CT the most accurate test is a diffusion-weighted MRI MRI is always more you're it than CT but we're not going to do an MRI because it takes a long time it takes like half an hour to an hour to get an MRI and we need to get these patients with possible strokes diagnose and treat it as quickly as possible they're losing millions of neurons a minute so we never do MRI to diagnose a stroke we we may do it to assess a stroke after we've after we've treated it but we we always do the non-contrast CT to diagnose the stroke never MRI so here's some cts of hemorrhagic strokes and of ischemic strokes so these two on the left here are both hemorrhagic strokes and the way you can tell is that you can see the blood so here we can see blood in the ventricles it's not always in the ventricles sometimes you just see it in the brain tissue itself but ultimately it can seep into the ventricles so this white here on the CT is ventricle that's why we don't use contrast because if we used contrast here we wouldn't be able to tell if there is blood it would look white no matter what so here's an ischemic stroke the way you can tell an ischemic stroke is that you have a blurring of the white gray matter so the white matter in the grey matter you can't really see the difference look at on the left side here this is patience patience left here in patients right see you can you can see your your gyros here but you can't see them here you've got just generalized inflammation and so that's what's causing the white grey matter the white grey matter look the same same thing here you don't you see a difference you don't see you see it's dark it's darkened here I'm not a radiologist so if you have been able to tell but though again it's it's one way to tell no matter what is if it looks different from the other side there's probably something wrong another way you can tell is an ischemic stroke is if the white matter becomes darker okay and then here's another ischaemic stroke so again you lose your differentiation between the white and grey matter you can't see those gyros as nice and this is an MC a stroke okay so let's just briefly go over the arterial circulation of the brain remember we have an anterior circulation both coming from the internal carotid artery that comes directly off of the heart on the left side it comes from the arch of the aorta as the common carotid artery and on the right side it comes from the anonymity artery then it the common carotid splits off into the external and internal carotid artery internal carotid artery continues it gives off the MCA which is the middle cerebral artery and the ACA which is the anterior anterior cerebral artery it also gives off the ophthalmic artery now something really important is that the internal carotid artery also gives off a communication artery and that communication artery goes to the posterior circulation so your posterior circulation is coming off from your anterior spinal artery and your vertebral artery they come together and merge to form the basilar artery the basilar artery gives off pike up which is your posterior inferior cerebellar artery and it gives off a ICA which is your anterior inferior cerebellar artery it continues as the basilar artery and gives off pontine branches and then it gives off bilaterally superior cerebellar arteries and then it splits to form the posterior communicating artery and that gives off your posterior cerebral artery and it communicates with the posterior communicating artery that the internal carotid artery gave us so we get we get blood from both sides posterior Lee and anteriorly but they're communicating through this posterior communicating artery and the anterior communicating artery which connects the circulation from left to right and then this is just another another way of looking at it from from the side here you can see this is our circle of willis here the posterior communicating artery if the atomic artery the ACA MCA cerebellar circulation and so forth okay so when you're looking at the brain there are a couple landmarks and well I don't have a brain here to show you there's a central salsa switch is a very deep celsus right between the frontal and the parietal lobes that landmark is important because because in front of it is going to be your sensory cortex and behind it is going to be your motor cortex now when you take a slice of the brain so here we are looking at it from the side and now imagine taking that slice and now you're looking at it in the front so this is this is medial here and this is lateral out here by the orange so lateral coming up superior Lee and then moving down and this is medial down on this side so the homunculus corresponds semeta topically to the body and you can see that if there's sort of a pattern on how it go so you have your tongue and your jaw and your lips so your lower face your lower face and then your eyes and your brow your upper face and then you've got your fingers here taking up a pretty good chunk and your hands and your upper extremities so your your upper extremities and hands and fingers and your face take up over two-thirds of the cortex that's a lot and that makes sense because your face and you need to have more control over those parts of the body from manipulating objects and so forth for speaking your hip lower extremity and genitals get the rest of it and this is going to be important when we talk about MCA versus ACA strokes so your mca your middle cerebral artery contrary to its name your middle cerebral artery runs laterally so your middle cerebral artery feeds this part of the motor cortex so your upper extremity hands fingers space on the other hand your anterior cerebral artery runs in the middle and it's going to feed your hip lower extremity and genitals so that's the reason why with the middle cerebral artery stroke it gives you different symptoms than an anterior cerebral artery stroke and this will come together in the next few slides okay so this is just looking back on arterial circulation of the brain okay so I want to give you one more look at the blood supply of the brain just to not to belabor this too much but I do think it's important to know so your anterior cerebral artery is primarily taking care of your frontal lobe and the midline of the brain your your middle cerebral artery is primarily taking care of the superior portion of the temporal lobe the rest of the frontal lobe that your a/ca is not taken care of and your pry it alone and then the ophthalmic artery is part of the anterior circulation but you can't see it here now the posterior circulation your basal ER and ponting arteries are taking care of your brain stem your anterior inferior cerebellar artery are taking care of your anterior inferior cerebellum just like the name implies your posterior inferior cerebellar artery pyka takes care of the posterior inferior cerebellum and also has some role with the lateral medulla the superior cerebellar artery takes care of the superior cerebellum and the posterior cerebral artery takes care of the posterior cerebrum the posterior part of the brain so the inferior part of the temporal lobe and the posterior part of the of the occipital lobe posterior part of the parietal lobe and the occipital lobe so it's taking care of the back just like its name implies okay so let's talk about what this what this section is about and that is the types of strokes you can get so we're going to talk about seven different kinds of strokes mca stroke ACA strokes pca strokes we're going to talk about two different kinds of pca strokes that are from deeper arteries of the pca and then we're going to talk about picus stroke we're not going to talk about basilar artery stroke basilar artery stroke is the locked-in syndrome will mention that in a different section you probably know what locked-in syndrome is so if you don't feel free to ask ok so the middle cerebral artery middle cerebral artery stroke is the most common it affects the upper body more than the lower body and that just goes back to that homunculus remember the middle cerebral artery is taking care of the lateral parts of the brain the lateral part of the homunculus was the upper body so it affects the upper body more than lower body it also causes some lower facial paralysis why because the lateral part of the homunculus takes care of the face and so you can get a little bit of facial paralysis why just the lower face the reason is because the upper face has bilateral innervation whereas the lower face just gets unilateral innervation so if you affect the face it's only going to affect the lower face upper face will be fine because it still has innervation from the other side so its lateral lower facial paralysis and this is epsilon all because all the innervation for the face goes straight to the face you're not going through any decussation now your body paralysis or sensory loss is going to be contralateral and that's because this lesion is before the motor decussation so you've got your your lesion in the cerebral cortex and the nerves go down and then they decussate and so the left part of the homunculus takes care of the right the the right side of the body and the right cortex takes care of the left body so you're going to have ifso lateral lower facial paralysis and contralateral body hemiplegia and sensory loss the middle cerebral artery also affects the nerve that innervates the muscles in the ipsilateral I and so this results in a bilateral I deviation towards the side of the infarct why towards the I side of the infarct well this is kind of more of a complicated reason and we'll see when we look at some of the different kinds of posterior cerebral artery strokes but there are six muscles in the eye for that are really important and three of them are innervated by this third cranial nerve oculomotor nerve the other one is innervated by a nerve called the abducens nerve if when you get an MCA stroke you can get it can affect the oculomotor nerve but the abducens nerve remains intact now the abducens nerve is responsible for moving your eye laterally and so if you have a stroke that affects your your third nerve then the only way you're going to be able to move your eye is laterally and so it's going to pull your eye towards that side and so the the abducens nerve of whichever side you had the stroke on is still working so if it's your if you have a right mca stroke your right oculomotor nerve is not working but you're right abducens nerve is working and so going to your right eye because these don't decussate you're going to have no oculomotor input to your right eye but you're going to have normal input to your teeth from your abducens nerve to the lateral rectus that's going to pull the i laterally and by reflex when you're right I moves laterally your left eye moves towards that side so it would move medially and same with your left eye if your left I were to move laterally you're right I would move towards that side you can't move your left eye laterally and you're right I laterally at the same time so that's just a really complicated way to explain that when you have an MC a stroke it can affect the ipsilateral I the eye on the side of the on the side of the stroke and you will have deviation of the eyes towards the side of the infarct so if it's a right-sided MCA stroke your eyes will be deviated to the right an MCA stroke can cause contralateral homonymous hemianopia but that's rare if the stroke is on the left side it can and usually does affect language both reception of language and production of language or one or the other it can also give verbal egg nausea so this is has to do with Broca's and Wernicke's area but you can have language deficits in addition to your your paralysis now i would think that it's pretty important to differentiate out that you can have motor deficits of the facial muscles and so that can cause luring it doesn't necessarily mean that you have a stroke of the language centers of the brain so make sure if you see a patient that appears to not be able to speak properly make sure that it's not because they can't move their facial muscles properly okay here's a MC a stroke you can see that we've got nice white grey matter differentiation here on the left side of the patient but on the right side we have not here's another one again on the right side here okay anterior cerebral artery stroke so this is going to affect the lower body more than the upper body the anterior cerebral artery supplies more of the midline in the front of the brain and so that's going to affect the the legs the hip and the feet we can also again also get contralateral body hemiplegia and sensory loss but this is unlike the MCA stroke the ACA stroke is going to be lower body because the because there are some voluntary muscles muscles of your motor cortex that are responsible for urinary continence you may have weakness of pelvic floor musculature and urinary incontinence with an AC a stroke so that's sort of a unique finding that you don't see in the MCA stroke some less common manifestations include anosmia and that's because the olfactory bulb is right in the middle of the brain and so if that loses if that loses oxygen it would dysfunction so you'd have a decreased ability of smell and personality change and that's because the frontal lobe is responsible for a lot of different corks in our personality so if you have if you have a defect to the frontal lobe it can cause personality change but most salient Lee what you're going to see in the anterior cerebral artery stroke is lower body hemming flea sensory loss as opposed to the MCA stroke where you see upper body and ecclesia and sensory loss and also the verbal issues so here's an AC a stroke you can see that our area of of interest is right here here's another one this is more towards the midline probably a penetrating branch of the ACA ok so how about TCA strokes so remember the posterior cerebral artery is the last branch of your posterior circulation before it in a stenosis as the posterior communicating artery PCA strokes are generally visual why is that because the posterior cerebral artery supplies your occipital lobe and your occipital lobe is responsible for vision it holds your visual cortex so the most salient features of PCA strokes are visual there are knows PCA strokes that don't have some kind of visual component now in a true PC a stroke there are never motor symptoms and I would expect that on the USMLE you will have a true PC a stroke if they're asking you for a PC a stroke the primary visual cortex is affected and this results in a contralateral homonymous hemianopia you might be confused as to what this contralateral homonymous hemianopia is or you might not remember certainly if you don't work in Neurology or emergency medicine that frequently you don't see a whole lot of it so we're going to give a quick review of the optic tract and a little bit PCA strokes can also cause visual hallucinations so seeing things that aren't there or visual agnosia so you see things but you don't know what it is and that the visual agnosia tends to be more with the with the the interface between the occipital and parietal lobe so remember our occipital lobe sees things our temporal lobe hears things but it's our parietal lobe that kind of helps us figure out what it is that we're hearing and seeing so if you have damaged closer to the parietal lobe on the occipital lobe but higher closer to the closer to the parietal lobe you may have this visual agnosia where you can see the thing but you don't know what it is okay so here's our visual track this is going to explain why we get the visual deficit we get in a PC a stroke so here's your eyes right here here's your left eye and your right eye and this is the field you're looking at so you're right your left eye rather always is looking at your so your left eye is always looking at your at the left side of the visual field and your right eye is always looking at the right side of your visual field that makes sense because your left your left eye is on the left side and your right eye is on the right side now the medial side of your eye always looks temporally so it always looks off laterally to the side whereas the lateral side of your eye always looks nasally it looks down your nose it looks towards the middle of the field so what we see here is we see that this side of the left eye is getting this part of the visual field this red side is getting this portion of the visual field this red part is getting this part of the visual field and this blue part is getting this part of the visual field okay this is always how it is in everybody now these give off neurons at the retina and it forms the optic nerve the optic nerve is what provides all of our information about what we see after the optic nerve what happens is the the temporal sites so this side here so the left part of the visual field in the left eye and the right part of the visual field in the right eye they cross so you have a decussation and that's called the optic chiasm so what you have then is this optic tract and the optic tract on the left side is carrying the right part of the visual field for both eyes so here you can see the red part which is the right part of the visual field for both eyes crossed from the right eye to the left eye so your left eye is carrying the right part of your visual field or the right part of each visual field for both eyes so it's carrying this and this and the right eye is carrying the left part of the visual field for both eyes so it's carrying this here and this here these the ones with the blue are connected to ok so we have the optic trapped the optic tract then goes to this LG body lateral geniculate body and that gives off these radiations which then go to your primary visual cortex and the primary visual cortex organizes all that and gives you your image now we'll talk more about the optic radiation and this whole pathway in a different section when we talk about neuro-ophthalmology but for now this will do so what happens when you get a PC a stroke well your PCA takes care of your primary visual cortex which is part of your occipital lobe if you get a PC a stroke you lose that visual cortex and so if you've lost the visual cortex on one side you've lost one side of both visual fields so you've lost in this case with the left so you've lost the left side of both visual fields and so that is homonymous hemianopia homonymous meaning both sides hemianopsia meaning of the fields so half being the right part of the left-sided field and half the right part of the right-sided field so homonymous hemianopia and it's a contralateral homonymous hemianopia because while it happened on the left side of the brain the stroke you've lost the right fields of vision and if you do this map and you do it with the blue side you'd see you would lose this part and this part and so you would have a left homonymous hemianopia due to a right pc a stroke now when you get into neuro-ophthalmology it becomes really interesting because what happens if you get a lesion here at the optic tract or here at the LG body or here at the optic chiasm as you often do if you get a tumor or if you have a lesion of the optic nerve it's going to be different so this is just homonymous hemianopia it's just one form a visual field deficit you could have and it's like it is the the visual field deficit contralateral homonymous hemianopia is the visual field deficit that you get when you have a PC a stroke here's a PC a stroke so you can see we lose our white grey boundaries on the posterior side of the brain and this is a right or sorry a left TC a stroke so this person would have right homonymous hemianopia ok let's talk about some strokes involving the oculomotor nerve so the strokes involving the oculomotor nerve cause oculomotor palsy or ophthalmoplegia the ones we're going to talk about are there are two of them and they both involve the deeper branches of pca so rather than having a stroke of the whole pca what you have here is you have a stroke of a of a particular penetrating branch of the PCA that innervates the rostral midbrain so rather than rather than having a stroke of the pca that's affecting the occipital lobe you're getting a stroke from a branch of the pca that innervates the midbrain because there are parts of the midbrain that are that are fed by branches of the pca so these two conditions we're going to talk about our strokes that involve strokes to that part to the midbrain so these are midbrain strokes up until now we've only been talking about strokes to the cerebrum now we're going to talk about strokes to the midbrain and these are both strokes that happen at the level of the ophthalmic nerve ok so the ophthalmic nerve innervates four of six muscles responsible for eye movement remember I said it innervates three of four important muscles well it innervates four of the six total muscles so you have in your eyes you have for reptile muscles superior rectus inferior rectus medial rectus and lateral rectus and then you've got superior oblique and inferior oblique and these oblique muscles they do a little bit of extra work on the side but it's these four wrecked a muscles that are the most important so cranial nerve three oculomotor nerve innervates the superior rectus the inferior rectus and the medial rectus that innervates all the rectus muscles except for the lateral rectus which is if you were paying attention a few slides earlier is innervated by the abducens nerve the oblique muscles the inferior oblique is innervated by the cn3 but the superior oblique is the only muscle innervated by the trochlear nerve so if you have a cn3 palsy you're going to lose innervation to all the muscles except for the lateral rectus and the superior oblique now what do these muscles do the superior rectus elevates your eye it allows your eye to move up so if you're looking up into the sky that's your superior rectus doing that for you your inferior rectus depresses you're on so if you look down at your shoes that's your inferior rectus doing that for you your medial rectus add ducks your eye so if you look at your nose the eye that's looking at your nose is being moved by your medial rectus your lateral rectus helps you look off to the side so if you look off to the side that I that's looking off to the side is being moved by the lateral rectus the superior oblique and the inferior oblique help you move your eye when it's at full medial position so if you're looking at your nose and you want to move your eye up or down there those oblique muscles are there to help you do that so if you're looking at your nose and then you look straight up that's your superior or separate that's your inferior oblique moving your eye so the inferior oblique elevates and the superior oblique depresses so their counter to their name unlike unlike the rect I muscles okay so why does why is this important if you lose cn3 and all you've got is CN 6 + CN four then all you've got is your lateral rectus and your superior oblique so the eye is going to move out because it's going to be abducted you've lost all your other rectus asst and your superior oblique is going to depress it so you can still abduct and depress and that's all you're going to do because your other muscles just become limp and so what you get out of that is the down and out I so remember cranial nerve 3 is a superior rectus medial rectus inferior rectus inferior oblique cranial nerve for is the superior oblique that's the trochlear nerve cranial nerve 6 is lateral rectus when you lose cranial nerve three all you can do is depress your eye and abduct your eye so this I is down and out and this is a sign of ophthalmic Lygia or cranial nerve three palsy now this LPS muscle what is this this is the levator pelle pelle key Bray superioris that is the muscle that holds your upper eyelid open that's also innervated by your buyer third cranial nerve so if you lose your third cranial nerve you're also going to have a heavy eyelid because you can't raise that eyelid up and so that's why this guy's eye is shot it's not because he got hit it's not because he's tired it's because he can't lift that eyelid up elevator healthy braid superioris cannot raise the lid because it doesn't have innervation another thing I thought I just mentioned real quick is that the superior rectus is also also responsible for in torsion of the eye and the inferior sorry God not superior rectus superior oblique is also responsible for in torsion of the eye and the inferior oblique is also responsible for extortion of the eye but though that doesn't really come into play here okay so here's another down-and-out I alright so the two cn3 palsy strokes are Weber syndrome and the more severe Benedict syndrome and they're both due to penetrating branches of the posterior cerebral artery that go into the rostral midbrain so we'll start talking about well let's first start with talking about the rostral midbrain the rostral midbrain at the point that it's that these strokes happen are not surprisingly at the level at which the third cranial nerve comes out and so that's why it affects the third cranial nerve other things that we have in the midbrain here we have our cortical pontine tracks substantial and red nucleus remember those are responsible for very coordinated motion substantial niagara's implicated in Parkinson's disease you have your lateral spinal final thalamic tracks and your ventral spinal thalamic traps that's your pain your pain areas so that's how you get pain and temperature up from your from the peripheral nerves then you've got your medial lemniscus that's part of the DC ml system so that's carrying fine touch and proprioception up to the thalamus and then and then you've got your cerebral aqueduct right in the middle here which is continuation and you've got your colliculi on either sides here okay and then your pyramidal trapped right here in that so your pyramidal tract is carrying you're carrying your your upper motor neurons alright so the first disease to talk about the first midbrain stroke is Weber syndrome and Weber syndrome is a blockage of a penetrating branch of the pca that that feeds the the midbrain and it goes up to the red nucleus so we don't have any red nucleus involvement the only place that there's involvement are the pyramidal tract and to a lesser extent the substantia and of course the third cranial nerve so the two parts that are most important here are the third cranial nerve which gives us the ophthalmic Lygia and the corticospinal tracts the pyramidal tract so the ophthalmic leah is going to be epsilon well there's no decussation of the third cranial nerve so you're going to get an ipsilateral oculomotor palsy so you're going to have that down and out of in this case it's the left the left sides are going to get down and out of the left eye and a heavy left leg and we also have we have damage to the pyramidal tract the corticospinal tract and that is going to cause contralateral hemiplegia and the reason it's contralateral is because it hasn't deca sated yet so this is carrying nerves from the left cortex but it's going to decussate at the medulla and it's going to go over to the right side and provide the it's going to provide innervation to the right musculature so even though the stroke is on the left side here because it hasn't deca sated yet you're going to have right-sided contralateral hemiplegia so epsilon motor palsy and contralateral hemiplegia now yes you are affecting the cortical pontine tracks and you are affecting the substantial that's going to be a little bit lesser as far as symptoms go but the substantial can cause some gate disturbances you can have some parkinsonian effects but primarily with Weber syndrome what you're going to see is is epsilon all oculomotor palsy and contralateral hemiplegia okay now Benedict syndrome is a little bit more severe so Benedict syndrome is really you can think of it as whether syndrome plus effect of the red nucleus and more substantial so look at the difference here it's just affecting more of the of the midbrain so again we have our oculomotor policy it's going to be epsilon well but we're also going to have in addition to our contralateral hemiplegia we're also going to have some severe gate disturbances and they are going to be contralateral so that's because of the effect of the on the red nucleus and the red nucleus helps us with gate and the substantia as well so you combine the two of those together and you're going to have severe gate disturbances so the way you can think of it is a Benedict syndrome is just Weber syndrome with more with more severe gate disturbances but they both have in common that ipsilateral oculomotor palsy so if you've got a patient that's got oculomotor palsy you should be thinking of a mid brain infarct okay so lateral medullary syndrome or wallenberg syndrome this last one this is an infarction of the postural lateral medulla and it's due to blockage or hemorrhage of the pike posterior inferior cerebellar artery so as mentioned the pyka primarily supplies blood to the posterior inferior cerebellum as a pleasant its name but it does give a little bit of of blood to the midbrain and or to the brain stem sorry okay last one so Wallenberg syndrome or lateral medullary syndrome is an infarction of pyka now pyka primarily is giving blood to the posterior inferior part of the cerebellum but as it branches off it is also giving off branches to part of the medulla so if you get a blockage of pyka very proximally you can get a an infarct of the lateral medulla it's not very common but it's such a stereotypic question that it's common on the USMLE because of the because of the anatomy and the neuroanatomy that that it implicates so the salient features are Apes a lateral facial sensory loss and contralateral body sensory loss how where else are you going to see that so if you have Ypsilanti's entry locks on one side of your face and on the other side of your body you've got sensory loss in your body that is Wallenberg syndrome it's also tends to be accompanied by dizziness ataxia dysarthria and Horner's syndrome and those are for various reasons which I will explain in a little bit so here is your inferior medulla approximately where the infarct where where it would affect so here's this little diagram I kinda looks like a little butterfly here but I showed the I drew out the important landmarks so this is anterior down here or ventral and this is posterior here ok so in red here you've got your corticospinal tracts these are your pyramids that are supplying your your motor function so these are upper motor neurons going down to their lower motor neuron destination this is a medial lemniscus so this is part of the DC ml tract responsible for fine touch proprioception and sensation this is the medial longitudinal fasciculus this is for we'll talk about that in a different section this here is your hypoglossal nucleus and it gives off your hypoglossal nerve you also have these three in the pink here are part of your vagal nerve and they give off they give off projections which form the vagal nerve solitary nucleus dorsal motor route and nucleus ambiguous this here is the inferior oliveri nucleus and green here and this is responsible for coordination now let's get into this yellow region because this yellow region is the region that is affected when you have wallenberg syndrome because it is fed by the posterior inferior cerebellar artery first we have our spinal thalamic trapped the spinothalamic tract is sensation and it is this is the second order neurons but remember with the spinothalamic tract it's the only tract that crosses right away it crosses at or about at the level of the vertebra so if if you have a problem anywhere in the vertebrae basically to the spinothalamic tract it's pretty much always going to be contralateral because it crosses so quickly so this is this spinothalamic tract here on the left side this is the left because this is anterior this is actually carrying fibers for the right side of the body so if this part is affected you get contralateral you get contralateral sensory loss now here's your track of your CN 5 and that's your trigeminal nerve now this is coming in this is coming in ypsilanti or sorry this is coming in contralaterally as well so now with this one you've got this this is helping you move your jaw so with with that if you have if that's affected that causes your dis are 30 now your dizziness and ataxia are caused by a loss of the vestibular nucleus here and this helps you with balance okay so but as far as wallenberg syndrome just remember its lateral facial loss contralateral body sensory loss lateral medullary syndrome or wallenberg syndrome is a sensory sensory disease so you're not going to have any paralysis here but you can have some weakness of some muscles just because you do have some cranial nerves coming off you're not going to have any body weakness if you have any weakness it's going to be facial and then this is just a recap I put the ones here in bold and blue the ones that really apart more of the giveaway so the MCA stroke the upper body and facial droop verbal deficits with the ACA it's a lower body posterior cerebral artery stroke you get the contralateral homonymous hemianopia also visual hallucinations and you don't have any motor sensory effects Weber is in Benedict syndrome you get the ipsilateral oculomotor palsy benedict's is just a little bit more severe as far as the gait disturbance and Wallenberg syndrome you've got the ipsilateral facial sensory loss and the contralateral body sensory loss you can also get dis our threa and vertigo and that is it

Channel: Paul Bolin, M.D.

Views: 63,475

Rating: 4.8734179 out of 5

Keywords: Stroke (Disease Or Medical Condition), Medicine (Field Of Study), USMLE Step 3, USMLE Step 2 Clinical Knowledge, USMLE Step 2 Clinical Skills, United States Medical Licensing Examination, Internal Medicine (Medical Specialty), Neurology (Medical Specialty), internal medicine review, internal medicine residency review, USMLE, Step 2, Step 3, neurology review

Id: NfST1Vq8skI

Length: 53min 44sec (3224 seconds)

Published: Sun Jan 19 2014