hi there my name is george richardson i'm a integrated medical student from the university of liverpool and today i'm going to be talking about brainstem stroke syndromes um i've put my email on the beginning on the last slide so if there's any questions about the slides do feel free to contact me at the address on screen so i'm going to start off by talking a little bit about stroke terminology and it's perhaps less pertinent to the topic because it doesn't really it's more um related to four brain strokes and but still thought it'd be worth going over so the ischemic core is a term that's used um to refer to an area of irreversible damage and that usually um results from occlusion of an end artery and which is an arteries that's the sole supply to an area of tissue and there's the ischemic penumbra which refers to an area of salvageable tissue and that relates to the concept of time his brain and that is um what we try to reverse when we give thrombolysis and mechanical thrombectomy um and that can be sort of demonstrated with homonymous hemianopia and nuts and you get maculous bearing with that and that occurs due to the occipital pole having a dual blood supply from both the middle and the posterior cerebral artery and then hemorrhagic transformation is just where you get an area you get hemorrhage into an area of infarction and that relates to thrombosis as well in the time limit that we set so the brainstem as i'm sure most people will know has a pretty complex and regional anatomy um and so um i've come across this brainstem rule of four which is i'm gonna try and emphasize because it's a really good way of understanding the complex and the complex anatomy that relates to these brainstem strokes syndromes and so there's four rules and each rule has four parts to it rule number one is to do with cranial nerves rule number two um is related to cranial nerve motor nuclei rule number three can be remembered as midline structures that begin with m and rule number four is side or lateral structures that begin with s um okay also just going to touch briefly on the cranial nerve nuclei and these can be seen in this diagram here and i really like this diagram because it sort of breaks it down quite easily and has also included some of the other structures like the medial longitudinal particulars which can be seen there in the center of the diagram and so from the midbrain you have um cranial nerve nuclei 3 4 and also brackets 5 because as you can see it stretches the whole sort of length of the brainstem from the ponds there's five six seven and eight and from the medulla and five again nine ten and eleven and these can also be seen as i said on the diagram to the right here so rule number one um so this is related to the cranial nerves and so there are four that um arise from above the pons four that arise from the pons and four that arise from the medulla the ones that arise from above the pons are cranial nerves one and two and those come can be broken down further because those come from above the midbrain and number three and number four which come from the mid brain and then from the pons you have five six seven and eight and so again there's four here also just to note as well the vestibular nucleus is located in the lateral medulla and so that can cause obviously similar um symptoms to um to if there is uh damage to the um vestibulocochlear nerve as well um and then from the medulla and there's cranial nerves 9 10 11 and 12. rule number two relates to the cranial nerve motor nuclei um so um the best way i think to remember this one because this is a little bit more of a complicated rule than the others um so just remember that there are four so obviously rule of four four for each so the four cranial nerve motor nuclei in the midline are three four six and 12 and they can be remembered e quite easily as the ones that equally divide into 12. and then there are five cranial nerve motor and nuclei that exist laterally and those are 5 7 9 10 and 11 and then there are three that have motor nuclei and also just to note as well that the lateral motor nuclei are ones which correspond to innovation of their bronchial arches as well except for cranial nerve 11. so the four midline structures that begin with m so there's the motor pathway which is obviously the quasi-spinal tract the medial lemis which is an extension of the columns obviously relates to proprioception and vibration and the medial longitudinal circulars now if this is affected it can cause an intranuclear ophthalmoplegia and basically what this results in um is an impairment of abduction on the affected side which leads to nystagmus and diplopia as well when the eyes are moved contralaterally so basically um if say for example my right eye was affected and i tried to adopt it so bring it over to the left i'd get represent with nystagmus and diploma in the eye and then the motor nuclei again and these are sort of what was said in the previous previous slide and then the fourth rule final rule is the four sunlight or lateral structures that begin with s so you've got the spinous cerebellar pathway and the spinal thalamic pathway and the sensory nucleus of cranial nerve five and the sympathetic pathway which obviously if affected would lead to a hornet syndrome which i'm sure most people will be familiar with the clinical presentation um of these strokes can obviously be quite complicated i think that's why people sort of get a bit bogged down and so the way i've approached it for this talk is to try and touch a bit more on the um more common ones or the ones that perhaps people are a bit more familiar with and give a little bit of extra detail for them and then just give some one sentence summaries for some of the more um less common ones are the ones that perhaps you don't need to know as much about to try and make them stick in the mind a bit more for example for medical school exams so the first one to talk about is weber syndrome and it's also known as superior alternating hemiplegia and so the the parts of the brainstem that can be affected with this um syndrome or that are affected with this syndrome the substantial uh the corticospinal tracts the cortical bulbatract and the oculomotor um and uh sorry and um as can be seen um on the slide each of these will generate corresponding symptoms related to um the function of that that sort of structure and obviously i'm not going to list them off but you can sort of see them there and just to know as well that this sort of this syndrome is is caused by an occlusion of the paramedium branch the posterior cerebellar artery and weber syndrome which i'll come on to in a little bit again um has a bit of overlap between three syndromes and i think when i come on to that it will make it a bit clearer and how to remember these um these three syndromes which which have quite considerable overlap um wallenbergs is also known as lateral medullary syndrome also known as inferior alternating hemiplegia and again the the structures that are affected by this type of stroke can be seen on the slide and so there's the vestibular nuclei and the inferior cerebellar peduncle um the central uh segmental tract um lateral spinophonic tract um spinal trigeminal nucleus and nucleus ambiguous and the descending sympathetic fibers and again each of these will relate to um the symptoms that are generated due to the functional anatomy of the structures um this type of stroke is caused by posterior inferior cerebellar artery stroke also known as pica and i've put this memory aid mnemonic here on the screen danver which is a good way to remember these the symptoms for wallenbergs and that can be broken down into dysphagia and ataxia which is interlateral nystagmus which is it's lateral vertigo anesthesia which um corresponds to its lateral facial numbness and absent corneal reflex with contralateral pain loss and then a horner syndrome which is a result of obviously the sympathetic fibers being affected and then just a couple of other ones as well so there's locked in syndrome which i'm sure people may well have heard of and that's due to a bazilla artery stroke um resulting in a ventral pontine infarct and but can also be caused by central pontine myolysis which can be also caused by rapid correction of hyponatremia um and then there's milled goblet syndrome as well and which is another type of pontine in fact and that causes sixth and seventh uh cranial nerve and causes spinal tract deficiencies so the one sentence summaries that i've come up with um for these conditions um can be seen on the screen here and so these three have considerable overlap and this is what i was talking about before when i was discussing weber syndrome and so as you can see um from the sentence from the summaries and each of these presents with an ipsilateral third palsy but the additional symptoms are what sort of defines these these um these syndromes so webbers as previously mentioned there's an ipsilateral third palsy with contractual weakness of the limbs and you can also get benedict syndrome which is an intellectual uh third nerve palsy with contralateral choreophthosis and ataxia and then you can also have cloud syndrome which is intellectual third nerve palsy um with contralateral limb attacks here as well and then wallenbergs as mentioned before um is epistle facial pain with a lot of temperature on the contractual side of the body and ataxia nystagmus and hornet syndrome and again that can be remembered with danver which was said just before and then you've also got a desireene syndrome which is a contractual hemiplegia and with its lateral hypoglossal palsy and desiring is also known as medial medullary syndrome as opposed to lateral medullary syndrome which is bollenberg's and then just another important one to mention here is top of basil syndrome which results in vision or oculomotor symptoms and behavioral change and often worth noting that there is a missing most component in this type of stroke so patients generally don't have any motor functional deficiencies investigations um for brainstem strokes so really quite simple just treat it as you would any other stroke obviously if someone's presenting with neurological deficits you you have you have um a set of um tests that you can you need to do to rule out the important mimics of strokes um ct head obviously is vital if you're going to be giving any kind of um any kind of uh anti-clotting and sort of thrombolysis or mechanical thrombectomy if obviously would be you would require imaging if you were gonna um go down that route and obviously also giving aspirin as well is is not a good idea if if the patients had a hemorrhagic strokes are really looking to rule that out and you also want to exclude hypoglycemia as well which is another quite common um stroke mimic and can be quite easily reversed um so simple to test with a bedside bm in addition um as with anything in medical school you want to break it down into stuff that you can do by the bedside and blood some imaging and then i'll see other stuff as well in addition and to the bedside stuff you might want to consider doing an ecg if you're thinking there might be some cardiac embolic pathology although perhaps less likely with brazilian brain stem strokes um bloods um full blood count group and save cotton eye and our usual sort of panel of stuff and imaging so in addition to your ct head you might want to consider a chest x-ray or an echo if there's any indication um of alternative pathology or or if you're looking for something specific the management of brainstem strokes and again like any other stroke so important with any acutely unwell patient you need to do an a3 assessment and that will include obviously a full assessment of them and managing any deficiencies they have in each of these sections so it may include oxygen if the hypoxia but obviously to note that not every patient that's that had a stroke will need oxygen and in fact sometimes it can actually be detrimental to give um a patient who's got normal oxygen that's uh additional oxygen um airway supports iv access um important to make them know by mouth until the swallow has been assessed obviously because these patients could be at risk of aspiration um medical management for these patients so they're gonna need some aspirin 300 milligrams od for two weeks and then they need to be switched to an alternative fancy play but usually clitoral and 75 milligrams for long term if the patient's presenting within a four and a half hour window a tpa tissue plasminogen activator can be used such as altipliers and and also and these patients can be considered from mechanical thrombectomy and specific guidance exists for this um but access to services vary depending on the region and what the service provisions like in your in your local trust and in addition to this stuff you obviously want to consider transferring them to a stroke unit where they can be given a neuro rehabilitation and other stuff like salt assessments ot import etc etc so here's just a quick um summary of the stuff that we've covered on this talk so the rule of four really useful way of remembering um the functional anatomy of the brain stem breaks it down quite simply um into the important structures um the clinical features try and perhaps for exams and learn the symbols of one sentence summaries um but if you are interested then you sort of can delve further into it investigations obviously and the fast score is something that everybody knows we haven't really touched on it here because it's not really end up pertinent to brainstem strokes but just something to be aware of as well and then the management you treat it as you would um any stroke and or any suspected stroke and and anyone well patient is or treated the same so thank you for listening i hope it's been useful as i said at the beginning my emails on this slide so do get in touch if there's um any any sort of queries or anything that i can you feel i might be able to help with here's some further reading and life in the fast lane is good for an explanation of the rule of four see also radiopaedia for that as well which is also quite useful um near anatomy and outside structures sections and systems is good and the nice guidance on the scheme of stroke in other 16s is very important to learn for medical school exams just because it's it's sort of always tested on and davidson's principles and practices medicine is quite good for strokes and pathophysiology um i'd just also like to say thank you to uh dr reese davis from the walton centre um for reviewing these slides as well as uh conor gatsby the nancy evans lead and for also reviewing them as well thank you very much for watching