Brainstem Stroke Syndromes

welcome to Soton brain hub for a video on brain stem stroke in this video I'll start by recapping the key vasculature which supplies the brain stem then move on to talk about the various important functions of the brain stem in relation to strokes and finally finish with a look at a few of the brain stem stroke syndromes to be familiar with as a medical student doing either your preclinical or clinical neuroscience modules let's start with the blood supply to the brain stem blood is derived from the posterior circulation formed by the vertebral arteries which joined to form the basilar artery from the two vertebral arteries come the posterior inferior cerebellar arteries or pica for short from the basilar artery comes the anterior inferior cerebellar arteries or Aker and also several small branches called the pontine arteries also from the basilar artery we have the superior cerebellar arteries and finally the posterior cerebral arteries at the top let's look at the blood supply to particular regions of the brainstem the medulla is predominantly supplied by the vertebral arteries and pica the pons is supplied by a cur upon tyne arteries from the basilar artery and superior cerebellar arteries the midbrain is supplied predominantly by the posterior cerebral arteries now we can move on to talk about the various functions of the brainstem as you know the brainstem contains lots of important structures and is detailed Anatomy is complex we will consider the functions of the brainstem as divided into three main categories tracts nuclei and physiological centers clinically important tracts the run through the brainstem include the corticospinal tract which is a motor pathway and the spinothalamic and dorsal column tracts which are sensory pathways damage to the corticospinal tract will result in weakness or paralysis of particular muscles damage to the spinothalamic tract will result in loss of pain and temperature sensation as we're talking about the brainstem these fibers have already decorated by this point and thus the sensory loss will be contralateral to the lesion the dorsal column pathway is less clinically important in brain stem stroke also first order sympathetic neurons passed through the brainstem as they descend from the hypothalamus to the cervical spinal cord in the so called hypothalamus spinal tracts damage to these neurons may result in an ipsilateral Horner's syndrome which presents as meiosis and partial ptosis there are also trikes which travel into and out of the cerebellum via the cerebellar peduncles of the brainstem I won't go into the details of the spinocerebellar tracts here but they behave functionally as Apes elastro tracts and thus damage will cause an ipsilateral ataxia many of the nuclei of the 12 pairs of cranial nerves also lie in the brainstem signs and symptoms will depend on which cranial nerves are affected if you're unsure of the functions of the cranial nerves I suggest you watch this video to recap physiological centers include the reticular formation which is involved in consciousness and arousal damage to the reticular formation may present as depressed consciousness now we can pace this information together to predict the likely symptoms from a brainstem stroke here I'll talk about a syndrome affecting the medulla wallenberg syndrome another syndrome affecting the midbrain weber's syndrome and finally a syndrome affecting the pons locked-in syndrome wallenberg syndrome is also called lateral medullary syndrome or pica syndrome given that it affects the medulla the most likely responsible blood vessels are the vertebral arteries or pica this is the common list of the brain stem strokes we can consider its presentation in terms of the brain stem structures that are affected as divided into the three main categories we talked about earlier tracts nuclei and physiological centers affected tracts within the medulla include the spinothalamic tract which results in contralateral loss of pain and temperature sensation also the spinocerebellar tract can be affected causing it's a lateral ataxia finally the hypothalamus spinal tract can also be affected causing an ipsilateral Horner's syndrome in wallenberg syndrome there are three main cranial nerve nuclei that are affected the nucleus ambiguus the vestibular nucleus and the cranial nerve five nucleus nucleus ambiguus is associated with the glossopharyngeal and vagus nerves and thus damage results in a hoarse voice and dysphagia damage to the vestibular nucleus can cause vertigo and nystagmus damage to the cranial nerve 5 nucleus results in Apes are astral facial loss of temperature and pain in terms of physiological centres the reticular formation it can also be affected which results in to press consciousness this clinical picture can be remembered with the mnemonic danver this stands for dysphasia 8 Axia most agamous vertigo anesthesia and Horner's syndrome now let's move on to talk about the next syndrome Weber's syndrome this is caused by an interruption to the blood supply to the midbrain typically the posterior cerebral artery the main tract affected is the corticospinal tract which results in a contralateral weakness the main nucleus affected is the cranial nerve three nucleus which results in an insulator all oculomotor nerve palsy physiological centers are often not affected finally a syndrome that affects the pons includes locked-in syndrome which may be caused by a stroke affecting the basilar artery or also a traumatic brain injury the two main tracks affected in locked-in syndrome are the corticospinal and corticobulbar tracts damaged of the corticospinal tract in the pons results in quadriplegia damage to the corticobulbar tract results in an r3 a' which is an inability to speak as a result sufferers are often heavily dependent on their carers there are several cranial nerve nuclei involved but clinically bilateral damage to the abducens nuclei restricts horizontal eye movement however vertical gaze is not affected as the oculomotor nucleus lies in the midbrain and is this unaffected physiological centers are often not affected in locked-in syndrome therefore there is no loss of consciousness and cognitive faculties can remain intact so to recap brain stem strokes are typically caused by an occlusion of a vessel in the posterior circulation signs and symptoms include those associated with the three main functions of the brain stem damage to the tracks may present with a motor or sensory disturbance a taxi or Horner's syndrome damage to cranial nerve nuclei may present as cranial nerve dysfunction which will depend on which nuclei are affected damage to physiological centers such as the reticular formation may present with diminished consciousness the most important brainstem stroke to remember wallenberg syndrome can be remembered with the acronym danver which stands for dysphagia eight axia nystagmus vertigo anaesthesia and Horner's syndrome I hope you found 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Channel: Soton Brain Hub

Views: 152,884

Keywords: brainstem, stroke, brainstem stroke, brain stem, brain stem stroke, medial medullary syndrome, wallenberg's syndrome, weber's syndrome, locked in syndrome, soton brain hub, sotonbrainhub, basillar artery, verterbral artery, posterior circulation, pica, midbrain, pons, medulla, latreral medullary syndrome, webers syndrome, wallenbergs syndrome

Id: qxiRfP9XmpE

Length: 9min 27sec (567 seconds)

Published: Mon Sep 03 2018