Stroke

hello it's Eric strong from strong medicine in today's episode of intern crash course I'm discussing stroke specifically focusing on ischemic stroke please keep in mind that this topic is huge and this will be just an intern level discussion that will not cover the nuances of neuroimaging endovascular knurl interventional procedures or advanced management issues with that caveat out of the way let's start with the ideologies of stroke which will help to understand the workup and small differences in treatment stroke as it's conventionally defined has two major subtypes the majority are ischemic strokes in which there is an interruption to the normal blood flow to part of the brain resulting in infarction of neurons a process which begins within minutes a minority of strokes are caused by hemorrhage which can either be intraparenchymal hemorrhage or subarachnoid hemorrhage although some physicians don't consider subarachnoid hemorrhage to be a form of stroke strictly speaking either way though aside from their seriousness and their acuity of onsets hemorrhagic strokes share relatively little with ischemic strokes and won't be discussed more in this specific video but let's take a closer look at these subtypes of ischemic strokes of which there are five ischemic strokes can be due to large vessel atherosclerosis most commonly a carotid artery they can be cardio embolic in which a thrombus originates in the heart before embolizing into the systemic circulation this is most commonly due to atrial fibrillation but other causes include prosthetic heart valves left ventricular aneurysms endocarditis and an acute MI ischemic strokes can be lacunar strokes which are small subcortical in parks usually affecting the basal ganglia pons and internal capsule there are a number of rare ideologies that don't really belong in another category such as carotid artery dissection or severe hypotension in which strokes can form in these so called watershed areas between vascular territories where blood delivery is already relatively low at baseline and last hour cryptogenic strokes these are strokes that appear to be without clear ideology even after neuro imaging and echocardiogram and rhythm monitoring when an etiology is eventually identified for cryptogenic stroke it might be hyper Qui global States a patent foramen ovale in which a deep vein thrombosis analyzes and instead of leading to a pulmonary embolism the embolus can gain access to the systemic circulation through the PFL causing a stroke this phenomenon is called a paradoxical embolism finally some cryptogenic strokes are due to a cult a fib a pin that happens so infrequently that it's not captured on a routine heart monitor sometimes they're called a fib can be identified on a two-week ambulatory monitor that a patient wears at home while other times the rhythm is so infrequent that a patient might require an implantable loop recorder to be inserted subcutaneously over the chest where it can remain for months in order to catch it moving on to how strokes presents they most often manifest as the rapid onset of specific neurologic deficits the specific symptoms can be unilateral limb weakness facial droop difficulty with speech or comprehension difficulty ambulating ataxia sensory loss or vertigo of these a rapid onset of any of the first three is most predictive of the presence of a stroke rarely a stroke can present with less focal symptoms including confusion without focal deficits particularly profound strokes can present with coma while strokes can cause a headache or trigger a seizure either of these as the only manifestation of a stroke would be highly unusual once you've identified a possible stroke there are five steps to evaluation and treatment the immediate workup to be completed within the first hour of arrival to the hospital the acute treatment referring mainly to reperfusion and blood pressure control then assessment of the etiology initiation of physical occupational and speech therapy and last to assess modifiable risk factors and initiate secondary prevention I'll go through each of these five steps one at a time in the emergent immediate workup of a possible ischemic stroke you want to confirm that diagnosis as the top priority so acquire a non-contrast head CT even if the ischemic stroke is either too small or too early to be seen on CT this will rule out the presence of hemorrhage as CT has a high negative predictive value for subarachnoid and intraparenchymal hemorrhage an MRI with MRA can certainly do this too and can also identify regions of ischemia earlier however for patients still within the TPA window which we'll talk about in a minute learning this additional info upfront is not worth a significant extra time required for an mr you also want to rule out stroke mimics these include hypoglycemia seizure with post ekdal paralysis migraine with aura hypertensive encephalopathy and conversion disorder of the stroke mimics all but hypoglycemia I can usually be sufficiently ruled out by history and exam alone which is why a glucose level is the only blood test that's strictly required prior to TPA administration you want to establish the timing of the stroke by the first onset of symptoms if the time of onset is uncertain for example if the patient wakes up with the deficits already present the time is assumed it'd be when the patient was last known to be at their baseline and you'll need to determine the severity of the stroke using the NIH Stroke Scale here's what the NIH Stroke Scale looks like I'm not going to read through it but the basic idea is that the patient's neurologic function in various domains such as cognition language strength and coordination are graded the higher the score for a specific domain the more severe the deficits all the points are then added up and the higher the overall score the worse the prognosis when it comes to acute treatment the most important consideration is whether the patient is a candidate for reperfusion either with TPA which stands for tissue plasminogen activator or with an invasive procedure called mechanical thrombectomy I've already mentioned TPA several times but I haven't yet explained what it is or what it does TPA is a naturally occurring enzyme that catalyzes the conversion of the inactive plasminogen to active plasmon which then in turn Cleaves fibrin which is the primary protein at the end of the clotting cascade responsible for blood clots so in contrast to anticoagulants like heparin which prevent clots from being formed TPA rapidly speeds up the degradation of pre-existing clots this makes TPA helpful in the hours following a stroke while heparin and other anticoagulants are not so who is potentially a candidate for TPA indications for TPA are a clinical diagnosis of ischemic stroke a measurable neurologic deficits and onset of symptoms within 4.5 hours prior to the TPA administration unless the patient's age is above 80 or other less common features are present in which case the onset must be within three hours there are a number of absolute contraindications to TPA an incomplete list of which is here there are also some relative contraindications to consider most notably pregnancy and spontaneously improving symptoms all of emergency departments and stroke teams is for no longer than 60 minutes to elapsed between the time a stroke patient arrives at the door and TPA is running through their IV unfortunately only a minority of patients presenting with an ischemic stroke actually receive TPA most often because too much time has elapsed prior to their arrival to the hospital regardless of whether TPA is administered if symptoms have been present for less than 24 hours the patient may be a candidate for mechanical thrombectomy the specific indications of which are beyond the scope of this particular video and before we move off of TPA I do want to note that there is a some degree of controversy over its effectiveness with neurologists in near universal agreements with the aforementioned indications and with a relatively small but vocal group of predominantly emergency medicine physicians disagreeing I'll post some links about this controversy in the video description beyond reperfusion there are a few other components to the acute management of ischemic stroke that need to be addressed in the first few hours intubation and mechanical ventilation should be undertaken in unconscious patients or in those who are otherwise unable to protect their airway blood pressure management is another key issue while hypertension is a major risk factor for stroke treating hypertension acutely following a stroke can be detrimental as the peri infarcts territory a region known as the ischemic penumbra may be relying on very high blood pressure to maintain perfusion of at-risk neurons so we typically tolerate much much higher blood pressures than normal what's commonly referred to as permissive hypertension in a patient who will be receiving TPA or who has already received it the goal systolic blood pressure is 185 or less and diastolic pressure of 110 or less if no TPA then the goal s BP is at or lower than 220 and diastolic pressure at or lower than 120 unless another hypertensive emergency is concurrently present such as angina heart failure or preeclampsia if antihypertensive medication is necessary IV meds are preferred such as micarta pain clavata pain and labetalol in hypotensive patients laser pressors to increase blood pressure can be rarely considered but only if the patient is experiencing additional neurologic deficits attributed to the hypotension in patients who are on outpatient antihypertensives before the stroke these can be gently restarted after about 24 hours in most patients if TPA was given or mechanical thrombectomy performed it's generally advised to wait at least 24 hours before starting aspirin otherwise aspirin can be started immediately the early use of anticoagulation such as heparin is only potentially indicated in unusual circumstances and is generally avoided even in most cases of cardio embolic strokes at this point you can start focusing on the etiology obtain an MRI and MRA if it wasn't already performed this will confirm for you the specific anatomic territory which you hopefully have already suspected from your exam and will also give you some idea about the degree of atherosclerosis in the large vessels while in inpatients anyone not already known to have afib should be on telemetry and if the telemetry remains without a fib during the hospital stay I'd recommend discharging the patient with an ambulatory ECG monitor for at least two weeks and echocardiogram should be ordered to examine the heart valves and to look for a ventricular aneurysm a transthoracic echo is usually sufficient but if there was a particular concern for clot in the left atrial appendage a transesophageal echo could be obtained and be sure to consider rare ideologies if the cause remains elusive most of the rare ideologies such as a carotid artery dissection and a cárdenas or an aneurysm as mentioned will be picked up with the aforementioned studies but some others such as vasculitis or a hypercoagulable states require additional testing however not every patient with a cryptogenic stroke requires an extensive hyper quad workup or requires 15 auto antibodies looking for an unusual presentation of an autoimmune disease these tests are expensive and have non-negligible false positive rates so be thoughtful about it next you want to initiate PT ot and speech therapy with your patient for example all patients who have suffered from a stroke should have a swallow assessment prior to oral meds or a diet PT ot and speech therapy should be started as soon as the patient is awake and stable enough to safely participate due to the logistics of scheduling inpatient therapy assessments these are most often done on the day following admission but there's no specific medical reason it can't begin on day one for most patients a timely initiation of therapy is a critical component to maximizing recovery the last of the five steps of evaluation and management is to initiate secondary stroke prevention this will include some a form of anti thrombotic medication the choice of which is most dependent upon the mechanism of stroke for all non cardio embolic ischemic strokes antiplatelet meds are indicated options include aspirin clopidogrel known by the brand name of plavix a temporary course of aspirin plus clopidogrel known as dual antiplatelet therapy followed by the long-term use of just one of those meds or a combination tablet of aspirin and diaper animal known as Agri knocks the decision regarding specific choice of med is nuanced and is a constantly evolving topic for which it's best to consult with a neurologist following all cardio embolic strokes anticoagulation is indicated meaning either warfarin or a doe AK although there are an increasing number of situations being found in which no acts are likely superior to warfarin at the present time it's unknown if this is true among patients post stroke the optimal timing to begin anticoagulation is unclear but most clinicians wait at least three days the more severe the stroke the longer the delay up to two weeks or sometimes even longer additional very important risk factors to consider include hypertension checking a hemoglobin a1c and treating for diabetes if indicated all patients should be placed on a high intensity statin such as a torva statin eighty milligrams independence of baseline LDL in a stroke patient who is still smoking needs smoking association counseling regular exercise and maintenance of a healthy BMI are believed to be protective against stroke and last patients who have had a minor stroke from large vessel atherosclerosis and who have significant EPSA lateral carotid artery stenosis should be offered expedited carotid endarterectomy in appropriately screen patients carotid endarterectomy reduces the risk of recurrent stroke [Music] you

Channel: Strong Medicine

Views: 86,974

Keywords: stroke, intern crash course, ischemic stroke, residency, medical residency, internal medicine, intern, thrombolysis, tpa, alteplase, neurology, neurologist

Id: 2i_u47EhHXc

Length: 16min 5sec (965 seconds)

Published: Mon Jan 06 2020