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Asthma for USMLE Step 2 Hello thanks for dropping by to today's video where we will be discussing asthma so we'll begin with a definition and the definition also describes its pathophysiology so the definition of asthma is when you have bronchial hyper responsiveness so it it over reacts and this leads to airway inflammation which can be chronic over time and this can and then lead to interment intermittent obstruction which would be the cause of the acute exacerbations so bronchial hyper responsiveness is typically there's some sort of trigger that causes the bronchial to be to respond or overreact to something and then this will lead to air inflammation which is triggered which is mediated by mast cells you know Center fills and you know other mediators inflammatory mediators and these can generally and these become very severe they can be too intimate obstruction and this obstruction is caused either by airway edema or mucus plug so airway edema is created by some of those the mucous glands secreting too much fluid and then the mucus plugs is when those plugs kind of go further down and they obstruct the bronchial or the bronchus completely and so what happens when you have area of airway edema mucus plugs these act together to equate increase the resistance and then this decreases the expiratory flow rate and so this is primarily an expiration type of problem and so that's why this is considered one the obstructive rather than restrictive diseases so this kind of summarize very briefly the pathophysiology enough that we need to know here of course for step one you probably know it needs it a little bit deeper than that and make a video about that in the future so what are the causes of asthma so the ethological causes one of the causes is any type of environments or allergens so it's almost like an allergy whether they were they when they get in contact with a specific type of substance they will hyper responsibility to asthma otherwise they can also be triggered by a viral infection more commonly by an upper respiratory tract infection and these are done by different viruses such as the Rhino virus and even the RSV virus and this viral infection is typically common in children and so when you when you can think of viral infections I think of the younger age group next also sinusitis in science is an interesting because 50% of people with asthma are an acute exacerbation tend to have concurrent designing cider so that's the kind of link there there's a specific type called exercise-induced and with this with these patients they only get an asthma attack when they sorry they don't only get it the attention whenever they do some exercise they get an asthma attack now 50% of the time they they tend to be completely silent except when they are exercising so the only time they'll get an atom attack is when they're exercising and so the other 50% they have other triggers however exercise is one of them as well and gently what happens if is when they exercise for 10 minutes then they then they start to get symptomatic asthmatic symptoms however if they if they exercise for shorter interval these symptoms will occur five to ten minutes after they begin resting so that's the kind of difference there and generally the higher the intensity of the workout the more severe the symptoms so they're they're kind of linked in severity of symptoms and the intensity workout GERD is another cost and the pathophysiology behind that is is thought to be you know the acid in the esophagus triggers a vagal response and so this vagal response will then you know generally cause constriction of the bronchus so that's the kind of idea there aspirin induced asthma this has to do with the kind of mechanism action of aspirin what it does is it decreases it inhibits decock psycho oxidase enzyme and so that decreases prostaglandins sort of the idea you increase the amount of leukotriene and leukotriene do cause bronchoconstriction and when someone doesn't have aspirin induced asthma then you want to use or what's called leukotriene receptor antagonist and that those tend to work better for these patients obesity is another cause on top of that occupational exposure so certain occupations tend to have asthma and these would be people who you know were like such as farmers and painters and even janitors they kind of get in contact with certain chemicals and of course there's probably many other occupations that people get can get exposed to certain chemicals that trigger their asthma and finally even emotional so certain emotions may be 50 you know becomes something emotional that can also trigger an attack so the people need to be careful you know okay so what we'll do is so we've finished etiology now let's talk about clinically what you can expect so asthma can't start at any age however about 75 percent of teachers who have it tend to be diagnosed less than seven years old and generally with these patients specially for their younger one they tend to remit once they get into the adolescence years and so it's it's it's not always gonna be some of the alleles your whole life so what is the main symptoms one of the main symptoms is cough generally described as a non-productive cough non proximal and these symptoms and actually all the symptoms tend to occur at the night or in the early morning so that's a very very key kind of feature there when you hear that you definitely want think of asthma the other thing is gonna be chest tightness or you know sometimes patients will describe it as a chest pain so this is also something that asthma patients will tend to have and finally there will be a wheeze and Louise initially will start off as as end expiratory wheezes however as these disease progresses this can be a wheeze throughout the entire expert ory expiration then as it progresses more it's going to be on inspiration and expiration and finally you'll get something called a silent chest and this means that you when you listen to the chest there is no sound and this suggests that there is complete occlusion of the alveoli of the of the airway and so obviously this is very serious if it's got very severe and this is generally considered an emergency so as soon as they get sound in chest you definitely want to you know treat it right away and give them at least an ER or something now when we talk about asthma these tends to be the three primary symptoms during an exacerbation cough chest tightness chest pain and weeds so these are the symptoms that we are looking for now as far as signs there are some other signs that you might wanna look for one is gonna be increased respiratory rate and of course there have a difficulty breathing so of course they're gonna start breathing more now as it becomes really severe they do tend to hyperventilate so hyperventilation occurs only when is really severe and this is generally due to a lack of respiratory effort so they just end up getting tired and they can't maintain their breath and so that's why they're hypoventilating also you they will get tachycardia or a high heart rate and actually ninjas go real quick back to respiratory rate they also tend to use your accessory muscles such as this Stern nuclear mastoid and they have something called what's called a tripod stance where they rest their hands up against the table to kind of lift and replicate and try to get more air so that's a call it tripod sense and that's also considered the use of accessory muscles also one of the sign is going to be pulsus paradoxus and what pulsus paradoxus is what happens to these patients is that on inspiration they get a drop in blood pressure well you'd expect an increase in blood pressure and this is blood pressure must be greater than 12 millimeters per mercury so I'm sorry the decrease in blood pressure must be greater than 12 lumens no mercury other symptoms the sign that they may have is they become credibly breathless they're unable to speak and when they do speak it tends to be in phrases or words and also they have a start becoming less alert so they started becoming kind of drowsy and tired so that's another symptom you want to look out for now how do you work up these patients typically it's diagnosed by either a the clinical findings or some clinicians just based on the very typical findings and maybe the age there just tends to just assume it's asthma they treat accordingly and a lot of times the treatment responsible treatment is considered definitive however you know you could do a spirometry to confirm and you also want to make sure you rule out other alternatives because there can be some so one of the tests that is not not really used but you can do is called a bronco provocation test this is considered the gold standard however very rarely used because again it's not always necessary because of the clinical findings and also it's kind of mean I guess you can say so what you do is you try to test the bronchus for hypersensitivity and one of the tests you can do is you give them either methacholine you can give a man a tall or if they have exercise-induced you can give that you can have them do some exercise and so what you do is you're actually waiting for the symptoms to occur and so methacholine is a colon colon urge ik agonist but a very temporary one so if you spray this in their mouth or you give this to them they will suddenly have a very minor type of episode and this is the same thing with the other ones and so if you do give this a high response that's what you're looking for you looking for a high response now if it does become positive that's not diagnostic actually because you do still need to rule out other causes are they positive and these can be you know COPD rhinitis and you know some of the other lung conditions that can't be there so many other that you need to rule out so positive you still need to do some investigation however if you do this and it's negative then you can just rule out asthma it can't be asthma anymore so that's the kind of a nice thing about this test but getting not really done what actually is done it was preferred is by River tree and spirometry is when you look at the you have the patient and as hard as they can into a device which measures how much air is being taken in and so one of the parameters that we take a look at is called a forced expiratory volume in one second so this would be the amount of air that they can push out in one second over the total for forced out of a vital capacity and this is the total ability to actually blow out air so generally P individuals normal individuals should we be able to blow out eighty percent of the air in one second however people with asthma they tend to have less than eighty percent and so when you do this initially all this tells you that this is an obstruction not this necessarily tell you it's asthma and so the the disease of obstruction are COPD emphysema bronchiectasis and asthma so you've kind of narrowed it down to these four however what do you need to do to narrow it make sure it's asthma well what you can do with the the interesting thing about asthma compared to the other four three is asthma is reversible with a bronchodilator so what you do you give them you know a bronchodilator and you look to see and then you do this by Dmitri again and if it improves by twelve percent or two hundred milliliters then you've got the diagnosis of asthma so asthma is reversible while the other three aren't and the other three are actually slightly reversible but asthma is more considerably reversible than the other three so something to keep in mind the other one is going to be a peak expiratory flow monitor peak expiratory flow is also written as PE F so this image right here shows that peak expiratory flow monitor so as you can see it's a very cheap device the patient blows as hard as they can here and then they see how far it measures up there now what is normal well depending on your height and weight there's a chart that you look at and so you get the patient height and weight and then they give you the normal values generally if the patient is between 80 percent 100 that normal value that's pretty good 60 to 80 percent that's gonna be mild and less than 50% well then that's pretty serious sorry fifty to eighty percent and if there's less than fifty percent that's pretty serious and they need to go to ER now generally what the user score is for monitoring and decision making so how do you treat the patient what to do and since it's very cheap and it can be used it's really easy to use patients tend to use it at themselves at home to kind of monitor how they're doing and it becomes part of what's called the asthma action plan where depending on whatever what where they fall into which range they fall into they you teach that you educate the patient on what to do in certain circumstances so it's very helpful in that and we get to management we'll talk about how they use that more specifically um next that you can do is you can do blood and sputum eosinophils so because it's kind of an allergic reaction you said if those do tend to be high in the blood and in the sputum if it tends to be greater than four percent that supports the diagnosis of asthma but it can't rule it out because there's also other things that are you might do that and if there's greater than 8 percent then you do get some differentials so I'm writing them over here so one of them is going to be the allergic problem allergic bronchopulmonary aspergillosis sure strauss syndrome can also have greater than 8% and a acidophilic pneumonia can also have that and these blood and sputum eosinophils do help guide therapy as well but not as used as much but they could possibly do that and finally you can't do a chest x-ray now in the asthma patient checks x-ray is normal so the only benefit is that it helps rule out other causes such as pneumonia and other things that might be actually causing these symptoms so chest x-rays there so now that you kind of talk about the workup next thing you want to do is you want to try and stage the patient and see where they are at so there's two main types it is either intermittent or you can have persistent so the difference is in intermittent they're actually asymptomatic between episodes are you know between stints of exacerbation whereas persistent they always tend to have some type of deficiency and in persistent it's differentiate into three different types and then it could be mild persistent moderate persistent or severe persistent and depending on certain symptomatic and assessment values you can you can you can differentiate which group someone belongs into so the first thing that you look at is symptomatic in the day and that symptomatic in the days sometimes refer to as the use of a short-acting beta agonist or you can also be the night symptoms so an intermittent they'll generally have less than two days a week where they need to use the short active beta agonist and they'll generally have less than two night symptoms a month for you know two days a month in mild however D Day symptoms are going to be to six days per week and persistent is going to be daily symptoms and suvir's whether they have systems throughout the whole day so you can see that'd be pretty severe and as far as monthly goes so that's four weeks three to four days out of the month out of night symptoms greater than once a week in persistent and then severe they have again nice and since every night so that's how you kind of differentiate based on how frequently they have symptoms you also get differentiated about the activity level so intermittent and mild they tend to be fairly normal there's an affected activity so - this are mild starts having my limitations persistent has some limitations and severe they have severe limitations so they're not able to do many because of their asthma so next what we'll do is actually before okay let's talk about severe exacerbation so severe exacerbation is defined as when an oral glucose coracoid is required so now an intermittent they only have zero to one per year whereas in mild and persistent they have greater than two per year so anytime you get to symptoms pre a to severe exacerbations per year you become you go into this category so there is sometimes overlap so you know they might have more night symptoms and you know less day symptoms what you tend to do is you go with whatever is the worst that's a category you belong in so that's kind of how you deal with that now as far as assessment values so of course we can look at the fev1 which is the amount of volume you can expand one second and fev1 over the FBC ratio so the fev1 is greater than eighty percent in intermittent and mild persistent and it tends to drop after that so persistent are some moderate persistent it goes down to about sixty to eighty percent and in severe it'll be less than sixty percent and with the ratio they attempt to be normal in intermittent miles however in persistent moderate it's going to be less than it's going to decrease by five percent and it's going to decrease by more than five percent in severe so as you can tell the everything would be normal as far as assessment BIOS will be normal in intermittent and mild persistent so it's only when you start having derangement of these Vata in these values that you start becoming into moderate and severe so that's kind of a easy way to kind of helpful way to memorize that remember that so now what we'll do is we will talk about management so now we will go ahead and move on to management so the first step in management and this is actually the most important is education and this has actually been shown to decrease mortality most and what you do in education is you give the patient and asthma action plan and so in the asthma action plan what you do is you educate the patient on what are the signs and symptoms of a severe mild and moderate attack and then depending on where they fit in there they'll do deal they'll know to certain things when to go the ER when to take increased doses of education or just you know it's not a big deal so that becomes one of the most important things and also you educate them and on avoiding triggers and so this actually means you have to identify the trigger and then avoid those triggers so that's these are actually the most important parts of management otherwise the what they've design is called a step system and so in the step system there's six steps and depending on these symptoms you either have them step up or step down so generally when you step up you're increasing the amount of drug that you're giving or the dosages and so you tend to step up whenever the patient has symptoms greater than two days a week and these symptoms have to be severe enough to require a short-acting beta agonist and with so when do you step now that you can step down when the symptoms are well controlled for about three months and so why do we do this step up and step down well this is because the you know asthma tends to be pretty dynamic disease and so as the patient feels better you could try to decrease the dosage or the types of medication umber of medications and as the symptoms get worse you can increase the dosage or the number of medications that you're using so this becomes very very important so let's go into actually what the steps are so you have six steps one two three four five and six and these are all the steps that you go through so the first step is going to be just a short-acting beta agonist and this is going to be generally patients who are intermittent not persistent and so in these patients there's no controller that's required and they just take the short activated agonist as needed and so if this is able to treat the patient pretty well then there's no problem they can continue to do that however if if they do get you know more than two symptoms per week that require the beta-agonist so they're gonna have to step up and so in the first step up what you do is you give them low-dose inhaled corticosteroids so ICS stands for inhaled corticosteroids and they take this daily and actually when we talk about all the rest of the stuff the steps there's going to be daily medication these are these are considered the actual controllers that will be required okay so now what one thing I want to point out is of course this is daily medication however you still want to for quick relief you want to still give them the short-acting beta-2 agonist and so whenever they have these episodes they take these short active beta agonist three times every twenty minutes so the short-acting beta-2 agonist doesn't matter what stage they're in they'll always be so they could be one two three four five or six they always use a short-acting beta-2 agonist whenever they need any quick relief so whenever they have an episode so in the third step you're still using the low IC low inhaled corticosteroids that you were using in step two however you add a long-acting beta agonist and in step four five and six all three of them you're going to be actually old from Step two all the way to six you're using inhaled corticosteroid however once you get to stage four instead of using the low corticosteroids you increase the dosage and you use a medium and sorry you also use it you're also using a long-acting beta agonist for all three four five and six so you can see that you pretty much using the same medication and all all these four steps however what changes because something has to change otherwise what's the purpose of having a step well the dosage of the inhaled corticosteroid changes so in step four you go to medium and Step five you go to high and then step six you're also going to high and why is it that inhaled corticosteroids are so popular that's because it has been shown that inhaled corticosteroids can decrease the amount of short activated required it can increase the quality of life it can decrease the number of exacerbations that they have and decrease the loss of lung function so because of such overwhelming evidence you will see that you know beside step one you will see in inhaled corticosteroids in every single section and of course ii would be the long-acting beta agonist so now if you're kind of wondering what's the difference between this age five to stage six well in stage six you also add an oral glucose coracoid so that is stage six now also in stage 5 in stage six they've introduced a new drug that's called Oh Melissa map this is an anti IgE and these are best for patients who have some type of allergy to especially people who have high eosinophils in the in the blood and the our sputum so so as you can see here this is this is the step so again inhaled corticosteroids and long-acting beta agonists are kind of found in all of them but as you go up the dosage of inhaled corticosteroid goes up and once you go to stage number six you also add an oral glucose quarter board so that's a good way to memorize it but before I finish in stage two three and four you can have an alternative to long-acting beta agonists and that can either be a lucrative receptor antagonist and this is you'd want to use in patients when it's aspirin induced beside lutein as well which is the mass so stabilizer and then theophylline which not used as much because of the kind of adverse effects but still can be still it is mentioned so this is how you treat you know on a regular basis however when they have an acute exacerbation or you know a very severe attack this requires a different type of management more emergency department and admission to management so firstly the patient should have an asthma action plan and in that plan they should know how to detect when a severe exacerbation is coming and so the way they detect it is by symptoms so the first thing to lose symptoms so if the patient realized he's breathless you know he's to speak only in phrases and words also if he starts noticing very severe cough severe wheezy that's going through the entire expert or even into inspiratory if they start using their accessory muscles or they start noticing drowsiness these are all symptoms that should trigger them to do a peak expiratory flow so whatever they feel these symptoms they should do the peak expiratory flow that a small device that I showed earlier now if it's if it's fifty to seventy nine percent of their best then what they should do is they should just take two to six puffs of these short-acting beta agonist and they should do it three times every 20 minutes and so once they've done that you know they should see how they feel so if they start to feel better or you know they don't feel any better at all you kind of want to be aware of that and so what you want to do then is you want to do a peak expiratory flow and so then you see what the results say so there can be three possible results here so if they're great at 80% which is normal that means that they had a fairly good response they're able to kind of go back to normal there and so what you want to do is just have the patient continue with the story active beta agonist because even though they're better sometimes they can kind of fall back in so you want to continue that and you want to continue maybe every three to four hours for about two days or for about 48 hours and then after that they do want to kind of talk to their doctor make it a pun with the doctor and change in medication so that's important there now if they do that if they do if they've already done the two to six puffs and then they take another they check out their extra flow again and it's between fifty to seventy nine percent that's the Synanon in complete response and so in these patients they want to go and go ahead and use an oral glucose corticoid and they want to continue the short-acting bid agonist and again go to doctor and their medications and that's what you want to do if there's less than 50% that's the poor response you definitely want the patient to take some oral glucocorticoids and a short-acting beta agonist and then they want to immediately go to the emergency department so that's and so this is why the as the action plan is very very important because they can figure out when should I go to the emergency department what should I just you know up my drugs or would I just you know kind of just do what I'm doing so very very important that patients are aware of this and so and by the way so you know this is less than 50% even if they get on the first flow they get less than 50% you want to do the same management so now what we'll do is we'll so so of course these patients are okay they're gonna go meet with their doctor you know probably step up or change their medications now let's talk about what happens to the patients within emergency department so these patients obviously what we'll do is we'll act like we are the ER Doc's and see what we will do okay so when the patient comes to the emergency department one of the first things you want to do is do a quick history and physical examination because you do want to make sure that they are having an asthma attack and so waiting for physical examination obviously a high respiratory rate and heart rate you're also looking for the use of accessory muscles also if they're you know if they're not able to talk that's a you know sign that this is pretty severe or if they have diaphoresis the others the other symptom that you will look for is pulsus paradoxus and so what does posters paradoxus pulsus paradoxus is of course where the client discussed is when they inspire the heart rate goes down more than 12 millimeters of mercury so we kind of discussed that already so once you've done the quick history and physical examination you want to divide the severity into three groups so it's either going to be mild to moderate it could be severe or they could be in respiratory arrest so how do you decide which one it is again you can do the peak hitori flow monitoring so if the if is greater than 40% that small to moderate if it's less than 40% that's severe so the first thing you want to do is you want to give them oxygen until the saturation is 90% and that doesn't matter which group they're in whether they're you know moderate or severe the first step in management is oxygen now say you give them oxygen so today of less than 40 percent you give them oxygen and you can't get to 90 percent well then that is you can't do it so then you're going into respiratory arrest immediately you want to intubate the patient and begin mechanical ventilation and again the kind of ventilation needs to be at a hundred percent and then admit them to ICU so that is very very serious and they need to you know it's life-threatening so you need to get them that right away and again those are with patients when you give them the oxygen they can't even get to ninety percent okay otherwise you know in mild to moderate you can just you know give them oxygen then go ahead and start a short-acting being agonist either by nebulizer or with the you know inhaler and in severe you want to do the short activate agnes with ipratropium and oral glucocorticoid if it's mild moderate or google coracoid that's a maybe depending on maybe the symptoms you know if this is a little more severe you might want to go ahead and add that a little bit it's you know depending on the clinical assessment so once you've done that you know for about an hour you want to go ahead and you want to reassess the patient i see how he's doing and again reassessment is done again with a pulmonary the peak expiratory flow monitor and so we divide them again depending on the next flow we divide with three groups so if they begin to react greater than seventy percent you consider that as improving so you go ahead and you continue doing a short-acting made a guinness every hour and give them oral glucocorticoids and you observe them for about four hours so after you observe them for about four hours and they seem to be improving you know you can go ahead and discharge them and when you discharge them tell them to continue these short activated agonists continue doing the oral glucocorticoids and he maybe the inhale glucocorticoids so again even though they might have gotten better you still want to try and prevent any type of real simulation so that's improving which is about seventy percent if they about forty to sixty nine percent that's considered not improving and so in these patients since they're not improving you want to just go ahead and MIT them to the wards and in the ward you want to go and continue the oxygen continue to short active beta agonist oral glucocorticoids and you want to just monitor them check their vitals every once in a while and then their force expertise load velocity in one second you want to continue to monitor them and then so continue to give them that until they get over the episode and then you can go ahead and discharge them now if it continues to be less than forty percent that means they're worsening and oftentimes these patients if you have a piece you to a greater than forty two and so what that means is because generally patients tend to be have low co2 because they have hyperventilation so as soon as they start accumulating co2 then that means they've lost respiratory drive and they're in a very serious state and these patients also have very severe symptoms in this case you want to admit these patients to ICU and in ICU of course you're going to give the oxygen and the short activated agonists those are kind of hallmarks of treatment but on top of that you'll give IV glucocorticoids you'll and also you'll be integrating the patient and you'll be giving mechanical ventilation so that obviously they can try to get over this episode and once you've done that and they kind of stabilized then you can admit them to the wards and you know continue monitoring and vitals and then once they get better you can go ahead and discharge so this is just a overview of the asthma so hope you guys found that beneficial see you guys in the future video bye

#asthma (disease or medical condition)#obstructive lung disease #pathophysiology #respiratory failure (cause of death)#respiratory system (literature subject)#signs #symptoms #treatment #usmle step 1 #usmle step 2 clinical knowledge

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