Influenza (Flu) Explained Clearly - Diagnosis, Vaccine, Treatment, Pathology

  today we're going to talk about the flu and the flu is something that we see seasonally and I'd like to talk about specifically the virus the strains the symptoms assigns the vaccine and treatment see if we can give you a primer here on the influenza virus okay so first of all there is a virus it's divided into different strains there is a type A and a type B strain the one that you've got to look out for in the type a is the one that seems to be most common anyway is the h3 and 2 strain but we also see the h1n1 that's the one that we're most concerned about that's one that seems to be associated with epidemics what are the signs and symptoms so .

how do you can you tell this from the cold viruses and of course you do get respiratory symptoms but the other thing that is really key is muscle aches so that's a key one you could also see nausea and vomiting the other thing that you might see is pneumonia and so I've seen people with the flu developed such a severe pneumonia that they actually go into AR D s and respiratory failure and this is what kills a lot of people so as a result of that what we do is we try to prevent this by using a vaccine okay so the flu vaccine usually becomes available in October and it goes throughout the end of the year and into the new year until late winter that you can get the vaccine so the the vaccine usually is trivalent which means that there are three different types of viruses that are in there and in the year most recently here in 2017 to 2018 for instance the the three types there's usually two type AIDS that they put in there and one type B and the type a they always seem to put in h1n1 and that's through research that they look at out there to see what is most likely to come across and this talk is going to be a little bit American centric here because of recommendations from the FDA and the CDC which are both in the United States the other one that they do is h3 and - and you may recall that's the one that we talked about over here there's so many different strains of each one of these though that they could actually put in one type of h3 and - for instance like the Hong Kong one and it could come out with something completely different there's also a B in the year that I'm talking about they did the Brisbane strain for that sometimes they'll do four different ones and if it's the four and the year we're talking about 2017 to 2018 they added an extra B in there so either three or four usually a couple of a's couple of B's try to hit the nail on the head sometimes it works and sometimes it doesn't work so that's just one of the things to be aware of so how do you make the diagnosis let's say somebody comes in with these symptoms how do you make the diagnosis of the flu well the two major ways of doing it is using something called the R I DT okay and the other one is using reverse transcriptase PC R this one here the R IDT can be done in about 10 to 15 minutes in the emergency room the problem is is though is that if this is negative because the sensitivity is not very high if it's negative you can't rule it out so if you've got a patient during an epidemic who's coming in with classic signs and symptoms it's better to treat them than it is to wait for the RI DT or even the rt-pcr the rit pcr is extremely sensitive so if it's negative that one you can rule out remember spin and snout just as a little aside SP means specific if something is very specific you can rule it in and then snout sensitive if it is something is very sensitive then you can rule it out well that means if it's not sensitive you can't rule it out the RI DT is not very sensitive and so you cannot rule things out with a negative RI DT however if you have a very sensitive test like the rt-pcr and it is negative then since because it is very sensitive you can rule it out so just be aware of that however in times of an epidemic people are pouring into the emergency room with respiratory symptoms and they're all being tested and they're all being positive for the for instance.

 the h3n2 if these people are coming in it's better to get the medication on board right away because the sooner you get antiviral medications on and we'll talk about those the sooner you get those on like for instance less than 48 hours from the onset of symptoms the more likely you're going to get a benefit from taking some of these antiviral medications so how effective are these antiviral medications we'll talk about treatment over here if we look at treatments and we'll switch to different color here there's basically three different types of medications that we can give for treatment they're all something called neuraminidase inhibitors Andy you are a men days inhibitors okay and what are those three ones that we we should be using during the flu epidemic well the first one is au cell Tam of there I'll talk about that one that's known as Tamiflu okay the next one is known as za na mi vir the name of air and that is known as the inhaler one which is relent okay and then the last one is P er a-m I VI R pyramid of error and that one is known as rap of AB okay so the Tamiflu or oseltamivir is an oral either capsule or solution Zen nimah vert is an inhaled and parameter or rabbim AB is intravenous now the thing you should know about is that all of these medications here are all greater than 99% effective for type A and for type B virus so a and B and when I say effective it's been shown to reduce the symptoms of uncomplicated viral flu by 24 hours which doesn't seem like a lot but it is important in that if you can reduce the infectivity you can reduce the spread the thing I do want to make very clear though early on here is that there are two medications that have been used for viruses in the past that really don't have any role in treating the flu and they are amantadine and rimantadine there is just way too much resistance against these two medications in the more recent strains of the influenza virus okay so let's talk a little bit more in a little bit more detail about these three medications and about how they're used and the dose and things of that nature okay let's talk about the first one which is Tamiflu or o sell Tam up there which is why otherwise known as Tamiflu and what we'll do here is we'll draw the treatment on the top line and we'll draw prophylaxis on the bottom what we mean by prophylaxis there is that if you have a close contact that has been exposed to it and it's had the flu and you want to take it to avoid getting it from them that's chemo prophylaxis or in this case prophylaxis okay so starting at zero years of age here what we're going to do is we're going to break this up into different sections so this is going to be at two weeks this is going to be here at three months this will be here at one year and that'll be further on so the treatment is 75 milligrams P o Q 12 hours times five days and the prophylaxis dose is 75 milligrams P o Q day and it could be anywhere from seven days all the way up through ten days all the way up to six weeks if necessary depending on this clinical situation now the thing that's interest thing about this is that there are some recommendations and differences in terms of who should get treatment and who can get prophylaxis and then the reason why I drew this out was to show you the difference between these two so the FDA has approved this drug basically for any patient that is greater than two weeks old can get this medication now for adults this is the dose okay for children you're gonna have to look up the dose because it's all weight based so just be aware that but for treatment purposes the FDA recommends treatment all the way down to two weeks of age and no upper limit what have you do for patients who are less than two weeks of age well the FDA didn't test it or approve it for that but the CDC and the American Academy of Pediatrics does recommend because of data that you can treat less than two weeks of age now in terms of prophylaxis the FDA recommends all the way down to one year so you can prophylaxis um one with Tamiflu in other words if somebody contracted it and you are next to them and you want to make sure that you don't get it or your patient doesn't get it you can give this medication in this dose and you can look up the prophylactic dosing for Pediatrics as well all the way down to one year of age and again the CDC goes a little bit further because of data so the CDC and the American Academy of Pediatrics would say well we're going to go even less than one year we can go all the way down to three months of age okay now the question is is what do you do for prophylaxis here and that's really going to be left up to the severity of the case and the physician and the decision that they make at that point in terms of prophylaxis so I wanted to make sure that you understood when tamiflu could be used in these situations whether you're using it for treatments whether you're using it for prophylaxis and knowing these dosages based on the weight you've got to look those up and knowing what the FDA has actually approved this drug to be used for but what the CDC and the American Academy of Pediatrics recommends you should know that Tamiflu comes in a capsule but you can also get it in oral solution that you can swallow so think about this in terms of ventilated patients who have og tubes think about this in terms of patients who can swallow okay the next note we're going to talk about is inhaled it's Anam of air otherwise known as Relenza the first thing you've got to know about this medication it's not for patients who are hospitalized so not for hospitalized the other thing that you should know is that it's really for patients who don't have COPD so not for patients with COPD or asthma okay these patients this is not good a Bronco dilated in fact it may do the opposite so you've got to be careful about it okay so we're going to divide this one up into five years and seven years so again the FDA is recommending in terms of treatments so we've got treatments and we've got prophylaxis here again same idea so the FDA allows treatments all the way down to seven years of age okay so you can treat it's FDA approved for that the FDA has also approved the prophylaxis all the way down to five years of age okay there is no CDC recommendation here or American Academy of Pediatrics so you're really kind of on your own and wouldn't recommend it so the FDA is only allowing you to treat with this medication down to seven years and prophylaxis and then of course what is the actual treatment well it's an inhaler so it's two puffs q twelve hours here whereas prophylaxis is two puffs q twenty-four hours and this one is five days the treatment is five days and here it is ten days okay let's talk about the last neuraminidase inhibitor and that one is paramah there otherwise known as wrap of AB and for this one the division is actually pretty easy to understand okay once again we've got treatment here on the top and prophylaxis on the bottom and the FDA and the cutoff here is two years and the dose is actually 600 milligrams IV believe it or not times one dose okay now you've got to be careful because there is renal dosing that you've got to look up FDA approves the use of this medication all the way down to two years of age for treatment purposes okay below that age there is no recommendation and furthermore there is no recommendation of course to give this intravenously for prophylaxis so just be aware of that issue okay so going back to the flu we talked about the different types of viruses the different symptoms the vaccine what we're actually trying to get in the vaccine how do you make the diagnosis I think the key here is understanding the medications that you have access to and quick observation and quick identification of these patients as they're coming into the emergency room especially in an epidemic that you really want to treat these patients really before you have the results in hand you can always stop the medications if you have to because the earlier the treatment typically less than 48 hours after onset the better the outcome is going to be however if it's been more than 48 hours I'd still recommend starting them especially in severe patient there was a question a number of years ago as to whether a higher dose would have made an improved difference in outcomes in the very severe hospitalized ICU patients and I think the data on that is showing that really the higher dose doesn't improve outcomes so I think you should stick with the current published doses that is the flu thanks for joining us.