 Welcome back to our meds smarter lecture series where we're taking a smarter approach to preparing future physician Before we get started if you'll take just a quick minute and click that like button and also Subscribe and turn the bell on so that you'll be notified when we post new videos All right, my go bacteria my go bacteria is a gram-positive acid fast rod So what that means is we're going to see a red Color when we do our acid fast stain, which you will see here in just a minute Mycobacterium tuberculosis is one of the species that we deal with as far as mycobacteria goes You can see it in this picture once again. This is an acid fast stain and all of these red rods here are our Mycobacterium tuberculosis we usually call this just TB and it is often resistant to many drugs So our treatment for mycobacterium is going to be a multi drug regimen Some other species of mycobacteria that we do deal with is mycobacterium avium Mycobacterium avium especially intracellular Mycobacterium avium does cause disseminated non-TB disease for patients that have AIDS And oftentimes this here is resistant to many drugs as well the one thing that we always do for patients that have AIDS when their CD4 count drops below 50 cells per millimeter That is when we will give them a prophylaxis treatment with azithromycin to help reduce the possibility of a mycobacteria avium infection some other mycobacterium Species mycobacterium scrophilacium This is causing cervical lymph adenitis in children and Then mycobacterium marinum. This causes hand infections for those that work at aquariums Because it's typically found in the waters So symptoms of a TB infection Most common ones you see you're gonna be your fever night sweats weight loss cough and Hormoptosis some more facts about mycobacteria Cord factor here actually creates a serpentine cord Appearance in our virulent mycobacteria tuberculosis strains Macrophages are activated by this mycobacteria which promotes that granuloma formation So that's one of the big things that we see with tuberculosis, which we'll talk about later is these granuloma formations And it's due to that activation of macrophages and finally it induces the release of tumor necrosis factor alpha Sulfatides which are glycolipids on the surface and those inhibit the phagolisosomal fusion That allows it to be able to stay in the body longer because the body is not able to Gather it up in the phagolisosome and what you're seeing here in this picture is another scanning electron micrograc So how do we test for tuberculosis one of the newer tests these days is called the interferon gamma release assay or Igra and we like this test better than another test that we've done for years and years called the ppd or purified protein derivative Because the interferon gamma release assay has fewer false positives from Patients that have the bcg vaccination the bcg vaccination is popular over in Europe and Patients get that and it oftentimes causes them to test positive on a ppd test when they really don't have a tuberculosis infection So we like to interfere on gamma release assay it is however a little bit more expensive So it's not the most common thing we do we still do the ppd test as a very cheap alternative For that, but if we do have a patient that has the bcg vaccination will know that if we give them a ppd test They will likely show up positive So the ppd test is positive Only if there is a current infection past exposure or like I said the cases where there is a bcg vaccination Oftentimes you will have a ppd test that will return a negative result if there's no infection or Patients that have sarcoidosis or hiv infections and specifically with that hiv infection It's because we have our low cd4 count So we're not going to see that response to the ppd test if you remember how the ppd test works You take a small insulin syringe and inject a small amount of the ppd protein underneath the skin and then within 48 hours you read it and your Amount of induration as you can see in this picture here or the redness or swelling that can occur will tell you whether or Not you have a positive or a negative test and one further point here is Case-eating granulomas that have a central necrosis as well as Langerhans giant cells are characteristic of second-degree tuberculosis So let's talk a little bit about the different types of tuberculosis. We can see so with primary Tuberculosis that's typically going to be where we have the pulmonary stages And you're gonna have hyaluronodes and gonfocuses in the mid and lower lobes So the hyaluronodes plus the gonfocus is what we call the gon complex And that is gonna be your most characteristic thing for primary TB 90% of the time these primary TB cases will heal They'll undergo some fibrosis and calcification and they will heal and Patients will get back to a normal state at this point in time. That means they will have a positive ppd test there is a possibility of reactivation of The primary TB and what actually happens there is our primary becomes a secondary TB And we see caseating granulomas Cavitations and scars that'll form in the lungs plus the potential for caseating Granulomas in the kidneys you can see here in this picture what we're seeing is a person that has advanced tuberculosis Likely a secondary tuberculosis and we're seeing infections in both sides Oftentimes it's usually only gonna be unilateral in a primary TB, but when we have advanced stages We're talking about bilateral so we've got bilateral as you're seeing in these white arrows here And then we have cavities this cavitation is formed in this around that red circle there now the other 10% of cases that aren't healed by Fibrosis and calcification those actually can progress in patients that have malnutrition or specifically have AIDS They can progress to bactericemia where the TB infection gets into the blood and moves throughout the body and causes What we know as milliary TB This here can then travel to meninges to the vertebrae and that's where we have POTS disease It can get into lymph nodes the liver the spleen the adrenal glands the joints and bones So it can get all over the body and milliary TB is a worse prognosis and a worse infection of Tuberculosis that has gotten into the blood and spread If you found this material helpful for your studying Please like and consider subscribing to the channel also share this video so that more people can benefit from it like you have