So occupational lungdiseases, once again, are diseases of the lungthat are somehow related to some work-related or someoccupational exposure. And I’m gonna talk about three types of occupational lung diseases. And the first type ofoccupational lung disease, we’re gonna talk about iscalled asbestosis, asbestosis. And asbestosis is caused byasbestos exposure, right. And what fields does that occur in? Well, it can occur in– The exposure can occur in construction. So it can occur in construction. It can also, plumbers canbe exposed to asbestos. So it can be seen in plumbers. And finally, it can also beseen in shipyard workers, so people who work on theship or people in the navy, like that might be a clue to exposure to shipyard environment. Those are some of thefields in which you can be exposed to asbestos andwind up with asbestosis. And asbestosis is reallyimportant because it increases, it increases the risk of lung cancer, of lung cancer, primarily. And it also increasesthe risk of mesothelioma. So it increases the risk of lung cancer, and it increases the risk of mesothelioma. And I guess mesotheliomatends to earn more media recognition, but somethingthat’s really important to keep in mind, that it’sactually lung cancer that’s most likely to arise after exposure to asbestos rather than mesothelioma. So a person exposed toasbestos is more likely to do up lung cancer than mesothelioma. So the second occupational lungdisease I’m gonna talk about is silicosis or exposure to silica. What fields does this occur in? Well, silicosis can beseen in sandblasters. Sandblasters. And it can also be seen in silica minors. To be honest, I didn’t evenknow there was such a thing as silica minors untilI explored this further. But there is such athing as silica minors. And silicosis is really,really, important because it increases the risk of tuberculosis. It increases the risk of TB. And the mechanism by whichit does this is important, and it’s interesting. So I wanted to explorethat a little bit further. Let’s see, what you see inthe orange here are little tuberculous bacilli. Okay, so those are, that’s a TB.
And we know that TB ishandled by our body, right, by macrophages. So there are these big,white blood cells that will engulf the TB bacteria,that will engulf them, that will eat them all up,just like I’m trying to show the macrophages taking up the TB bacilli. So these are the macrophages, right, so the white blood cells thatare responsible for protecting our body against this bacteria. And what silica exposure doesis it inhibits the function of the macrophages so thatthe macrophages are no longer able to take up the TB. And so that predisposes aperson who’s been exposed to silica to developing TB infection. So the third type ofoccupational lung disease, I’d like to talk about issick, is sick building, Sick Building Syndrome. These are only three types ofoccupational lung diseases. I’d really like to pointthat out that I picked three important ones, but theseare not the only ones. So Sick Building Syndrome, where do you get exposedto Sick Building Syndrome?
Usually it’s seen when youhave AC or heating ventilation problems and also when peopleare exposed to different mold found in older buildingsor unkempt buildings. So these three types ofoccupational lung diseases, actually have a common threadthat runs through them. They have a common pathogenesis. I’m gonna scroll down just a touch. I’m gonna bring up backthis picture of the lung. And let’s say– For example, let’s say that weare inhaling these particles. These are particles of asbestos,called asbestos fibers. Or inhaling silica particles or molds in Sick Building Syndrome. So we inhale these particlesand they go and they deposit into the tissue of the lungs. So that’s what I’m showing over here. It’s being deposited intothe tissue of the lungs. And really importantly, we havewhite blood cells scattered all throughout the tissue of the lung. And these white blood cellswill take up any particles, any dust particles also,any silica, any asbestos, any molds, that maketheir way into the lung. And that’s what I’m trying to show. I’m trying to show the whiteblood cells sort of engulfing these bad particles thatcan damage the lung. So through the engulfing,through the function of these macrophages or white blood cells, they’re sort of engagingin battle in the lung. And by their engaging inbattle in the lung, it leads to a sort of environment ofinflammation in the lung. So because they’re tryingto destroy these particles, it leads to this environmentof inflammation in the lung. And that inflammation over the course of not days or weeks or months, but over the course of several years, leads to the development ofscarring and of fibrosis, so that’s really important. So over the course of many years, all this inflammationthat’s present through the continual inhalation ofthese particles will lead to fibrosis of the lung.
That fibrosis is what’sresponsible for the lung disease, for the lung manifestation. So difficulty breathing andall the things that happen in occupational lungdisease in these three cases is due to fibrosis of the lung. So in asbestosis, silicosis,and in Sick Building Syndrome, you end up with scarringand fibrosis of the lungs. So keep in mind that theseare only three types of the many, many, types ofoccupational lung diseases. And this is the mechanismby which they cause disease, eventually leading tofibrosis of the lungs.