Occupational asthma and mesothelioma

- So occupational lung diseases are diseases of the lung that occur in response to some occupational or some work-related exposure. And at least in the developed world, the most common type of occupational lung disease is occupational, occupational, occupational asthma. So the most common type of occupational lung disease is occupational asthma. And you've probably heard of plain old regular asthma before but what distinguishes occupational asthma from regular old asthma is firstly, that occupational asthma is something that develops in adulthood. So it's a type of adult onset asthma. And secondly, occupational asthma occurs in response to some trigger that's found at work. So these patients will often experience signs and symptoms of asthma when they're at work, when they're exposed to this trigger at work. But when they come home, within a few hours of coming home, these symptoms will resolve on their own. And on days that they don't go into work, such as let's say the weekend, they don't experience these signs and symptoms of asthma. So here's a lung, okay. And let's say I was to take a cross-section of one of these airways like that and I was to look at that head on, so that this is my eye over here, what I would see would be something like this. I'd see the wall of the airway. This is the wall of the airway end. On the inside, this is the inner lining or-- Actually, that's not really good. So on the inside what I'd see is the inner lining of the airway. So that this hole in the center is a lumen through which the air actually travels, so this white arrow that I'm drawing is the air traveling through lumen of the airway. So what happens in occupational asthma is in response to some work-related trigger, some work-related trigger, a couple of changes occur to this airway. So firstly what happens to the airway is that it becomes smaller. So you can see this airway is smaller than it normally is. And secondly, you see that-- Secondly, you see that the lumen of the airway becomes smaller as well. And just looking at this very plain and simplistic diagram, you can see that trying to breathe through this airway is much more difficult than trying to breathe through a normal airway and this is what accounts for the symptoms of asthma. So I guess what's left to explore is what are these work-related triggers that I'm talking about. And actually, there have been greater than 350 described causes of occupational asthma. And at least in the United States, the most common cause, one of the most common causes is different types of flours. So that bakers are at an increased risk. And also different types of isocyanates. And isocyanates are these molecules that different industry workers, such as plumbers, such as plumbers and those who work with roofing and painters can often times become exposed to and also insulators can become exposed, too. And something that is really important to keep in mind, is that even though there are 350 identified causes, not everyone exposed to one of these causes is going to develop occupational asthma. So occupational asthma, most common type of occupational lung disease. Now let's move on to another type of occupational lung disease and that is-- Let me get that squared away. And that is mesothelioma, so meso, meso, thelioma. Mesothelioma. And I'm sure you've heard of mesothelioma before, because it's hard to watch even a day of TV without encountering one of those ads about mesothelioma. And how you or a loved one with mesothelioma are entitled to compensation. So what is mesothelioma? Well, first, let's explore the linings of the lungs. So in pink over here, you see the visceral pleura. So this is the lining of the lung that's directly adjacent to the lung, closest to the lung. And then what you see in orange over here, is the parietal pleura, the parietal pleura. So the parietal pleura is the lining of the lung, that's adjacent to the chest wall, so further away from the lung. Now the pleura or the lining of the lung, is made up of cells called mesothelial, mesothelial cells. And mesothelial cells have this really important function. They secrete this fluid that comes in between these two layers of the pleura and this fluid is really important because it reduces the friction between the two layers of the pleura. And mesothelioma is a cancer of mesothelial cells. And the reason why we consider it an occupational lung disease is because mesothelioma is related to asbestos exposure. It's related to asbestos exposure. And asbestos exposure occurs with many types of occupations such as painters. Painters can be exposed to asbestos, as can shipyard workers. Shipyard, shipyard workers, and also those in plumbing. So plumbers can also become exposed to asbestos. And something, unfortunately, to keep in mind about mesothelioma is that, unfortunately, mesothelioma has a very high associated mortality, a very high associated mortality. And so those are two of the, two types of occupational lung diseases and now we'll consider some other types.