Restrictive Lung Diseases | Clinical Medicine

foreign what's up Ninja nerds in this video today we're going to be talking about restrictive lung disease this is for our clinical medicine section if you guys like it it makes sense please support us and you can do that by hitting that like button commenting down the comment section please subscribe also really urge you guys to go down the description box below there's a link to our website please consider becoming a member we have a lot of things to offer notes illustrations we're developing question Banks we're developing exam prep programs we even have merchandise there so please become a member and check out all the good stuff that you guys can help out in your actual academic career there all right let's start talking about restrictive lung diseases we talk about restricted lung diseases there's actually two phenotypes that we can look at one is the patient who has an intrinsic lung disease something is wrong with the lungs they have fibrosis there's injury there and then the extrinsic lung disease the lungs are healthy there's no fibrosis there's no lung injury there's something wrong with the chest wall or the muscles are really just jammed up for some reason and we'll talk about that a little bit our intrinsic lung diseases this is really one of those unfortunate things that there's so many causes of restrictive lung disease especially in the intrinsic category that it's a lot to digest and it's a lot to memorize so if you guys need to go back through this a couple times if you have to to really kind of go this get this stuck into the cerebral cortex first thing I like to classify them in this particular way I just think it helps me to organize it in my brain one is that there's certain drugs that can cause lung fibrosis you guys know what they are first one I want you to remember is going to be amiodarone so amiodarone is one of those antiarrhythmic so if you see a clinical history somewhere that suggests that the patient has afib or v-tac or something like that and they've been on amiodarone for a long time that can definitely do it also loves to attack the thyroid gland the other one is um bleomycin bleomycin is an anti kind of like neoplastic drugs if you seek some type of history of cancer and they've taken bleomycin that definitely can cause a lot of fibrosis as well the other one is two granulomatous diseases one is we don't really know the cause of we just know that they generate these kind of like nasty granulomas that kind of go and aggregate in the lungs especially near the higher lymph nodes you guys know what that one is sarcoidosis so sarcoidosis is a really really big one that I think is pretty common to kind of come up in this category of intrinsic lung diseases so definitely don't forget about this one especially in African-American individuals female of that type of gender this is a very common disease the next one that's a granulominus disease is hypersensitivity pneumonitis so with this one the thing that I want you guys to remember is this is usually going to be in some type of like farmer they've had some type of like bird droppings are they working on a farm and they develop features of interstitial lung disease that's one of the classic ones that I want you guys to think about as well the other one that's really really big and they'll definitely ask you about this on the exam is pneumoconiosis this is an exposure to particular types of dust usually inorganic and the couple of them that I want you guys to remember the first one is silicosis so with silicosis this is usually some person who works in sandblasting or they work in quarries this is a really really big one as well sometimes even mines but sandblasters Corey workers those are pretty common another one is asbestosis asbestosis will definitely also potentially come up somewhere in shape or form this one is usually a good hit because you can get a lot of things with lung cancer which we'll talk about but this one's usually in like people who work with insulation or ship builders the other one is going to be broliosis now with berylliosis the thing that I want you guys to remember about this one is this is usually in those who work with Ceramics Aerospace nuclear types of power plants that's what the people that you'll see this one in there's one last one that's probably the easiest one to remember but it's the Coal Miner's lung and I bet you'll never guess where these people work this is usually those who work in Coal Mines oh man I bet that came as a shock right so this is the big things to remember here for the pneumoconiosis so again sandblasters it's going to be Quarry workers insulators and shipbuilders Aerospace Ceramics nuclear kind of plants and then coal miners lungs and then again this is the people who work in Coal Mines all right the next one is auto antibodies so these are people that actually generate Auto antibodies that are systemic but they go and attack other tissues that happens to be the lungs this would include things like rheumatoid arthritis this would include things like systemic lupus erythromatosis another one that I would want you guys to remember is going to be what's called granulomatosis polyangiitis also known as wegeners um another one is called good pasture this one can also do it as well so good pasture syndrome which is a type of Auto antibody like the anti-gbm antibodies the last one which I think is probably the most likely one to remember and it's the easiest one thankfully is idiopathic causes so this is someone who developed something called idiopathic pulmonary fibrosis it's the nicest one to remember you want to know why because it's the one that we don't have any particular reason as to why it occurs but it is going to be by far one of the most common causes so idiopathic pulmonary fibrosis it has been associated with those who are of older age it has been associated with smoking but again we don't have a complete identifiable cause we just know that there is undesirable what fibrosis of the lungs so say that we have a patient Who develops this insane fibrosis let's represent without this pink kind of coloring here all of these patients develop some type of fibrosis of the lungs now when you cause fibrosis of the lung tissue this isn't just of the lung tissue this can be of the alveoli this can be of the bronchioles all of those tissues when you cause lung fibrosis which is the consequence of all of these particular scenarios that's the overarching theme is all of these particular types of etiologies all precipitate what they will all precipitate lung fibrosis if a patient experiences increasing lung fibrosis which we have here the problem that we'll ensue is two things one is the lungs will naturally want to assume the small size possible what's that called when the lungs I'm going to use this kind of like Arrow here the lungs will want to assume the small size possible that's called elastic recoil so there will be an increase in the elastic recoil of the lungs but in the same scenario whenever your lungs are super fibrous they lose the natural ability to stretch so then moving out this way is affected so they have a stimulus here and then an inhibition here and they have a decrease in what's called compliance or distension of the lungs the ability of the lungs to stretch any way you want to think about it the lungs will not stretch but they'll want to assume the small size possible if that occurs the overarching theme Here is that the lungs will be tiny and if the lungs are really fibrotic and they don't want to stretch and they want to recoil they'll assume the small size possible they won't stretch why is that a problem when a patient tries to take a deep breath in what's going to happen they're not going to be able to because the lungs want to be the smallest size possible and they don't want to stretch so what happens is this leads to decreasing lung expansion and if these lungs are tiny my friends they can't take in these big deep breaths what's that called when you can't take in a deep breath you can't generate good tidal volumes that's called hypoventilation and often what happens with these patients is they experience features of hypoventilation and one of the ways that we can say that which we'll get into when we get into the Diagnostics is they have very low lung volumes they have low tidal volumes vital capacities and inspiratory reserves volumes all of that stuff all that stuff is jacked up but again that's the big thing where their lungs want to be as Tiny as possible so all of the lungs will want to assume this small tiny size they'll want to be as small as possible and they will not want to expand let's come up to the next scenario here we have another patient who doesn't have any lung injury they have something that affects their chest wall but the chest wall is just as important for breathing as is the lung parenchyma itself so if patient has a chest wall deformity let's say that we have two scenarios here one is the patient has what's called obesity hypoventilation syndrome or the second one is they have a deformity let's say called kaifo scoliosis now in these two scenarios both of these are going to be unfortunate because what they're going to do is they're going to decrease chest wall expansion all right let's write that down here they will have and they'll cause chest wall dysfunction that will then this will cause decreased chest expansion so this problem here is going to be decreased ability of the chest to move out this way you want the chest to move out this way this will be inhibited in these particular diseases so they'll have decreased chest movement all right in this scenario the patient has neuromuscular dysfunction so now they have a deep decreased function of their actual muscles are the nerves that Supply the muscles and so because of that these patients actually can't generate good contractions so they decrease they have decreased chest wall contraction if they have decreased chest wall contraction again the overall concept is that they're not going to be able to take in a good deep breath so now what are the processes or diseases that you will have that can actually lead to this Pro this decreased chest wall contraction this is usually especially acutely this could be things like Guillain-Barre syndrome so I want you to remember Guillain-Barre syndrome another one could be Myasthenia gravis another one could be spinal cord injuries or ALS so you can write down like ALS would be a big one spinal cord disease spinal cord injury these are all things that are 100 percent going to cause decreased flow via the nerves to the actual muscles that are supposed to help you to take in deep breaths and generate good tidal volumes so it's either a spinal cord injury ALS myasthenia gravis or Guillain-Barre syndrome now in both of these scenarios these chest wall muscles won't contract to help me to bring my lungs outward so this is again inhibited Now watch how this kind of is the same concept the chest wall can't expand the lungs can't inflate in this scenario the lung just couldn't inflate because they were super fibrotic if the chest wall won't expand then they can't take the deep breath in so if we come down now what happens here they don't have good contractions of the chest wall they don't have good chest movement the chest will not expand and if there is decreased chest expansion then the lungs will not be able to properly inflate and if they cannot move this way if all of this is being inhibited all of this expansion is being inhibited then the patient won't be able to inflate their lungs properly they won't be able to ventilate what is that called hypoventilation so these patients will experience features of what's called hypoventilation all right so now both of these patients can have features of hypoventilation it's just the etiologies are different the pathophysiologies are different but now what I want to do is I want to take a patient who has a restrictive lung disease whether it is due to Intrinsic or extrinsic causes and talk about what are the clinical features or complications associated with these diseases all right my friend so the patient comes in they have restrictive lung disease whether it's intrinsic or extrinsic you've gone through that whole process of determining oh is it a long expansion problems that a chest expansion problem either way they're both hypoventilating right what's the complications of that over a long period of time one is respiratory failures it may be acute in times but it's more chronic respiratory failure so what do I mean here so there's two actual like mechanisms behind this one so one of them we already talked about that the patient is developing decreased lung or chest expansion so let's put both of that let's decrease lung or chest expansion again this is depending upon the underlying etiology if it's intrinsic lung disease or if it's due to some other type of process for example extrinsic lung diseases but they have decreased lung expansion or chest expansion when that occurs what do we know we develop hypoventilation so when you develop hypoventilation what really occurs here is the alveoli aren't getting an adequate amount of ventilation into the alveoli they're not getting a good amount of air that's coming in or coming out of the alveoli so they're getting alveolar hypoventilation so what do we expect here that the V is going to be reduced the ventilation will be reduced to this alveoli when ventilation is reduced to the alveoli what do we know about that well what we know is that this affects the gas exchange process and so this can contribute to less oxygen and CO2 moving across the alveoli here and so when blood moves through this pulmonary capillary but undergoes gas exchange what is going to come out with less oxygen maybe even potentially a increased CO2 but for right now we're going to have a reduction in oxygen and this is what we refer to as hypoxemia this is unfortunately very common chronically in patients who develop interstitial lung diseases all right one other concept which is really interesting so we have decreased lung chest expansion leading to hypoventilation that leads to under ventilation of the alveoli decreased gas exchange so this gas exchange process is impaired and then hypoxemia ensues the other mechanism which is even kind of more interesting here is that when you have lung fibrosis right so lung fibrosis let's actually write this one down so this would be more particular to the intrinsic lung diseases so if you experience lung fibrosis what this will do is is this will thicken the respiratory membrane so you develop a thick or we're going to abbreviate respiratory membrane what that's going to do is that's going to lead to decreased diffusion capacity so a decreased diffusion capacity we refer to so lung fibrosis causes thick respiratory membrane which we're going to talk about here is this pink thick layer around the alveoli and that decreases the diffusion capacity of gases across the actual alveoli into the capillary blood so if you have this very thick respiratory membrane you have to remember the equation that talks about diffusion of gases it's it's basically proportional to what well if you have a very kind of like uh decreased surface area that'll decrease your diffusion capacity and if you have a very thick respiratory membrane that'll decrease your diffusion capacity so they're inversely related and so what happens is gases don't move across this alveoli as easily and so this will become impaired and as a result when blood comes undergoes gas exchange they come out with hypoxemia this is called diffusion in compared diffusion capacity as the cause of these patients hypoxemia this is usually more common in exertional activities it's not a very common cause of acute respiratory failure all right so these are the ways that patients can experience hypoxemia and this can look a lot of different ways patients can have respiratory failure chronically and they may just have low O2 saturation or they may have other features so some of the other ways that these patients can present is maybe they present with an increased respiratory rate maybe they present with an increased work of breathing potentially or they just complain of dyspnea so again this is a big thing to watch out for core pulmonale is another unfortunate complication they can develop in restrictive lung diseases and patients who experience what we just talked about chronic hypoxemia so if they have impaired gas exchange because of these mechanisms here and they have very low O2 within the bloodstream which we call hypoxemia and this is chronic what will happen is the unfortunate event here is that this is a very potent vasoconstrictor it'll go to the pulmonary capillaries and I'm sorry pulmonary arterials cause the smooth muscle to just vasoconstrict like a son of a gun so unfortunately these patients will have what's called pulmonary vasoconstriction pulmonary vasoconstriction now when these bad boys clamp down so right this pulmonary vessel is going to clamp down as a result what does it do to the pulmonary vascular resistance now it goes up and so what happens is the vascular resistance in these pulmonary vessels is very very high so develop an increase in the pulmonary vascular resistance and then unfortunately the pressure is in the pulmonary vascular system go up and so they develop a very high pulmonary artery pressure some will say greater than 20 some will say greater than 25 I think that most consensus recently is greater than 20 millimeters of mercury but that's how patients develop things like pulmonary hypertension now when pulmonary artery pressures are high due to Chronic hypoxemia we say that this is what's a very specific term we say that this is class 3 or type 3 or group three pulmonary artery hypertension when this occurs what this does is this imagine here this this resistance is super high right now you have blood here within the right ventricle and you want to squeeze it out if the vascular resistance is super high here that means that the afterload is going to be high and it's going to be really hard to push blood here into the pulmonary arteries and so because of that that is impaired and so what results is if you can't get a good cardiac output outwise it starts backing up and it backs up into the Supreme cave or into the inferior vena cava because of why the central venous pressure the right heart pressures are going to be very high and when the right heart pressures are high via the CVP they back up and cause a lot of complications one is if it backs up via the superior vena cava it can lead to jugular venous distension so you'll have a big old plethoric and plumpy good old jugular vein that you can see here the other ways is it could plump downwards into the inferior vena cava and lead to a couple complications here one is it may cause swelling of the liver and potentially liver failure if chronic so this is called hepato megaly another complication is it can cause the portal venous pressures to become very high and if the portal venous pressures are high it can cause fluid leakage in the peritoneal capillaries into the peritoneal space and this can cause the patient to develop what's called ascites and lastly it can cause swelling of the lower extremities which we call pedaledema or lower extremity edema this is the classic features now of where pulmonary artery hypertension can then precipitate a patient developing features of what's called right heart failure when a patient develops right heart failure due to Chronic hypoxemia from underlying interstitial lung diseases or restrictive lung diseases that's called group 3 pulmonary artery hypertension and again group 3 or type 3 pulmonary hypertension over time can potentially stimulate especially if chronic the development of right heart failure which we classify by pedaledema ascites hepatomegaly jvd and again sometimes these patients may also present with dyspnea on exertion all right we come to the last son of a gun here this is a very specific one that I want you guys to remember associated with a very particular cause of intrinsic lung diseases and this is called asbestosis it's just an important one to remember asbestosis is one of those pneumoconiosis that are due to insulation workers or shipbuilders and what happens is is asbestos can do two things it can affect What's called the lower low bronchi all right so we can hit your lower lobe bronchi and cause dysplasia there all right and when it causes dysplasia it unfortunately can lead to cancer and we call this Broncho alveolar so we call this Broncho alveolar carcinoma so Bronco alveolar carcinoma this is one potential cause of cancer that we can see in asbestosis because it can stimulate lower lobe bronchi dysplasia so these patients can start developing potential cancer here that involve the lower lobes the other unfortunate event here is that it likes to attack the pleura and when it attacks the pleura it causes pleural dysplasia so it causes plural dysplasia and unfortunately that can lead to a very common cancer that we call to as mesothelioma that's why whenever you hear all those like commercials of have you ever been exposed to an insulation you know and you can have mesothelioma this is the kind of thing that they're talking about is again you're potentially stimulating pleural dysplasia which can cause mesothelioma which is a type of cancer that involves the pleura so that's a big thing to remember here so with restrictive lung disease I think the two important complications to be aware of is these two but then just to add on a little bit of an extra step here especially with pneumoconiosis think about asbestosis here all right especially if the patient has cancer findings as well but again we'll get into this more when we talk about lung cancer itself all right that covers the complications of restrictive lung diseases now let's go into the patient and talk about how do we diagnose them you have a patient who comes in with cough they come in with clubbing of the digits they come in with coarse by basil or crackles real quick what's the clubbing from the clubbing is from chronic hypoxemia it's not specific but it can sometimes be seen in a chronic hypoxemic disorders when a patient has these restrictive lung disease with the three C's then you say okay let me get a chest X-ray let's just see what I got here if it's intrinsic lung disease I'll be able to see this reticular nodular opacities so it's really really fine and small like like white dots all over the chest super suggestive somewhat of interstitial lung disease the next thing I can do is I could say okay let's get a better look at the lungs and really see if I can get something more specific so I'm going to get a high resolution CT I'm going to get a bunch of different slices and with that I see oh the upper lobes they got a lot of fibrosis up here well that's way suggestive of silicosis and coal miner's lung oh they got a lot of lower lobe fibrosis oh that's way more specific of asbestosis or inter uh the idiopathic pulmonary fibrosis oh they got pleural fibrosis as well that's definitely more suggestive of asbestos so if I see lower lobe plaques and pleural plaques I'm really thinking asbestosis but also don't forget about autoimmune loves to damage the actual pleura as well the next thing is if I see this lymphadenopathy lymphadenopathy in combination with lung fibrosis is really suggestive of sarcoidosis especially if it's bilateral Hyler lymphadenopathy that's super suggestive of sarcoid all right the last one is if I see honeycombing so you see this kind of like pattern right here if you ever eat the honeycomb cereal this is literally what it looks like this is super suggestive of inter idiopathic pulmonary fibrosis so if I see lower lobe and honeycombing I'm going to be really thinking about idiopathic pulmonary fibrosis if I say upper lobes I want you to think silicosis if I say lower lobes and plural plaques asbestos if I say bilateral lipidinopathy you think sarcoidosis those are the big things to remember is high yield all right my friends now if I have findings that suggest intrinsic lung disease I then want to prove is it obstructive or restrictive so rule out obstructive and rule in restrictive by doing pfts the PFT should tell me oh these patients are going to have all the classic findings their total on capacity residual volume FRC fec's low they should also have what else if I do their force spirometry their fev1 is going to be low their fev1 over FEC ratio is going to be normal that's definitely suggestive of restrictive all right so I definitely have a concept of restrictive and I may start being able to identify which one of these it is based upon the presence of where the fibrosis is occurring but let's take another step obtain the dlco because I really want to understand I already have an idea here if like there is lung disease present on the CT or the chest x-ray I can say it's intrinsic but if I obtain the dlco that's another test that I do with the pfts to prove it's intrinsic and not extrinsic because if the DLC is normal it's extrinsic and I think about chest wall dysfunction or I think about neuromuscular disease but if the dlco is normal it's intrinsic and then I got to start thinking about the causes is there definite history of pneumoconiosis so exposure we talked about silicosis asbestosis borreliosis coal miners if any of those things are likely present you can automatically say it's pry exposure rate or have they been on amiod or a bleomycin it's product exposure related if there's no exposures rule out autoimmune obtain your Ana obtain the RF obtain anchor and anti-gbn this will help you to really determine is there any good pastures is there any GPA or is any ra or SLE if that's positive you've got an autoimmune diagnosis if it's negative though then you got to say okay you still don't know what it is let's take the next step the next thing I would do is I get a Bronco alveolar lavage if I have a patient who has bilateral hylar lymphadenopathy and I get a bronchial lavage I'm going to test for a CD4 over cd8 count all we do is we take this bronc we go down we go into this area where there's some fibrosis and we take a sample of kind of fluid bronchial fluid when I test it and I get a CD4 over cd8 ratio that's really low that's suggestive of hypersensitivity pneumonitis but it's not necessary to have to do this oftentimes hypersensitivity pneumonitis is an exposure get them away from farming get them away from the pigeon droppings and usually they'll improve but if you don't find that then you can do this test and if it's low it's hypersensitivity if it's high they also have we'll talk about sarcoidosis in its own lecture but they have increasing level of Ace they have increasing calcium levels they have bilateral hylar lymphadenopathy and they have an increased CD4 of a CDA ratio from the Bal it's more suggestive of sarcoid if this doesn't tell me anything then I'm probably going to get to the point where I I definitely am pretty confident if I've ruled everything out I've gone through all of this it's idiopathic and it's idiopathic pulmonary fibrosis if I really wanted to guarantee the diagnosis I could obtain a biopsy but this is not necessary you can probably with confidence say I've ruled everything out it's likely ipf you don't have to obtain a biopsy unless you want the most definitive diagnosis all right my friends that's how we would diagnose this I know it's a doozy let's talk about treatment there's a lot of stuff here but it's not too bad I think the treatment approach is relatively straightforward you have to ask yourself the question is this exposure related is it silicosis asbestosis bariliosis coal miners or hypersensitivity pneumonitis is it amiodarone bleomycin related because if it is okay I just avoid the exposure so again drug enthused avoid the exposure don't take those drugs unless you absolutely have to pneumoconiosis silicos asbestosiberiosis avoid the exposure hypersensitivity avoid the exposure however sometimes in hypersensitive pneumonitis they may not improve with remover of the removal of the exposure so sometimes you may need to try corticosteroids so let's say that if you don't think that it's exposure related or it doesn't improve with avoidance of the exposure trichorticosteroids because you're probably at this point thinking that this patient probably has sarcoidosis or idiopathic pulmonary fibrosis or they may even have an autoimmune cause if that is the case and you treat them with cardio steroids look to see if they improve if they improve usually that sarcoidosis or an autoimmune cause but if they don't continue to improve then usually what happens is you're probably thinking that dissipation probably has ipf and usually ipf is refractory to corticosteroids it's refractory to removal of the exposure and oftentimes for these patients you need to use anti-fibrotic agents like perphenidone or an antetonab and these are going to help to try to slow the progression of the disease all right and that's generally only going to be good enough to bridge these patients to a lung transplant okay so again find out exposure if there is avoided they should resolve if there's no exposure or they didn't improve with removal of the exposure consider is it sarcoid is it ipf or could it even be autoimmune treat them with steroids if it improves it's probably granulomatous or autoimmune if it fails to resolve it's probably ipf you'll probably have to do antiviric agents and get them a lung transplant all right last thing is if it is an extrinsic lung disease it's all about treating the cause so usually the biggest one that you can easily treat is obesity and that's generally going to be weight loss all right my friends that covers restrictive lung diseases I hope it made sense I hope that you guys enjoyed it and as always until next time foreign [Music] foreign [Music]