Interstitial Lung Disease (ILD) - Classification, pathophysiology, signs and symptoms

interstitial lung disease also known as diffuse parenchymal lung disease are a group of disorders based on similar clinical radiographic physiologic and pathologic changes when people think about interstitial lung disease they think about fibrosis restriction in the lungs and there are many many causes of interstitial lung disease so interstitial lung disease or diffuse parenchymal lung disease is more of an umbrella term interstitial means the interstitium which is where the disease process often begins the interstitium is between the alveoli and capillaries of the lung here interstitial fibroblasts produce lots of products such as collagen and they proliferate producing more collagen and extracellular matrix substances these interstitial changes is what causes the restrictive pattern however in reality the disease affects more than the interstitium it affects the alveolar walls and often the related small airways and distal pulmonary vasculature and so diffuse parenchyma lung disease is more appropriate name of the disease rather than interstitial lung disease and again these interstitial changes causes an abnormality in gas exchange so you have an impairment in gas exchange between oxygen and carbon dioxide like other lung diseases these disorders present primarily with shortness of breath usually chronic over weeks to months without response to initial treatment of puffers it's associated with a non-productive cough if there's clinical suspicion of diffuse parenchyma lung disease they should undergo full pulmonary function test you want to identify a restrictive lung disease which is identified by a reduced total lung capacity and vital capacity you also want to check the dlco which would be low the dlco is the diffusing capacity of the lung for carbon monoxide it measures the ability of the lungs to transfer gas from inhaled air to the red blood cells in pulmonary capillaries a low dlco combined with reduced lung volumes suggests diffuse parenchyma lung disease a low dlco because gas is unable to transfer through the diseased alveoli interstitium and capillaries a normal dlco associated with low lung volumes is consistent with an extra pulmonary cause of restriction extrapulmonary causes of restriction means something outside the lung causing restriction of the lungs so restricting the lungs to expand and this includes obesity pleural effusion or pleural thickening neuromuscular weakness or kyphosis as well as many other causes a normal chest radiograph or chest x-ray does not rule out diffuse parenchymal lung disease the diagnosis of diffuse parenchymal lung disease can often be made based on high resolution ct without a lung biopsy so high res ct of the chest is gold standard you can say as mentioned diffuse parenchyma lung disease is an umbrella term because there's so many causes but the hallmark is the same you know you have the restrictive pattern with the reduced dlc the diffuse parenchyma lung disease are divided into those that are associated with a known cause of diffuse parenchyma lung disease or unknown cause of diffuse parenchyma lung disease or weird and wonderful rare causes so let's look at each of these in a bit more detail so known causes of diffuse parenchyma lung disease include drug induced smoking related radiation induced interstitial changes chronic aspiration secondary from let's just say gastroesophageal reflux pneumoconiosis which is like workers lung connective tissue disease including you know sle rheumatoid arthritis scleroderma hypersensitivity pneumonitis which is essentially a response to an allergen so it's a hypersensitivity reaction then you have the unknown causes of diffuse parenchymal lung disease and this includes idiopathic interstitial pneumonia which comprises of three main ones idiopathic pulmonary fibrosis which is a classic honeycomb appearance on ct chest acute interstitial pneumonia and cryptogenic organizing pneumonia which looks like just pneumonia in both lungs patchy all throughout uh subplural then you have sarcoidosis which can present as a diffuse parenchyma lung disease as in a late stage and this is the classic mediastinal lymphadenopathy finally you have the rare causes of diffuse parenchymal lung disease with well-defined features this include lymphangioleomyoma esotomophilic pneumonia pulmonary alveolar proteinosis pulmonary langerhan cell histocytosis or histiocytosis x and there are many other types of diffuse parenchyma lung disease which i have not mentioned but these are the main ones i hope to create videos on the main diffuse parenchyma lung disease soon some high yield points to remember when approaching diffuse parenchyma lung disease or interstitial lung disease or any other lung disease for that matter is to consider which areas of the lungs these disease affects because some of these lung diseases affect having upper low predominance and other diseases have a lower low predominant disease so let's look at upper lobe predominant disease with this you can remember the different causes by the acronym breasts so b is for beryllosis which is a type of pneumoconiosis r is for radiation fibrosis e is for econophilic pneumonia as well as hypersensitivity pneumonia which have essentials a is for allergic bronchopulmonary aspergillosis as well as ankylosing spondylitis which is a type of rheumatic connective tissue disease s is for sarcoidosis t is for tuberculosis remember sarcoidosis is typically mediastinal but it also has upper low predominance s is for silicosis and again this holds true for majority of pneumoconiosis that they have upper low predominance interestingly they also present with small nodules typically in the upper lobes for lower low predominant disease you can remember the different causes by the acronym aids so a is for asbestosis i is for idiopathic pulmonary fibrosis which is the classic honeycomb changes on ct chest d is for drug induced fibrosis and there's three to remember amiodarone nitropharyntoin and methotrexate s is for scleroderma and other connective tissue disease remember that ankylosing spondylitis is the only one of the rheumatic diseases that typically affects the upper lobes upper zones of the lungs so breasts for upper low predominant disease and aids for lower low predominant disease the clinical manifestation of diffuse parenchymal lung disease is worsening dyspnea with associated usually non-productive cough they may have features of connective tissue disease so features of scleroderma systemic lupus arithmetosis or rheumatic rheumatoid arthritis it's important to also know the occupational history as well as exposure history which can help identify potential causes of cold workers lung or other pneumoconiosis as well as exposure to birds and pets which may help diagnose hypersensitivity pneumonitis which is the allergic response medication history is also important such as amiodarone causing interstitial lung disease on examination lung sounds are variable it can be normal you could have a wheeze there can be you can have velcro inspiratory crackles which are patho mnemonic for classic idiopathic pulmonary fibrosis usually with diffuse parenchyma lung disease patients develop some form of pulmonary hypertension and so they can have features of right heart strain or heart failure and this typically represents severe disease you can imagine a fibrosed lung this will increase pressure in the pulmonary capillaries which means it will increase pressure in the pulmonary arteries which will lead to increased pressure on the right side of the heart so right heart strain and this is really what pulmonary hypertension is so features of pulmonary hypertension and right heart failure include a raised jvp peripheral edema a loud p2 as well as an s3 heart sound some diffuse parenchyma lung disease have features of clubbing namely idiopathic pulmonary fibrosis however clubbing is not specific for diffuse parenchyma lung disease other causes of clubbing include cystic fibrosis cyanotic heart disease cancer of the lungs and pleura as well as colitis the inflammatory bowel disease patients may have borderline normal pulse oximetry at rest but on ambulation a four percent drop is consistent with really a diffusion limitation finally the six minute walk test is a useful test to assess functional status in patients with diffuse parenchyma lung disease and to check response to any treatment so you can do the six minute walk test again after treatment to check if they've improved thank you for watching i hope you enjoyed this video on an overview of diffuse parenchyma lung disease um there'll be some links to watch the specific causes of diffuse para chromologists in more detail thank you

Channel: Armando Hasudungan

Views: 160,686

Keywords: Interstitial Lung disease pathophysiology, Diffuse parenchymal lung disease pathophysiology, diffuse parenchymal lung disease types, ILD types, Interstitial lung disease classification, ILD vs obstructive lung disease, interstitial lung disease treatment, interstitial lung disease osmosis, interstitial lung fibrosis, interstitial lung disease ILD, restrictive vs obstructive lung disease, interstitial lung disease symptoms, interstitial lung disease vs COPD

Id: le9KH4Wxm74

Length: 11min 40sec (700 seconds)

Published: Sun Jan 17 2021