Restrictive Lung Diseases Flashcards
What is the main physiologic problem in restrictive lung diseases? How does it compare with obstructive?
In restrictive lung diseases there is a problem with filling the lung, as opposed to emptying the lung (obstructive).
What lab values classify restrictive lung diseases and what do they mean?
Since there is a problem with filling the lung, TLC (total lung capacity, which is the amount of total air the lungs can take in) will decrease. Similarly, FVC (Forced vital capacity, the amount of air you breathe out after breathing in all the way) will also decrease because you’re taking in less air so you will breathe out less air. FEV (forced expiratory volume, amount of air breathed out in the 1st second after lungs are full) will also decrease due to same reason. FEV1/FVC ratio will be increased to over 80%.
How does the FEV1/FVC ratio compare with restrictive lung disease patients? What’s normal?
It will be greater than 80%. Normal FEV1 is 4L, FVC should be about 5, thus the ratio should be 80% or less.
Why does FEV1 not decrease in proportion to FVC if both are decreasing?
There is fibrosis associated with restrictive lung diseases so the fibrosis actually helps the elastic recoil in squeezing out the air. However, since there is some sort of restriction to the lungs expanding the lungs CANNOT expand and thus cannot fill, so it will drop more in value relative to FEV1.
What is the most common cause of restrictive lung diseases?
Disease of the interstitum, particularly the fibrosis of the interstitum. This first of all prevents efficient gas exchange, and prevents filling of the lung (because its harder to open an fibrosed airway). Can also occur due to restriction of lungs to open mechanically, i.e. obesity.
What is Idiopathic Pulmonary Fibrosis (IPF)?
Fibrosis of the lung interstitium. Walls of the alveolar air sacs become extremely thick because of this.
Although idiopathic in etiology, what seems to be the pathophys of IPF?
Chronic and cyclical lung injury due to something, that results in damaged pneumocytes. These pneumocytes release TGF-beta in order to heal, which includes fibrosis. Drugs and radiation can also cause this.
Which two drugs can cause IPF?
Bleomycin and Amiodarone.
Where does the fibrosis begin in IPF? What is the term if the fibrosis spreads diffusely to all over the lung?
In the sub-pleural regions and eventually can spread to the entire lung, which is called “honey comb lung.”
How does IPF present?
Shortness of breath that gets progressively worse and cough. CT will reveal fibrosis.
How is IPF treated?
Requires lung transplantation.
What is “pneumoconiosis?”
Interstitial fibrosis induced by exposure to small fibrogenic particles that are found in various occupation.
What is the general theory behind pneumoconiosis?
If the particles were big it would’ve been filtered out by the lung cilia and mucous but if they are small, they will accumulate in areas where only the macrophages can get to, leading to the macrophages reacting via fibrosis.
What are the 4 types of pneumoconiosis?
Coal worker’s pneumoconiosis, Silicosis, Berylliosis, Asbestosis.
What is “Caplan syndrome?”
Coal worker’s pneumoconiosis + RA = Caplan syndrome.
What is “Coal worker’s lung,” how does it come about and how does it present?
Coal workers get exposed to Carbon dust, often in excess. This leads to diffuse fibrosis all over the lung resulting in a shrunk “black lung.”
What is “Anthracosis?”
Mild carbon exposure induced blackening of the lung due to macrophages filled with carbon, seen in people living in cities and exposed to pollutants. Also occurs in hilar lymph nodes.
What is “Silicosis?” Who gets it?
Sand blasters get it. and this is exposure to silica.
What happens when silica enters the macrophages? What is the very significant clinical ramification of this and how does this disease present?
It prevents the phagolysosomes to form and thus it is the ONLY PNEUMOCONIOSIS THAT HAS AN INCREASED RISK OF TB INFECTIONS. Fibrotic nodules in the upper lobes of the lungs (where TB would present).
What is Berylliosis, who gets it and how does it present?
This is pneumoconiosis due to beryllium exposure, seen in children and those working in aerospace industry. Presents VERY SIMILAR TO SARCOIDOSIS, because it causes non caseating granulomas in the lung, hilar lymph nodes and systemic organs, just like sarcoidosis would.
What is Berylliosis pneumocosis associated with?
Increased risk of lung cancer.
What is asbestosis pneumoconiosis?
Seen in construction workers, plummers and shipyard workers.
What are the pathological findings of asbestosis?
Fibrosis in the lung or pleura (plaques), cancer of the lung or pleura.
What kinds of cancer are asbestos exposure associated with and which is more common?
Associated with lung cancer (most commonly) or cancer of the pleura, aka mesothelioma (less common).
How can we confirm the presence of asbestos in patients?
Look for “Asbestos bodies” which are long, thin rod shaped particles with brown beads (which are iron).
What is the general pathology of sarcoidosis?
Noncaseating granulomas form in the interstitium of the lung, resulting in restricted filling of the lung. These granulomas are due to some systemic disease and seen in multiple organs, particularly the lung and hilar lymph nodes.
Who classically presents with sarcoidosis?
African American women.
What is the etiology of sarcoidosis?
Unknown but might be CD4 T cell response to unknown antigen.
What is the defining cell of a granuloma?
An epithelioloid histocyte. ALSO will have some giant cells as characteristic cells.
What does noncaseating mean in the noncaseating granuloma?
All cells are alive, no necrosis.
What is a characteristic cell finding in sarcoidosis?
“Asteroid Bodies” which is a conglomeration of giant cells.
Besides the lungs where else can sarcoidosis present?
Uvea (uveitis), skin (cutaneous nodules or erethema nodosum), salivary or lacrimal glands (MIMICS SJOGREN’S SYNDROME!) and any other tissue.
Why does sarcoidosis patients also present with hyper Ca?
The noncaseating granulomas has 1 alpha hydroxylase activity and can activate vitamin D. Any disease that have a lot of noncaseating granulomas will have excess 1 alpha hydroxylase activity leading to hyper Ca.
How do sarcoidosis pt’s present?
Dyspnea/cough, elevated serum ACE, hypercalcemia. Tx is steroids but can resolve on its own without tx.
What is hypersensitivity pneumonitis?
Granulomatous reaction in response to some inhaled organic compound like bird feces (Pigeon Breeder’s lung). Chronic exposure will lead to interstitial fibrosis. Since it is a HS reaction, there will be eosinophils present as well.
How are patients presenting with HS pneumonitis?
Fever, cough and dyspnea (initially) hours after exposure, but resolves when the offending substance is removed.
