T4 - Restrictive lung disease Flashcards
what is restriction defined by?
decrease in lung volume which prevents the lung expanding
by what three mechanisms can normal interstitial structures be altered?
fluid accumulation, inflammation and fibrosis
what is the defining feature of RLD?
reduced residual volume
give three examples of interstitial lung disease and what do these affect?
pneumoconioses, hypersensitive pneumonitis and idiopathic pulmonary fibrosis
- affects alveolar filing processes
what does interstitial lung disease result in?
pulmonary oedema, haemorrhage, infection and cancer
what happens to the intrarlobular septa in ILD and what does this cause?
septa become thick and this causes a diffusion limitation
where are intralobular septa found?
surrounding the alveoli
where are interlobular septa found and what is within them?
found outlining the secondary lobules and lymphatics and veins are found within then
when can interlobular septa be visualised on CT?
only when thickened
exposure to what two things found in the environment causes hypersensitivity pneumonitis?
mould and bird proteins
give three types of pneumoconioses
coal miners lung, silicosis, asbestosis
how is interstitial lung disease categorised?
by cause
what are four causes of ILD?
inorganic exposure (asbestos, dust, silica), organic exposure (bird, hay, mould, mycobacteria), smoking or connective tissue disease (RA)
what do problems associated with coal miners lung start and how long do they last?
begin as soon as you inhale the dust and last forever
what does coal miners lung result in?
massive fibrosis and inflammation due to dust particles being engulfed by MPs and laying down of tough non elastic collagen
what is created with MPs destroy dust particles from coal and what can this progress to?
fibrotic ring around it which can progress to massive fibrosis
does exposure to asbestos mean you will get disease?
no
what are two markers of significant asbestos exposure on imaging?
pleural plaques and honeycomb cysts (fine lines on CT)
how does mesothelioma form?
asbestos is taken up by dendritic ells and deposited in the pleural space (which is lined with mesothelial cells) that can undergo malignant transformation
what are three characteristics of silica and dust exposure in the lung?
1) nodular disease
2) tissue pulled into the lungs so they can’t expand
3) massive fibrosis
what type of septa are inflammed in hypersensitive pneumonitis?
intralobular septa (become thick)
what forms when mould or bird dust are inhaled?
body sees it as infection and forms a granuloma in small terminal bronchioles