Interstitial lung diseases Flashcards
What does this chest x-ray show?
Interstitial shadowing
What are the features of interstitial shadowing on a chest x-ray?
- Reticular i.e. linear, lace-like pattern
- “too many lung markings”
- May be focal or diffuse
What is the interstitium?
Refers to supporting structures of the lung
Includes:
- alveolar endothelium
- capillary endothelium
- basement membrane
- connective tissue
What can thicken the interstitium?
In disease it can be thickened by:
- Fluid
- Cells
Fibrosis
Where does interstitial lung disease affect?
What does the second image show?
Thickened septa
What is the extraceullar matrix?
3D fibre mesh filled with macromolecules e.g. collagen, elastin
What are the functions of the extracellular matrix?
- Tensile strength/elasticity
- Low resistance for effective gas exchange
- Tissue repair/modelling
What does aberrant wound healing cause in fibrosis?
In fibrosis, aberrant wound healing leads to excessive deposition in the interstitium
What are the types of interstitial lung disease?
ENVIRONMENTAL EXPOSURE
◦Occupational lung disease
- Silicosis (silica exposure)
- Coal miners lung (coal dust exposure)
- Asbestosis (asbestos exposure)
◦Hypersensitivity pneumonitis - mold and bird proteins are common causes
IDIOPATHIC (unknown cause)
Idiopathic pulmonary fibrosis is the prototypical ILD
SYSTEMIC INFLAMMATORY DISEASES
Connective tissue disease-ILD
Sarcoidosis
What is the simplified classification of interstitial lung disease?
What does this chest x-ray show?
◦Small lungs
◦Increased reticular shadowing
What do these lung function tests indicate?
◦FEV1 56%
◦FVC 50%
◦FEV1/FVC 86%
◦TLCO 50%
◦FEV1 56%
◦FVC 50%
◦FEV1/FVC 86%
= restrictive
◦TLCO 50%
= impaired gas transfer
Whats the diagnosis?
◦Older man
◦Chronic history of dyspnoea
◦Radiological evidence of ILD
◦Restrictive lung function with impaired gas transfer
◦No identifiable cause
◦Dx = Idiopathic Pulmonary Fibrosis
What are the symptoms of idiopathic pulmonary fibrosis?
Symptoms and clinical signs of IPF often appear gradually and include:
◦Slowly progressive exertional dyspnoea
◦Non-productive cough
◦Dry, inspiratory bibasal “Velcro®” crackles
◦+/- Clubbing of fingers
◦Abnormal pulmonary function test results
◦restriction and impaired gas exchange
What is the HRCT pattern?
To diagnose idiopathic pulmonary fibrosis on CT -
Basal distribution
Subpleural
Traction bronchiectasis
Honeycombing
If present on CT – no biopsy needed
What disease is this?
Idiopathic pulmonary fibrosis
Who is more likley to have idiopathic pulmonary fibrosis?
◦is a disease of older age (median age 66yrs)
◦is more common in men (2:1)
◦is more common in smokers (60%)
What are the clinical features of idiopathic pulmonary fibrosis?
◦is of unknown cause
◦causes progressive, irreversible fibrosis and is fatal
◦is limited to the lungs (unlike other ILDs eg sarcoidosis)
◦Affects lower and peripheral lung
◦Minimal inflammation – no role for steroids
Is prevelance of IPF in the UK increasing or decreasing?
Increasing
What is the prognosis for IPF patients?
◦median survival is 3 years from diagnosis
◦BUT 20% still alive at 5 years
◦no reliable way to predict prognosis
◦patients therefore live with considerable uncertainty
How is IPF managaed?
oAssess suitability for anti-fibrotic drugs
- Pirfenidone or Nintedanib
- Can only be prescribed by specialist centres
- Aim is to slow rate of disease progression
- Criteria
- diagnosis of IPF
- FVC 50-80% predicted
oAssess suitability for Lung transplant
- Age <65
- No significant comorbidities
oOffer best supportive care to all
- Treat co-morbidities
- Palliate symptoms
- Refer to palliative care
Why are anti-fibrotic drugs often poorely tolerated?
Often poorly tolerated – weight loss, GI upset, photosensitivity
Whats the diagnosis?
- 24yo man
- Rapidly progressive SOB and cough over 3 months, struggling with ADLs
- No response to antibiotics or inhalers
- PMHx: depression, on Sertraline
- Smoker 20/day
- Unemployed
- Unable to complete sentences, bilateral crackles, sats 89%
- No rheumatological symptoms, CTD screening bloods normal
Sertraline-induced ILD
Whats the diagnosis?
◦63yo lady
◦Admitted with 10/52 history dry cough and SOB
◦Bilateral crackles all zones, sats 85%
◦
◦No PMHx or regular meds
◦Non smoker
◦No occupational exposures
◦Kept budgies for several years
Hypersensitivity Pneumonitispe
What is Hypersensitivity Pneumonitis?
- Diffuse inflammation of parenchyma in response to inhaled antigen
- Tends to involve upper lobes
What are the antigens that cause Hypersensitivity Pneumonitis?
- Bird-fanciers (bird droppings)
- Farmers lung (thermophilic fungi)
- Aspergillus (ubiquitous fungus)
- Can be anything…
- Antigen unknown in 50%