Idiopathic pulmonary fibrosis Flashcards
What is interstitial lung disease?
An umbrella term for a large group of disorders of scarring (fibrosis) of the lungs. The scarring causes stiffness in the lungs which makes it difficult to breathe.
Some example of ILDs include:
- Idiopathic Pulmonary Fibrosis.
- Hypersensitivity Pneumonitis.
Define idiopathic pulmonary fibrosis.
A chronic, life-threatening disease that manifests over several years and is characterised by the formation of scar tissue within the lungs and progressive dyspnoea.
It is the most common interstitial lung disease among the idiopathic interstitial pneumonias → shortness of breath, diffuse pulmonary infiltrates on imaging, and varying degrees of inflammation, fibrosis, or both on lung biopsy.
Descirbe the epidemiology of IPF.
- 7.44 per 100,000 population in UK
- Median age of presentation is 70 years.
- Most people with IPF smoke or have a history of smoking. IPF often co-exists with COPD.
- Men> women
- Median survival = 2 to 5 years from the time of diagnosis
- IPF may show familial clusters (<5% of all cases; occurs at 55-60yr) but the genetic reason for this is not yet fully understood, as it does not occur in a predictable fashion.
Describe the risk factors for IPF.
- Smoking - especially >20 pack years.
- Occupational - for example, in people who work with silica, asbestos, heavy metals or mouldy foliage.
- Environmental - pigeon breeding and contaminated ventilation systems.
- Chronic viral infections e.g. hepatitis C and Epstein-Barr viruses.
- Gastro-oesophageal reflux disease with micro-aspiration.
- Male sex
- Older age
- Diabetes - insulin use
Descirbe the aetiology of IPF.
Aetiology and pathogenesis unknown.
Theory: Insult causes damage to alveolar epithelium, endothelium and BM → pro-inflammatory and pro-fibrotic response → macrophages, fibroblasts, and other inflammatory cells → dysregulated tissue repair → fibroblastic and myofibroblastic activity → progressive fibrosis
Can occur in association with other connective tissue disorders.
What are the presenting symptoms of idiopathic pulmonary fibrosis?
- SOB on exertion.
- Dry cough.
- Weight loss, fatigue, malasie
- Extrapulmonary features: arthralgia, muscle pains and skin rashes. OSA may be common.
-
O/E:
- Bibasal crackles of dry/Velcro quality
- Clubbing
- Tachypnoea,
- Cyanosis
- Signs of cor pulmonale and right heart failure in the later stages.
How do you diagnose IPF?
Clinical signs and symptoms +
- CT +/- lung biopsy - interstitial pneumonia shown; biopsy may not be needed if CT is diagnostic
- CXR
- CT - bilateral shadowing (small, irregular, ‘ground glass’ opacities later progresses to ‘honeycombing’)
- Spirometry - reduced diffusion capacity, restrictive pattern (normal or low FEV1/low FVC)
- Impaired gas exchange
- ANA positive in 30%, RF in 10%
What do you see on imaging of IPF?
CXR - basilar, peripheral, bilateral, asymmetrical, reticular opacities
CT - basilar- and subpleural-predominant areas of increased reticulation ground-glass opacification, honeycombing, and possible traction bronchiectasis or bronchiolectasis.
Below: CT image of idiopathic pulmonary fibrosis
Describe what is meant by restrictive lung disease.
Restricted lung expansion → reduced FEV1 and FVC (FVC decline is greater so FEV1/FVC ratio is higher than 80% of >0.8)
TLC 80% less than predicted.
Seen in: pneumoconiosis, fibrotic lung disease, hypersensitivity pneumonitis, ARDS, TB, sarcoidosis, pulmonary Langerhans’ cell histiocytosis, pectus carinatum/excavatum, obesity, pleural thickening.
When would it be appropriate to take a surgical lung biopsy/trans-bronchial biopsy when you suspect IPF? What are the differentials?
Better suited to rule out other diseases than to make a diagnosis.
Differentials include: sarcoidosis, interstitial pneumonia (non-specific), connective tissue disease-associated ILD, drug-related pulmonary fibrosis, asbestosis, hypersensitivity pneumonitis, Langerhans’ cell histiocytosis.
Which drugs may cause pulmonary fibrosis?
amiodarone, nitrofurantoin and bleomycin.
What is the management of IPF?
Stop smoking
Pulmonary rehabilitation
Supplemental oxygen
Antifibrotic e.g. pirfenidone or nintedanib
Lung transplant
What is the prognosis with IPF?
Poor
Average life expectancy is 3-4yrs
What is shown?
Chest X-ray shows sub-pleural reticular opacities that increase from the apex to the bases of the lungs
What is shown?
CT scan from a patient who presented with dyspnoea. Demonstrates honeycombing and traction bronchiectasis
The x-ray shows reitcular opacities predominantly in the bases.
