Expansion
CHARTS for the upper zones, STAIR for the lower
Expansion
CHARTS for upper zone fibrosis:
- C - Coal worker’s pneumoconiosis, Cystic fibrosis
- H - Histiocytosis, Hypersensitivity pneumonitis
- A - Ankylosing spondylitis, Allergic bronchopulmonary aspergillosis
- R - Radiation
- T - Tuberculosis
- S - Sarcoidosis, Silicosis
STAIR for lower zone fibrosis:
- S - Scleroderma and connective tissue disease
- T - Toxins and drugs: amiodarone, methotrexate, bleomycin, nitrofurantoin, busulfan
- A - Asbestosis
- I - Idiopathic pulmonary fibrosis
- R - Rheumatoid arthritis
“Asbestos and idiopathic go to the bottom.”
Idiopathic pulmonary fibrosis is the commonest: over 60, progressive breathlessness, dry cough, fine bibasal end-inspiratory crackles and clubbing, with a usual interstitial pneumonia pattern on CT showing honeycombing and traction bronchiectasis. It has a poor prognosis and is treated with antifibrotics (pirfenidone, nintedanib), not with steroids.
Lung function shows a restrictive pattern with a reduced transfer factor: FEV1 and FVC both reduced with a normal or raised FEV1/FVC ratio, low TLCO and low KCO, which is what distinguishes intrapulmonary from extrapulmonary restriction.