Idiopathic Pulmonary Fibrosis
Related Subjects:
|Idiopathic Pulmonary Fibrosis
|Diffuse Parenchymal Lung disease
|Asbestos Related Lung disease
|Sarcoidosis
|Coal Worker's Pneumoconiosis
|Silicosis
|Farmer's Lung
|Cryptogenic Organising Pneumonia (COP-BOOP)
|Extrinsic Allergic alveolitis (Hypersensitivity)
|Byssinosis
|Pneumoconiosis
|Cor Pulmonale
|Chest X Ray Interpretation
๐ซ Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive interstitial lung disease of unknown cause.
Median survival is ~2โ5 years. Always consider referral to an ILD MDT (multidisciplinary team).
๐ About
- Previously termed Cryptogenic Fibrosing Alveolitis.
- Diffuse parenchymal lung disease with relentless fibrosis of alveoli & interstitium โ โhoneycomb lung.โ
- Rarely, an acute presentation (HammanโRich syndrome).
๐ Epidemiology
- Risk factors: ๐ฌ smoking, exposure to wood/metal dust, some viral triggers.
- More common in men, usually >50 yrs.
- Strong association with โ risk of lung cancer.
โ๏ธ Pathophysiology
- Genetic predisposition: telomerase mutations, MUC5B gene variant.
- Repeated alveolar epithelial injury โ abnormal repair โ fibrosis.
- Fibrogenic mediators: TNF, TGF-ฮฒ, PDGF, IGF-1, endothelin-1.
- Excess fibroblast proliferation & collagen โ stiff, non-compliant lungs.
๐ฌ Histology
- Usual Interstitial Pneumonia (UIP): Patchy fibrosis, architectural distortion, honeycomb cysts, minimal inflammation.
- Desquamative Interstitial Pneumonia (DIP): More inflammatory, alveolar macrophages, โground glassโ on HRCT, better steroid response.
๐ฉบ Clinical Features
- Progressive exertional dyspnoea and dry cough over months.
- Velcro-like inspiratory crackles at bases.
- Finger clubbing in ~50% (similar to asbestosis).
- Weight loss, fatigue, โ exercise tolerance.
- Haemoptysis = ๐ฉ consider malignancy or PE.
- Late disease โ pulmonary hypertension + cor pulmonale.
๐ Differentials
- Occupational lung disease: ๐ชจ asbestosis, silicosis.
- Connective tissue diseases: Scleroderma, RA, SLE.
- Sarcoidosis, hypersensitivity pneumonitis.
- Lymphangitis carcinomatosis, miliary TB, fungal infections.
- Drug-induced (e.g., busulfan, methotrexate, amiodarone, nitrofurantoin).
๐งช Investigations
- PFTs: Restrictive pattern, โ FVC, โ TLC, โ DLCO.
- ABG: Resting/exercise hypoxaemia โ Type 1 resp failure.
- Autoantibodies: ANA, RF positive in up to 30%.
- CXR: Bilateral basal reticular shadowing.
- HRCT:
- UIP โ subpleural honeycombing, traction bronchiectasis.
- DIP โ ground-glass, better steroid response.
- Lung Biopsy: Consider if HRCT not diagnostic (risk of complications).
โ ๏ธ Complications
- Progressive respiratory failure.
- Pulmonary hypertension & cor pulmonale.
- Recurrent chest infections.
- โ Risk of lung cancer.
- Death usually from respiratory failure.
๐ Prognostic Indicators
- Better: ๐ฉโโ๏ธ younger females, ground-glass on HRCT, DIP histology, steroid response.
- Poorer: Honeycombing, older age, male sex, persistent hypoxia.
๐ Management
- Antifibrotics: Pirfenidone & Nintedanib (NICE-approved if FVC 50โ80% predicted).
- Lifestyle: ๐ญ stop smoking, optimise nutrition, graded exercise.
- Symptom control: PPI for reflux, cough suppressants, pulmonary rehab.
- Vaccination: Pneumococcal + annual flu vaccine.
- Antibiotics: Treat infections promptly.
- Lung Transplant: Consider in suitable patients (single or double lung).
- Palliation: Oxygen therapy, opioids for dyspnoea, early palliative care input.
๐ References
3 Clinical Cases โ Idiopathic Pulmonary Fibrosis (IPF) ๐ซ๏ธ๐ซ
- Case 1 โ Progressive breathlessness ๐ถโโ๏ธ: A 68-year-old ex-smoker presents with 12 months of progressive exertional dyspnoea and a dry cough. Examination: fine โVelcroโ crackles at the lung bases and digital clubbing. HRCT: basal, subpleural reticular opacities with honeycombing. Teaching: Classic presentation of IPF. Diagnosis relies on HRCT pattern (usual interstitial pneumonia, UIP). Other causes of fibrosis must be excluded. Prognosis is poor, with median survival 3โ5 years.
- Case 2 โ Acute exacerbation ๐ก๏ธ: A 72-year-old man with known IPF presents with rapidly worsening breathlessness over 5 days. CXR: new bilateral diffuse ground-glass opacities superimposed on chronic fibrotic changes. Teaching: Acute exacerbations of IPF resemble ARDS and carry a high mortality. Often triggered by infection, surgery, or sometimes idiopathic. Management is mainly supportive (oxygen, steroids, palliative care planning).
- Case 3 โ Assessment for transplant ๐: A 55-year-old man with IPF (FVC 40%, DLCO 32%) struggles with activities of daily living. He desaturates to 82% on a 6-minute walk test. Teaching: Lung transplantation is the only treatment shown to improve survival in advanced IPF. Patients must be referred early, before severe comorbidity develops. Antifibrotic agents (pirfenidone, nintedanib) may slow decline but do not cure.