Idiopathic Pulmonary Fibrosis
A fatal disease where the lungs become progressively scarred and stiff for unknown reasons, making breathing extremely difficult.
- Sudden, rapid worsening of dyspnea indicating Acute Exacerbation.
Emergency Management: Acute Exacerbation of IPF. High-dose IV steroids (Methylprednisolone 1g/day) and broad-spectrum antibiotics, though evidence is weak.
Idiopathic Pulmonary Fibrosis (IPF) is a specific form of chronic, progressive, and fatal fibrosing interstitial pneumonia of unknown cause, characterized by the radiologic/histologic pattern of usual interstitial pneumonia (UIP).
Detailed Overview
IPF predominantly affects older adults. It involves aberrant healing of alveolar epithelial micro-injuries, causing relentless fibroblast proliferation and scar tissue deposition. Lung volume decreases, impairing gas exchange. The disease is inexorably progressive, with a median survival of 3-5 years without lung transplant.
Epidemiology & Demographics
Incidence of 3-9 per 100,000. Peak incidence in the 60s and 70s. More common in males and former smokers.
Etiological Mechanism
Idiopathic. Involves interaction of genetic variants (MUC5B) and environmental exposures.
Primary Causes
Unknown (Idiopathic)
- Cigarette smoking: Strongest environmental risk factor.
- Genetic variants: MUC5B promoter variant, TERT mutations.
Recurrent alveolar injury leads to failed re-epithelialization. Epithelial cells secrete profibrotic TGF-beta, recruiting myofibroblasts forming 'fibroblastic foci'. Massive collagen deposition destroys the alveolar-capillary network, causing restrictive lung disease and severe hypoxemia.
Characteristic Clinical Presentation
- Progressive exertional dyspnea: Slowly worsening shortness of breath.
- Chronic dry cough: Persistent, hacking, non-productive cough.
Physical Examination Signs
- Fine 'Velcro-like' basilar inspiratory crackles.
- Digital clubbing.
- Acute Exacerbation of IPF: Sudden respiratory failure with high mortality.
- Cor Pulmonale: Right heart failure from pulmonary hypertension.
Diagnostic Criteria & Guidelines
Exclusion of known causes of ILD + definite UIP pattern on High-Resolution CT (or surgical lung biopsy).
Differential Diagnosis
- Rheumatoid Arthritis-ILD
- Chronic Hypersensitivity Pneumonitis
- Asbestosis
Laboratory Tests & Biomarkers
- Autoimmune panel: Negative (rules out connective tissue disease).
- PFTs: Restrictive pattern (low FVC, normal FEV1/FVC) with severely reduced DLCO.
Imaging Modalities & Findings
- High-Resolution CT (HRCT):
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Mild/Moderate IPF
FVC 50-80% predicted, dyspnea on exertion.
-
Advanced IPF
FVC < 50% predicted, profound resting hypoxemia.
Antifibrotic agents: Nintedanib 150 mg PO BID OR Pirfenidone 801 mg PO TID. Supplemental oxygen for resting O2 sat ≤ 88%.
Second-Line & Adjunctive Therapy
Pulmonary rehabilitation. Aggressive management of GERD with PPIs (Omeprazole 40 mg daily).
Surgical & Procedural Management
Lung Transplantation (only definitive cure/life-prolonging treatment).
Recommended Lifestyle Changes
- Strict smoking cessation.
- Up-to-date respiratory vaccinations (Influenza, Pneumococcal, RSV).
Patient Counseling & Advice
Antifibrotics slow disease progression by ~50% but do not reverse scarring or cure the disease. Initiate early discussions on lung transplant and palliative care.
Follow-Up & Monitoring Schedule
PFTs (FVC and DLCO) every 3-6 months. Liver function tests for patients on antifibrotics.
Preventive Strategies
None.
Poor. Median survival 3-5 years from diagnosis.
Frequently Asked Questions
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