Respiratory · Year 1 · from Respiratory
Case 1: Idiopathic Pulmonary Fibrosis
Clinical Image
Source: Wikimedia Commons - IPF CT - CC BY 2.0
Case Presentation
A 67-year-old man presents with progressive exertional dyspnea over the past 18 months. He describes gradually worsening exercise tolerance, now becoming short of breath walking up a single flight of stairs. He has a dry, nonproductive cough. He has a 20 pack-year smoking history but quit 15 years ago. On examination, he has digital clubbing and fine, inspiratory "Velcro-like" crackles at both lung bases. Vital signs show respiratory rate 18/min and oxygen saturation 94% at rest, dropping to 86% with a 6-minute walk test.
Pulmonary function tests show FEV1 2.4 L (72% predicted), FVC 2.8 L (68% predicted), FEV1/FVC ratio 0.86 (normal), TLC 4.2 L (65% predicted), and DLCO 45% predicted. The pattern is restrictive (reduced TLC with preserved or elevated FEV1/FVC ratio) with markedly reduced diffusing capacity.
High-resolution CT chest reveals bilateral, predominantly basal and peripheral reticular opacities, honeycombing (clusters of cystic airspaces with thick walls), and traction bronchiectasis. This pattern of usual interstitial pneumonia (UIP) on CT, combined with the clinical presentation in a patient over 60 with no identifiable cause, is diagnostic of idiopathic pulmonary fibrosis (IPF) without need for surgical lung biopsy.
The pathophysiology involves repetitive alveolar epithelial injury leading to abnormal wound healing, myofibroblast activation, and excessive collagen deposition. This fibrosis reduces lung compliance (explaining restrictive physiology), thickens the alveolar-capillary membrane (reducing DLCO), and causes progressive destruction of lung architecture (honeycombing).
The patient is started on nintedanib, an antifibrotic tyrosine kinase inhibitor that slows the rate of FVC decline but does not reverse existing fibrosis. He is referred for pulmonary rehabilitation and evaluated for lung transplant listing. Corticosteroids are NOT indicated and may be harmful in IPF - an important distinction from other interstitial lung diseases. He is counseled on the poor prognosis, with median survival of 3-5 years from diagnosis.
Key Learning Points
- IPF shows the UIP pattern on CT: basal/peripheral honeycombing, reticular opacities, traction bronchiectasis
- Pulmonary function shows restrictive pattern (low TLC, normal/high FEV1/FVC) with reduced DLCO
- "Velcro crackles" and digital clubbing are characteristic physical findings
- Antifibrotics (nintedanib, pirfenidone) slow decline but do not cure - corticosteroids are contraindicated
- Lung transplantation is the only potentially curative option for eligible patients