Idiopathic Pulmonary Fibrosis

Definition

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive interstitial lung disease of unknown etiology, characterized by fibrosis of the lung parenchyma leading to restrictive lung physiology and impaired gas exchange.

Epidemiology

• Typically affects adults over 50 years of age
• More common in men than women
• Incidence increases with age
• Prevalence varies by region, higher in North America and Europe
• Accounts for a significant proportion of interstitial lung diseases

Etiology

• Idiopathic (exact cause unknown)
• Genetic predisposition in some cases (e.g., mutations in surfactant protein or telomerase genes)
• Environmental exposures: smoking, dust, metal fumes, wood dust
• History of gastroesophageal reflux may contribute
• Viral infections have been proposed as triggers
• Comorbidities may influence disease progression

Pathophysiology

• Repeated epithelial injury triggers aberrant wound healing
• Fibroblast proliferation and extracellular matrix deposition
• Progressive fibrosis leads to stiffening of lung parenchyma
• Alveolar architecture disruption impairs gas exchange
• Reduced lung compliance and restrictive ventilatory defect
• Hypoxemia develops, especially on exertion
• Progressive disease eventually causes respiratory failure