Idiopathic Pulmonary Fibrosis (IPF)

Overview – Idiopathic Pulmonary Fibrosis (IPF)

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive, and ultimately fatal interstitial lung disease of unknown cause. It is characterised by fibrosis and thickening of the pulmonary interstitium, particularly within the alveolar walls, resulting in impaired gas exchange and progressive respiratory failure. Most cases occur in adults over 50 years of age and present with exertional dyspnoea and a persistent dry cough.

Definition

A specific form of chronic, progressive fibrosing interstitial pneumonia of unknown cause, limited to the lungs and associated with the histopathological and/or radiological pattern of usual interstitial pneumonia (UIP).

Aetiology

• Idiopathic – No known underlying cause
• May have associations with:
  • Smoking
  • Environmental or occupational exposures
  • Viral infections
  • Genetic predisposition (e.g. TERT, TERC mutations)

Pathogenesis

• Aberrant wound healing response following alveolar epithelial injury
• Results in excessive deposition of extracellular matrix and collagen
• Leads to irreversible fibrosis and architectural distortion of the lungs
• Progressive restriction of lung expansion and impaired gas exchange

Morphology

• Histological Features:
  • Patchy interstitial fibrosis
  • Dense collagen deposition
  • Honeycombing in later stages
• Imaging Features:
  • Reticular opacities (especially basal and subpleural regions)
  • Honeycombing and traction bronchiectasis on HRCT

Clinical Features

• Typical Demographic: Males >50 years
• Symptoms:
  • Progressive exertional dyspnoea
  • Chronic, dry cough
  • Fatigue
• Signs:
  • Bibasal “Velcro” fine inspiratory crackles
  • Digital clubbing
  • Hypoxaemia ± central cyanosis

Investigations

• Spirometry:
  • Restrictive pattern: ↓ FVC, ↓ TLC, normal or ↑ FEV₁/FVC ratio
• DLCO (Diffusion Capacity for Carbon Monoxide): ↓
• High-Resolution CT (HRCT):
  • Reticulonodular opacities
  • Honeycombing
  • Subpleural and basal predominance
• ABG: Hypoxaemia in advanced disease
• Exclusion of other ILDs (interstitial lung diseases): e.g. connective tissue diseases, hypersensitivity pneumonitis

Management

• No known curative treatment; however, disease progression may be slowed
• Pharmacologic therapy:
  • Antifibrotics: Pirfenidone or Nintedanib (may slow decline in lung function)
• Supportive care:
  • Oxygen therapy for hypoxia
  • Pulmonary rehabilitation
  • Vaccinations (Influenza, Pneumococcal)
• Lung transplantation – Considered for eligible patients
• Palliative care – In advanced stages to improve quality of life

Prognosis

• Poor overall prognosis
• Median survival ~3–5 years from diagnosis
• Progressive course with eventual respiratory failure

Summary – Idiopathic Pulmonary Fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a relentlessly progressive interstitial lung disease marked by fibrosis of the alveolar walls, leading to reduced lung compliance and impaired gas exchange. It presents with exertional dyspnoea and dry cough in older adults, with clubbing and Velcro-like crackles on auscultation. Despite limited treatment options, antifibrotic agents may modestly slow disease progression. For broader context, visit our Respiratory Overview page.