Chest Medicine













Idiopathic pulmonary fibrosis (IPF)
  • Inflammatory infiltrates of cells into the pulmonary interstitium associated with fibrosis of unknown cause

Signs and Symptoms
  • Symptoms: dry cough, extertional dyspnoea, weight loss, malaise
  • Signs: cyanosis, finger clubbing, fine end-inspiratory crackles
  • Complications: respiratory failure, may be associated with an increased risk of lung cancer

Investigation
  • Blood tests: ABG, CRP, immunoglobulins, rheumatoid factor, ANA
  • CXR: reduced lung volume, bilateral reticulo-nodular shadows, may see honeycombing in end-stage interstitial disease

    A chest radiograph of a patient with IPF. Note the small lung fields and peripheral pattern of reticulonodular opacification. (courtesy of wikipedia.org)

  • High-resolution CT chest:
    • UIP (usual interstitial pneumonia) pattern: honeycombing (> 5% of lung parenchyma), reticular opacity (dominant) and ground-glass opacity (less extensive than reticular pattern) → carries a poor prognosis (50% survival at 3-4 years)
    • NSIP (Non-specific interstitial pneumonia) pattern: bilateral ground glass opacity (dominant), reticular opacity (less extensive), usually absence of honeycombing → carries a better prognosis (divided into fibrotic and cellular subtypes → 90% survival at 5 years if cellular type or 60% at 5 years if fibrotic type)

    • CT scan in a patient with usual interstitial pneumonia, showing interstitial thickening, architectural distortion, honeycombing and bronchiectasis. (courtesy of Darel Heitkamp, MD, wikipedia.org)

  • Spirometry: restrictive pattern
  • BAL: may show alveolitis (lymphocytosis, neutrophilia and/or eosinophilia)
  • Lung biopsy: gives histological diagnosis

Management
  • Supportive care: O2, pulmonary rehabilitation, palliative care
  • Anti-fibrotic agents: nintedanib, pirfenidone
  • Lung transplant
  • High-dose steroids are not used unless diagnosis of IPF is doubtful

Reference: Oxford Handbook of Clinical Medicine (10th Edition)