IDIOPATHIC PULMONARY FIBROSIS

Idiopathic pulmonary fibrosis is a disease characterized by diffuse interstitial fibrosis of unknown etiology and frequently occurs between the ages of 50-70.
Clinical Picture
  • Patients present with dry cough and shortness of breath and sometimes with fever, arthralgias and Raynaud's phenomenon.
  • Clubbing (40-70%) tachypnea and persistent coarse basal crackles are encountered on physical exam. Often they are using accessory muscles of inspiration for tidal breathing.
  • CXR: Normal to reticulonodular to honeycombing. HRCT may show ground glass appearance or honeycomb cysts.  In Desquamative interstitial pneumonitis alveolar features can be recognized..
  • PFT shows a restrictive and diffusion defects. Patients are hypoxic and desaturate significantly with exercise.
  • In 25-45%, serum cryoglobulins, RF and ANA are present.
  • BAL: Predominance of neutrophils.
Pathology
Desquamative Interstitial pneumonitis(DIP), Usual Interstitial Pneumonitis(UIP), Lymphocytic Interstitial Pneumonitis( LIP) are various subgroups, probably of the same disease process.
a.      Early IPF: Desquamation predominates where alveolar macrophages fill alveolar spaces (desquamative interstitial pneumonitis or DIP).
b.     Late IPF: Inflammation of alveolar walls continues and fibroblast proliferation with collagen formation occurs (usual interstitial pneumonitis or UIP).
Diagnosis
  •  By exclusion, it will be necessary to rule out other known causes for fibrosis like Silicosis or drugs. A long list of conditions can give rise to interstitial fibrosis 
  • Transbronchial lung biopsy  can identify interstitial fibrosis. Usually need open lung biopsy to confirm.
Treatment
  • Therapy is useful in acute stages when there is significant inflammatory process.
  • Once the fibrosis is chronic or if the chest X-ray has been stable for years or if there is honeycombing, therapy is of no benefit.
  • Corticosteroids + immunosupressants (cyclophosphamide or azathioprine); anecdotal reports describing colchicine or methotrexate or cyclosporine.
  • Oxygen is often prescribed for these patients, probably not influencing pulmonary hypertension.
  • In some cases  Plasmapheresis and Lung Transplant are considerations.
  • Transplantation: 50% two year survival with single lung.
Prognosis

  • In the acute progressive form "Hamman-Rich Syndrome" the prognosis is poor.
  • In the chronic form patients can live long with disability.

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