ILD

Idiopathic Interstitial Pneumonia

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Idiopathic Interstitial Pneumonia, Idiopathic Pulmonary Fibrosis, Usual Interstitial Pneumonia, Desquamative Interstitial Pneumonia, Respiratory Bronchiolitis, RB-ILD, Acute Interstitial Pneumonia, Hamman-Rich Disease, Nonspecific Interstitial Pneumonia

  • Epidemiology
  1. Prevalence
    1. Men: 29 per 100,000
    2. Women: 26 per 100,000
  2. Ages: 40-70 years
  • Types of Idiopathic Interstitial Pneumonia
  1. Usual Interstitial Pneumonia (UIP)
    1. Previously known as Idiopathic Pulmonary Fibrosis
    2. Associated conditions
      1. Collagen vascular disease
      2. Drug Reaction (e.g. Nitrofurantoin when GFR<30 ml/min)
      3. Pneumoconioses (Asbestosis)
      4. Idiopathic Pulmonary Fibrosis (IPF)
    3. Imaging appearance: Honey combing
    4. Poor response to Corticosteroids
    5. Recovery not possible
    6. Mortality 68% with mean survival 5-6 years
  2. Desquamative Interstitial Pneumonia (DIP)
    1. Imaging appearance: Ground Glass Appearance
    2. Good response to Corticosteroids
    3. Mortality 27% with mean survival 12 years
  3. Respiratory Bronchiolitis (RB-ILD)
    1. Imaging appearance: Ground Glass Appearance
    2. Good response to Corticosteroids
    3. Mortality 0%
  4. Acute Interstitial Pneumonia (AIP)
    1. Also known as Hamman-Rich Disease
    2. Acute, severe Interstitial Lung Disease
    3. Poor response to Corticosteroids
    4. Mortality 62% with mean survival 1-2 months
  5. Nonspecific Interstitial Pneumonia (NSIP)
    1. Subacute onset
    2. Good response to Corticosteroids
    3. Mortality 11% with mean survival 17 months
  • Symptoms
  1. Non-productive cough for 1 to 3 years
  2. Increasing breathlessness
  • Signs
  1. Bilateral basilar crackles
  2. Fingernail Clubbing
  • Associated Conditions
  1. Associated Autoimmune Disease in 30%
  • Radiology
  1. Chest XRay (Normal in 16% of IPF patients)
    1. Diffuse reticular pattern
    2. Predominately lower zones
  2. CT Chest
    1. Linear opacities, honeycombing
    2. Ground glass attenuation
  • Diagnosis
  1. Pulmonary Function Testing
    1. Restrictive disease
    2. Low Lung Volumes
    3. Impaired gas exchange (diminished DLCO)
  2. Transbronchial lung biopsy or Bronchoalveolar lavage
    1. Will not confirm IPF
    2. Rules out other causes of Interstitial Lung Disease
      1. Sarcoidosis
      2. Cryptococcus
      3. Lung Cancer
  • Differential Diagnosis
  1. See also Interstitial Lung Disease
  2. Other causes of fibrosing alveolitis
  3. Occupational exposure etiologies
  • Management
  1. Corticosteroid Therapy
    1. Efficacy
      1. Corticosteroid Responders: 10-15%
      2. Indicators of responders
        1. Young women
        2. Ground glass appearance on CT Chest
        3. Active inflammation on lung biopsy
    2. Adverse Effects
      1. Serious complications in 26%
  2. Cytotoxic Drugs
    1. Available preparations
      1. Azathioprine
      2. Cyclophosphamide
    2. Indications
      1. Second line drugs
      2. Used in combination with Corticosteroids
  • Prognosis
  1. Poor (recently improved on combination therapy)
  • Resources
  1. Pulmonary Fibrosis Association
    1. http://www.pulmonaryfibrosisassn.com/
  2. Pulmonary Fibrosis Foundation
    1. http://www.pulmonaryfibrosis.org
  • References
  1. Chan-Yeung (1997) Lancet 350:651-6 [PubMed]