Interstitial Lung Disease Flashcards Preview

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Flashcards in Interstitial Lung Disease Deck (8)
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What happens in diffuse parenchymal lung diseases (=intersitital lung diseases)?

  • large group of conditions characterised by inflammation centres on the interstitium of alveolar walls
  • interstitium becomes expanded by inflammatory cell infiltrate ('pneumonitis' or 'alveolitis')
  • impairs gas exchange + causes breathlessness
  • episodes of alveolitis may be followed by complete regeneration without residual damage to alveoli


With interstitial lung disease where most inflammation may completely regenerate, sometime the inflammation is followed by repair with scarring.

What happens here?

  • macrophages release fibrogenic cytokines
  • stimulate fibroblasts in interstitium
  • secrete collagen (scar tissue)
  • thickened alveolar walls are ineffective at gas exchange
  • resulting in worsening breathlessnes



What is meant by the terms 'pneumonitis', 'alveolitis' and 'pneumonia'?

  • pneumonitis - inflammation of lung parenchyma ie. the alveoli (alveolitis is an alternative name) - usually due to non-infective causes. Inflammation is limited to interstitium
  • pneumonia - inflammation of the lung parenchyma due to an infective agent - characterised by consolidation - acute inflammatory exudate filling alveolar spaces.


There are 200+ DPLDs. They can be caused by anything which sets up chronic inflammation within the interstitial space of alveolar walls.

What are the 5 basic categories that can divide up the causes?

  • unknown cause (idiopathic intersitital lung disease)
  • pneumoconioses (inhaled inorganic/mineral dusts), eg. coal dust, silica, asbestos
  • extrinsic allergic alveolitis (inhaled organic) eg. bird fancier lung, farmer's lung
  • side-effects of treatment - eg. therapeutic chest radiation, certain drugs (amiodarone)
  • multisystem diseases involving lung eg. sarcoid, SLE, RA, scleroderma


How is interstitial lung disease diagnosed?

  • history + exam
    • a meticulous history vital in identifying cause
  • CXR -> reticulation
  • spriometry -> restrictive
  • high-res CT -> reticulation
  • lung biopsy sometimes necessary 


What are signs and symptoms of interstitial lung disease?

  • dry cough, progressive dyspnoea, wheeze, chest pain
  • clubbing
  • reduced chest wall expansion bilaterally
  • dull percussion note
  • inc vocal resonance
  • bronchial breathing
  • fine, late-pan inspiratory crackles

Also depends on the underlying cause


How do DLPDs such as pulmonary fibrosis cause cor pulmonale (right heart failure due to lung disease)?

  • important cause of cor pulmonale
  • fibrosis of lung tissue obliterates pulm arterioles + caps 
  • -> gradual development of pulmonary hypertension
  • right ventricule undergoes compensatory right ventricular hypertrophy
  • eventually, right ventricle decompensates
  • right heart failure ensues



What is the management of intersitital lung disease?

  • oxygen
  • pulmonary rehabilitation
  • corticosteroids, cycophosphamide, azothiaprine
  • lung transplantation