Desquamative Interstitial Pneumonia

DIAGNOSTIC TESTS

• Pulmonary function tests
  • DL_CO is moderately decreased^3,7
  • Normal lung volumes or a mild restrictive abnormality³
• HRCT
  • Features: ground-glass opacities, irregular linear or reticular opacities, sometimes cysts⁸
  • Distribution: apicobasal gradient, peripheral predominance⁸

RB-ILD, hypersensitivity pneumonitis, sarcoidosis, and infections such as Pneumocystis carinii pneumonia may not be distinguishable from DIP on HRCT.³

• Surgical lung biopsy should be used in certain cases⁹
  • Histopathology results featuring diffuse accumulation of macrophages in distal airspaces, mild interstitial fibrosis, mild chronic inflammation indicate a diagnosis of DIP⁸

• Bronchoalveolar lavage findings are not usually very specific¹
  • Features:
    • Increased number of alveolar macrophages
    • Large number of which have granules of smoker's-pigment consisting of intracellular yellow, gold, brown, or black smoke particulates³

• Chest X-ray is not sensitive enough for detection of DIP and appears normal in 3%-22% of biopsy-proven cases³
  • Features:
    • Widespread patchy ground glass opacification
    • Lower zone predilection
    • Sometimes a peripheral predominance