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For further information, see CMDT Part 9-21: Diffuse Interstitial Pneumonias

Key Features

  • Presentation similar to usual interstitial pneumonitis (UIP) but occurs in younger patients

  • Patients are invariably heavy smokers

  • Usually occurs without symptoms or physiologic evidence of lung disease

  • Prognosis is better than in UIP; median survival > 10 years

Clinical Findings

  • Age 40–45 years

  • Insidious dry cough with exertional dyspnea over months to years

  • Diffuse parenchymal infiltrates


  • Pulmonary function test shows restriction with decreased DLCO, usually less severe than that seen in UIP

  • High-resolution CT more likely to reveal diffuse ground-glass opacities and upper lobe emphysema

  • Biopsy shows increased numbers of macrophages localized within the peribronchiolar space; alveolar architecture is preserved, honeycomb change and fibrosis are minimal


  • Spontaneous remission occurs in up to 20% of patients

  • Smoking cessation is crucial

  • Trial of prednisone, 1–2 mg/kg/day orally for a minimum of 2 months

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