Pneumonia, Usual Interstitial

Key Features

• Clinical presentation is similar to that of other idiopathic interstitial pneumonias

• Median survival is approximately 3 years

Clinical Findings

• Onset at age 55–60 with slight male predominance

• Presents as insidious dry cough with months to years of exertional dyspnea

• Clubbing is present at diagnosis in 25–50%

• Pulmonary function tests: restrictive pattern and decreased diffusion capacity

• Antinuclear antibodies (ANA) and rheumatoid factor (RF) are positive in 25% of patients without documented collagen vascular disease

Diagnosis

• Chest radiographic findings

  • Decreased lung volumes with linear or reticular bibasilar or subpleural opacities

  • Normal in 2–10% at diagnosis

• High-resolution CT scan shows minimal ground-glass and variable honeycombing changes

• Biopsy shows nonuniform distribution of fibrosis, with loss of type I pneumocytes and proliferation of alveolar type II cells

• Usual interstitial pneumonia can be diagnosed with 90% confidence in patients age > 65 with classic features, avoiding biopsy

Treatment

• Nintedanib and pirfenidone appear to reduce rate of decline in lung function