Cryptogenic Organizing Pneumonia (COP)

Clinical history¹

Infections/Drugs/Comorbid diseases

• Connective tissue disease (CTD)
• Thoracic radiotherapy for breast cancer
• Inflammatory bowel disease
• Cancer
• Exposure to drugs
• Aspiration
• Common variable immune deficiency (less common)
• Toxic exposures (less common)

Complete blood count (CBC)²

• Raised erythrocyte sedimentation rate
• Elevated C-reactive protein
• Peripheral blood neutrophilia

Pulmonary function tests²

• Lung volumes are normal in about 75% of patients
• Restrictive pattern (mild to moderate)
• Reduced DL_CO
• Mild resting hypoxemia

HRCT⁴

• Features: Airspace consolidation, mild bronchial dilatation, ground-glass opacities, large nodules are rare
• Distribution: Patchy, peripheral or peribronchial, basal predominance, sometimes sparing of subpleural space, migration tendency

Bronchoalveolar lavage²

• Increased number and proportion of lymphocytes
• Decreased ratio of CD4⁺ to CD8⁺ cells
• Increased number of neutrophils and eosinophils

Surgical lung biopsy is not always necessary¹

• Only typical cases at imaging with compatible clinical and BAL features should be treated without biopsy¹
• Patchy distribution of intraluminal organizing fibrosis in distal airspaces, preservation of lung architecture, uniform temporal appearance⁴

Chest X-ray

• Bilateral or unilateral areas of consolidation with patchy distribution²