Ground Glass Opacities in Pulmonary Diseases
Infectious Pneumonia
- COVID-19 pneumonia characteristically presents with multiple patchy ground glass opacities in bilateral multiple lobules with peripheral distribution 1
- Pneumocystis pneumonia (PcP) demonstrates diffuse bilateral perihilar infiltrates and patchy areas of ground-glass attenuation with peripheral sparing 2
- In febrile neutropenic patients, GGOs can indicate various infectious etiologies requiring bronchoscopy and targeted antimicrobial therapy 2
Critical Differential Diagnoses Beyond Pneumonia
- Cryptogenic organizing pneumonia (COP) characteristically demonstrates patchy consolidation commonly associated with ground-glass opacity 3
- Nonspecific interstitial pneumonia (NSIP) most commonly presents with bilateral ground-glass opacity, often with subpleural sparing 5
- Extensive ground-glass opacification with subpleural sparing suggests fibrotic NSIP rather than usual interstitial pneumonia (UIP) 7
Diagnostic Approach for Persistent GGOs
- Obtain thin-section HRCT to characterize the GGO pattern and distribution, looking for crazy-paving pattern, peripheral and lower lung predominance, centrilobular nodules, and traction bronchiectasis 4
- Expected resolution of post-pneumonic ground glass opacities occurs within 2-3 weeks after clinical symptom onset 4
- Serial HRCT at 4-6 week intervals should be performed when GGOs persist to document progression, stability, or resolution 4
- Proceed to bronchoscopy with bronchoalveolar lavage when ground glass opacity persists beyond 4 weeks or clinical deterioration occurs 4