Bilateral, peripheral, lower-lobe ground glass with or without consolidation and crazy paving suggests COVID-19 or another viral pneumonia; say how typical the pattern is, and look for what changes management — PE, superinfection and later fibrotic change.
Orient first
- Viral pneumonias injure the alveoli diffusely: ground glass, crazy paving and consolidation; bronchiolitis gives tree-in-bud and bronchial wall thickening (influenza, RSV).
- COVID-19 typically starts peripheral and posterior, lower-lobe, and evolves to consolidation and an organising pattern (reversed halo) by the second week.
- The pattern is not specific: PJP, organising pneumonia, drug reaction, pulmonary oedema and vasculitis overlap — report the category of likelihood, not a microbiological diagnosis.
Acquire the study
- Chest radiograph for triage and follow-up; non-contrast thin-section CT for diagnosis or complications; CTPA when PE is suspected.
The manoeuvre
- Distribution: bilateral, peripheral, posterior, lower-lobe predominant ground glass (typical for COVID-19); central or upper-lobe predominance is less typical.
- Pattern: ground glass ± consolidation, crazy paving, reversed halo (organising phase).
- Features that point elsewhere: tree-in-bud, lobar consolidation, cavitation, nodes, effusion.
- Assign a likelihood category (typical / indeterminate / atypical / negative — verify the current consensus wording).
- Complications: pulmonary embolism, superinfection, pneumothorax/pneumomediastinum; at follow-up, residual ground glass versus fibrotic-like change.
What confirms it
- A typical pattern in a compatible clinical setting with a positive viral test.
What licenses you to exclude it
- A normal CT does not exclude early infection; the test result decides.
The classic misread
- Reporting "COVID-19" from CT alone; missing a PE in a deteriorating patient.