The white hemithorax: collapse, effusion, pneumonia or pneumonectomy
- Finding
One side of the chest X-ray is completely white. Where the heart and trachea have moved tells whether the lung has collapsed, filled or been pushed.
What it is
A white (opaque) hemithorax means one side of the chest has lost all its air on the film. The question is what took the place of the air, and the answer comes mainly from the position of the trachea and mediastinum. If they are pulled toward the white side, the lung has lost volume: collapse of the whole lung or a previous pneumonectomy. If they are pushed away, something is taking up space: usually a large pleural effusion, less often a big mass or a diaphragmatic hernia. If they stay in the midline, think of consolidation of the whole lung, or a collapse and an effusion on the same side balancing each other, which often means a central tumour. Before any of this, check that the film is not rotated.
What it looks like
- First check rotation: the spinous processes should sit midway between the medial ends of the clavicles.
- Trachea and heart pulled toward the white side: volume loss (whole-lung collapse, pneumonectomy).
- Trachea and heart pushed away: mass effect (large effusion, large mass, diaphragmatic hernia).
- Midline: whole-lung consolidation, or collapse plus effusion on the same side, or a pleural tumour encasing the lung.
- Air bronchograms point to consolidation; a cut-off main bronchus points to central obstruction.
- Pneumonectomy: missing or cut rib, surgical clips or sutures at the hilum, and the history.
Why it looks that way
- A collapsed lung shrinks and pulls the mediastinum and diaphragm toward it; fluid or a mass adds volume and pushes them away.
- Consolidated lung keeps its volume: alveoli fill with fluid or pus but are not lost, so nothing shifts.
- After pneumonectomy the empty space slowly fills with fluid over weeks to months and the mediastinum moves toward that side.
| Trachea and mediastinum | Think of | Clues |
|---|---|---|
| Toward the white side | Whole-lung collapse; pneumonectomy | Raised hemidiaphragm, crowded ribs; surgical clips, missing rib |
| Away from the white side | Large pleural effusion; large mass; diaphragmatic hernia | Meniscus, fluid on ultrasound; bowel gas in the chest in a hernia |
| Midline | Whole-lung consolidation; collapse plus effusion; pleural tumour | Air bronchograms in consolidation; central mass or pleural thickening on CT |
Differential and pitfalls
- Intubated patient with a white left lung: the endotracheal tube may be in the right main bronchus; check its tip before anything else.
- Rotation alone can move the mediastinal outline; judge the trachea against the spine and clavicles.
- A white hemithorax with no shift is the dangerous one: a central tumour can cause collapse and effusion together.
- After pneumonectomy, a sudden drop in the air-fluid level or the mediastinum moving back suggests a bronchopleural fistula.
- In children, an absent or underdeveloped lung (agenesis or hypoplasia) also gives a small white hemithorax with shift toward it.
Next step
- Intubated: check and pull back the tube if it sits in a main bronchus, then repeat the chest X-ray.
- Shift away or midline: ultrasound of the chest to separate fluid from solid lung and to guide a diagnostic tap.
- Shift toward with no surgery: suspect central obstruction (tumour, mucus plug, foreign body); CT with contrast and bronchoscopy.
- Unclear cause or suspected cancer: contrast CT of the chest and discuss with the radiologist and pulmonology.
- Post-pneumonectomy with new fever, cough or a change in the fluid level: call thoracic surgery the same day.
Test yourself
Think of the answer, then tap the question to see it.
A white left hemithorax with the trachea pulled to the left: what are the main causes?
Volume loss: collapse of the whole left lung (central tumour, mucus plug, foreign body or a misplaced tube) or a previous left pneumonectomy.
A white hemithorax with the mediastinum pushed away: what is the most likely cause?
A large pleural effusion; less often a large mass or a diaphragmatic hernia.
Why is a white hemithorax with no mediastinal shift worrying?
Collapse and effusion on the same side can balance each other, which often means a central tumour; whole-lung consolidation is the other main cause.
What should you check first in an intubated patient whose left lung has become white?
The tip of the endotracheal tube: it may have slipped into the right main bronchus, collapsing the left lung.
Elsewhere in DurgiPedia
- Pleural effusion syndrome
- Atelectasis syndrome
- The pleuropulmonary syndromes: the comparison table to know
Connections
Educational content; it does not replace a radiologist's report and is not a clinical instruction. Each study is ordered on the patient's assessment and your institution's protocols.
Sources: Pneumonectomy (StatPearls (NCBI Bookshelf), 2024); Pleural Effusion (StatPearls (NCBI Bookshelf), 2024); Atelectasis (StatPearls (NCBI Bookshelf), 2024).
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Representative model, for educational purposes only.