Chest x-ray abnormalities
Hilar abnormalities
The hila consist of vessels, bronchi and lymph nodes. On a chest x-ray, abnormalities of these structures are represented by a change in position, size and/or density.
Hilar enlargement
Hilar enlargement may be unilateral or bilateral, symmetrical or asymmetrical. In combination with clinical information, each of these patterns is often helpful in reaching a diagnosis. Bilateral, symmetrical hilar enlargement should raise the suspicion of sarcoidosis, particularly if there is evidence of paratracheal enlargement, or lung parenchymal shadowing.
Key points
- The left hilum is usually higher than the right
- Check the size of the hila
- Check the density of the hila
- If a hilum is displaced, ask yourself if it has been pushed or pulled
Hover over image to show findings
Bilateral hilar enlargement
- Both hila are larger and denser than normal
- A small degree of patient rotation is irrelevant in this case - the observation of bilateral, symmetrical hilar enlargement can still be made
- Patchy bilateral lung parenchymal shadowing
Clinical details
- Joint pain
- Erythema nodosum
Diagnosis
- Sarcoidosis
Differential
- Lymphoma, metastatic disease or infection may occasionally look similar
- Pulmonary arterial hypertension may also cause bilateral symmetrical hilar enlargement
Hover over image to show findings
Asymmetric hilar enlargement
- Both hila are larger and denser than normal
- The right hilum is bigger than the left
- Multiple small lung nodules
- Missing right breast shadow (mastectomy)
Clinical details
- Known breast cancer
- Increasing shortness of breath
Diagnosis
- Metastatic disease
- Breast cancer
Hilar position
If a hilum has moved, you should try to determine if it has been pushed or pulled, just like you would for the trachea. Ask yourself if there is a lung abnormality that has reduced volume of one hemithorax (pulled), or if there has been increase in volume or pressure of the other hemithorax (pushed).
Hover over image to show findings
Abnormal hilar position
- The left hilum is large, dense and pulled laterally and upwards to the left
- The trachea is deviated (pulled) towards the left, indicating loss of lung volume in the left hemithorax
Clinical details
- History of left hilar malignancy treated with radiotherapy
Diagnosis
- Radiation fibrosis