A 42-year-old female smoker with a 20-pack-year history is admitted with progressive shoness of breath. On exam, she has distant hea sounds with decreased breath sounds on lung exam bilaterally. No summation gallop is heard. ECG shows low voltage. Chest x-ray is shown in. The findings on the CXR may be associated with
Correct Answer: Positional change of chest x-ray findings
Description: The cardiac silhouette is enlarged, with normal pulmonary vasculature, suggesting pericardial disease. There is a linear hyperlucent margin along the left cardiac border, suggesting an air-soft tissue interface. This is seen in pneumopericardium. The chest x-ray shows a pneumopericardium. This refers to the presence of air within the pericardial sac. Pathologically, air can enter the pericardium from the mediastinum near the pulmonary veins. Air can also develop within the pericardium due to production by gas-forming organisms in cases of infection. At times the pneumopericardium may be complicated by the presence of fluid (hydropneumopericardium) or pus (pyopneumopericardium). Closed chest injury with or without perforation of the pericardium is the most frequent nonsurgical cause associated with this kind of pattern. Contiguous organ involvement (pulmonary abscess, bronchogenic carcinoma, esophagitis, perforated gastric ulcer, foreign body) also can result in the involvement of the pericardium and hence cause pneumopericardium. Septicemia causing direct seeding of the pericardial space can also produce a common communication with the lung. With pneumopericardium, the lucent halo of air paially or completely surrounds the hea but does not extend superiorly to the attachments of the pericardium, and the concomitant subcutaneous emphysema is absent. If supine and erect radiographs are obtained, pericardial air will immediately shift in location whereas mediastinal air change will not occur.The "continuous diaphragm sign" is seen in pneumomediastinum. In this sign, the right and the left hemidiaphragms appear continuous due to mediastinal air present along the diaphragm and below the hea, giving the appearance of a single continuous diaphragm. Both adults and children can develop life-threatening cardiac tamponade due to pneumopericardium. A pericardial rub is a sign of pericarditis and is usually not heard once an effusion develops. The Hamman sign is a crunching noise heard with the apex beat and heard best in the left lateral decubitus position. It is seen in 50% of cases of mediastinal emphysema (pneumomediastinum) and is associated with subcutaneous emphysema in the suprasternal notch. Malignant pericardial effusions are most commonly seen secondary to breast and lung cancer, but local spread is commonly due to the latter.
Category:
Radiology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now