Today I am showing chest radiographs of a 81-years-old man with chest pain five years after left pneumonectomy for lung carcinoma
1. Broncho-pleural fistula
2. Intestinal hernia
4. None of the above
What do you see?
Check the images below, leave your thoughts in the comments section, and come back on Friday for the answer.
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Findings: PA radiograph shows an opaque left hemithorax with a central cavity (A, black arrow) with an air-fluid level (A, red arrow). The splenic flexure of the colon is right below (A, yellow arrow). In the lateral view the central cavity has an inverted U-shape (B, black arrows) with two air-fluid levels (B, red arrows).
Unenhanced coronal and sagittal CT show that the central cavity is a dilated stomach (C and D, arrows), herniated through a large rent in the left hemidiaphragm (C and D, red arrows).
Final diagnosis: herniated stomach and colon through a wide diaphragmatic defect
I present this case to increase your awareness of an often forgotten subdiaphragmatic structure: the gastric bubble. Due to its air content, the gastric fornix is visible in most upright PA chest radiographs, and it can provide valuable information.
I have classified changes in the gastric bubble as follows:
4. Miscellaneous findings
An absent gastric bubble occurs in 10% of the normal population and 50% of patients with achalasia. Therefore, lack of a gastric bubble should prompt a review of the mediastinum to investigate a dilated esophagus (Fig. 1).
Remember that although an absent gastric bubble may suggest a diagnosis of achalasia, visible air in the fornix does not rule it out, as demonstrated in the case below (Fig. 2).
An absent air bubble may happen when the stomach is not in the left upper quadrant. This occurs in a rare congenital condition, abdominal heterotaxia, in which there is rotation only of the abdominal structures. In these cases, the gastric bubble is located under the right hemidiaphragm (Fig. 3).
Malpositioned gastric bubble occurs when the fornix is in an abnormal location. The most common cause is diaphragmatic hernia either through the esophageal hiatus (Fig. 4) or secondary to traumatic rupture of the diaphragm (Fig. 5).
In left hemithorax opacification, an abnormally located gastric bubble indicates the position of the hemidiaphragm and clarifies the etiology. Downward displacement indicates massive pleural effusion (Fig. 6), whereas elevation favors collapse of the whole lung (Fig. 7).
Gastric bubble displacement is also an indirect sign of an abdominal mass. The most common cause is splenomegaly, which pushes the aerated fornix towards the midline (Figs. 8 and 9).
Miscellaneous findings include visualization of masses outlined by air in the gastric bubble and occasionally air within the stomach wall. Masses in the gastric fornix may be due to carcinoma and other tumors, gastric varices, or postoperative deformities (Fig. 10) .
Air in the gastric wall may be seen after ingestion of corrosive substances or, more commonly, after forceful vomiting or secondary to an endoscopic procedure (Fig. 11).
Dilated stomach can occur alone or in generalized bowel dilatation. In the second case think of diabetes or mechanical pyloric obstruction (Fig. 12).
Follow Dr. Pepe’s advice:
1. Absent gastric bubble occurs in 50% of patients with achalasia.
2. Diaphragmatic hernias cause malposition of the gastric bubble.
3. Splenomegaly is the most common cause of displacement of the gastric bubble.