air fluid levels

[dendrites]

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Can someone explain what exactly an "air fluid level" is (as seen in a lung abscess or small bowel obstruction)

 

[illegallysmooth]

Can someone explain what exactly an "air fluid level" is (as seen in a lung abscess or small bowel obstruction)

It means the cavity or mass is partially filled with liquid. Say you have a lung abscess partially filled with pus. When you lay down, the liquid pus shifts due to gravity. On a CT, you can see the mass as a pocket with liquid on the lower part of it, and a sharp horizontal line separating air from pus.

check it out -> http://www.learningradiology.com/archives2008/COW 306-Lung abscess/lungabscesscorrect.html

 

[dendrites]

thanks. I just did a Q on gallstone ileus and it described the pait as having air in the biliary tree. I stilll dont understand where the air is coming from? (just trying to understand the mechanism)

 

[illegallysmooth]

thanks. I just did a Q on gallstone ileus and it described the pait as having air in the biliary tree. I stilll dont understand where the air is coming from? (just trying to understand the mechanism)

The air is coming from the intestine. Gallstone ileus happens when there is a fistula between the intestine and the gall bladder. A stone from the gall bladder moves through the fistula into the intestine and blocks it, creating the ileus. However, since there is the fistula, air from the intestine will move through the fistula into the biliary system, giving you the convenient "air in the bililary tree" sign.

 

[Phloston]

The air is coming from the intestine. Gallstone ileus happens when there is a fistula between the intestine and the gall bladder. A stone from the gall bladder moves through the fistula into the intestine and blocks it, usually at the ileocecal junction, creating the ileus. However, since there is the fistula, air from the intestine will move through the fistula into the biliary system, giving you the convenient "air in the bililary tree" sign.

Good explanation.

 

[MCV 2016]

It basically all comes down to fluid showing up on imaging. The "air" component is inconsequential. Fluid anywhere will interface to some degree with atmosphere, creating the so called "air-fluid level."