Toddler with a cough after being seen placing a peanut in their mouth

Chest
Decubitus CXR of airway foreign body
Right lateral decubitus CXR (left) shows deflation of the right lung when placed in a dependent position. Left lateral decubitus CXR (right) shows lack of deflation of the left lung when placed in a dependent position and note the left lung remains hyperlucent when compared to the right lung.

The diagnosis was an airway foreign body in the left mainstem bronchus.

Published