This patient has bilateral emphysematous disease. There is bullous formation and marked parenchymal destruction in the right lung, creating the appearance of a hyperlucent lung.

Differential considerations for a unilateral hyperlucent lung include the following, as per the CRAWLS mnemonic (not all are pertinent to this case) ¹ :

C – Contralateral lung increased density, e.g. pleural effusion

R – Rotation

A – Air, e.g. pneumothorax

W – Chest wall mass/abnormality, e.g. Poland syndrome

L – Lungs, e.g. airway obstruction, Swyer-James syndrome, unilateral large bullae

S – Scoliosis

Case submitted by Dr. N. Larocque.