Bilateral Hyperlucent Lung
Daniel J. Podberesky, MD
DIFFERENTIAL DIAGNOSIS
Common
Technical Factors
Asthma
Cyanotic Heart Disease
Less Common
Foreign Body
Rare but Important
Obliterative Bronchiolitis
Emphysema
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Difficult diagnosis to make if appearance is symmetric
If issue is not technical, look for clues of hyperaeration
e.g., small cardiomediastinal silhouette and depressed diaphragms
Consider inspiratory/expiratory images
Helpful Clues for Common Diagnoses
Technical Factors
Overexposed chest x-ray attenuates pulmonary markings, resulting in hyperlucent appearance of lungs
Good inspiratory effort can result in bilateral, hyperinflated, hyperlucent lungs
Asthma
Airway inflammation results in intermittent airflow obstruction
During acute exacerbation, chest x-ray typically shows hyperinflated, bilateral, hyperlucent lungs
Cyanotic Heart Disease
Decreased pulmonary vascularity can result in hyperlucent lung appearance
Patients with tetralogy of Fallot, pulmonary atresia, tricuspid atresia, Ebstein anomaly
Hyperinflated lungs due to cyanosis
Helpful Clues for Less Common Diagnoses
Foreign Body
Tracheal foreign body may cause bilateral air-trapping and hyperlucent lungs
Esophageal foreign body can cause edema with resulting tracheal compression and hyperlucent lungs
Helpful Clues for Rare Diagnoses
Obliterative Bronchiolitis
Bronchial inflammation resulting in airway obstruction
Due to toxic fumes, postinfectious and drug-related causes, connective tissue disorders, lung transplantation, bone marrow transplantation
Hyperlucent lungs with mosaic perfusion and ground-glass opacities on high-resolution chest CT
Emphysema
