What causes lungs to appear slightly hyperinflated on a chest X-ray (X-ray)

From the Guidelines

Lungs that appear slightly hyperinflated on a chest X-ray are most likely caused by obstructive lung diseases, such as chronic obstructive pulmonary disease (COPD), as stated in the American Thoracic Society/European Respiratory Society statement 1. The diagnosis of COPD is often suspected when a patient complains of symptoms such as cough, sputum production, dyspnea, or recurrent lower respiratory infections, and chest radiography is performed to exclude other diseases and establish the presence of concomitant respiratory diseases. Some key points to consider when evaluating hyperinflated lungs on a chest X-ray include:

• The radiographic changes associated with COPD, such as lung hyperinflation and hyperlucent areas in the lungs with peripheral trimming of vascular markings 1
• The use of computed tomography (CT) to estimate the degree of emphysema and its distribution, and to identify bronchial wall thickening and gas trapping 1
• The importance of clinical correlation of symptoms, such as shortness of breath, chronic cough, or wheezing, when evaluating hyperinflation on a chest X-ray
• The potential for technical factors, such as X-rays taken during deep inspiration, poor patient positioning, or if the film is taken from too close a distance, to create the appearance of hyperinflation. It is essential to note that hyperinflation can also be caused by other conditions, such as asthma, emphysema, cystic fibrosis, bronchiolitis, and foreign body aspiration, especially in children. Therefore, a thorough evaluation, including pulmonary function tests and clinical correlation of symptoms, is necessary to determine the underlying cause of hyperinflation and to guide treatment.

From the Research

Possible Causes of Slightly Hyperinflated Lungs on Chest X-ray

• Chronic Obstructive Pulmonary Disease (COPD): Lung hyperinflation is a common clinical feature in patients with COPD, resulting from a combination of reduced elastic lung recoil and expiratory airflow limitation 2.
• Airflow Limitation: Expiratory airflow limitation can lead to lung hyperinflation, as the lungs are not able to fully deflate 2, 3.
• Destruction of Lung Parenchyma: Irreversible destruction of lung parenchyma can contribute to lung hyperinflation, as the lungs lose their elastic recoil 2.
• Systemic Inflammation: Systemic inflammation is associated with various complications in COPD, including lung hyperinflation 4.

Factors that May Contribute to Hyperinflation

• Reduced Elastic Lung Recoil: Reduced elastic lung recoil can lead to lung hyperinflation, as the lungs are not able to fully deflate 2, 3.
• Expiratory Flow Limitation: Expiratory flow limitation can contribute to lung hyperinflation, as the lungs are not able to fully exhale 3.
• Eosinophilic Airway Inflammation: Eosinophilic airway inflammation may play a role in lung hyperinflation, although the relationship between eosinophilia and lung function is not fully understood 5.

Treatment and Management

• Pharmacological Interventions: Various pharmacological interventions, such as inhaled corticosteroids and long-acting beta2-adrenoceptor agonists, may help reduce lung hyperinflation and improve symptoms in COPD patients 2, 4, 5.
• Non-Pharmacological Interventions: Non-pharmacological interventions, such as lung deflating exercises, may also be beneficial in reducing lung hyperinflation and improving physical functioning 3.