What causes wheezing lung sounds?

Wheezing lung sounds are primarily caused by constricted airways. When the airways become narrow, such as during times of bronchospasm or airway edema, air flows through these restricted passages more rapidly and creates a high-pitched sound, which is recognized as wheezing. This phenomenon often occurs in conditions like asthma, chronic obstructive pulmonary disease (COPD), and bronchitis, where inflammation or spasms lead to narrowing of the airways.

In contrast, fluid accumulation in the lungs typically results in other abnormal lung sounds, such as crackles, instead of wheezing. Similarly, while infections in the lungs can cause a variety of respiratory symptoms and sounds, they are usually associated with other signs like cough or purulent sputum rather than specifically wheezing on their own. Inflammation of the pleura, or pleuritis, affects the pleura surrounding the lungs and may lead to sharp chest pain and pleuritic rubs rather than wheezing. Thus, the mechanism of airway constriction is central to the production of wheezing sounds.