Wheezing is a symptom characterized by a continuous coarse audible whistling sound when a patient breathes. Wheezing indicates that part of the airways in the respiratory systm have been narrowed. It is common among patients which chronic diseases of the lungs, although the most common cause of wheezing is asthma.
Wheezing can occur either when a patient inhales or exhales. If it presents on exhallation, it most likely is the result of a constriction in the brochial airways of the lungs. Wheezing on inhallation often indicates an obstruction such as a scar, tumor or physical obstruction. Wheezing during both inhallation and exhallation usually indicates problems deep in the lung, often occurring just before a pneumothorax.
A physician will often use a stethoscope to pinpoint the location of the wheezing. If the volume is consistent throughout the chest and back, the problem is most likely throughout the respiratory tract. However, where the problem is localized, the volume will be loudest at that point and will get quieter further away from it.