Rales are abnormal sounds heard within the lungs during breathing. These sounds can sometimes indicate an underlying change in lung function. Understanding what rales are and what they might signify can help individuals recognize when medical attention is needed.
The Distinct Sounds of Rales
Rales, also known as crackles, are discontinuous lung sounds. They can be compared to various everyday noises, such as the sound of salt dropped onto a hot pan or the crumpling of cellophane. Another common analogy for fine crackles is the sound of pulling apart a Velcro fastener. These sounds are often heard when a person breathes in.
Fine rales are typically short, high-pitched, and very brief sounds. Imagine the soft crackling of hair being rubbed between your fingers near your ear. Fine crackles are usually heard in the lower lung bases and occur in mid to late inspiration.
Coarse rales, in contrast, are louder, lower in pitch, and last longer than fine rales. These sounds might be described as rattling, bubbling, or clicking noises. Coarse rales are often likened to the slurping of a drink through a straw.
Why Rales Occur
Rales are believed to occur when air moves through airways that contain fluid or mucus. They can also happen when previously collapsed small airways or air sacs in the lungs suddenly open during inspiration. This mechanism involves the rupture of fluid bridges or mucus bubbles. As the airways open, these ruptures create audible vibrations, resulting in the crackling or bubbling sound.
Fluid or secretions in the air sacs, known as alveoli, or in the small airways can cause these sounds. When air attempts to fill these air sacs, they can produce a crackling sound if they are weighed down with fluid or mucus. Stiff lungs can also make crackling sounds with deep breathing. The presence of fluid in the lungs, inflammation, or blockages in the airways can all contribute to the generation of rales.
What Rales Might Indicate
Rales are a symptom that can signal various underlying conditions affecting the lungs. They are not a diagnosis on their own, but rather an indication that further medical evaluation may be necessary.
It is important to seek professional medical evaluation if rales are heard, especially if they are accompanied by other symptoms such as shortness of breath, a cough, or fever. A healthcare professional uses a stethoscope to properly identify and interpret lung sounds within the context of a complete medical assessment. This comprehensive evaluation helps to determine the underlying cause and guide appropriate treatment.