Rales

From Wikipedia, the free encyclopedia

Name of Symptom/Sign:
**Rales**
*Classifications and external resources*
ICD-10	R09.8
ICD-9	786.7

Rales, crackles or crepitations, are the clicking, rattling, or crackling noises heard on auscultation of the lungs with a stethoscope during inhalation. The sounds are caused by the "popping open" of small airways and alveoli collapsed by fluid, exudate, or lack of aeration during expiration.

Rales can be heard in patients with pneumonia, atelectasis, pulmonary fibrosis, acute bronchitis, or bronchiectasis. Pulmonary edema secondary to left-sided congestive heart failure can also cause rales.

[edit] The sound of rales

Crackles (or rales) are caused by explosive opening of small airways. Crackles are referred to as discontinuous sounds; they are intermittent, nonmusical and brief. Crackles may be heard on inspiration or expiration. Crackles are often associated with inflammation or infection of the small bronchi, bronchioles, and alveoli. Crackles that don't clear after a cough may indicate pulmonary edema or fluid in the alveoli due to heart failure or adult respiratory distress syndrome (ARDS).

Crackles are often described as fine, medium, and coarse.They can also be characterized as to their timing: fine crackles are usually late-inspiratory, whereas coarse crackles are early inspiratory.
Fine crackles are soft, high-pitched, and very brief. You can simulate this sound by rolling a strand of hair between your fingers near your ear, or by moistening your thumb and index finger and separating them near your ear. Their presence usually indicates an interstitial process, such as pulmonary fibrosis or congestive heart failure.
Coarse crackles are somewhat louder, lower in pitch, and last longer than fine crackles. They have been described as sounding like opening a Velcro fastener. Their presence usually indicates an airway disease, such as bronchiectasis.