Breath sounds

Alternative names:

auscultation of the lungs; chest sounds - lung; lung sounds - abnormal; rales; rhonchi

Definition:

The sounds produced by the structures of the lungs during breathing.

Considerations:

The lung sounds are usually examined by listening with a stethoscope.

Normal lung sounds occur in all parts of the chest area, including above the collarbones and as low as the bottom of the rib cage. When listening to the lungs, the categories of findings include normal breath sounds, decreased or absent breath sounds, and abnormal breath sounds.

Absent or decreased sounds are inaudible (absent) or reduced in loudness (decreased) when the lungs are examined with a stethoscope. They reflect reduced airflow to a portion (segment) of the lungs, over inflation of a portion of the lungs (such as with emphysema), air or fluid around the lungs, or sometimes increased thickness of the chest wall.

There are several types of abnormal breath sounds: rales, rhonchi, and wheezes are the most common. Wheezing can sometimes be heard without a stethoscope, and other abnormal sounds are sometimes also loud enough to be detected with the unaided ear.

Rales (crackles or crepitations) are small clicking, bubbling, or rattling sounds in a portion of the lung. They occur when air moves through fluid-filled airways. Rales are further described as moist, dry, whistling, fine, coarse, or other descriptions.

Rhonchi are sounds with a loud, low, coarser sound. They may be further described as musical, groaning, snoring, and so on. They are produced when the larger airways are filled with fluid.

Wheezes are high-pitched, musical sounds produced by narrowed airways, occurring during expiration.

Common causes:

• lung tumors
• foreign body obstruction of the airway
• mucus plugs in the airway
• emphysema
• asthma
• obesity (thick chest wall)
• extremely muscular people (thick chest wall)
• adult respiratory distress syndrome (ARDS)
• bronchiectasis
• chronic bronchitis
• acute bronchitis
• interstitial fibrosis
• Legionnaire's disease
• lung abscess
• pneumonia
• atypical pneumonia
• psittacosis
• pulmonary edema
• pulmonary tuberculosis
• sarcoidosis
• tracheobronchitis

Note: See also wheezing.

Note: There may be other causes of abnormal breath sounds. This list is not all inclusive, and the causes are not presented in order of likelihood. The causes of this symptom can include unlikely diseases and medications. Furthermore, the causes may vary based on age and gender of the affected person, as well as on the specific characteristics of the symptom such as location, quality, time course, aggravating factors, relieving factors, and associated complaints. Use the Symptom Analysis option to explore the possible explanations for abnormal breath sounds, occurring alone or in combination with other problems.