Overview
This lecture reviews five main types of adventitious (abnormal) lung sounds, their distinguishing features, causes, and associated respiratory conditions.
Types of Adventitious Lung Sounds
Crackles (Rales)
- Crackles are abnormal, discontinuous lung sounds, divided into fine and coarse types.
- Fine crackles are brief, high-pitched, heard at end of inspiration, and sound like popping or crackling fire.
- Fine crackles originate from small airways and are not cleared by coughing; seen in CHF, atelectasis, pneumonia, pulmonary fibrosis.
- Coarse crackles are longer, low-pitched, heard at start of inspiration (sometimes expiration), and sound like gurgling or bubbling.
- Coarse crackles are located in large airways, not cleared by coughing; seen in heart failure with pulmonary edema, severe pneumonia, bronchiectasis.
Wheezes
- Wheezes are continuous, high-pitched musical or whistling sounds, mainly on expiration.
- Wheezes are heard throughout the respiratory system and are due to narrowed airways (e.g., asthma, COPD, viral infections).
Rhonchi
- Rhonchi are continuous, low-pitched, snoring or snorting sounds, primarily on expiration but can occur during inspiration.
- Located in large airways and may clear with coughing or suctioning; associated with bronchitis, pneumonia, COPD.
- Some sources classify rhonchi as a type of coarse crackle or wheeze.
Stridor
- Stridor is a continuous, high-pitched screeching or squawking sound heard on inspiration or expiration, mainly in the upper airway.
- Indicates narrowing of the larynx or trachea (e.g., epiglottitis, croup, anaphylaxis, foreign body), and can be life-threatening.
Pleural Friction Rub
- Pleural friction rub is a harsh, grating sound heard on both inspiration and expiration, sometimes continuous or discontinuous.
- Originates from inflamed pleural layers rubbing together, often causes pain on deep breathing or coughing.
- Seen in pleurisy, pneumonia, pulmonary embolism, tuberculosis, lung cancer.
Assessment Tips
- Assess timing (inspiration vs. expiration), pitch, continuity (discontinuous vs. continuous), location, and unique sound characteristics to identify the lung sound type.
Key Terms & Definitions
- Adventitious Lung Sounds — Abnormal breath sounds heard during auscultation.
- Crackles (Rales) — Discontinuous, popping respiratory sounds from collapsed or fluid-filled airways.
- Wheezes — Continuous, high-pitched, musical sounds from narrowed airways.
- Rhonchi — Continuous, low-pitched, snoring sounds from secretions in large airways.
- Stridor — High-pitched, harsh respiratory sound from upper airway obstruction.
- Pleural Friction Rub — Grating sound from inflamed pleural surfaces rubbing together.
Action Items / Next Steps
- Review the characteristics and causes of each adventitious lung sound.
- Practice identifying lung sounds with provided audio examples.
- Refer to facility/professor guidelines for classifying rhonchi.