Lecture Notes: Adventitious Lung Sounds

Introduction

• Adventitious lung sounds are abnormal sounds during auscultation.
• Five main types to know:
  1. Crackles (Fine and Coarse)
  2. Wheezes
  3. Ronchi
  4. Stridor
  5. Pleurofriction Rub

Key Questions to Identify Lung Sounds

1. Timing:
   • Inspiration, expiration, or both?
2. Pitch:
   • High-pitched or low-pitched?
3. Continuity:
   • Discontinuous (individual sounds) or continuous (sustained sound)?
4. Location:
   • Large airways (trachea, large bronchi) or small airways (alveoli, bronchioles)?
5. Defining Characteristic:
   • Unique sound descriptions like grating, squeaky, or snoring?

Types of Adventitious Lung Sounds

Crackles

Fine Crackles

• Timing: End of inspiration
• Pitch: High-pitched
• Continuity: Discontinuous
• Location: Small airways
• Sound Characteristic: Popping or light crackling, not cleared by coughing.
• Causes: Air entering deflated small airways (e.g., congestive heart failure, atelectasis, pneumonia, pulmonary fibrosis).

Coarse Crackles

• Timing: Beginning of inspiration, can extend into expiration
• Pitch: Low-pitched
• Continuity: Discontinuous
• Location: Large airways (bronchi)
• Sound Characteristic: Gurgling or bubbling, not cleared by coughing.
• Causes: Air in partially blocked large airways (e.g., heart failure, pneumonia, bronchiectasis).

Wheezes

• Timing: Loudest on expiration but can occur on inspiration
• Pitch: High-pitched
• Continuity: Continuous
• Location: Throughout respiratory system
• Sound Characteristic: Squeaky, musical whistling
• Causes: Narrowed airways (e.g., asthma, COPD, infections).

Ronchi

• Timing: Mainly on expiration, can occur on inspiration
• Pitch: Low-pitched and loud
• Continuity: Continuous
• Location: Large airways (trachea, bronchi)
• Sound Characteristic: Snoring or snorting, can be decreased with suctioning/coughing.
• Causes: Secretions in airways (e.g., bronchitis, pneumonia, COPD).

Stridor

• Timing: Inspiration or expiration
• Pitch: High-pitched
• Continuity: Continuous
• Location: Upper respiratory system (trachea/throat)
• Sound Characteristic: Screeching or squawking
• Causes: Narrowed larynx/trachea (e.g., epiglottitis, croup, anaphylaxis).

Pleurofriction Rub

• Timing: Inspiration and expiration
• Pitch: Low-pitched
• Continuity: Can be discontinuous or continuous
• Location: Pleura layers (visceral and parietal)
• Sound Characteristic: Harsh grating
• Causes: Inflamed pleural layers (e.g., pleurisy, pneumonia, pulmonary embolism).

Conclusion

• Each type of adventitious lung sound varies by timing, pitch, continuity, location, and defining characteristics.
• Correct identification is crucial for diagnosing underlying conditions.

For further learning, refer to additional resources provided in the respiratory series.