Adventitious lung sounds are abnormal sounds heard during auscultation.
Five main types: crackles (also known as rales), wheezes, rhonchi, stridor, and pleura friction rub.
Important Questions for Identification
Timing: Occurrence on inspiration, expiration, or both.
Pitch: Whether it's high or low pitched.
Nature: Discontinuous (individual sounds) or continuous (constant sound).
Location: Origin in large airways (trachea, bronchi) or smaller airways (alveoli, bronchioles).
Defining Characteristics: Unique qualities like harsh grading noise, squeaky, musical whistling, snoring, or squawking.
Types of Adventitious Lung Sounds
1. Crackles (Rales)
Fine Crackles
Timing: End of inspiration.
Pitch: High pitched.
Nature: Discontinuous, individual popping sounds.
Location: Small airways.
Characteristics: Popping or light crackling like fire, not cleared with coughing.
Causes: Occur due to deflated or collapsed alveoli or bronchioles reopening. Conditions include congestive heart failure, atelectasis, pneumonia, and pulmonary fibrosis.
Coarse Crackles
Timing: Beginning of inspiration, can extend into expiration.
Pitch: Low pitched.
Nature: Discontinuous.
Location: Large airways.
Characteristics: Gurgling or bubbling sound, not cleared with coughing.
Causes: Blocked large airways with fluid or thick mucus, such as in heart failure with pulmonary edema, severe pneumonia, bronchiectasis.
2. Wheezes
Timing: Mainly on expiration, but can occur on both.
Pitch: High pitched.
Nature: Continuous.
Location: Throughout the respiratory system.
Characteristics: Squeaky, musical whistling.
Causes: Narrowed airways due to asthma, COPD, or lung infections.
3. Rhonchi
Timing: Mainly on expiration, can occur on inspiration.
Pitch: Low pitched.
Nature: Continuous.
Location: Large airways.
Characteristics: Snoring or snorting sound, may decrease or clear with coughing.
Causes: Air passing through secretions in the trachea and bronchi, as in bronchitis, pneumonia.
4. Stridor
Timing: Inspiration or expiration.
Pitch: High pitched.
Nature: Continuous.
Location: Upper respiratory area (trachea, throat).
Characteristics: Screeching, squawking noise.
Causes: Narrowing of larynx/trachea from swelling or obstruction, potentially life-threatening. Conditions include epiglottitis, croup, anaphylaxis.
5. Pleura Friction Rub
Timing: Inspiration and expiration.
Pitch: Low pitched.
Nature: Discontinuous or continuous.
Location: Pleura layer.
Characteristics: Harsh grading sound.
Causes: Inflamed pleural layers rubbing against each other, seen in pleurisy, pneumonia, pulmonary embolism, tuberculosis, lung cancer.
Conclusion
Understanding these sounds can help identify various respiratory conditions.
Listening attentively to audio samples can enhance recognition skills.