Meaning of Rhonchi on Lung Exam
Rhonchi are low-pitched, continuous rumbling lung sounds (approximately 200 Hz or less) that indicate airway secretions or obstruction, most commonly heard during forced expiration, and while they suggest underlying respiratory pathology, they are not specific enough to diagnose any particular disease without objective testing. 1, 2
Acoustic Characteristics
- Rhonchi are continuous adventitious sounds with a dominant frequency of about 200 Hz or less, distinguishing them from higher-pitched wheezes (≥400 Hz) 1, 2
- They are especially prominent during forced expiration 3, 1
- Unlike other adventitious sounds, rhonchi may clear or change after coughing as secretions move within the airways 1, 4
Clinical Significance and Associated Conditions
Rhonchi indicate the presence of airway secretions or obstruction but are found across multiple respiratory conditions: 1
Common Associated Diseases:
- Chronic Obstructive Pulmonary Disease (COPD) - particularly in moderate to severe disease 3, 1
- Bronchiectasis - commonly presents with variable degrees of rhonchi and crackles 4
- Acute and chronic bronchitis - frequently associated with airway secretions 1, 4
- Pneumonia - may present with rhonchi among other findings 1
Critical Diagnostic Limitations
The presence of rhonchi alone is insufficient for diagnosis and has important limitations: 3
- Rhonchi cannot predict the degree or severity of airway obstruction 3, 1
- Physical examination findings including rhonchi are not sufficiently diagnostic to determine the specific underlying condition 3, 1, 4
- The presence or absence of rhonchi does not reliably correlate with objective measures like spirometry or high-resolution CT findings 4
Recommended Clinical Approach
When rhonchi are detected, the following systematic evaluation is required: 1, 4
Immediate Assessment:
- Document whether rhonchi are present at rest or only on forced expiration 3
- Assess if sounds clear with coughing (suggests mobile secretions) 1
- Look for associated findings: cyanosis, peripheral edema, signs of overinflation, clubbing 3, 4
Mandatory Objective Testing:
- Spirometry with bronchodilator response is essential to confirm and quantify airway obstruction (FEV1, FEV1/FVC ratio) 3, 5
- Chest radiograph initially; high-resolution CT if bronchiectasis is suspected based on clinical context 4
- Sputum cultures if chronic productive cough is present 4
Key Clinical Pitfall:
Never rely on rhonchi alone to guide treatment decisions - the British Thoracic Society emphasizes that diagnosis rests on objective demonstration of airways obstruction by spirometric testing, not physical examination findings 3