Lung Auscultation
February 15th, 2021
Breath Sounds
Interpretation
- Vesicular breath sounds: soft, non-musical, heard in inspiration and early expiration
- Bronchial breath sounds - hollow sounds similar to those normally heard over the trachea
Causes of Reduced Breath Sounds
- Shallow breathing - e.g. due to anxiety or CNS depression
- Obstruction - foreign body, tumour, asthma, COPD
- Pleural effusion
- Pneumothorax
- Obesity
Stridor
Stridor refers to musical, high-pitched heard in the upper airways or even without a stethoscope. This finding is suggestive of upper airway obstruction.
Causes
- Soft tissue swelling - peritonsillar abscess, epiglottitis
- Deformity - laryngomalacia, laryngeal mass / web, tracheomalacia
- Foreign body aspiration (infants)
- Laryngotracheobronchitis (croup)
- Vocal cord lesion / paralysis
- Psychogenic stridor
Wheeze
Wheeze refers to high-pitched musical sounds, which suggest small airway narrowing.
Causes
- Asthma
- Chronci obstructive pulmonary disease (COPD)
- Viral bronchospasm
- Bronchiectasis
- Pulmonary oedema
- Aspiration
- Bronchial / tracheal obstruction - foreign body, tumour, stenosis
- Churg-Strauss syndrome
- Carcinoid syndrome
- Allergic bronchopulmonary aspergillosis (ABPA)
Crackles / Crepitations
Crackles / crepitations are short, explosive sounds. These may be fine or coarse, and may be cleared by coughing (if due to secretions)
Causes
Coarse Crepitations
- Pneumonia
- Bronchiectasis
- Chronic bronchitis
- Pulmonary oedema - congestive cardiac failure, fluid overload
Fine Crepitations
- Interstitial lung fibrosis
Pleural Rub
A pleural rub is a classical sign of pleural inflammation, or pleurisy.
Listen For
- Non-musical, explosive sounds best heard at the lung bases
Causes of Pleurisy
- Infection - viral, bacterial, tuberculosis, fungal
- Malignancy - lung cancer, mesothelioma, lymphoma
- Autoimmune - rheumatoid arthritis, SLE
- Pulmonary embolism
- Familial Mediterranean fever
- Asbestosis
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