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Deteriorating Patient

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 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 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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