Question 2

College Answer

Monophonic wheeze suggests large airway – ETT malposition, foreign body, blood, secretions, tumour, compression by lymph nodes, aortic aneurysm

Polyphonic wheeze suggests smaller airway and multiple sites – aspiration, unilateral emphysema, contralateral pneumothorax, asthma in a pneumonectomised lung

Diagnostic approach

1.  History of depressed conscious state, trauma, previous lung disease

2.  Examination for tracheal position, contralateral signs, position ETT, clubbing, lymphadenopathy elsewhere

a.   Consider complications such as intrinsic PEEP, depressed venous return and hypotension, pneumothorax

3.  CXR for ETT position, contralateral disease, foreign body

4.  Bronchoscopy for luminal pathology such as blood clot, foreign body, tumour, compression

5.  CT chest if necessary

Discussion

The differential diagnosis of a unilateral wheeze really comes down to how many different ways of obstructing a main bronchus you can think of.

This question could benefit from a systematic answer.

Differential diagnosis of unilateral wheeze:

• ETT malposition
• foreign body
• blood clot
• Sputum secretions
• Tumour
  • Bronchogenic carcinoma
  • Thymus carcinoma
  • Retrosternal goitre
• compression by lymph nodes
• compression by aortic aneurysm
• traumatic dissection
• Bronchial stenosis post infection
• Bronchiectasis
• Bronchial compression by enlarged left side of heart

• Immediate management:
  • Attention to ABCs, with simultaneous focused examination and the retrieval of a detailed history.
  • Assess the need for urgent intubation;
    • or, assess the position of the existing ETT, ensuring it ventilates both lungs
  • Administer high FiO2
  • Collect an ABG and perfrom a CXR
• Diagnostic strategies
  • CT of the chest to investigate lung parenchyma and find the cause of the obstruction
  • Bronchoscopy and biopsy of the lesion,
    • also permits aspiration/retriveal of the blood clot or foreign body, lavage of the lung for culture/cytology, and the potential stenting of the obstructed bronchus.
  • Alternatively, CT-guided biopsy