Clinical scenario: recurrent chest infections | Lung collapse | mucous secretions
A 4-year-old boy is admitted with recurrent episodes of cough, wheeze, and difficulty breathing over the past year. He has required multiple courses of antibiotics for “recurrent pneumonia”. Examination reveals reduced air entry over the left lower chest.
Chest X-ray shows persistent left lower lobe collapse with volume loss. Bronchoscopy demonstrates that the left lower lobe bronchus is patent, with no foreign body or endobronchial lesion. Bronchoalveolar lavage shows thick mucus secretions.
Which underlying condition is most likely responsible for this recurrent lobar collapse?
A. Cystic fibrosis
B. Foreign body aspiration
C. Pleural effusion
D. Primary pulmonary tuberculosis
E. Congenital diaphragmatic hernia
Correct answer & Explanation:
Correct answer: A. Cystic fibrosis
Explanation:
Persistent or recurrent lobar collapse despite a patent bronchus suggests that the collapse is due to mucus plugging rather than an obstructing lesion.
In children, conditions causing excessive or thick airway secretions include:
- Cystic fibrosis (classically)
- Severe asthma
- Primary ciliary dyskinesia
Cystic fibrosis causes abnormal chloride transport leading to viscous mucus, recurrent airway obstruction, infection, and areas of atelectasis.
Why other options are incorrect:
- B. Foreign body aspiration: Usually causes bronchial obstruction; bronchoscopy would show a blocked bronchus.
- C. Pleural effusion: Causes compression collapse, not mucus-related lobar collapse.
- D. Tuberculosis: May cause lymph node compression of bronchi, but persistent collapse with a patent bronchus and thick mucus points elsewhere.
- E. Congenital diaphragmatic hernia: Presents in the neonatal period and causes lung hypoplasia.
Exam pearl:
When a child has persistent lobar collapse:
- Bronchus blocked → foreign body, tumour, lymph node compression
- Bronchus patent → mucus plugging, asthma, CF, ciliary disorders
