Clinical scenario: dyspnea | jaundice | emphysema
A 13-year-old boy is referred for evaluation of progressive exertional dyspnea and recurrent episodes of wheeze that have shown minimal improvement with inhaled corticosteroids and bronchodilators. He has never smoked. Since infancy, he has had intermittent jaundice, and examination reveals mild hepatomegaly. His BMI is below the 10th centile.
Respiratory examination demonstrates reduced breath sounds bilaterally with a prolonged expiratory phase but no crackles. High-resolution CT of the chest shows predominantly basal panacinar emphysema. Spirometry demonstrates a severe obstructive ventilatory defect with poor reversibility.
Which is the most likely underlying diagnosis?
A. Alpha-1 antitrypsin deficiency
B. Allergic bronchopulmonary aspergillosis
C. Cystic fibrosis
D. Primary ciliary dyskinesia
E. Severe steroid-resistant asthma
Correct answer & Explanation:
Correct answer: A. Alpha-1 antitrypsin deficiency
Explanation:
This child has several features pointing to Alpha-1 antitrypsin (AAT) deficiency:
- Early-onset emphysema in a non-smoker
- Basal (lower lobe)-predominant panacinar emphysema (highly characteristic)
- Airflow obstruction with poor bronchodilator reversibility
- History of neonatal/childhood liver disease and persistent hepatomegaly
AAT deficiency results from mutations in the SERPINA1 gene. Deficiency of AAT allows unchecked neutrophil elastase activity, leading to destruction of alveolar walls and emphysema. Misfolded AAT protein accumulates in hepatocytes, causing liver disease.
Why the other options are incorrect
B. Allergic bronchopulmonary aspergillosis
- Usually occurs in patients with asthma or cystic fibrosis.
- Characterized by eosinophilia, markedly elevated IgE, and central bronchiectasis.
C. Cystic fibrosis
- Causes recurrent chest infections, bronchiectasis, pancreatic insufficiency, and malabsorption rather than isolated basal emphysema.
D. Primary ciliary dyskinesia
- Causes chronic sinusitis, recurrent otitis media, bronchiectasis, and sometimes situs inversus, not emphysema.
E. Severe steroid-resistant asthma
- Does not explain childhood liver disease or basal panacinar emphysema.
MRCPCH Pearl
In a child or adolescent with COPD-like airflow obstruction or emphysema, particularly when:
- there is no smoking history,
- emphysema is basal (panacinar) rather than apical,
- and there is coexisting liver disease,
Alpha-1 antitrypsin deficiency should be the first diagnosis to consider.
