Swyer-James Syndrome

Also called Swyer-James-MacLeod syndrome: a unilateral (or occasionally lobar or bilateral) hyperlucent lung of reduced size and reduced perfusion, caused by post-infectious obliterative bronchiolitis in early childhood, with the lung failing to develop normally.

• Typical causes in the first 8 years of life: adenovirus (types 3, 7 and 21), measles, influenza, respiratory syncytial virus, pertussis, Mycoplasma, and tuberculosis.
• Rare: prevalence is not known; it is found in about 0.01% of chest X-rays and reported more often in regions with a high burden of childhood measles and adenovirus infection.
• Mechanism: bronchiolitis obliterans after infection arrests alveolar and pulmonary artery growth, leaving an air-trapped, hypoperfused, small lung with collateral ventilation.

Many are asymptomatic and found incidentally on a chest X-ray.

• Symptoms: recurrent chest infections, cough, wheeze, exertional breathlessness, reduced exercise tolerance, haemoptysis, sputum production.
• Examination: reduced chest expansion on the affected side, hyperresonance, reduced breath sounds, expiratory wheeze, crackles.
• Differential diagnosis: congenital lobar emphysema, pneumothorax, foreign body with air trapping, bronchial atresia, pulmonary artery agenesis or hypoplasia, bronchiectasis, asthma, Poland syndrome (chest wall abnormality), obliterative bronchiolitis after transplant, lung cancer with obstruction.
• Complications: recurrent infection, bronchiectasis (common in the affected lobe), haemoptysis (bleeding from bronchial arteries), respiratory failure, pulmonary hypertension (late), and rarely pneumothorax.

Chest X-ray: unilateral hyperlucent lung with small hilum and decreased vascular markings, and air trapping on expiration with the mediastinum shifting toward the normal side.

• High-resolution CT with expiratory images: hyperlucent lung with mosaic attenuation, air trapping, pruned small vessels, small ipsilateral pulmonary artery, bronchiectasis, and normal or hyperinflated contralateral lung.
• Ventilation and perfusion scan: matched or reduced ventilation and markedly reduced perfusion in the affected lung.
• Pulmonary function: obstruction (FEV1/FVC less than 0.70), reduced FEV1, air trapping (raised residual volume), reduced diffusing capacity, poor bronchodilator response.
• Bronchoscopy for suspected foreign body or stenosis; sputum cultures (including mycobacteria); full blood count and immunoglobulins when infections are frequent.

Asymptomatic patients: no treatment, explanation, vaccination and avoidance of smoke.

• Prevention of infection: annual influenza vaccine, pneumococcal conjugate vaccine, and early treatment of respiratory infections.
• Airway clearance: active cycle of breathing technique, oscillating positive expiratory pressure device, chest physiotherapy; hypertonic saline 3% to 7% 4 mL nebulised twice daily after salbutamol 2.5 mg for bronchiectasis.
• Antibiotics for exacerbations guided by sputum: amoxicillin-clavulanate 625 mg three times daily for 7 to 14 days (children 25 to 30 mg/kg of amoxicillin component three times daily); ciprofloxacin 500 mg twice daily for Pseudomonas (750 mg in severe infection).
• Prevention of frequent exacerbations (three or more a year): azithromycin 250 mg once daily or 500 mg three times weekly for 6 to 12 months, after ECG (QTc less than 450 ms) and checks for non-tuberculous mycobacteria and hearing; stop if the QT interval lengthens.
• Bronchodilators: salbutamol 100 micrograms as needed, tiotropium 18 micrograms once daily, or formoterol 12 micrograms twice daily in obstructive disease; inhaled corticosteroids (budesonide 400 micrograms twice daily) for asthma-like features (benefit is limited).
• Haemoptysis: tranexamic acid 1 g three times daily for 3 to 5 days, bronchial artery embolisation for moderate to massive bleeding (more than 100 mL in 24 hours), and surgery if embolisation fails.
• Surgery (lobectomy or pneumonectomy) for localised severe bronchiectasis with recurrent infection, recurrent or massive haemoptysis, or destroyed lung, with preoperative assessment of the contralateral lung.
• Oxygen: long-term oxygen for PaO2 of 7.3 kPa or less; pulmonary rehabilitation; smoking cessation (varenicline 0.5 mg once daily for 3 days, 0.5 mg twice daily for 4 days, then 1 mg twice daily for 12 weeks).
• Special groups: children (growth is monitored; vaccination; many remain stable, and bronchiectasis is managed with physiotherapy and antibiotic courses); pregnancy (usually tolerated with normal contralateral lung; physiotherapy, avoid fluoroquinolones and doxycycline); elderly (prevention of infection and falls); renal impairment (adjust ciprofloxacin); immunosuppression (check immunoglobulins; treat infections early).
• Red flags: haemoptysis, fever with purulent sputum, respiratory failure, new pulmonary hypertension signs, weight loss, abnormal findings in the opposite lung.
• Follow-up: review yearly with spirometry and oximetry; chest X-ray when symptoms change; CT every 2 to 3 years or with deterioration; sputum culture at each exacerbation; echocardiogram if symptoms of pulmonary hypertension appear.