Swyer-James-MacLeod Syndrome
Swyer-James-MacLeod Syndrome
Swyer-James-MacLeod Syndrome (SJMS), also known as unilateral hyperlucent lung syndrome, is a rare pediatric condition characterized by emphysema-like changes in one lung or lobe. It is typically a result of post-infectious bronchiolitis obliterans occurring in early childhood.
Key Points:
- Rare condition affecting one lung or lobe
- Usually caused by post-infectious bronchiolitis obliterans
- Characterized by hyperlucency on chest X-ray
- Often diagnosed incidentally in older children or adults
Etiology
SJMS is believed to be an acquired condition, typically resulting from a severe lower respiratory tract infection during early childhood. The most common causative agents include:
- Adenovirus (most frequent)
- Mycoplasma pneumoniae
- Influenza A
- Measles virus
- Bordetella pertussis
The infection leads to bronchiolitis obliterans, causing:
- Inflammation and fibrosis of terminal and respiratory bronchioles
- Obstruction of small airways
- Impaired alveolar development
- Reduced pulmonary arterial flow
Clinical Presentation
Symptoms can vary widely, from asymptomatic cases to severe respiratory distress. Common presentations include:
- Recurrent respiratory infections
- Chronic productive cough
- Dyspnea on exertion
- Hemoptysis (rare)
- Wheezing
- Chest pain
Physical examination may reveal:
- Decreased breath sounds on the affected side
- Hyperresonance to percussion
- Chest wall asymmetry (in severe cases)
Diagnosis
Diagnosis of SJMS typically involves a combination of imaging studies and functional tests:
Imaging:
- Chest X-ray: Unilateral hyperlucency with small hilar shadow
- CT scan: Confirms hyperlucency, bronchiectasis, and air trapping
- Ventilation-perfusion scan: Decreased ventilation and perfusion in affected area
Functional Tests:
- Pulmonary function tests: Obstructive pattern with decreased FEV1 and FVC
- Bronchoscopy: May show narrowed bronchi and increased collapsibility
Differential diagnosis should include:
- Congenital lobar emphysema
- Pneumothorax
- Foreign body aspiration
- Pulmonary embolism
Treatment
Management of SJMS is primarily supportive and aims to prevent complications:
- Prompt treatment of respiratory infections
- Bronchodilators for symptomatic relief
- Chest physiotherapy and postural drainage
- Pneumococcal and influenza vaccinations
- Smoking cessation counseling (for older patients)
In severe cases or complications:
- Long-term oxygen therapy may be required
- Surgical intervention (lobectomy or pneumonectomy) in cases of recurrent infections or significant symptoms
Prognosis
The prognosis for patients with SJMS is generally good, especially if diagnosed and managed early:
- Many patients remain asymptomatic or have mild symptoms
- Regular follow-up is essential to monitor lung function and prevent complications
- Severe cases may experience progressive respiratory insufficiency
- Complications can include recurrent pneumonia, bronchiectasis, and hemoptysis
Long-term outcomes depend on:
- Extent of initial lung damage
- Presence of associated bronchiectasis
- Adherence to treatment and prevention strategies
