What are the symptoms and treatment options for a patient presenting with volume loss on a chest X-ray?

Symptoms of Volume Loss on Chest X-Ray

Volume loss on chest X-ray manifests as decreased lung volumes with specific radiographic signs including ipsilateral hemidiaphragm elevation, mediastinal shift toward the affected side, rib crowding, and compensatory hyperinflation of the contralateral lung. 1

Key Radiographic Features

Direct signs of volume loss include:

• Displacement of interlobar fissures toward the area of volume loss 1
• Ipsilateral hemidiaphragm elevation due to reduced lung volume pulling the diaphragm upward 1
• Mediastinal shift toward the side of volume loss, particularly evident with the tracheal deviation 1
• Rib crowding on the affected side with narrowed intercostal spaces 1

Indirect compensatory signs include:

• Contralateral lung hyperinflation as the unaffected lung expands to fill available thoracic space 2
• Hilar displacement toward the area of volume loss 1

Clinical Context and Associated Symptoms

Patients with volume loss typically present with:

• Dyspnea or shortness of breath, which is the primary symptom driving evaluation 1, 3
• Reduced exercise tolerance and functional capacity 1
• Cough, which may be chronic and is a common presenting complaint 3
• Pleuritic chest pain in some cases, particularly when pleural disease is involved 1, 3

The degree of dyspnea depends on both the volume of lung affected and the underlying condition of the remaining lung parenchyma 1. Importantly, significant underlying pathology can exist even when symptoms are minimal or absent 1.

Common Etiologies to Consider

Volume loss has distinct causes that guide management:

Obstructive causes:

• Endobronchial tumor or mucus plug causing lobar or segmental collapse 1
• Mainstem bronchial occlusion preventing lung expansion 1

Restrictive causes:

• Trapped lung from extensive pleural tumor infiltration, particularly in malignant pleural mesothelioma where nodular pleural thickening encases the lung 1
• Pleural adhesions from previous pleurodesis or repeated thoracentesis 1
• Pulmonary fibrosis with characteristic peripheral reticular opacities and decreased lung volumes 1

Cardiac causes:

• Right ventricular volume overload from conditions like atrial septal defect can alter hemithoracic volumes 1

Diagnostic Approach

When volume loss is identified on chest X-ray, the following algorithmic approach is recommended:

1. Obtain frontal and lateral chest radiographs to fully characterize the volume loss pattern and identify associated findings 1

2. Assess for pleural effusion - if present with volume loss and no contralateral mediastinal shift, suspect trapped lung or endobronchial obstruction 1

3. Measure pleural fluid pressure during thoracentesis if effusion is present - initial pressure <10 cm H₂O makes trapped lung likely 1

4. Proceed to cross-sectional imaging with CT to determine the extent of disease and differentiate between causes 1:

   • High-resolution CT is essential for evaluating parenchymal lung disease like fibrosis 1
   • CT with three planes of imaging helps assess pleural disease and chest wall invasion 1

5. Perform bronchoscopy if endobronchial obstruction is suspected to identify tumor or mucus plugging 1

6. Consider thoracoscopy if pleural disease is suspected and tissue diagnosis is needed 1

Critical Pitfalls to Avoid

Do not rely on chest X-ray alone - sensitivity for detecting pulmonary pathology ranges from only 43.5% to 73%, meaning significant disease can be missed 4, 5. Normal chest X-ray does not exclude serious underlying pathology 4, 6.

Do not attempt pleurodesis without confirming complete lung expansion - failure of the lung to expand after pleural drainage indicates either endobronchial obstruction or trapped lung, both of which are contraindications to pleurodesis 1.

Recognize that portable AP films can overestimate cardiac size - cardiothoracic ratio >0.55 on AP films (versus >0.5 on PA films) is needed to diagnose cardiomegaly 6. Volume loss can also alter the apparent cardiac silhouette 7.

In patients with known asbestos exposure and volume loss, maintain high suspicion for malignant pleural mesothelioma, which typically presents with nodular pleural thickening, unilateral pleural effusion, and hemithoracic volume loss 1.

Treatment Considerations

Management depends entirely on the underlying cause:

For obstructive causes:

• Bronchoscopic intervention to remove obstructing lesions or mucus 1
• Surgical resection if malignant endobronchial tumor is identified 1

For trapped lung:

• Avoid pleurodesis attempts as they will fail and cause unnecessary morbidity 1
• Consider pleurectomy or decortication in select cases with good performance status 1

For pulmonary fibrosis:

• Initiate antifibrotic therapy with pirfenidone 2,403 mg/day in three divided doses with food for idiopathic pulmonary fibrosis, which reduces decline in FVC by approximately 193 mL compared to placebo 8

For cardiac causes:

• Treat underlying heart failure with guideline-directed medical therapy including ACE inhibitors, beta-blockers, and diuretics 7, 6
• Consider device closure for hemodynamically significant atrial septal defects with RV volume overload 1