What is fibrothorax?

What is Fibrothorax?

Fibrothorax is a condition characterized by extensive pleural fibrosis that encases the lung, restricting its expansion and causing restrictive lung function impairment. 1, 2

Definition and Pathophysiology

Fibrothorax represents the end-stage consequence of pleural inflammation where thick, inelastic fibrous tissue forms over the visceral and parietal pleura, creating a rigid "peel" that prevents normal lung expansion. 2 This fibrotic process can result from various inflammatory insults to the pleural space, with the response of pleural mesothelial cells to injury determining whether normal healing or pathologic fibrosis occurs. 2

The condition can be conceptually divided into two clinical horizons: 3

• Pleural fibrosis - primarily involving the pleural surfaces
• Lung parenchymal fibrosis - extending into the underlying lung tissue

Common Etiologies

The most frequent causes include: 1, 3, 2

• Asbestos exposure - particularly in workers with prolonged occupational contact (insulators, shipyard workers, construction trades)
• Tuberculous pleuritis - a major cause in endemic regions
• Empyema - especially when inadequately drained or treated
• Hemothorax - particularly when blood is not evacuated promptly
• Uremic pleuritis - in patients with end-stage renal failure 1
• Iatrogenic causes - including complications from ventriculopleural shunts 4

Calcification may develop within the fibrothorax and can occur on both parietal and visceral pleural surfaces, contrary to older teaching that suggested only visceral pleural involvement. 5

Clinical Presentation

Dyspnea on exertion is the predominant symptom, typically mild in most cases but present in approximately 95% of patients with diffuse pleural thickening or fibrothorax. 1 Additional features include:

• Chest pain - present in more than half of patients, usually intermittent but constant in 9% 1
• Restrictive ventilatory defect - found in approximately one-third of cases 1
• Physical examination - may reveal decreased breath sounds and reduced chest wall expansion on the affected side 3

Diagnostic Approach

Diagnosis requires: 1, 3

• Chest imaging - plain radiography showing pleural thickening with or without calcification
• CT scanning - better delineates extent of pleural thickening and underlying lung parenchymal changes
• Pulmonary function tests - typically demonstrate restrictive physiology with reduced lung volumes
• Occupational/exposure history - essential for identifying asbestos-related disease, requiring documentation of exposure occurring 15+ years before presentation 1

Rapidly progressive or severe chest pain should raise immediate suspicion for either malignancy (mesothelioma, metastatic disease) or active nonmalignant pleuritis requiring tissue diagnosis. 1, 6

Important Clinical Pitfalls

• Chronic fibrothorax may envelop a fluid-filled cavity that can become infected after prolonged latency, often associated with bronchopleural or pleurocutaneous fistula formation 5
• Adequate pleural drainage during acute inflammatory processes is the physician's responsibility and represents the primary prevention strategy for pleural fibrosis, while patient medication compliance is more relevant for preventing primary parenchymal fibrosis 3
• Tissue sampling in fibrothorax is challenging with standard flexible forceps, and novel techniques such as electrosurgical biopsy may be required to obtain adequate samples for distinguishing malignant from benign disease 6

Management Considerations

Treatment of established fibrothorax is primarily surgical: 1

• Decortication - surgical removal of the fibrous peel to allow lung re-expansion
• Lung release procedures - may improve lung function and clinical course in selected cases 1

However, these invasive interventions carry significant morbidity, particularly in elderly or frail patients with end-stage renal disease. 1 The decision for surgical intervention must weigh the restrictive physiology severity against operative risks and patient functional status.