While this procedure usually generates only limited scar tissue, in rare cases a fibrothorax can develop. Mechanism
Fibrosis can affect one or both of the two layers of tissue forming the pleura—the visceral pleura adjacent to the lung and the parietal pleura adjacent to the ribcage. The term fibrothorax implies severe fibrosis affecting both the visceral and the outer (parietal) pleura, fusing the lung to the chest wall. The condition starts as an undrained pleural effusion. Over time, the undrained pleural effusion causes sustained inflammation of the pleura, which can then lead to deposition of fibrin in the pleura and the development of a fibrotic scar. Eventually, a "peel" that is rich in collagen forms around the fluid collection. From this point, the illness can no longer be treated with thoracentesis, since the fluid will return to the cavity maintained by the peel.Over time, generally over the years, the fibrotic scar tissue slowly tightens and thickens, contracting the contents of one or both halves of the chest and reducing the mobility of the ribs. The peel can become deeper than 2 cm. Within the chest, the lung is compressed and unable to expand (trapped lung), making it vulnerable to collapse and causing breathlessness. Restrictive lung disease from fibrothorax may occur when pleural fibrosis is so severe that it involves the diaphragm and ribcage and results primarily from decreased rib movement. Microscopic
At the microscopic level, collagen fibres deposit in a basket weave pattern and form scar tissue.
Prognosis
Fibrothorax complicating another condition, such as tuberculous pleuritis, empyema, or acute haemothorax often spontaneously resolves in 3-6 months.The prognosis after surgical decortication is variable and depends on the health of the underlying lung before the procedure takes place. If the lung was otherwise healthy, then certain aspects of lung function, such as vital capacity, may improve after decortication. If, however, the lung had significant disease, then lung function often does not improve and may even deteriorate after such intervention. The duration of fibrothorax does not affect prognosis.The mortality of surgery is less than 1% overall, but rises to 4-6% in the elderly. Other factors predicting poorer surgical outcomes include intraoperative complications, incomplete surgery, lung disease beyond the fibrothorax being treated, and specific causes of fibrothorax such as asbestosis. Epidemiology
Sporadic cases are rarely reported in the medical literature, for example, due to iatrogenic or postoperative complications. Fibrothorax is rare in developed countries, mainly due to a lower incidence of tuberculosis. The condition is far more common in workers exposed to asbestos, with 5–13.5% of those exposed subsequently developing some degree of pleural fibrosis, sometimes not diagnosed until decades after the initial exposure. == References ==