Fibrothorax is an overgrowth of the pleural cavity with dense fibrous tissue, leading to a restriction of the respiratory excursion of the chest and lungs. It is formed due to a long course of pleurisy, empyema, hemothorax, collagenoses. Accompanied by the inability to inhale fully, progressive shortness of breath, chest pain, dry cough, respiratory failure. In the diagnosis of fibrothorax, the main role belongs to radiation methods: radiography, CT of the lungs. Treatment includes elimination of the causal factor, oxygen therapy, corticosteroids. Surgical aid may be required: pleurectomy, decortication.
Fibrothorax is a syndrome caused by the presence of connective tissue mooring in the pleural cavity. It is a secondary process in relation to respiratory diseases accompanied by chronic inflammation and pleural effusion syndrome. Men get sick more often. The proportion of fibrothorax in the structure of pleural lesions is 2-4%. There is a tendency to an increase in morbidity due to the deterioration of the environmental situation, an increased flow of migration, and a high percentage of injuries.
Causes of fibrothorax
A prerequisite for the manifestation of the pathological process is the prolonged presence of inflammatory exudate in the pleural cavity. Undrained pleural effusion (fibrinous, purulent) is eventually replaced by connective (fibrous) tissue. Fibrothorax can be formed as a result of the following processes:
- infectious: pleural tuberculosis, parapneumonic pleurisy, pleural empyema;
- autoimmune: rheumatoid arthritis, systemic lupus erythematosus, sarcoidosis;
- recurrent pleural effusions: with asbestos, pancreatitis, uremia, after open heart surgery;
- chest injury: coagulated hemothorax;
- drug reactions: when taking ergot alkaloids, dopamine receptor agonists;
- surgical interventions: chemical pleurodesis, pneumonectomy.
Fibrothorax is the most severe form of pleural fibrosis. The prolonged presence of an undrained effusion causes an inflammatory reaction of the pleural leaflets, which is accompanied by the deposition of fibrin on their surfaces. Fibrin deposits seal the parietal and visceral pleura. Loose adhesions are formed, which contribute to the formation of intrapleural osmosis.
A significant role in the development of fibrothorax is played by profibrotic cytokines and, first of all, the protein TGF-β (transforming growth factor β), which is synthesized by mesothelial cells of the pleura. TGF-β activates the proliferation and migration of fibroblasts to the focus of inflammation, stimulates the production of collagen.
Under the influence of these processes, the fibrous organization of pleural junctions occurs. Connective tissue is formed, which thickens the pleural leaves, making them inactive. Powerful mooring lines contribute to the maintenance of infectious foci in the pleural cavity, recurrent accumulation of effusion.
The thickness of the pleura can vary from 5 to 10-20 mm. The fibrous shell restricts the excursion of the lungs during the act of breathing, which functionally leads to a violation of gas exchange. Sometimes pleural fibrosis spreads to the lung tissue – pleurogenic cirrhosis develops.
Fibrous changes in the pleural cavity undergo three stages, which are well traced during diagnostic videothoracoscopy:
- 1 – loose splices up to 3 mm thick are detected in the pleural cavity, which are easily destroyed in a blunt way. The pariental pleura is covered with fibrinous plaque, the mobility of the lung is not limited;
- 2 – pleural adhesions have different thicknesses, are tightly attached to the visceral and pariental leaves. When they are separated, damage to the pleura and pulmonary parenchyma is possible. Respiratory excursion of the lung is reduced moderately;
- 3 – dense fibrous strands fill the entire pleural cavity, the thickness of the parietal pleura is more than 5 mm. A “shell lung” is formed, the fibrous capsule prevents the expansion of the parenchyma.
Symptoms of fibrothorax
Clinical manifestations may vary depending on the causes of the disease and the degree of damage to the pleura. The most typical complaints with fibrothorax are shortness of breath during physical activity, which progresses over a number of months or years. Also, patients complain of dull chest pains, inability to take a full breath, unproductive cough, increased fatigue.
Signs of a chronic infectious and inflammatory process are subfebrility, intoxication syndrome. Recurrent pleural effusions may occur. With a severe degree of fibrothorax, tachypnea, tachycardia, cyanosis of the skin, deformation of the phalanges of fingers and nails are noted.
The main consequence of fibrothorax is a significant restriction of respiratory excursions, a decrease in the vital capacity of the lungs, a violation of pulmonary ventilation and gas exchange. Restrictive respiratory failure of varying severity develops. Typical signs are shortness of breath, hypoxemia, diffuse cyanosis, decreased exercise tolerance. Over time, pulmonary hypertension forms, the pulmonary heart develops.
Diagnostics of fibrothorax
Examination of patients with suspected fibrothorax is carried out by a pulmonologist. A thorough analysis of the medical history is necessary to clarify the causal factors, conduct physical and instrumental diagnostics. During an objective examination, there is a lag of the affected side of the chest during respiratory movements, dulling of percussion. Weakened breathing, pleural friction noise is heard. Confirmatory instrumental studies include:
- Chest X-ray. Radiological signs of fibrothorax are unilateral homogeneous shadow, obliteration of the pleural sinus, high standing of the diaphragm dome, thickening of pleural leaves, sometimes calcification of the pleura, displacement of the mediastinum to the affected side.
- Ultrasound of the pleural cavity. Fibrothorax is usually detected by sonography when the thickness of the pleura exceeds 10 mm. When scanning, a homogeneous echogenic layer covering the lung is visualized (with calcification, hyperechogenic areas). The pleural line is thickened, the “sliding” sign is weakened.
- CT of the lungs. Gives more detailed information about the thickness of the pleural leaflets, the condition of the pleural cavity and the underlying pulmonary parenchyma. CT of the lungs allows for a densitometric analysis of the density of the contents of the pleural cavity, to identify concomitant pulmonary fibrosis, bronchiectasis and other pathological processes.
- FER. During spirography, ventilation disorders are determined according to the restrictive type: a decrease in blood pressure, a decrease in blood pressure, an increase in respiratory rate. Bronchial patency, as a rule, is not impaired.
Invasive diagnostics. Diagnostic thoracoscopy makes it possible to examine the pleural space, determine the stage of fibrothorax. Sometimes they resort to a pleural puncture.
Conducting a complete imaging and functional diagnosis allows differentiating fibrothorax from other pathologies with similar clinical and radiological manifestations:
- pleural effusion syndrome: exudative pleurisy, hydrothorax;
- pleural tumors: mesothelioma, carcinomatosis;
- pulmonary tissue compaction syndrome: atelectasis, focal or lobar pneumonia.
Treatment for fibrothorax
Pharmacotherapy is aimed at eliminating the cause that provokes pleural fibrosis, slowing the progression and stabilizing the pathological process. Treatment is prescribed taking into account the leading etiological factor:
- with pleural empyema: antibacterial therapy;
- in case of tuberculosis infection: anti-tuberculosis chemotherapy;
- in systemic diseases: glucocorticosteroids;
- in drug-induced fibrothorax: withdrawal of medications with fibrogenic effect.
To remove the pleural contents that serve as the pathophysiological basis of fibrothorax, puncturing or drainage of the pleural cavity, sanitizing procedures (washing, intrapleural administration of drugs) are performed. With severe respiratory insufficiency, respiratory support is required.
Indications for surgical intervention are the prescription of fibrothorax for more than 4-6 weeks, progressive respiratory failure, radiological signs of a carapace lung, lack of improvements from conservative therapy. The operation being performed – pleurectomy with lung decortication – is aimed at removing the altered pleura and freeing the lung from fibrous adhesions.
Decortication can be performed both by thoracotomy and video-assisted thoracoscopy. Surgical intervention in fibrothorax involves a number of technical difficulties associated with penetration into the thoracic cavity and separation of the pleura. In this regard, there is a risk of developing postoperative pleuropulmonary complications: bleeding, bronchopleural fistulas, exacerbation of respiratory failure.
Prognosis and prevention
After the causal disease is stopped, the progression of fibrothorax stops, the patient’s condition stabilizes within 3-6 months. However, the further prognosis depends on the stage of pleural fibrosis. The most favorable option is timely surgical intervention, which allows to radically eliminate the problem.
To prevent the formation of fibrothorax, early drainage of pleural effusion (pleurisy, hemothorax, empyema), etiotropic treatment of the underlying disease, monitoring of patients receiving long-term medications with a fibrogenic mechanism of action, having professional contact with asbestos is recommended.
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