Tracheobronchopathia osteochondroplastica is a condition in which areas of calcification and ossification protrude into the lumen of the respiratory tract in the submucosal layer of the trachea and bronchi. It may manifest as shortness of breath, cough, hemoptysis. Creates favorable conditions for the development of inflammatory processes in the lower respiratory tract. It is diagnosed using fibrobronchoscopy, CT, MRI of the chest organs. Symptomatic conservative therapy is prescribed, aimed at eliminating inflammation and improving self-purification of the respiratory tract. With pronounced stenoses, surgical treatment is carried out.
J98.0 Bronchial diseases not classified elsewhere
Tracheobronchopathia osteochondroplastica, or ossification of the lungs, is a rare pathology. It occurs with the same frequency in men and women. In vivo, it is detected in 0.01-4.5% of cases of all fibrobronchoscopies performed for any reason. It is found in people aged 20 to 80 years, older people are more likely to suffer. There are isolated cases of respiratory tract ossification in children and adolescents. Usually, the pathological process is localized in the middle and lower third of the trachea and bronchi. Isolated pathology of the trachea occurs in 80% of cases, bronchi – in 5%. Simultaneous damage to the bronchi and trachea develops in approximately 15% of patients. Sometimes areas of calcification are determined in the walls of the larynx.
Causes of tracheobronchopathia osteochondroplastica
The etiological factor has not been established. Specialists in the field of clinical pulmonology consider several theories of the occurrence of this disease. It is assumed that there is an innate predisposition to calcification of the areas of the submucosal layer of the respiratory tract, as well as the proliferation of bone tissue by the type of tumor growth. Some authors associate the development of the pathological process with inflammation of the mucous membrane of the airways or cartilage of the trachea of a specific (tuberculosis, syphilis) and non-specific etiology. Tracheobronchopathia osteochondroplastica has been found to be a frequent outcome of primary respiratory amyloidosis.
The pathogenesis of pathology is insufficiently studied. Researchers suggest that the bone tissue in the walls of the respiratory tract is formed from connective tissue. Collagen fibers combine into bundles, swell, and partially calcify. Fibroblasts are transformed into osteoblasts. The cartilage tissue cells that have fallen into the calcification zone decrease in size and change shape. Bone plates are formed, which germinate through blood vessels and form cavities with the rudiments of the bone marrow. As such plates grow in the thickness of the walls of the air-bearing organs, the patency of the respiratory tract worsens, its barrier function is disrupted.
Pathomorphological examination reveals dense whitish nodules of irregular shape or strands in the lumen of the trachea, bronchi or larynx. The formations are located exclusively in the cartilaginous part of the organ, never affecting the membranous. Microscopically, ossification zones and cartilaginous growths localized between the cartilages of the tracheobronchial tube and unrelated to them are revealed. The mucous membrane can remain unchanged for a long time. Sometimes there is its thinning, atrophy, signs of metaplasia of the ciliated epithelium into a multilayer flat.
Symptoms of tracheobronchopathia osteochondroplastica
Initially, tracheobronchopathia osteochondroplastica is asymptomatic for a long time. Characteristic changes are detected accidentally when performing bronchoscopy, CT or MRI of the chest. Later, a cough appears, which can be persistent. A small amount of light mucous sputum is separated with difficulty. Hemoptysis often joins. Shortness of breath is a non-permanent sign of the disease. For a long period of time, breathing remains uncomplicated. With a massive proliferation of bone formations, shortness of breath of the expiratory type is formed (the patient notes difficulty breathing on exhalation). Inhalation is accompanied by pain in the chest, more often behind the sternum. When the larynx is affected, the timbre of the voice changes – hoarseness or hoarseness appears.
With the addition of a secondary infection, prolonged purulent laryngotracheitis, bronchitis, pneumonia develop. There are pains and tickling in the throat, the voice changes. Signs of intoxication are added – general weakness, sweating, increased fatigue. Body temperature rises to subfebrile or febrile values. The cough becomes more frequent, the production of bronchial secretions increases. Sputum acquires a yellowish tint. Shortness of breath appears or increases. Habitual physical exertion causes difficulty breathing. The pains behind the sternum bother more often, they become more intense.
In most cases, tracheobronchopathia osteochondroplastica proceeds benign. Rarely develop laryngeal stenosis requiring surgical intervention, tracheobronchial tree. Tracheitis, bronchitis and pneumonia in this pathology often recur. Narrowing of the bronchial lumen leads to stagnation of sputum in small bronchi and the formation of bronchiectasis. Persistent foci of infection appear. Long-term inflammation of the mucous membrane of the respiratory organs, along with changes in the submucosa, are a favorable background for the appearance of tumors of the bronchi and larynx.
A pulmonologist is engaged in the diagnostic search for suspected osteoplastic tracheopathy. When collecting anamnesis, pay attention to frequent respiratory infections, the presence of periodic hemoptysis. During auscultation of a patient with a common process, stridorous breathing is heard. There are no specific signs of the disease. The final diagnosis is established by:
- Functional diagnostic methods. In the initial stage of the disease, spirometric indicators are within normal values. Later, moderate or significant violations of the function of external respiration may occur in an obstructive or mixed type. The test for the reversibility of bronchial obstruction is negative.
- Visualization techniques. Lung CT with virtual bronchoscopy allows you to determine high density zones in the walls of the airways, deformation of the tracheobronchial tree, assess the relief of the mucous membrane, detect the presence of protruding formations. Lung MRI reveals thickening of the bronchial wall, areas of calcification in its thickness.
- TBT endoscopy. During bronchoscopy, whitish tubercles are visualized in the lumen of the tracheobronchial tube. Changes in the organ wall resemble a “cobblestone pavement” or a “rock garden”. In the later stages of the disease, massive formations are found hanging down into the cavity of the air-bearing organs and narrowing their lumen. The friction of the growths on the bronchoscope causes a characteristic noise. The rigidity of the respiratory tract wall, atrophy and slight bleeding of the mucous membrane are determined.
Tracheobronchopathia osteochondroplastica is differentiated with multiple cancerous lesions of the tracheobronchial tree, primary respiratory amyloidosis, some systemic diseases, tuberculosis. Differential diagnosis is performed using a transbronchial biopsy followed by histological examination of the pathological material. If necessary, consultations of an oncologist, a phthisiologist, a rheumatologist, an otorhinolaryngologist are appointed.
Tracheobronchopathia osteochondroplastica treatment
There is no etiotropic treatment for this pathology. In the absence of pronounced narrowing of the tracheobronchial tube, conservative therapy is performed. It is carried out with the development of secondary infectious complications of the pathological process. Antibiotics are used to sanitize foci of infection. To improve the drainage function of the respiratory system, nebulizer therapy is prescribed using alkaline solutions and mucolytics. For the same purpose, endotracheal fillings, sanitization bronchoscopy are performed. In some cases, positive dynamics is observed against the background of treatment with corticosteroid hormones and antihistamines.
Tracheobronchopathia osteochondroplastica with clinically significant stenosis is an indication for surgical intervention. The destruction of bone formations is carried out by laser or cryodestruction, the breathing tube is booged with a bronchoscope, the tubercles are removed with biopsy forceps. The medical literature describes isolated cases of resection of a part of the trachea. If necessary, an endotracheal or endobronchial stent is installed.
Prognosis and prevention
The prognosis of the disease is more often favorable. Tracheobronchopathia osteochondroplastica progresses slowly, sometimes there is a spontaneous stabilization of the process, the cessation of the formation of new areas of ossification. Rapid progression of the disease and critical stenosis of the respiratory tract are rarely observed (in 15-17% of patients). Primary prevention of pathology has not yet been developed. Secondary preventive measures are reduced to timely treatment of inflammatory diseases of the respiratory system, smoking cessation, seasonal vaccination against influenza and pneumococcal infection.
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- Tracheobronchopathia Osteochondroplastica: End Stage of Tracheo-Bronchial Amyloidosis? Zaibi H, Fessi R, Dhahri B, Ben Amar J, Aouina H. Tanaffos. 2019 Mar;18(3):272-275. link
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