Dust bronchitis is an occupational disease of the respiratory tract that occurs with prolonged inhalation of industrial dust and leads to atrophic and sclerotic changes in the wall of the trachea and bronchi. The main clinical manifestations include cough, shortness of breath, bronchial obstruction syndrome. To confirm the diagnosis, a connection between bronchitis and professional activity is established, spirometry is performed, methods of radiation diagnostics, bronchoscopy are used. Conservative treatment is carried out with bronchodilators and expectorants, corticosteroid hormones. For exacerbations, antibiotics are prescribed.
Dust bronchitis occurs in persons who have been in contact with inorganic and organic dust for a long time. It is one of the most common occupational diseases. Chronic bronchitis , classified as dust bronchitis , develops in 15-80% of coal and iron ore miners; 20% of metallurgists, foundry workers, as well as workers involved in the production of cement and other building mixtures. Inhalation of dust leads to pathology in 10-30% of workers in mills, woodworking, textile and some agricultural enterprises. The risk of developing bronchitis increases in direct proportion to professional experience. The symptoms of the disease appear on average after 7-10 years from the start of work in harmful conditions.
The reasons of Dust Bronchitis
Dust Bronchitis, Occupational chronic bronchitis is caused by long-term regular exposure to a number of harmful factors. The main reason is solid dust particles of medium size (5-10 microns). The damaging agent is the dust itself, as well as its toxic chemical components and the allergens present. Dust provoking the development of the disease is:
- Organic. Most often formed during coal mining and processing. The composition of the inhaled aerosol depends on the deposit of the fossil and the production technology used. Mercury, arsenic, lead and other harmful chemical components are present as impurities. Often, the cause of the disease is woolen, flour, peat and other types of organic dust.
- Inorganic. Formed during the extraction and processing of minerals and metals. It is present in the air of shops of metallurgical and machine-building enterprises. It is the main harmful factor in the production of cement. In high concentrations, it has toxic and irritating properties.
Tobacco smoking plays an important role in the onset of the disease. Tobacco smoke independently causes damage to the bronchial wall. Together with the harmful effect of dust, the inflammatory process develops more often and faster. Additional causal factors for the appearance of pathology of the respiratory system are hypothermia or overheating of the body, high humidity in the room, acute and chronic diseases of the respiratory tract. Many patients have a genetic predisposition to lung disease.
Pathogenesis of Dust Bronchitis
When dust aerosol is inhaled, the barrier functions of the respiratory system are activated. There is an increase in the work of the mucociliary apparatus and an increased secretory activity of mucus-producing cells and glands. Over time, with prolonged exposure to dust particles on the respiratory organs, the cilia of the ciliated epithelium atrophy, the epithelium itself is replaced by a stratified flat epithelium. The function of removing bronchial secretions is impaired. There is a change in the composition of the sputum. The secret becomes more viscous and stagnates in the lumen of the respiratory tract. Excess phlegm and irritating dust components cause coughing. The presence of sensitizing agents in the pollutant provokes episodes of bronchospasm .
The muscular membrane of the bronchus initially hypertrophies, then acquires atrophic changes. The wall of the tracheobronchial tree is remodeled. All its layers are affected, normal tissue is replaced by a connective tissue that is incapable of stretching. This process causes even greater stagnation of sputum and leads to obstruction of the bronchial lumen, the occurrence of emphysema . The wall of the bronchi is overstretched, bronchiectasis is formed .
Classification on Dust Bronchitis
Dust bronchitis is classified by etiological factor. The irritating, toxic and allergic properties of the components of the pollutant are taken into account. During bronchitis, episodes of remission and exacerbation alternate. During an exacerbation, phases of aggression, extensive inflammation and resolution are observed. Depending on the pathomophological endoscopic changes, there are catarrhal, catarrhal-atrophic and catarrhal-sclerosing forms of dust inflammation of the bronchi. The disease can proceed in asthmatic and obstructive variants. Specialists in the field of pulmonology and occupational pathology distinguish the following stages in the course of the pathological process:
- Stage I. It is characterized by long periods of remission. Exacerbations occur no more than 2 times a year. The function of external respiration is not impaired, or there are slight deviations from normal values. Blood oxygen saturation is within normal limits.
- Stage II. Clinical manifestations of the disease are expressed. The periods of exacerbation are protracted, last more than 3 weeks, occur more often 2-3 times a year. Spirometry reveals significant reductions in the main indicators (VC, FEV1, MVL) compared to normal values. Blood oxygenation is 85-94%.
- III stage. The remission periods are short. There is diffuse pulmonary emphysema, pneumosclerotic and bronchiectasis changes, pulmonary heart failure . There are sharp disturbances in the function of external respiration, a significant decrease in VC. The oxygen content in arterial blood is below 80-85%.
Dust bronchitis symptoms
In Dust Bronchitis, Clinical manifestations of bronchial pathology depend on the stage of the process and the nature of the pollutant. It is difficult to suspect dust bronchitis at the initial stage of development. Its rare exacerbations are manifested by a dry or productive cough. They occur more often during the cold season. Sometimes they are accompanied by shortness of breath on exertion or bouts of shortness of breath. Body temperature rarely rises. Symptoms of general malaise are poorly expressed. An exacerbation of the pathological process is mistaken for an acute respiratory infection . Contact with a harmful production factor does not stop, and the disease takes on a steadily progressive course.
At the II stage of the disease, the cough becomes constant. Mucous sputum is difficult to cough up. With the asthmatic variant of bronchitis, episodes of dry, painful cough occur more in the evening and morning hours, attacks of suffocation. The patient complains of heaviness in the chest . Shortness of breath appears with little exertion – brisk walking, climbing stairs. Difficulty exhaling is usually noted . Exacerbations occur more often, become protracted. When a secondary infection is attached, fever appears, the sputum becomes purulent, yellow-green.
As the pathology of the respiratory tract progresses further, shortness of breath increases. Its appearance is provoked by the slightest physical activity – slow walking, a change in body position. The feeling of lack of air becomes constant. The patient is worried about a frequent unproductive cough. Palpitations, cardiac arrhythmias, pain in the region of the heart of a aching and constrictive nature, a feeling of heaviness in the right hypochondrium join. Disturbed by severe general weakness, a feeling of constant fatigue, increased sweating.
Complications of Dust Bronchitis
Dust Bronchitis, Bronchitis detected at an early stage, with the exclusion of contact with a damaging agent and timely treatment started, proceeds relatively favorably, progresses slowly. Complications of dusty occupational pathology appear at the II – III stages of the course of the disease. Emphysema of the lungs occurs early, further aggravating expiratory dyspnea. Bronchiectasis, being an endogenous source of infection, is complicated by the development of pneumonia . Respiratory failure gradually joins . Stagnation in the small circle of blood circulation leads to the formation of a severe disabling pathology – chronic pulmonary heart disease .
Diagnostics of Dust Bronchitis
Diagnostic search is carried out by an occupational pathologist with the involvement of specialist pulmonologists. The length of service, the nature of the hazard, the incidence of chronic bronchitis at work is being specified. When viewed in the later stages of the disease, cyanosis of the lips and terminal phalanges of the fingers or diffuse cyanosis is observed. The rib cage often acquires a barrel-shaped emphysematous shape. To clarify the diagnosis, the following are performed:
- Physical research. At the onset of the disease, physical data are scarce. During the period of exacerbation, a few dry rales can be heard against the background of hard breathing. Later, the number of whistling and buzzing rales increases. Breathing becomes weakened, quickened. Heartbeat joins, a feeling of interruptions in the work of the heart.
- Functional diagnostics. With spirometry , gradually progressive respiratory dysfunctions are observed in a mixed (restrictive-obstructive) type. The electrocardiogram shows signs of overload, and later hypertrophy of the right heart, tachycardia , extrasystole .
- Visualizing techniques. With bronchitis in the initial form, radiographic changes are usually absent. Later, there is an increase and deformation of the vascular pattern, signs of emphysema, pneumosclerosis . CT and MRI of the chest organs can reveal the presence of bronchoctasis and differentiate dust bronchitis with other pathologies of the respiratory system.
- Laboratory tests. With the course of the pathological process, the parameters of the peripheral blood change. At the last stage of the disease, symptomatic erythrocytosis is observed , a slowdown in ESR. The study of sputum by various methods makes it possible to determine the microbial composition and reveal the presence of bacterial resistance to antibiotics, as well as exclude pulmonary tuberculosis.
To clarify the degree of respiratory failure, blood oxygenation is determined. For the purpose of differential diagnosis with oncological pathology and clarification of the level of damage to the bronchial wall, bronchoscopy with biopsy is performed . To exclude bronchial asthma, the patient is examined by an allergist. If necessary, prick tests are carried out, the level of general and specific immunoglobulin E is determined. A patient with suspected dust bronchitis needs to consult an oncologist, pulmonologist and phthisiatrician.
Dust bronchitis treatment
The main treatment-and-prophylactic measure after diagnosis is the termination of contact with dust. The patient is advised to change jobs. A smoker should quit smoking. Conservative pathogenetic treatment is carried out. The drugs are prescribed for a long time. The following groups of medicines are used:
- Expectorants and bronchodilators. At the onset of the disease, predominantly expectorant drugs are used. Reflex action drugs and mucolytics are prescribed. At later stages, M-cholinergic receptor blockers or their combinations with beta-adrenergic agonists, short-acting and prolonged-acting methylxanthines are added to the treatment.
- Corticosteroid hormones. Inhalation, oral and parenteral forms of drugs are used. Inhaled corticosteroids are selected individually; combinations with bronchodilators are possible. Parenteral and oral forms are prescribed in short courses to relieve obstructive syndrome.
- Antibiotics and heart medications. The use of antibiotics is indicated during the period of an infectious exacerbation, with a complication of the course of the disease by bronchopneumonia . Appointed taking into account the sensitivity of the microflora. Cardiac remedies are used to treat cor pulmonale and symptomatic hypertension. Calcium antagonists and cardiac glycosides are preferred.
With a general strengthening purpose, immunomodulators, vitamins, adaptogens are prescribed. Physiotherapy procedures for the chest, physiotherapy exercises, massage are shown . If necessary, a sanitation bronchoscopy is performed. Severe respiratory failure is an indication for long-term oxygen therapy through an oxygen concentrator.
Forecast and prevention
Dust Bronchitis, Dust bronchitis is a chronic progressive disease. With the timely exclusion of inhalation of industrial dust, the prognosis is favorable. Late diagnosed disease, complicated by respiratory failure, chronic pulmonary heart disease leads to the patient’s disability. Death can occur from severe pneumonia, pulmonary heart disease.
For primary prevention, collective and individual protective equipment is used. Preliminary (before employment) and regular preventive (for workers in hazardous work) medical examinations are carried out. Secondary prevention comes down to rational employment. It is recommended to avoid contact with a respiratory infection, get vaccinated against influenza .