Cotton pneumoconiosis

Cotton Pneumoconiosis From the early civilized activities, human cotton fiber woven fabrics such as cotton have been exposed to cotton dust. The emergence of the textile industry with industrialization has caused the health effects of occupational exposure to cotton dust. Attention, the basic production process of large cotton and linen textile mills, such as unpacking, blending cotton, and carding, produces a large amount of cotton dust, which is the main source of occupational exposure. A person who first comes into contact with cotton dust or occasionally exposes high concentrations of cotton dust can experience "millfever", which is characterized by chills after a few hours of exposure to cotton dust, muscle and joint pain, dry cough, fatigue, fever, early symptoms like flu. . It is now known that this is actually Organic Dust Toxicity Syndrome (ODTS). A small number of workers exposed to cotton dust experienced a decrease in lung ventilation after half an hour of exposure, and they were progressively aggravated during the working week, which may be accompanied by wheezing, consistent with occupational asthma. basic knowledge Sickness ratio: 0.05% Susceptible people: no special people Mode of infection: non-infectious Complications: emphysema, pulmonary heart disease

Cotton pneumoconiosis

(1) Causes of the disease

Byssinosis is a respiratory obstructive disease caused by the inhalation of plant dust such as cotton, flax, and soft cannabis.

(two) pathogenesis

Pathogenesis

What is the cause of disease in cotton dust is not fully understood at present. Many studies have shown that cotton fiber itself is not a pathogenic substance, but a plant ingredient mixed in cotton dust, most likely cotton stipule, but cotton stipule The extract does not induce the typical symptoms of cotton stagnation, and the medical cotton extract test also shows similar biological activity. Some chemicals in cotton plants, such as citric acid, histamine, polyphenols, methyl piperene , 7-hydroxy-6-methoxycoumarin, etc. are also considered to be pathogenic substances. Some studies have focused on microbial contamination. It is believed that Gram-negative bacteria and their endotoxin are the cause of the disease. The pathogenesis has the following three hypotheses:

(1) Histamine release: Early studies suggested that bronchoconstriction caused by cotton dust exposure was caused by histamine release. The researchers used cotton dust extract and human ex vivo lung tissue culture to find histamine release in the medium. Histamine plays an important role in bronchospasm caused by allergen-induced acute attacks, but it is completely different from the slow-occurring bronchospasm caused by cotton dust exposure. Although cotton dust exposed workers can see histamine metabolites, but antihistamines The drug does not inhibit the reaction caused by cotton dust exposure. Therefore, histamine release is likely to be the result of a general inflammatory response, not a direct cause.

(2) Immunology: The typical symptoms of cotton smear occur after a long period of exposure, which seems to suggest that some components of cotton dust may have antigenic effects, stimulating the body to produce specific antibodies, which are related to disease. There have been reports confirming the existence of this specific antibody, which may be a condensed tannic acid, but later experiments have shown that it is only a non-specific protein precipitant, looking for specific IgG and IgE antibodies to cotton dust components. The study has not yielded satisfactory results. Recent studies have shown that cotton dust can activate mast cells or platelets to secrete a medium, and the inflammatory response can explain the respiratory response after cotton dust exposure.

(3) Endotoxin stimulates inflammatory response: Many studies suggest that cotton dust is contaminated by Gram-negative bacteria and endotoxin. The inflammatory response triggered by endotoxin is the basis of the onset of cotton smear. Rylander heats the cotton dust extract to 80. °C 2h, at this time all bacteria have been killed, but the biological activity of the extract still exists, indicating that this biological activity is caused by endotoxin, which can activate lung macrophages to produce bioactive substances. , causing neutrophil aggregation and a series of biological reactions, causing acute or chronic inflammation of the lungs, using E. coli endotoxin and cotton dust extract for animal inhalation experiments, resulting in the same histological changes, but damp The biological activity of dust in the environment has not increased, and unpolluted cotton dust also causes cotton stagnation.

2. Pathology

There are few reports of pathological examination. From the lung specimens obtained by cotton dust exposure workers due to other diseases, there may be inflammatory cell infiltration, mucous gland hyperplasia, and smooth muscle atrophy on the tracheobronchial wall, but this change rarely extends to the lung segment. Bronchi, lobular central emphysema is rarely seen, cotton fibers can be seen under polarized light microscopy, and a few cotton-dust bodies are visible, round or oval, with black staining positive in the center. The nucleus, outsourcing yellow protein coat, is generally considered to be of no diagnostic significance. Individual reports have a fibrous thickening of the alveolar wall, and emphysema and right heart hypertrophy are seen in advanced cases.

Cotton pneumoconiosis prevention

Prevention is first of all to reduce the dust in the working environment. China's national standards stipulate that the maximum allowable concentration of 50% to 80% free silica dust in the air of the workshop is 1.5mg/m3. Strengthen industry management and establish strict health supervision and environmental monitoring systems. Establish and improve dust-proof mechanisms, including regular monitoring of dust systems, and evaluate the effectiveness of dust-proof measures. Starting from technical measures, we must do a good job in technological reform, and basically eliminate the generation of dust from the production process and process. Strengthen publicity and education, formulate a health cleaning system, and achieve civilized production. Pre-employment and regular physical examinations, regular chest radiographs, and regular follow-up for those who have been out of dust. Those with upper respiratory tract disease, bronchopulmonary disease, especially those with tuberculosis, and cardiovascular disease are not allowed to engage in this operation. Strengthen personal protection, pay attention to personal hygiene, carry out physical exercise, pay attention to nutrition and so on.

Cotton pneumoconiosis Complications emphysema pulmonary heart disease

Combined with emphysema, pulmonary heart disease and so on.

Cotton pneumoconiosis symptoms common symptoms chest tightness, difficulty breathing, heavy chest, dry cough, breath sounds, weakened voice

The characteristic symptom of cotton smear is chest tightness or chest tightness, although the language of the worker may describe the symptoms, such as chest tightness, hernia, chest pressure, chest tightness, etc. However, they all express the same feeling. The above symptoms in the early stage of the disease mainly occur after 2 to 3 hours of work on the first day after returning to work on holidays or weekends. However, unlike occupational asthma, the disease immediately after work, may be accompanied by mild dry cough. This symptom may persist for many years without change. Continue to contact with cotton dust. Patients may suddenly find that the symptoms are aggravated. Not only do they have dry cough, chest tightness, chest tightness on the first day of work after rest, but also on the other days of the work week. Symptoms, and cough can be aggravated, accompanied by cough, the symptoms can persist without disappearing, the patient gradually develops breathing difficulties, early lung examination patients have no lung positive signs, late patients can have voices in the lungs, breath sounds Attenuation and emphysema signs, combined with chronic bronchitis and smokers significantly increased symptoms.

Cotton pneumoconiosis

Cotton pneumoconiosis patients with bacterial infection, blood white blood cells increased.

Changes in lung function: Workers exposed to cotton dust may experience a decrease in acute lung ventilation during the working day, ie, decreased lung ventilation function before and after work, as well as chest tightness, and the reduction in acute ventilation is also the first to work after a holiday or weekend break. The day is obvious, and then gradually relieved, and has a certain correlation with the severity of the symptoms. This acute change can be relieved by bronchodilators. It is generally believed that FEV1 is a reliable and easy indicator for determining acute changes in pulmonary ventilation function. Indicators such as indirect maximal breathing capacity (IMBC), PEFR, CV (closing volume), CC (closing capacity), etc., have also been studied, but these indicators are highly variable, not stable enough, and FEV1 declines after class. How many have clinical significance, there are different opinions at present, China's cotton smear disease diagnosis standard stipulates that the FEV1 decline of more than 10% after the class has a diagnostic significance. Some people analyzed the decline of FEV1 in the case of 22 cases of cotton stagnation disease, which is greater than 10% were in 16 cases, 3 cases were between 5% and 10%, and 3 cases were less than 5%.

At present, the focus of research on lung function damage is whether cotton dust exposure causes permanent respiratory damage. In theory, the decline of acute lung ventilation is based on respiratory inflammatory response and bronchial smooth muscle spasm, long-term repeated acute reaction. It will lead to chronic damage to respiratory function, and most studies have proved this. Some people surveyed 1,323 dust-collecting workers with 4 years of service in 4 cotton mills, and 135 people who did not touch cotton dust were used as controls. FVC was lower than expected. 80% of the value or 70% of the FEV1 lower than the predicted value were defined as abnormal lung function. The study found that the lung function of the dust-exposed workers was 5%, and the control group was only 0.7%, and the abnormality of lung function was related to the service age. (r=0.945), 14.3% of workers with abnormal working age of more than 15 years, 16.6% of those with more than 20 years of age, 851 dust workers in a cotton mill, and 190 people with typical Monday symptoms 18.4% of workers had chronic lung function impairment (FEV1 was less than 80% predicted), and only 2 out of 135 (1.7%) in the control group. Smoking increased the effect of cotton dust on respiratory function.

Diagnosis and diagnosis of cotton pneumoconiosis

According to the occupational history of contact with cotton, flax, soft cannabis and other plant dusts for a long time, clinically characteristic chest tightness, dry cough and other typical symptoms, accompanied by acute or chronic lung ventilation function damage, combined with on-site labor hygiene An investigation can be made to rule out obstructive respiratory diseases caused by other causes.

With reference to the foreign diagnostic criteria for clinical and pulmonary function of cotton dampness, the diagnostic criteria for cotton dampness in China is divided into two levels:

Cotton smear level: Frequently, there are characteristic respiratory symptoms such as chest tightness or chest tightness, dry cough, etc. on the first day of work after work break or several days during work week. After the shift, FEV1 decreased by more than 10% compared with before class.

Cotton smear secondary: On the basis of repeated episodes of cotton smear, respiratory symptoms continue to increase, accompanied by chronic lung ventilation impairment, FVC or FEV1 is less than 80% of the predicted value.

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